Bandgap Circuit with Current Mirror Feedback for Voltage Stability
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Solution Overview
Problem
Conventional electronic circuits with bandgap reference circuits fail to sufficiently suppress temperature and power supply voltage dependencies in reference voltages, leading to fluctuations that are not adequately managed.
Innovation Solution
An electronic circuit design incorporating a bandgap circuit with first and second bipolar transistors coupled at a first node, a current mirror circuit with third and fourth transistors coupled at a second node, and a control circuit that adjusts current based on the output of the current mirror circuit to output a reference voltage with reduced temperature and power supply dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bandgap circuit with feedback is used, then a reference voltage with reduced power supply dependency is obtainable, but the suppression of temperature dependency and power supply dependency is not sufficient
Solution Approach 1:
The patent implements a feedback mechanism where the bandgap circuit output is fed back to the control transistor, and additionally incorporates a current mirror circuit that mirrors the reference current to control the bandgap circuit current. This dual feedback approach allows dynamic adjustment of the reference voltage to compensate for both temperature variations and power supply voltage changes, achieving superior suppression of these harmful factors compared to conventional single-feedback designs.
Solution Approach 2:
The patent utilizes the temperature-dependent characteristics of bipolar transistors, specifically the base-emitter voltage (Vbe) which has a negative temperature coefficient, and combines it with a positive temperature coefficient voltage generated through resistive dividers and current mirrors. By carefully selecting transistor emitter areas and resistor ratios, the circuit achieves temperature compensation where the negative and positive temperature coefficients cancel each other out, producing a stable reference voltage across temperature ranges.
2Reliability
If feedback from bandgap circuit to control transistor is implemented, then reference voltage power supply dependency is reduced, but temperature dependency suppression remains insufficient
Solution Approach 1:
The patent divides the temperature compensation function into separate components: the bandgap circuit handles the core reference voltage generation with power supply compensation, while the current mirror circuit specifically addresses temperature compensation by mirroring currents through transistors with matched temperature characteristics. This segmentation allows each component to optimize for its specific function, achieving both power supply and temperature stability simultaneously.
Data Source
AI summary
An electronic circuit is disclosed. The electronic circuit includes a bandgap circuit provided with first and second bipolar transistors that are coupled at a first node and a current mirror circuit provided with third and fourth transistors with respective control terminals coupled at a second node. The electronic circuit further includes a fifth transistor that is bipolar which is coupled to an output terminal of the third transistor where a base of the fifth transistor is coupled to a collector of the second transistor and a sixth transistor that is bipolar that is coupled to an output terminal of the fourth transistor with a base of the sixth transistor coupled to the first node. A control circuit controls a current provided to the bandgap circuit based on an output of the current mirror circuit. A reference voltage output terminal is provided between the control circuit and the bandgap circuit and outputs a reference voltage.