ir. Z.Y. Chang

Technician
Electronic Instrumentation (EI), Department of Microelectronics

Expertise: IC Process Design support / PCB Design / Altium Designer / Wirebonding / Impedance measurement

Biography

Zu-yao Chang received his M.Sc. degree in Electrical Engineering from the Delft University of Technology, Delft, The Netherlands, in 2003. Since 2003 he has been a staff member of the Electronic Instrumentation Laboratory of Delft University of Technology, Delft, The Netherlands, doing research on impedance-measurement systems and smart sensor system.

Publications

A 125μm-Pitch-Matched Transceiver ASIC with Micro-Beamforming ADC and Multi-Level Signaling for 3-D Transfontanelle Ultrasonography
Peng Guo; Fabian Fool; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
pp. 1--14, 2024. early access. DOI: 10.1109/JSSC.2024.3355854
A 2000-Volumes/s 3D Ultrasound Imaging Chip with Monolithically-Integrated 11.7x23.4mm2 2048-Element CMUT Array and Arbitrary-Wave TX Beamformer
Nuriel N.M. Rozsa; Zhao Chen; Taehoon Kim; Peng Guo; Yannick Hopf; Jason Voorneveld; Djalma Simoes dos Santos; Emile Noothout; Zu-Yao Chang; Chao Chen; Vincent A. Henneken; Nico de Jong; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Michiel A. P. Pertijs;
In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
2024. Accepted.
A Pitch-matched Low-noise Analog Front-end with Accurate Continuous Time-gain Compensation for High-density Ultrasound Transducer Arrays
Peng Guo; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 58, Issue 6, pp. 1693--1705, June 2023. DOI: 10.1109/jssc.2022.3200160
A 1.2 mW/Channel Pitch-Matched Transceiver ASIC Employing a Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3-D Ultrasound Imaging
Peng Guo; Fabian Fool; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 58, Issue 9, pp. 2607--2618, September 2023. DOI: 10.1109/jssc.2023.3271270
A Pitch-Matched High-Frame-Rate Ultrasound Imaging ASIC for Catheter-Based 3D Probes
Yannick M. Hopf; Djalma Simoes dos Santos; Boudewine W. Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 59, Issue 2, pp. 476--491, February 2023. DOI: 10.1109/JSSC.2023.3299749

Abstract: ...
This article presents an application-specific integrated circuit (ASIC) for catheter-based 3-D ultrasound imaging probes. The pitch-matched design implements a comprehensive architecture with high-voltage (HV) transmitters, analog front ends, hybrid beamforming analog-to-digital converters (ADCs), and data transmission to the imaging system. To reduce the number of cables in the catheter while maintaining a small footprint per element, transmission (TX) beamforming is realized on the chip with a combination of a shift register (SR) and a row/column (R/C) approach. To explore an additional cable-count reduction in the receiver part of the design, a channel with a combination of time-division multiplexing (TDM), subarray beamforming, and multi-level pulse amplitude modulation (PAM) data transmission is also included. This achieves an 18-fold cable-count reduction and minimizes the power consumption in the catheter by a load modulation (LM) cable driver. It is further explored how common-mode interference can limit beamforming gain and a strategy to reduce its impact with local regulators is discussed. The chip was fabricated in TSMC 0.18-μm HV BCD technology and a 2-D PZT transducer matrix of 16 × 18 elements with a pitch of 160 μm and a center frequency of 6 MHz was manufactured on the chip. The system can generate all required TX patterns at up to 30 V, provides quick settling after the TX phase, and has an reception (RX) power consumption of only 1.12 mW/element. The functionality and operation of up to 1000 volumes/s have been demonstrated in electrical and acoustic imaging experiments.
A Pitch-Matched Transceiver ASIC for 3D Ultrasonography with Micro-Beamforming ADCs based on Passive Boxcar Integration and a Multi-Level Datalink
Guo, P.; Chang, Z. Y.; Noothout, E.; Vos, H. J.; Bosch, J. G.; de Jong, N.; Verweij, M. D.; Pertijs, M. A. P.;
In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
IEEE, pp. 1-2, 2023. accepted.
A 13.56MHz Fully Integrated 91.8% Efficiency Single-Stage Dual-Output Regulating Voltage Doubler for Biomedical Wireless Power Transfer
Lu, Tianqi; Chang, Zu-Yao; Jiang, Junmin; Makinwa, Kofi; Du, Sijun;
In 2023 IEEE Custom Integrated Circuits Conference (CICC),
pp. 1-2, 2023. DOI: 10.1109/CICC57935.2023.10121186
A 13.56MHz Fully Integrated 91.8% Efficiency Single-Stage Dual-Output Regulating Voltage Doubler for Biomedical Wireless Power Transfer
Lu, T.; Chang, Z. Y.; Jiang, J.; Makinwa, K.; Du, S.;
In 2023 IEEE Custom Integrated Circuits Conference (CICC),
pp. 1-2, 2023. DOI: 10.1109/CICC57935.2023.10121186
A Compact Integrated High-Voltage Pulser Insensitive to Supply Transients for 3D Miniature Ultrasound Probes
Yannick M. Hopf; Boudewine Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
IEEE Solid-State Circuits Letters,
Volume 5, pp. 166--169, 2022. DOI: 10.1109/lssc.2022.3180071

Abstract: ...
In this paper, a compact high-voltage (HV) transmit circuit for dense 2D transducer arrays used in 3D ultrasonic imaging systems is presented. Stringent area requirements are addressed by a unipolar pulser with embedded transmit/receive switch. Combined with a capacitive HV level shifter, it forms the ultrasonic HV transmit circuit with the lowest reported HV transistor count and area without any static power consumption. The balanced latched-based level shifter implementation makes the design insensitive to transients on the HV supply caused by pulsing, facilitating application in probes with limited local supply decoupling, such as imaging catheters. Favorable scaling through resource sharing benefits massively arrayed architectures while preserving full individual functionality. A prototype of 8 x 9 elements was fabricated in TSMC 0.18 μm HV BCD technology and a 160 μm x 160 μm PZT transducer matrix is manufactured on the chip. The system is designed to drive 65 V peak-to-peak pulses on 2 pF transducer capacitance and hardware sharing of 6 elements allows for an area of only 0.008 mm2 per element. Electrical characterization as well as acoustic results obtained with the 6 MHz central frequency transducer are demonstrated.
A Pitch-Matched Transceiver ASIC with Shared Hybrid Beamforming ADC for High-Frame-Rate 3D Intracardiac Echocardiography
Yannick M. Hopf; Boudewine W. Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 57, Issue 11, pp. 3228--3242, November 2022. DOI: 10.1109/jssc.2022.3201758

