Design of a Power Management Circuit for an Opto-Electro Stimulator

Abstract

This paper presents the design of an integrated power management circuit for use in an implantable optoelectro stimulator. It features an active rectifier with pulse width modulation (PWM) regulation to generate a 3.3 V regulated output, and a 3-stage high voltage charge pump that generates a 12 V output from a 3.3 V input with a 20 MHz, two-phase nonoverlapping clock generator. The circuits were designed in a 0.18-m CMOS technology requiring a chip area of 0.048 mm 2 . Simulation results show that the regulating rectifier has a voltage conversion efficiency of 94.3% and 92.8% with an input of 3.5 V and 3.6 V, respectively. The peak power transfer efficiency for a regulated output voltage of 3.3 V is 70.7% with an output power range of 30.3 mW. The charge pump overall capacitance is 60 pF. Keywords-Active rectifier, charge pump, integrated circuits, optogenetics, power management.' ) depending on the output of the PWM controller. The comparators ( 1 and 2 ) drive the cross-coupled nMOS ( 1 and 2) via the inverters. A dynamic body

A Fully Implantable Opto-Electro Closed-Loop Neural Interface for Motor Neuron Disease Studies

“…2 comprises four parallel stimulator units, each consisting of a 11-bit current driver and a 4 × 4 channel output stage for multi-channel optical or electrical stimulation, a 2-stage amplifier for EMG recording, and a control logic module for managing the operation. There is also a 10-bit SAR ADC multiplexed among the four stimulator units, and a global power management unit consisting of a regulating rectifier that converts the received ac voltage over the inductive link into a stable 3.3 V dc supply [25], a charge-pump dc-dc converter to step up the supply voltage to 12 V for the output stage, and a 1.8 V linear voltage regulator for supplying the low voltage modules.…”

“…The 3.3 V output is up-converted to 12 V by a 3-stage crosscoupled charge-pump for the stimulator output stage, and down-converted to 1.8 V by a linear regulator. The details of the power management unit are provided in [25]. With a 1 kΩ load under a 6.56 MHz input, the voltage conversion efficiency (VCE) and power conversion efficiency (PCE) of the regulating-rectifier are 87.5% and 84.2%, respectively.…”

Dual Output Regulating Rectifier for an Implantable Neural Interface

“…The PMU also consists of an adiabatic CP to power a dual-mode stimulator within the neural interface. The design of the dual output regulating rectifier consists of: 1) different size of pMOS transistors and adaptive body biasing (ABB) to improve the power conversion efficiency; 2) a body biased high-speed comparator [4]; 3) ABB to decrease leakage current; and 4) dual voltage outputs of 1.8 V and 3.3 V.…”

High Efficiency Power Management Unit for Implantable Optical-Electrical Stimulators

“…This work is an expansion of [10] and provides further details on the circuit design topology; it includes measured results from the fabricated chip of the PMU highlighted in FIGURE 1. Further circuit details on the stimulator unit and EMG sensor can be found in [11].…”