Floating Internal Power Supply for Wide Common-Mode Amplifiers
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Solution Overview
Problem
Existing amplifier designs that accommodate a range of common mode voltages using high-voltage devices compromise performance and increase size, while schemes to improve performance, such as chopping architectures, add complexity.
Innovation Solution
An amplifier system with an internal floating power supply that generates a regulated voltage range, allowing a low-voltage core amplifier to operate over a high-voltage range of common mode voltages, reducing the need for high-voltage devices and incorporating a selector circuit to select maximum and minimum voltages from external and common mode voltages, and a floating supply circuit to level-shift the voltage range based on the input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-voltage devices are used in the input stage to accommodate a range of common mode voltages, then the amplifier can operate over a wider voltage range, but the performance of the amplifier is reduced
Solution Approach 1:
The amplifier is divided into two distinct stages: a low-voltage input stage for signal amplification and a high-voltage output stage for voltage level adaptation. This segmentation allows each stage to be optimized independently - the input stage uses low-voltage devices for high performance while the output stage handles the high voltage requirements, thus resolving the contradiction between voltage range adaptability and amplifier performance
Solution Approach 2:
A voltage translation circuit is introduced as an intermediary between the low-voltage input stage and the high-voltage output stage. This intermediary circuit translates the low-voltage signal from the input stage to the appropriate high-voltage level for the output stage, enabling the system to operate over a wide voltage range while maintaining high performance in the input stage
2Reliability
If chopping architectures are used to improve performance, then the amplifier performance is enhanced, but the device complexity increases
Solution Approach 1:
The voltage translation function is extracted from the main amplifier signal path and implemented as a separate, dedicated circuit. This extraction allows the amplifier to achieve high performance through proper voltage level matching without requiring complex modulation techniques like chopping, thus improving performance while avoiding increased complexity
Data Source
AI summary
An internal power supply for an amplifier is disclosed. The internal power supply floats according to a common mode voltage at the input to the amplifier and according to an input voltage at an input stage of the amplifier. Powering the input stage of the amplifier using the floating supply allows for the use of low voltage devices even when the range of possible common mode voltages includes high voltages. The use of low voltage devices can correspond to performance improvement for the amplifier and can help reduce the size of the amplifier. The internal supply can accommodate both positive and negative common mode voltages and can be used for current sense amplifiers of any gain.