Abstract: ...
In this article, an application-specific integrated circuit (ASIC) for 3-D, high-frame-rate ultrasound imaging probes is presented. The design is the first to combine element-level, high-voltage (HV) transmitters and analog front-ends, subarray beamforming, and in-probe digitization in a scalable fashion for catheter-based probes. The integration challenge is met by a hybrid analog-to-digital converter (ADC), combining an efficient charge-sharing successive approximation register (SAR) first stage and a compact single-slope (SS) second stage. Application in large ultrasound imaging arrays is facilitated by directly interfacing the ADC with a charge-domain subarray beamformer, locally calibrating interstage gain errors and generating the SAR reference using a power-efficient local reference generator. Additional hardware-sharing between neighboring channels ultimately leads to the lowest reported area and power consumption across miniature ultrasound probe ADCs. A pitch-matched design is further enabled by an efficient split between the core circuitry and a periphery block, the latter including a datalink performing clock data recovery (CDR) and time-division multiplexing (TDM), which leads to a 12-fold total channel count reduction. A prototype of 8×9 elements was fabricated in a TSMC 0.18- μm HV BCD technology and a 2-D PZT transducer matrix with a pitch of 160μm , and a center frequency of 6 MHz was manufactured on the chip. The imaging device operates at up to 1000 volumes/s, generates 65-V transmit pulses, and has a receive power consumption of only 1.23 mW/element. The functionality has been demonstrated electrically as well as in acoustic and imaging experiments.
A Crystal-Less Clock Generation Technique for Battery-Free Wireless Systems
Chang, Z.; Zhang, Y.; Yang, C.; Luo, Y.; Du, S.; Chen, Y.; Zhao, B.;
IEEE Transactions on Circuits and Systems I: Regular Papers,
pp. 1-12, 2022. DOI: 10.1109/TCSI.2022.3201196
A Pitch-Matched ASIC with Integrated 65V TX and Shared Hybrid Beamforming ADC for Catheter-Based High-Frame-Rate 3D Ultrasound Probes
Y. Hopf; B. Ossenkoppele; M. Soozande; E. Noothout; Z. Y. Chang; C. Chen; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
February 2022. DOI: 10.1109/ISSCC42614.2022.9731597

Abstract: ...
With applications moving to 3D imaging, catheter-based ultrasound probes need to reach a new level of integration. This paper presents the first chip to combine high-voltage transmitters, analog front-ends, micro-beamforming, digitization and transducers, enabling high-frame-rate 3D imaging. Its pitch-matched architecture, made possible by a shared SAR/slope ADC that is 4x smaller and consumes 1.5x less power than the prior art, makes it a scalable solution for future digital imaging catheters.
A 1.2mW/channel 100μm-Pitch-Matched Transceiver ASIC with Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3D Ultrasound Imaging
P. Guo; F. Fool; E. Noothout; Z. Y. Chang; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
February 2022. DOI: 10.1109/ISSCC42614.2022.9731784
Transceiver ASIC Design for High-Frame-Rate 3D Intracardiac Echocardiography
Yannick M. Hopf; Boudewine Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
2022.
Design of an Ultrasound Transceiver ASIC with a Switching-Artifact Reduction Technique for 3-D Carotid Artery Imaging
T. Kim; F. Fool; D. Simoes dos Santos; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
Sensors,
Volume 21, Issue 1, pp. 150, January 2021. DOI: 10.3390/s21010150

Abstract: ...
This paper presents an ultrasound transceiver application-specific integrated circuit (ASIC) directly integrated with an array of 12 × 80 piezoelectric transducer elements to enable next-generation ultrasound probes for 3D carotid artery imaging. The ASIC, implemented in a 0.18 µm high-voltage Bipolar-CMOS-DMOS (HV BCD) process, adopted a programmable switch matrix that allowed selected transducer elements in each row to be connected to a transmit and receive channel of an imaging system. This made the probe operate like an electronically translatable linear array, allowing large-aperture matrix arrays to be interfaced with a manageable number of system channels. This paper presents a second-generation ASIC that employed an improved switch design to minimize clock feedthrough and charge-injection effects of high-voltage metal–oxide–semiconductor field-effect transistors (HV MOSFETs), which in the first-generation ASIC caused parasitic transmissions and associated imaging artifacts. The proposed switch controller, implemented with cascaded non-overlapping clock generators, generated control signals with improved timing to mitigate the effects of these non-idealities. Both simulation results and electrical measurements showed a 20 dB reduction of the switching artifacts. In addition, an acoustic pulse-echo measurement successfully demonstrated a 20 dB reduction of imaging artifacts.

document
A Transceiver ASIC for a Single-Cable 64-Element Intra-Vascular Ultrasound Probe
D. van Willigen; J. Janjic; E. Kang; Z. Y. Chang; E. Noothout; M. Verweij; N. de Jong; M. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 56, Issue 10, pp. 3157-3166, October 2021. DOI: 10.1109/jssc.2021.3083217

Abstract: ...
This article presents an application-specific integrated circuit (ASIC) designed for intra-vascular ultrasound imaging that interfaces 64 piezoelectric transducer elements to an imaging system using a single micro-coaxial cable. Thus, it allows a single-element transducer to be replaced by a transducer array to enable 3-D imaging. The 1.5-mm-diameter ASIC is intended to be mounted at the tip of a catheter, directly integrated with a 2-D array of piezoelectric transducer elements. For each of these elements, the ASIC contains a high-voltage (HV) switch, allowing the elements to transmit an acoustic wave in response to an HV pulse generated by the imaging system. A low-noise amplifier then amplifies the resulting echo signals and relays them as a signal current to the imaging system, while the same cable provides a 3-V supply. Element selection and other settings can be programmed by modulating configuration data on the supply, thus enabling full synthetic aperture imaging. An integrated element test mode measures the element capacitance to detect bad connections to the transducer elements. The ASIC has been fabricated in a 0.18-μm HV CMOS technology and consumes only 6 mW in receive. Electrical measurements show correct switching of 30-V transmit pulses and a receive amplification with a 71-dB dynamic range, including 12 dB of programmable gain over a 3-dB bandwidth of 21 MHz. The functionality of the ASIC has been successfully demonstrated in a 3-D imaging experiment.
A Pitch-Matched Analog Front-End with Continuous Time-Gain Compensation for High-Density Ultrasound Transducer Arrays
P. Guo; Z. Y. Chang; E. Noothout; H. J. Vos; J. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
In Proc. European Solid-State Circuits Conference (ESSCIRC),
pp. 163-166, September 2021.

Abstract: ...
This paper presents a compact programmable high-voltage (HV) pulser for ultrasound imaging, designed for driving capacitive micro-machined ultrasonic transducers (CMUTs) in miniature ultrasound probes. To enable bipolar return-to-zero pulsing and embedded transmit/receive switching, a compact back-to-back isolating HV switch is proposed that employs HV floating-gate drivers with only one HV MOS transistor each. The pulser can be digitally programmed to generate bipolar pulses with and without return-to-zero, with a peak-to-peak swing up to 60 V, as well as negative and positive unipolar pulses. It can generate bursts of up to 63 pulses, with a maximum pulse frequency of 9 MHz for an 18 pF transducer capacitance. Realized in TSMC 0.18 μm HV BCD technology, the pulser occupies only 0.167 mm2. Electrical characterization results of the pulser, as well as acoustic results obtained in combination with a 7.5-MHz CMUT transducer, are presented.
A Low-Power Reconfigurable Transceiver ASIC for a CMUT-based Wearable Ultrasound Patch
Mingliang Tan; Tim Hosman; Jae-Sung An; Zu-Yao Chang; Michiel Pertijs;
In Annual Workshop on Circuits, Systems and Signal Processing (ProRISC),
July 2021.
An Area-Efficient Continuous Time-Gain Compensation Amplifier for Ultrasound Application
P. Guo; Z.Y. Chang; E. Noothout; H.J. Vos; J.G. Bosch; N. de Jong; M.D. Verweij; M.A.P. Pertijs;
In Annual Workshop on Circuits, Systems and Signal Processing (ProRISC),
July 2021. poster.
An Automated and Process-Portable Generator for Phase-Locked Loop
Wang, Z.; Choi, M.; Chang, E.; Wright, J.; Bae, W.; Du, S.; Liu, Z.; Narevsky, N.; Schmidt, C.; Biwas, A.; Nikolic, B.; Alon, E.;
In 2021 58th ACM/IEEE Design Automation Conference (DAC),
pp. 511-516, 2021. DOI: 10.1109/DAC18074.2021.9586318
An Automated and Process-Portable Generator for Phase-Locked Loop
Wang, Z.; Choi, M.; Chang, E.; Wright, J.; Bae, W.; Du, S.; Liu, Z.; Narevsky, N.; Schmidt, C.; Biwas, A.; Nikolic, B.; Alon, E.;
In 2021 58th ACM/IEEE Design Automation Conference (DAC),
pp. 511-516, 2021. DOI: 10.1109/DAC18074.2021.9586318
A 64-Channel Transmit Beamformer with ±30V Bipolar High-Voltage Pulsers for Catheter-Based Ultrasound Probes
M. Tan; E. Kang; J.-S. An; Z. Y. Chang; P. Vince; T. Matéo; N. Sénégond; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 55, Issue 7, pp. 1796-1806, July 2020. DOI: 10.1109/JSSC.2020.2987719

