GaN Reference Voltage Circuit With Feedback Temperature Compensation
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Solution Overview
Problem
Current GaN-based reference voltage generation circuits in power converter circuits are sensitive to temperature, loading, and power supply variations, leading to unstable reference voltage generation due to the lack of P-type transistors in GaN-based fabrication processes.
Innovation Solution
A GaN-based reference voltage generation circuit is designed with a feedback mechanism using impedance elements with positive and zero temperature coefficients, allowing the output voltage to track and stabilize against temperature and power supply changes, eliminating the need for external reference voltage circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional reference voltage generation circuit is used in GaN-based power converters, then the circuit can operate at high frequency with high efficiency, but the reference voltage becomes unstable due to sensitivity to temperature and power supply variations
Solution Approach 1:
The patent implements a feedback mechanism using an operational amplifier that continuously monitors the reference voltage node and adjusts the gate voltage of the GaN transistor to compensate for temperature and power supply variations, thereby stabilizing the reference voltage output
Solution Approach 2:
The patent exploits the temperature-dependent characteristics of GaN transistor threshold voltage and drain-source on-resistance, combined with the positive temperature coefficient of the sense resistor, to create a compensation effect that stabilizes the reference voltage across temperature variations
2Reliability
If external silicon-based reference voltage circuits are used, then stable reference voltage can be achieved, but the device size and complexity increase
Solution Approach 1:
The patent merges the reference voltage generation function directly into the GaN-based power converter circuit by integrating the operational amplifier, GaN transistor, and sense resistor on the same substrate, eliminating the need for separate external silicon-based reference voltage circuits
Solution Approach 2:
The GaN transistor serves multiple functions: as the main power switching device for high-frequency operation and as part of the reference voltage generation circuit, enabling the same component to fulfill both power conversion and voltage reference functions
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
The circuit generates a constant reference voltage independent of temperature and power supply variations, ensuring stable operation of GaN-based ICs and reducing the reliance on external silicon-based circuitry.
Implementation Method 1
the first impedance element having a positive temperature coefficient
Implementation Method 2
a feedback circuit coupled between the first source terminal and the second source terminal
Data Source
AI summary
Gallium nitride reference voltage generation circuits. In one aspect, the circuit includes a first gallium nitride (GaN)-based transistor having a first gate terminal, a first source terminal and a first drain terminal, a second GaN-based transistor having a second gate terminal, a second source terminal and a second drain terminal, the second gate terminal coupled to the first drain terminal, an input terminal coupled to the first gate terminal and arranged to receive a first voltage, an output terminal coupled to the second source terminal, a power supply terminal coupled to the first drain terminal and the second drain terminal, and a feedback circuit coupled between the first source terminal and the second source terminal, where the first source terminal is coupled to a ground through a first impedance element, the first impedance element having a positive temperature coefficient.