High PSRR Wide Supply Range Dual-Voltage Reference Circuit for Bio-Implantable Applications

Ruhaifi Bin Abdullah Zawawi,Hojong Choi,Jungsuk Kim

doi:10.3390/electronics10162024

Ruhaifi Bin Abdullah Zawawi, Hojong Choi + Show 1 more

Open Access

https://doi.org/10.3390/electronics10162024

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Abstract

On-chip systems are challenging owing to the limited size of the components, such as the capacitor bank in the rectifier. With a small on-chip capacitor, the output voltage of the rectifier might ring if the circuit experiences significant changes in current. The reference circuit is the first block after the rectifier, and the entire system relies on its robustness. A fully integrated dual-voltage reference circuit for bio-implantable applications is presented. The proposed circuit utilizes nonlinear current compensation techniques that significantly decrease supply variations and reject high-supply ripples for various frequencies. The reference circuit was verified using a 0.35 µm complementary metal-oxide semiconductor (CMOS) process. Maximum PSRR values of −112 dB and −128 dB were obtained. With a supply range from 2.8 to 12 V, the proposed design achieves 0.916 and 1.5 mV/V line regulation for the positive and negative reference circuits, respectively.

Highlights

On-chip systems are challenging owing to the limited size of the components, such as the capacitor bank in the rectifier
The transmitted power enables the operation of an implantable system comprising a rectifier, reference circuit, low dropout regulator (LDO), digital controllers, analog circuits, and stimulators
The prior methods were based on compensating the negative temperature coefficient of a diode-connected bipolar junction transistor (BJT) or complementary metal-oxide semiconductor (CMOS) with a positive temperature coefficient thermal voltage

Summary

Introduction

On-chip systems are challenging owing to the limited size of the components, such as the capacitor bank in the rectifier. With a small on-chip capacitor, the output voltage of the rectifier might ring if the circuit experiences significant changes in current. The reference circuit is the first block after the rectifier, and the entire system relies on its robustness. The transmitted power enables the operation of an implantable system comprising a rectifier, reference circuit, low dropout regulator (LDO), digital controllers, analog circuits, and stimulators. The DC voltage is generated by passing through a rectifier and LDO from an AC power signal, which is wirelessly transmitted via an inductive link [1,2] or infrared radiation [3]. The implanted rectifier produces an unstable output voltage ripple, which is fed to the input terminal of the reference circuit. The voltage reference circuit must provide a stable output over the device process, power supply, and temperature variations. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

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