Abstract: ...
This article presents a fully integrated 64-channel programmable ultrasound transmit beamformer for catheter-based ultrasound probes, designed to interface with a capacitive micro-machined ultrasound transducer (CMUT) array. The chip is equipped with programmable high-voltage (HV) pulsers that can generate ±30-V return-to-zero (RZ) and non-RZ pulses. The pulsers employ a compact back-to-back isolating HV switch topology that employs HV floating-gate drivers with only one HV MOS transistor each. Further die-size reduction is achieved by using the RZ switches also as the transmit/receive (T/R) needed to pass received echo signals to low-voltage receive circuitry. On-chip digital logic clocked at 200 MHz allows the pulse timing to be programmed with a resolution of 5 ns, while supporting pulses of 1 cycle up to 63 cycles. The chip has been implemented in 0.18-μm HV Bipolar-CMOS-DMOS (BCD) technology and occupies an area of 1.8 mm x 16.5 mm, suitable for integration into an 8-F catheter. Each pulser with embedded T/R switch and digital logic occupies only 0.167 mm². The pulser successfully drives an 18-pF transducer capacitance at pulse frequencies up to 9 MHz. The T/R switch has a measured ON-resistance of ~180 Ω . The acoustic results obtained in combination with a 7.5-MHz 64-element CMUT array demonstrate the ability to generate steered and focused acoustic beams.
A Variable-Gain Low-Noise Transimpedance Amplifier for Miniature Ultrasound Probes
E. Kang; M. Tan; J. S. An; Z. Y. Chang; P. Vince; N. Sénégond; T. Mateo; C. Meynier; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 55, Issue 12, pp. 3157--3168, December 2020. DOI: 10.1109/jssc.2020.3023618

Abstract: ...
This article presents a low-noise transimpedance amplifier (TIA) designed for miniature ultrasound probes. It provides continuously variable gain to compensate for the time-dependent attenuation of the received echo signal. This time-gain compensation (TGC) compresses the echo-signal dynamic range (DR) while avoiding imaging artifacts associated with discrete gain steps. Embedding the TGC function in the TIA reduces the output DR, saving power compared to prior solutions that apply TGC after the low-noise amplifier. The TIA employs a capacitive ladder feedback network and a current-steering circuit to obtain a linear-in-dB gain range of 37 dB. A variable-gain loop amplifier based on current-reuse stages maintains constant bandwidth in a power-efficient manner. The TIA has been integrated in a 64-channel ultrasound transceiver application-specific integrated circuit (ASIC) in a 180-nm BCDMOS process and occupies a die area of 0.12 mm². It achieves a gain error below ±1 dB and a 1.7 pA/√ Hz noise floor and consumes 5.2 mW from a ±0.9 V supply. B-mode images of a tissue-mimicking phantom are presented that show the benefits of the TGC scheme.
A 12×80 Element Ultrasound Transceiver ASIC With Enhanced Charge Injection Performance for 3-D Carotid Artery Imaging
T. Kim; F. Fool; E. Kang; Z. Y. Chang; E. Noothout; J. G. Bosch; M. D. Verweij; N. de Jong; M. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
September 2020. abstract.
An Integrated Programmable High-Voltage Bipolar Pulser with Embedded Transmit/Receive Switch for Miniature Ultrasound Probes
M. Tan; E. Kang; J.-S. An; Z. Y. Chang; P. Vince; N. Sénégond; M. A. P. Pertijs;
IEEE Solid-State Circuits Letters,
Volume 2, Issue 9, pp. 79-82, September 2019. DOI: 10.1109/LSSC.2019.2938141

Abstract: ...
This letter presents a compact programmable high-voltage (HV) pulser for ultrasound imaging, designed for driving capacitive micromachined ultrasonic transducers (CMUTs) in miniature ultrasound probes. To enable bipolar return-to-zero (RZ) pulsing and embedded transmit/receive switching, a compact back-to-back isolating HV switch is proposed that employs HV floating-gate drivers with only one HV MOS transistor each. The pulser can be digitally programmed to generate bipolar pulses with and without RZ, with a peak-to-peak swing up to 60 V, as well as negative and positive unipolar pulses. It can generate bursts of up to 63 pulses, with a maximum pulse frequency of 9 MHz for an 18-pF transducer capacitance. Realized in TSMC 0.18um HV BCD technology, the pulser occupies only 0.167mm2 . Electrical characterization results of the pulser, as well as acoustic results obtained in the combination with a 7.5-MHz CMUT transducer, are presented.
A 1.54mW/Element 150μm-Pitch-Matched Receiver ASIC with Element-Level SAR/Shared-Single-Slope Hybrid ADCs for Miniature 3D Ultrasound Probes
J. Li; Z. Chen; M. Tan; D. van Willigen; C. Chen; Z. Y. Chang; E. Noothout; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
IEEE, pp. 1-2, June 2019.
An Integrated Programmable High-Voltage Bipolar Pulser with Embedded Transmit/Receive Switch for Miniature Ultrasound Probes
M. Tan; E. Kang; J.-S. An; Z. Y. Chang; P. Vince; N. Sénégond; M. A. P. Pertijs;
In Proc. European Solid-State Circuits Conference (ESSCIRC),
pp. 325--328, October 2019.

