Multi-power Domain Op Amp Voltage Generator
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Solution Overview
Problem
Conventional voltage generators require high voltage elements to generate positive and negative reference voltages, leading to poor element properties, increased circuit complexity, and layout area, as well as power noise and voltage offset issues.
Innovation Solution
A multi-power domain operational amplifier with an input stage circuit, power domain transforming circuit, and active load is used to shift the common mode range, allowing the generation of reference voltages without high voltage elements, utilizing a cascade resistor and regulators with negative feedback configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage elements are used to generate positive and negative reference voltages, then the voltage generation function is achieved, but the element properties deteriorate and the layout area increases
Solution Approach 1:
The voltage generation function is divided into multiple regulator stages (first regulator, second regulator, third regulator), each operating within safe voltage domains. The multi-power domain operational amplifier segments the power domains into first power domain (VDD to GND), second power domain (GND to -VDD), and third power domain (-VDD to -2VDD), allowing each stage to operate independently within medium voltage element limits while collectively achieving the required ±5V output.
2Reliability
If high voltage elements are used to generate reference voltages, then the voltage generation function is achieved, but the circuit complexity increases
Solution Approach 1:
The circuit is segmented into multiple regulator stages, each handling a specific voltage conversion task within safe operating domains. This segmentation allows each stage to use standard medium voltage elements rather than requiring high voltage elements, reducing individual component complexity while maintaining overall functionality.
Solution Approach 2:
The multi-power domain operational amplifier acts as an intermediary device that bridges different power domains. It transforms signals between first power domain, second power domain, and third power domain, enabling voltage generation without direct high voltage element usage. The power domain transforming circuit serves as the mediator that converts between different voltage domains safely.
3Ease of operation
If unity gain buffers are used to provide current output, then the driving ability is improved, but the circuit complexity and layout area increase
Solution Approach 1:
The driving function is merged into the regulator stages themselves rather than being separated into dedicated unity gain buffers. The multi-power domain operational amplifier and regulator circuitry are designed to provide both voltage regulation and current driving capability in an integrated manner, eliminating the need for separate buffer stages.
4Reliability
If additional regulator stages are cascaded to avoid high voltage elements, then the voltage domain is kept within safe range, but the output voltage offset increases and power noise influence increases
Solution Approach 1:
Each regulator stage is equipped with negative feedback mechanisms that regulate the output voltage accurately. The multi-power domain operational amplifier uses feedback to maintain precise voltage levels across power domain transformations, compensating for potential offsets and reducing the accumulation of errors that would otherwise occur with cascaded stages.
Solution Approach 2:
The invention changes the operating parameters of the operational amplifier to enable direct operation across multiple power domains without requiring cascaded regulator stages. The multi-power domain operational amplifier is designed with enhanced common mode rejection ratio and optimized biasing that allows it to handle wide voltage ranges directly, reducing the number of stages needed and thereby minimizing offset accumulation and power noise influence.
Data Source
AI summary
A multi-power domain operational amplifier includes an input stage circuit, a power domain transforming circuit and an active load. The input stage circuit is configured to transform a set of input voltages into a set of input currents in a first power domain. The power domain transforming circuit is configured to transform the set of input currents into a set of output currents in a second power domain. The active load is configured to generate an output voltage according to the set of output currents. A common mode range of the output voltage is shifted as compared with a common mode range of the set of input voltages.