CMOS Bridge Rectifier for Medical Implants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
CMOS bridge circuits used for AC to DC conversion in medical implants face challenges with diode voltage drops and space constraints, especially in low-power applications like retinal implants, where traditional rectifiers are inefficient and impractical due to the need for discrete capacitors and diodes.
Innovation Solution
A signal processing circuit utilizing a CMOS bridge rectifier with a resistive load and integrated on a single chip, which applies a rectangular wave input signal to generate a rectified DC output voltage without a discrete parallel capacitor, effectively providing both power and data components, thus eliminating the need for additional diodes and capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional rectifier circuits with diodes and discrete capacitors are used, then AC to DC conversion is achieved, but space requirements increase and diode voltage drops occur reducing efficiency
Solution Approach 1:
The patent combines the rectifier and capacitor into a single integrated circuit structure. The CMOS bridge rectifier is integrated with an on-chip capacitor that is coupled to the output, eliminating the need for discrete external capacitors and diodes. This integration reduces the number of separate components while maintaining the AC to DC conversion function and eliminating diode voltage drops.
Solution Approach 2:
The integrated circuit serves multiple functions: it performs AC to DC rectification through the CMOS bridge and simultaneously provides energy storage through the integrated capacitor. The single chip structure combines what were previously separate discrete components, reducing space requirements and improving efficiency by eliminating intermediate voltage drops.
2Reliability
If discrete capacitors and diodes are added to the bridge circuit, then smoothing and rectification are improved, but space constraints in medical implants are violated
Solution Approach 1:
The patent merges the rectifier circuit and capacitor into a single integrated structure on one chip. The CMOS bridge rectifier and the smoothing capacitor are both fabricated on the same semiconductor substrate, eliminating the need for separate discrete components. This integration maintains reliable rectification performance while dramatically reducing the total area required.
Solution Approach 2:
The capacitor is integrated within the same chip structure as the rectifier circuit, essentially nesting the energy storage function within the rectification function. This nested integration allows both functions to coexist in a compact form factor suitable for medical implant applications where space is at a premium.
3Area of stationary object
If the bridge circuit is integrated on a single chip, then space requirements are reduced, but additional diodes and capacitors become unnecessary
Solution Approach 1:
The patent integrates both power rectification and data signal processing functions on a single chip. The CMOS bridge rectifier handles power conversion while the integrated capacitor couples to the output to provide both power smoothing and data signal transmission. This consolidation eliminates the need for separate discrete diodes and capacitors while maintaining functional reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient power supply and data transmission in medical implants like retinal and cochlear implants, reducing space requirements and avoiding diode voltage drops, while maintaining stability and safety by using parasitic capacitances and minimizing DC voltage exposure.
Implementation Method 1
The gates of the CMOS switches may be directly connected to the input voltage terminals. Assuming a purely resistive load and an ideal switching performance of the transistors, the following conditions are fulfilled: U2=|u1(t)|, if |u1(t)|≧uTHR
Implementation Method 2
Each inverter has a signal input for receiving an input rectangular signal, a signal output for providing an inverted output rectangular signal, and a pair of voltage outputs for developing a rectified dc output voltage
Implementation Method 3
A chip may include the signal processing circuit, with a resistive load coupled between the first and second output terminals without a discrete parallel capacitor
Data Source
AI summary
A signal processing circuit includes an input inverter and an output inverter. Each inverter has a signal input for receiving an input rectangular signal, a signal output for providing an inverted output rectangular signal, and a pair of voltage outputs for developing a rectified dc output voltage. A first circuit input terminal is connected to the output of the input inverter and the input of the output inverter. A second circuit input terminal is connected to the input of the input inverter and the output of the output inverter, wherein the signal input terminals receive an input signal having a data component. A pair of supply voltage output terminals is connected to the voltage output terminals of the inverters for providing a rectified dc supply voltage output. A first circuit output terminal is connected to one of the supply voltage output terminals, and a second circuit output terminal connected to the second circuit input terminal, wherein the circuit output terminals provide an output signal including the data component.