Abstract: ...
This paper presents a compact programmable high-voltage (HV) pulser for ultrasound imaging, designed for driving capacitive micro-machined ultrasonic transducers (CMUTs) in miniature ultrasound probes. To enable bipolar return-to-zero pulsing and embedded transmit/receive switching, a compact back-to-back isolating HV switch is proposed that employs HV floating-gate drivers with only one HV MOS transistor each. The pulser can be digitally programmed to generate bipolar pulses with and without return-to-zero, with a peak-to-peak swing up to 60 V, as well as negative and positive unipolar pulses. It can generate bursts of up to 63 pulses, with a maximum pulse frequency of 9 MHz for an 18 pF transducer capacitance. Realized in TSMC 0.18 μm HV BCD technology, the pulser occupies only 0.167 mm2. Electrical characterization results of the pulser, as well as acoustic results obtained in combination with a 7.5-MHz CMUT transducer, are presented.
A Reconfigurable Ultrasound Transceiver ASIC With 24 × 40 Elements for 3D Carotid Artery Imaging
E. Kang; Q. Ding; M. Shabanimotlagh; P. Kruizinga; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 53, Issue 7, pp. 2065-2075, July 2018. DOI: 10.1109/JSSC.2018.2820156

Abstract: ...
This paper presents an ultrasound transceiver application-specific integrated circuit (ASIC) designed for 3-D ultrasonic imaging of the carotid artery. This application calls for an array of thousands of ultrasonic transducer elements, far exceeding the number of channels of conventional imaging systems. The 3.6 x 6.8 mm² ASIC interfaces a piezo-electric transducer (PZT) array of 24 x 40 elements, directly integrated on top of the ASIC, to an imaging system using only 24 transmit and receive channels. Multiple ASICs can be tiled together to form an even bigger array. The ASIC, implemented in a 0.18 μm high-voltage (HV) BCD process, consists of a reconfigurable switch matrix and row-level receive circuits. Each element is associated with a compact bootstrapped HV transmit switch, an isolation switch for the receive circuits and programmable logic that enables a variety of imaging modes. Electrical and acoustic experiments successfully demonstrate the functionality of the ASIC. In addition, the ASIC has been successfully used in a 3-D imaging experiment.
A Front-End ASIC with High-Voltage Transmit Switching and Receive Digitization for 3D Forward-Looking Intravascular Ultrasound Imaging
M. Tan; C. Chen; Z. Chen; J. Janjic; V. Daeichin; Z. Y. Chang; E. Noothout; G. van Soest; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 53, Issue 8, pp. 2284-2297, August 2018. DOI: 10.1109/JSSC.2018.2828826

Abstract: ...
This paper presents an area- and power-efficient application-specified integrated circuit (ASIC) for 3-D forward-looking intravascular ultrasound imaging. The ASIC is intended to be mounted at the tip of a catheter, and has a circular active area with a diameter of 1.5 mm on the top of which a 2-D array of piezoelectric transducer elements is integrated. It requires only four micro-coaxial cables to interface 64 receive (RX) elements and 16 transmit (TX) elements with an imaging system. To do so, it routes high-voltage (HV) pulses generated by the system to selected TX elements using compact HV switch circuits, digitizes the resulting echo signal received by a selected RX element locally, and employs an energy-efficient load-modulation datalink to return the digitized echo signal to the system in a robust manner. A multi-functional command line provides the required sampling clock, configuration data, and supply voltage for the HV switches. The ASIC has been realized in a 0.18-μm HV CMOS technology and consumes only 9.1 mW. Electrical measurements show 28-V HV switching and RX digitization with a 16-MHz bandwidth and 53-dB dynamic range. Acoustical measurements demonstrate successful pulse transmission and reception. Finally, a 3-D ultrasound image of a three-needle phantom is generated to demonstrate the imaging capability.
An Element-Matched Electro-Mechanical ΔΣ ADC for Ultrasound Imaging
M. D'Urbino; C. Chen; Z. Chen; Z. Y. Chang; J. Ponte; B. Lippe; M. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 53, Issue 10, pp. 2795-2805, October 2018. DOI: 10.1109/JSSC.2018.2859961

Abstract: ...
This paper presents a power- and area-efficient approach to digitizing the echo signals received by piezoelectric transducer elements, commonly used for ultrasound imaging. This technique utilizes such elements not only as sensors but also as the loop filter of an element-level Δ Σ analog to digital converter (ADC). The receiver chain is thus greatly simplified, yielding savings in area and power. Every ADC becomes small enough to fit underneath a 150 μ m x 150 μ m transducer element, enabling simultaneous acquisition and digitization from all the elements in a 2-D array. This is especially valuable for miniature 3-D probes. Experimental results are reported for a prototype receiver chip with an array of 5 x 4 element-matched ADCs and a transducer array fabricated on top of the chip. Each ADC consumes 800 μ W from a 1.8 V supply and achieves a SNR of 47 dB in a 75% bandwidth around a center frequency of 5 MHz.
A Pitch-Matched Front-End ASIC with Integrated Subarray Beamforming ADC for Miniature 3-D Ultrasound Probes
C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; M. Tan; H. Vos; J. Bosch; M. Verweij; N. de Jong; M. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 53, Issue 11, pp. 3050-3064, November 2018. DOI: 10.1109/JSSC.2018.2864295

Abstract: ...
This paper presents a front-end application-specified integrated circuit (ASIC) integrated with a 2-D PZT matrix transducer that enables in-probe digitization with acceptable power dissipation for the next-generation endoscopic and catheter-based 3-D ultrasound imaging systems. To achieve power-efficient massively parallel analog-to-digital conversion (ADC) in a 2-D array, a 10-bit 30 MS/s beamforming ADC that merges the subarray beamforming and digitization functions in the charge domain is proposed. It eliminates the need for costly intermediate buffers, thus significantly reducing both power consumption and silicon area. Self-calibrated charge references are implemented in each subarray to further optimize the system-level power efficiency. High-speed datalinks are employed in combination with the subarray beamforming scheme to realize a 36-fold channel-count reduction and an aggregate output data rate of 6 Gb/s for a prototype receive array of 24 x 6 elements. The ASIC achieves a record power efficiency of 0.91 mW/element during receive. Its functionality has been demonstrated in both electrical and acoustic imaging experiments.
A 2D Ultrasound Transducer with Front-End ASIC and Low Cable Count for 3D Forward-Looking Intravascular Imaging: Performance and Characterization
J. Janjic; M. Tan; E. Noothout; C. Chen; Z. Chan; Z. Y. Chang; R. H. S. H. Beurskens; G. van Soest; A. F. W. van der Steen; M. D. Verweij; M. A. P. Pertijs; N. de Jong;
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
Volume 65, Issue 10, pp. 1832--1844, October 2018. Featured Cover Article. DOI: 10.1109/TUFFC.2018.2859824

Abstract: ...
Intravascular ultrasound is an imaging modality used to visualize atherosclerosis from within the inner lumen of human arteries. Complex lesions like chronic total occlusions require forward-looking intravascular ultrasound (FL-IVUS), instead of the conventional side-looking geometry. Volumetric imaging can be achieved with 2D array transducers, which present major challenges in reducing cable count and device integration. In this work we present an 80-element lead zirconium titanate (PZT) matrix ultrasound transducer for FL-IVUS imaging with a front-end application-specific integrated circuit (ASIC) requiring only 4 cables. After investigating optimal transducer designs we fabricated the matrix transducer consisting of 16 transmit (TX) and 64 receive (RX) elements arranged on top of an ASIC having an outer diameter of 1.5 mm and a central hole of 0.5 mm for a guidewire. We modeled the transducer using finite element analysis and compared the simulation results to the values obtained through acoustic measurements. The TX elements showed uniform behavior with a center frequency of 14 MHz, a -3 dB bandwidth of 44 % and a transmit sensitivity of 0.4 kPa/V at 6 mm. The RX elements showed center frequency and bandwidth similar to the TX elements, with an estimated receive sensitivity of 3.7 μV/Pa. We successfully acquired a 3D FL image of three spherical reflectors in water using delay-and-sum beamforming and the coherence factor method. Full synthetic aperture acquisition can be achieved with frame rates on the order of 100 Hz. The acoustic characterization and the initial imaging results show the potential of the proposed transducer to achieve 3D FL-IVUS imaging.
A 0.91mW/Element Pitch-Matched Front-End ASIC with Integrated Subarray Beamforming ADC for Miniature 3D Ultrasound Probes
C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; M. Tan; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
pp. 186-187, February 2018. DOI: 10.1109/ISSCC.2018.8310246
ASIC design for a single-cable 64-element ultrasound probe
D. van Willigen; J. Janjic; E. Kang; Z. Y. Chang; E. Noothout; M. Verweij; N. de Jong; M. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 1-4, October 2018.

Abstract: ...
This paper presents an ASIC (Application Specific Integrated Circuit) design for a catheter probe that interfaces 64 piezoelectric elements directly integrated on top of the ASIC to an imaging system using a single micro-coaxial cable. Each of the piezo elements can be used for both transmit (TX) and receive (RX), enabling full synthetic aperture imaging. A prototype has been realized with a 1.5mm diameter circular layout, intended for 3D intra-vascular ultrasound imaging. The functionality of this ASIC has been successfully demonstrated in a 3D imaging experiment. The design allows a single-element transducer to be replaced by a transdcuer array while using the same cable, making it a promising solution for 3D imaging with size constrained probes.
A Power-Efficient Transmit Beamformer ASIC for 3-D Catheter-Based/ Endoscopic Probes
Z. Chen; E. Kang; Z. Y. Chang; E. Noothout; J. G. Bosch; M. Verweij; N. de Jong; M. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, October 2018. (abstract).

Abstract: ...
To reduce cable count in 3D catheter-based or endoscopic probes, generation of the (HV) transmit (TX) signals using an in-probe ASIC is a promising solution. However, such ASICs are subject to stringent power-consumption constraints to limit self-heating. The power consumed by conventional HV pulsers is at least fCV^2, due to the periodic charging/discharging of the transducer element capacitance C. HV switches can be used to connect elements to a pulser in the imaging system, thus only dissipating a fraction of fCV^2 in the probe, but full TX beamforming (BF) cannot be realized using switches. In this work, we propose a power-efficient HV TX circuit capable of providing full TX BF using only 3 HV connections to the system. Implemented in a 0.18um BCD process, the ASIC was fully evaluated by means of post-layout simulations.
A 7μW Offset-and Temperature-Compensated pH-to-Digital Converter
S. H. Shalmany; M. Merz; A. Fekri; Z. Y. Chang; R. J. O. M. Hoofman; M. A. P. Pertijs;
Journal of Sensors,
Volume 2017, Issue 6158689, January 2017. DOI: 10.1155/2017/6158689

Abstract: ...
This paper demonstrates a micropower offset- and temperature-compensated smart pH sensor, intended for use in battery-powered RFID systems that monitor the quality of perishable products. Low operation power is essential in such systems to enable autonomous logging of environmental parameters, such as the pH level, over extended periods of time using only a small, low-cost battery. The pH-sensing element in this work is an ion-sensitive extended-gate field-effect transistor (EGFET), which is incorporated in a low-power sensor front-end. The front-end outputs a pH-dependent voltage, which is then digitized by means of a co-integrated incremental delta-sigma ADC. To compensate for the offset and temperature cross-sensitivity of the EGFET, a compensation scheme using a calibration process and a temperature sensor has been devised. A prototype chip has been realized in a 0.16 μm CMOS process. It occupies 0.35 × 3.9 mm2 of die area and draws only 4 μA from a 1.8 V supply. Two different types of custom packaging have been used for measurement purposes. The pH sensor achieves a linearity of better than ±0.1 for pH values ranging from 4 to 10. The calibration and compensation scheme reduces errors due to temperature cross-sensitivity to less than ±0.1 in the temperature range of 6°C to 25°C.
A Front-end ASIC with Receive Sub-Array Beamforming Integrated with a 32 × 32 PZT Matrix Transducer for 3-D Transesophageal Echocardiography
C. Chen; Z. Chen; D. Bera; S. B. Raghunathan; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; J. Ponte; C. Prins; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 52, Issue 4, pp. 994‒1006, April 2017. DOI: 10.1109/JSSC.2016.2638433

Abstract: ...
This paper presents a power- and area-efficient front-end application-specific integrated circuit (ASIC) that is directly integrated with an array of 32 × 32 piezoelectric transducer elements to enable next-generation miniature ultrasound probes for real-time 3-D transesophageal echocardiography. The 6.1 × 6.1 mm2 ASIC, implemented in a low-voltage 0.18-μm CMOS process, effectively reduces the number of receive (RX) cables required in the probe's narrow shaft by ninefold with the aid of 96 delay-and-sum beamformers, each of which locally combines the signals received by a sub-array of 3 × 3 elements. These beamformers are based on pipeline-operated analog sample-and-hold stages and employ a mismatch-scrambling technique to prevent the ripple signal associated with the mismatch between these stages from limiting the dynamic range. In addition, an ultralow-power low-noise amplifier architecture is proposed to increase the power efficiency of the RX circuitry. The ASIC has a compact element matched layout and consumes only 0.27 mW/channel while receiving, which is lower than the state-of-the-art circuit. Its functionality has been successfully demonstrated in 3-D imaging experiments.
A Front-End ASIC with High-Voltage Transmit Switching and Receive Digitization for Forward-Looking Intravascular Ultrasound
M. Tan; C. Chen; Z. Chen; J. Janjic; V. Daeichin; Z. Y. Chang; E. Noothout; G. van Soest; M. Verweij; N. de Jong; M. Pertijs;
In Proc. IEEE Custom Integrated Circuits Conference (CICC),
IEEE, pp. 1‒4, April 2017. DOI: 10.1109/cicc.2017.7993708
An Element-Matched Band-Pass Delta-Sigma ADC for Ultrasound Imaging
M. D’Urbino; C. Chen; Z. Chen; Z. Y. Chang; J. Ponte; B. Lippe; M. Pertijs;
In Proc. IEEE Asian Solid State Circuits Conference (A-SSCC),
IEEE, pp. 137-140, November 2017. winner Student Design Contest. DOI: 10.1109/ASSCC.2017.8240235
A Reconfigurable 24 × 40 Element Transceiver ASIC for Compact 3D Medical Ultrasound Probes
E. Kang; Q. Ding; M. Shabanimotlagh; P. Kruizinga; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
In Proc. European Solid-State Circuits Conference (ESSCIRC),
IEEE, pp. 211-214, September 2017.
A Front-End ASIC for Miniature 3-D Ultrasound Probes with In-Probe Receive Digitization
C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; H. Vos; J. Bosch; M. Verweij; N. de Jong; M. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 1-4, September 2017. Winner Best Student Paper Competition. DOI: 10.1109/ULTSYM.2017.8091913

Abstract: ...
This paper presents a front-end application-specific integrated circuit (ASIC) that demonstrates the feasibility of inprobe digitization for next-generation miniature 3-D ultrasound probes with acceptable power- and area-efficiency. The proposed design employs a low-power charge-domain ADC that is directly merged with the sample-and-hold delay lines in each subarray, and high-speed datalinks at the ASIC periphery to realize an additional channel-count reduction compared to prior work based on analog subarray beamforming. The 4.8 × 2 mm 2 ASIC, which has a compact layout element-matched to a 5-MHz 150-μm-pitch PZT matrix transducer, achieves an overall 36-fold channel-count reduction and a state-of-the-art power-efficiency with less than 1 mW/element power dissipation while receiving, which is acceptable even when scaled up to a 1000-element probe. The prototype ASIC has been fabricated in a 0.18 μm CMOS process. Its functionality has been successfully evaluated with both electrical and acoustical measurements.
Forward-Looking IVUS Transducer with Front-End ASIC for 3D Imaging
J. Janjic; M. Tan; C. Chen; Z. Chen; E. Noothout; Z. Y. Chang; G. van Soest; M. Verweij; A. F. W. van der Steen; M. Pertijs; N. de Jong;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 1-1, September 2017. (abstract).

Abstract: ...
Forward-looking intravascular ultrasound (FL-IVUS) transducers are needed to image complex lesions in the coronary arteries, such as chronic total occlusions (CTOs). To achieve 2D and 3D FL-IVUS imaging, transducer arrays can be integrated at the tip of the catheter. However, connecting the elements is challenging due to the limited space available. In this work, we present a FL-IVUS matrix transducer consisting of 16 transmit and 64 receive elements, which are interfaced with an ASIC that requires only 4 micro-coaxial cables. The transducer performance was characterized by hydrophone measurements and FL imaging of three spherical reflectors.
Towards 3D ultrasound imaging of the carotid artery using a programmable and tileable matrix array
P. Kruizinga; E. Kang; M. Shabanimotlagh; Q. Ding; E. Noothout; Z. Y. Chang; H. J. Vos; J. G. Bosch; M. D. Verweij; M. A. P. Pertijs; N. de Jong;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 1-3, September 2017. DOI: 10.1109/ULTSYM.2017.8091570

Abstract: ...
Accurate assessment of carotid artery disease by measuring blood flow, plaque deformation and pulse wave velocity using ultrasound imaging requires 3D information. Additionally, the volume rates should be high enough (> 1 kHz) to capture the full range of these fast transient phenomena. For this purpose, we have built a programmable, tileable matrix array that is capable of providing 3D ultrasound imaging at such volume rates. This array contains an application-specific integrated circuit (ASIC) right beneath the acoustic piezo-stack. The ASIC enables fast programmable switching between various configurations of elements connected to the acquisition system via a number of channels far smaller than the number of transducer elements. This design also allows for expanding the footprint by tiling several of these arrays together into one large array. We explain the working principles and show the first basic imaging results of a 2-by-1 tiled array.
A Prototype PZT Matrix Transducer with Low-Power Integrated Receive ASIC for 3D Transesophageal Echocardiography.
C. Chen; S. Raghunathan; Z. Yu; M. Shabanimotlag; Z. Chen; Z. Y. Chang; S. Blaak; C. Prins; J. Ponte; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
Volume 63, Issue 1, pp. 47‒59, January 2016. DOI: 10.1109/tuffc.2015.2496580

Abstract: ...
This paper presents the design, fabrication, and experimental evaluation of a prototype lead zirconium titanate (PZT) matrix transducer with an integrated receive ASIC, as a proof of concept for a miniature three-dimensional (3-D) transesophageal echocardiography (TEE) probe. It consists of an array of 9 × 12 piezoelectric elements mounted on the ASIC via an integration scheme that involves direct electrical connections between a bond-pad array on the ASIC and the transducer elements. The ASIC addresses the critical challenge of reducing cable count, and includes front-end amplifiers with adjustable gains and microbeamformer circuits that locally process and combine echo signals received by the elements of each 3 × 3 subarray. Thus, an order-of-magnitude reduction in the number of receive channels is achieved. Dedicated circuit techniques are employed to meet the strict space and power constraints of TEE probes. The ASIC has been fabricated in a standard 0.18-μm CMOS process and consumes only 0.44 mW/channel. The prototype has been acoustically characterized in a water tank. The ASIC allows the array to be presteered across ±37° while achieving an overall dynamic range of 77 dB. Both the measured characteristics of the individual transducer elements and the performance of the ASIC are in good agreement with expectations, demonstrating the effectiveness of the proposed techniques.
A 30-ppm <80 nJ Ring-Down-Based Readout Circuit for Resonant Sensors
H. Jiang; Z. Y. Chang; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 51, Issue 1, pp. 187‒195, January 2016. DOI: 10.1109/JSSC.2015.2470552

Abstract: ...
This paper presents an energy-efficient readout circuit for micro-machined resonant sensors. It operates by briefly exciting the sensor at a frequency close to its resonance frequency, after which resonance frequency and quality factor are determined from a single ring-down transient. The circuit employs an inverter-based trans-impedance amplifier to sense the ring-down current, with a programmable feedback network to enable the readout of different resonant sensors. An inverter-based comparator with dynamically-adjusted threshold levels tracks the ring-down envelope to measure quality factor, and detects zero crossings to measure resonance frequency. The excitation frequency is dynamically adjusted to accommodate large resonance frequency shifts. Experimental results obtained with a prototype fabricated in 0.35 μm standard CMOS technology and three different SiN resonators are in good agreement with conventional impedance analysis. The prototype achieves a frequency resolution better than 30 ppm while consuming less than 80 nJ/meas from a 1.8 V supply, which is 7.8x less than the state-of-the-art.
Acoustic Characterisation of a 32 × 32 Element PZT-on-CMOS Matrix Transducer for 3D TEE
S. Raghunathan; D. Bera; C. Chen; Z. Chen; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; H. Vos; C. Prins; J. Ponte; J. Bosch; M. Pertijs; N. de Jong; M. Verweij;
In Proc. IEEE International Ultrasonics Symposium (IUS),
September 2016. (abstract).
A front-end ASIC with receive sub-array beamforming integrated with a 32 × 32 PZT matrix transducer for 3-D transesophageal echocardiography
C. Chen; Z. Chen; D. Bera; S. B. Raghunathan; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; J. Ponte; C. Prins; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
IEEE, pp. 1‒2, September 2016. DOI: 10.1109/vlsic.2016.7573470
Water-enhanced guarding of polymer-coated IDE platforms as a key mechanism for achieving response immunity towards parasitic coupling events
J. Staginus; Z.Y. Chang; E.J.R. Sudholter; LC.P.M. de Smet; G.C.M. Meijer;
Sensors and Actuators A: Physical: an international journal devoted to research and development of physical and chemical transducers,
Volume 234, pp. 239-247, 2015. Available online 10-9-2015.
Low Power Receive Electronics for a Miniature Real-Time 3D Ultrasound Probe
Z. Chen; C. Chen; S. B. Raghunathan; D. Bera; Z. Chang; S. Blaak; C. Prins; J. Ponte; J. G. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
In Proc. Conference for ICT-Research in the Netherlands (ICT.OPEN),
The Netherlands, March 2015.
A compact 0.135-mW/channel LNA array for piezoelectric ultrasound transducers
C. Chen; Z. Chen; Z. Y. Chang; M. A. P. Pertijs;
In Proc. European Solid-State Circuits Conference (ESSCIRC),
IEEE, pp. 404‒407, September 2015. DOI: 10.1109/esscirc.2015.7313913
Low-power receive electronics for a miniature real-time 3D ultrasound probe
M. Pertijs; C. Chen; S. Raghunathan; Z. Yu; M. ShabaniMotlagh; Z. Chen; Z. Y. Chang; E. Noothout; S. Blaak; J. Ponte; C. Prins; H. Bosch; M. Verweij; N. de Jong;
In Proc. IEEE International Workshop on Advances in Sensors and Interfaces (IWASI),
IEEE, pp. 235‒238, June 2015. invited paper. DOI: 10.1109/iwasi.2015.7184963
A 30ppm <80nJ ring-down-based readout circuit for resonant sensors
H. Jiang; Z. Y. Chang; M. Pertijs;
In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
IEEE, pp. 482‒483, February 2015. DOI: 10.1109/ISSCC.2015.7063136

Abstract: ...
A readout circuit for MEMS resonant sensors, realized in 0.35μm CMOS, employs a dynamically-switching level-crossing detector to determine resonance frequency and quality factor from a single ring-down transient. Results obtained with three different resonators are in good agreement conventional impedance analysis. The circuit achieves a frequency resolution better than 30 ppm while consuming less than 80 nJ/meas from a 1.8V supply, 7.8x less than the state-of-the-art.
A 0.05mm² 1V capacitance-to-digital converter based on period modulation
Y. He; Z. Y. Chang; L. Pakula; S. H. Shalmany; M. Pertijs;
In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
IEEE, pp. 486‒487, February 2015. DOI: 10.1109/ISSCC.2015.7063138

Abstract: ...
This paper presents a digitally assisted period modulation (PM)-based capacitance-to-digital converter (CDC) that is >9× smaller than prior CDCs with >10b resolution, and improves the energy efficiency by >10× compared to previous PM-based CDCs. This is achieved with the help of a piece-wise charge transfer technique that eliminates the need for a large on-chip integration capacitor, a dual-integration-capacitor scheme that reduces the front-end noise contribution, a sampled-biasing technique that reduces the noise of the integration current, and a current-efficient inverter-based design.
A mixed-signal multiplexing system for cable-count reduction in ultrasound probes
Q. Liu; C. Chen; Z. Y. Chang; C. Prins; M. A. P. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 1‒4, October 2015. DOI: 10.1109/ultsym.2015.0141

Abstract: ...
This paper presents an approach to time-multiplexing multiple receive signals in a miniature ultrasound probe onto a single micro-coaxial cable. The resulting reduction in the number of receive cables alleviates the design of high-element-count endoscope- or catheter-based ultrasound probes. A prototype multiplexing system is presented that employs a custom multiplexing chip that uses current-mode drivers to combine four receive channels, sampled at 25 MHz each, on a single 3-m micro-coaxial cable. On the system-side of the cable, a transimpedance amplifier turns the multiplexed signal back into a voltage, after which it is digitized and equalized to correct for channel-to-channel crosstalk due to non-idealities of the cable. The chip has been implemented in a 0.18 μm CMOS process and consumes less than 1 mW per input channel. Experimental results show that the system can successfully convey 6 MHz Gaussian-shaped pulses applied to the four input channels of the multiplexing chip to the system with a channel-to-channel crosstalk below -31 dB.
Highlights of the ISSCC 2013 Processors and High Performance Digital Sessions
T. Fischer; B. G. Nam; L. Chang; T. Kuroda; M. A. P. Pertijs;
IEEE Journal of Solid-State Circuits,
Volume 49, Issue 1, pp. 4‒8, 2014. DOI: 10.1109/jssc.2013.2284658

Abstract: ...
This special issue covers the ISSCC conference held in San Francisco, CA, USA, on February 17-21, 2013. The issue includes the topics from the low power and high performance digital, memory, and technology directions as well as imagers, medical and sensors. There are 27 papers in the issue.
Dedicated Impedance-Sensor Systems
G. Meijer; X. Li; B. Iliev; G. Pop; Z. Y. Chang; S. Nihtianov; Z. Tan; A. Heidari; M. Pertijs;
In Smart Sensor Systems: Emerging Technologies and Applications,
John Wiley \& Sons, May 2014.

Abstract: ...
Impedance sensors can be defined as being a set of electrodes which can be used to measure electrical properties of materials or structures. Once these properties are known, it appears that the features of measurements performed with such sensors depend for a large part on the properties of the material or structure to be characterized and only partly on the characteristics of the electrodes. The electrical properties of the sensor in its application can be modeled with passive elements in equivalent electrical circuits. The challenging task for the designer is to make such a sensor system sensitive for the measurands and to obtain immunity for other parameters. In this chapter, we consider impedance sensors to be sensors in a certain measurement environment, and that in the electric model presentation of this setup there is at least one resistive or one reactive component of interest which has to be measured.

document
An energy-efficient reconfigurable readout circuit for resonant sensors based on ring-down measurement
Y. Yan; Z. Zeng; C. Chen; H. Jiang; Z. Y. Chang; D. M. Karabacak; M. A. P. Pertijs;
In Proc. IEEE Sensors Conference,
IEEE, pp. 221‒224, October 2014. DOI: 10.1109/icsens.2014.6984973
An eddy-current displacement-to-digital converter based on a ratio-metric delta-sigma ADC
A. Fekri; M. Nabavi; N. Radeljic-Jakic; Z. Y. Chang; M. Pertijs; S. Nihtianov;
In Proc. European Solid-State Circuits Conference (ESSCIRC),
IEEE, pp. 403‒406, September 2014. DOI: 10.1109/esscirc.2014.6942107
Capacitive response of PDMS-coated IDE platforms directly exposed to aqueous solutions containing volatile organic compounds
J. Staginus; I.M. Aerts; Z.Y. Chang; G.C.M. Meijer; LC.P.M. de Smet; E.J.R. Sudholter;
Sensors and Actuators B: Chemical: international journal devoted to research and development of physical and chemical transducers,
Volume 184, pp. 130-142, 2013.
A 7μW pH-to-digital converter for quality monitoring of perishable products
S. H. Shalmany; M. Merz; A. Fekri; Z. Chang; R. Hoofman; M. A. P. Pertijs;
In Proc. International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS),
IEEE, pp. 1747‒1750, June 2013. DOI: 10.1109/Transducers.2013.6627125

Abstract: ...
This paper describes an energy-efficient smart pH sensor intended for use in RFID tags to monitor the quality of perishable products. The sensor is based on an Extended Gate Field-Effect Transistor (EGFET). In a measurement time of 20 ms, it achieves a pH resolution of 0.05 and an accuracy of 0.1 in a pH range from 3 to 10, while consuming only 7 μW. This level of power consumption, which is orders of magnitude lower than the prior art, is achieved by incorporating the EGFET in an ultra-low-power frontend based on a differential source-follower, and digitizing the resulting pH-dependent voltage using an incremental first-order ΔΣ ADC.
Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography
Z. Yu; S. Blaak; Z. Y. Chang; J. Yao; J. G. Bosch; C. Prins; C. T. Lancee; N. de Jong; M. A. P. Pertijs; G. C. M. Meijer;
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
Volume 59, Issue 7, pp. 1500‒1512, July 2012. DOI: 10.1109/tuffc.2012.2350

Abstract: ...
There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-μm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.
Surface-engineered sensors: polymer-based sensors for the capacitive detection of organic water pollutants
J. Staginus; I.M. Aerts; Z.Y. Chang; G.C.M. Meijer; LC.P.M. de Smet;
conference, 2012. TU Delft.
Surface-engineered sensors: polymer-based sensors for the capacitive detection of organic pollutants in water
J. Staginus; I.M. Aerts; Z.Y. Chang; G.C.M. Meijer; LC.P.M. de Smet; E.J.R. Sudholter;
In s.n. (Ed.), Water, IMCS 2012 - The 14th International Meeting on Chemical Sensors,
AMA Association, pp. 1141-1144, 2012.
A 9-channel low-power receiver ASIC for 3D transesophageal echocardiography
Z. Yu; S. Blaak; C. Prins; Z. Y. Chang; C. T. Lancée; J. G. Bosch; N. de Jong; G. C. M. Meijer; M. A. P. Pertijs;
In Proc. IEEE International Ultrasonics Symposium (IUS),
IEEE, pp. 2063‒2066, October 2012. DOI: 10.1109/ultsym.2012.0516

Abstract: ...
This paper presents a 9-channel low-power receiver ASIC dedicated to a matrix piezoelectric ultrasound transducer for 3D Trans-Esophageal Echocardiography (TEE). It consists of 9 low-noise amplifiers (LNAs), 9 time-gain-compensation (TGC) amplifiers and a 9:1 micro-beamformer. A prototype ASIC has been implemented in 0.35 μm CMOS technology, with a core area of 0.98 mm × 1.7 mm. It is operated at a 3.3 V supply and consumes only 0.5 mW per channel. The measured channel-to-channel mismatch is within ±1 dB. Acoustic measurements proved the micro-beamforming function of the ASIC when processing real ultrasound signals from a 3 × 3 transducer array. These promising results show that this design, after layout optimization, is suitable to be scaled up to accommodate a full matrix transducer.
A high resolution universal integrated interface for capacitive sensors
A. Heidary; Z.Y. Chang; G.C.M. Meijer;
In P.J. French (Ed.), Proceedings of STW-ICT conference 2010,
STW, pp. 4-7, 2010.
Dedicated impedance sensors with reduced influence of undesired physical effects
G.C.M. Meijer; X. Li; Z.Y. Chang; B.P. Iliev;
In s.n. (Ed.), Proceedings of ISMTII 2009,
D. S. Rozhdestvensky Optical Society, pp. 297-301, 2009.
A comparison of two-and four-electrode techniques to characterize blood impedance for the frequency range of 100 Hz to 100 MHz
Z.Y. Chang; G.A.M. Pop; G.C.M. Meijer;
IEEE Transactions on Biomedical Engineering,
Volume 55, Issue 3, pp. 1247-1249, 2008.
Extending the limits of a capacitive soil-water-content measument (U_SP_2_I_IC_T)
Z.Y. Chang; B.P. Iliev; G.C.M. Meijer; J.F. de Groot;
IEEE Transactions on Instrumentation and Measurement,
Volume 56, Issue 6, pp. 2240-2244, 2007.
A sensor interface system for measuring the impedance (Cx Rx) of soil at a signal frequency of 20 MHz
Z.Y. Chang; B.P. Iliev; G.C.M. Meijer;
In s.n. (Ed.), Proceedings of the Sixth IEEE Sensors Conference 2007,
IEEE, pp. 1-4, 2007.
The noise performance of evaluation boards for a universal transducer interface with USB connecction
Z.Y. Chang; G.C.M. Meijer;
In s.n. (Ed.), Proceedings of Electronics ET 2007,
s.n., pp. 47-52, 2007.
A universal transducerconnection interfaces with USB
Z.Y. Chang; G.C.M. Meijer;
In s.n. (Ed.), A universal transducerconnection interfaces with USB,
Sense of Contact 2009, pp. 1-4, 2007.
Smart capacitive-resistive sensors
G.C.M. Meijer; X. Li; Z. Chang; B.P. Iliev;
In s.n. (Ed.), Proceeding of: XLII International Scientific Conference on Information, Communication and Energy Systems and Technologies - ICEST2007,
ICEST, pp. 3-12, 2007.
Water-content meter (U-SP-2-I-ICT)
Z.Y. Chang;
STW, , 2006.
Dedicated smart admittance-sensor systems-progress report-part 3 9/17-01-2006 (U-SP-2-I-ICT)
Z.Y. Chang; B.P. Iliev; G.C.M. Meijer;
STW, Volume STW report , 2006.
Dedicated smart admittance-sensor systems-progress report-part 2 9/17-01-2006 (U-SP-2-I-ICT)
Z.Y. Chang; B.P. Iliev; G.C.M. Meijer;
STW, Volume STW report , 2006.
High- and low-frequency model of blood impedance
Z.Y. Chang; B.P. Iliev; G.C.M. Meijer;
In s.n. (Ed.), Proceedings of the Sense of Contact 7 workshop,
Sense of Contact 2009, pp. 1-6, 2005. Editor onbekend JH.
In-vitro and in-vivo plasma resistance measurement system
B.P. Iliev; Z.Y. Chang; G.C.M. Meijer;
In s.n. (Ed.), Proceedings of the Sense of Contact 7 workshop,
Sence of Contact, pp. 1-5, 2005. Editor onbekend JH.
Extending the limits of a capacitive soil-water-content measurement
Z.Y. Chang; B.P. Iliev; F. de Groot; G.C.M. Meijer;
In s.n. (Ed.), IEEE, pp. 376-379, 2005. Editor onbekend JH.
On-line electrical impedance measurement for monitoring blood viscosity during on-pump heart surgery
G.A.M. Pop; T.L.M. de Backer; M. de Jong; P.C. Struijk; L. Moraru; Z.Y. Chang; H.G. Goovaerts; C.J. Slager; AJJC bogers;
European Surgical Research: clinical and experimental surgery,
Volume 36, Issue 5, pp. 259-265, 2004.
Blood electrical impedance closely matches whole blood viscosity as parameter of hemorheology and inflammation
G.A.M. Pop; W.J. Hop; L. Moraru; M. Jagt; J. Quak; D. Dekkers; Z.Y. Chang; F.J. Gijsen; DJ Duncker; C.J. Slager;
Applied Rheology: Fliessverhalten steuern,
Volume 13, Issue 6, pp. 305-312, 2004.
Catheter-based impedance measurements in the right atrium for continuously monitoring hematocrit and estimating blood viscosity changes; an in vivo feasibility study in swine
G.A.M. Pop; Z.Y. Chang; C.J. Slager; B.J. Kooij; E.D. van Deel; L. Moraru; J. Quak; G.C.M. Meijer; DJ Duncker;
Biosensors and Bioelectronics,
Volume 19, Issue 12, pp. 1685-1693, 2004.
Electrical characterization of wetted substrates
B.P. Iliev; M.D. Verweij; Z.Y. Chang; G.C.M. Meijer;
In SAFE 09dcb9aaa96a4f04b679e224b65b2df8 ProRISC 2004; Proceedings of semiconductor advances for future electronics,
STW Technology Foundation, pp. 1-4, 2004. ed. is niet bekend.
A novel model of blood impedance for indirect viscosity measurement
Z.Y. Chang; G.C.M. Meijer; G.A.M. Pop;
In S Tabakov (Ed.), Electronics ET'2004,
Technical University Sofia, pp. 15-21, 2004. nog niet eerder opgevoerd JH.

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Last updated: 21 Dec 2022

ir. Z.Y. Chang

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Zu Yao Chang