Direct Gate-Sense Bipolar Supply for Accurate GaN Gate Voltage
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Solution Overview
Problem
Existing power supply output devices for bipolar gate drive applications, particularly those using GaN switches, face challenges in maintaining accurate positive and negative voltages due to voltage drops and fluctuations in the gate driver circuit, leading to increased costs and complexity with traditional solutions.
Innovation Solution
The implementation of a power supply output device that includes a Direct Gate Sense (DGS) line and a circuit with a voltage divider, voltage clamp, and adjusting circuit, allowing direct sensing of the gate voltage and adjustment to maintain the peak positive voltage at the required level, even with losses or fluctuations, using a low-cost unregulated DC-DC converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a regulated DC-DC converter is used to maintain accurate gate voltage, then voltage accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent implements a feedback mechanism where the gate driver circuit monitors the actual gate voltage and adjusts the power supply output accordingly. The gate driver receives feedback from the gate terminal and modifies the bipolar voltage output to compensate for voltage drops, maintaining accurate gate voltage without requiring a complex regulated DC-DC converter.
Solution Approach 2:
The gate driver circuit acts as an intermediary between the unregulated DC-DC converter and the power switch gate terminal. It takes the unregulated voltage from the converter and conditions it to provide the required accurate bipolar gate voltages, simplifying the overall power supply architecture while maintaining voltage accuracy.
2Measurement precision
If a regulated DC-DC converter is used to maintain accurate gate voltage, then voltage accuracy is improved, but device cost increases
Solution Approach 1:
The patent replaces an expensive regulated DC-DC converter with a combination of a low-cost unregulated converter and a relatively simple gate driver circuit that provides the necessary voltage regulation functionality. This substitution significantly reduces component cost while achieving the same voltage accuracy requirement.
Solution Approach 2:
The gate driver circuit serves as a cost-effective intermediary that performs the voltage regulation function previously requiring an expensive dedicated regulated converter, thereby reducing overall device cost while maintaining gate voltage accuracy.
3Device complexity
If traditional power supply output is used without direct gate sensing, then device complexity is reduced, but voltage accuracy deteriorates due to un compensated drops
Solution Approach 1:
The patent employs feedback by having the gate driver circuit monitor the actual gate voltage at the power switch terminal and use this information to adjust its output. This closed-loop approach compensates for voltage drops in real-time, maintaining accurate gate voltage with minimal additional complexity.
Solution Approach 2:
The gate driver circuit performs self-adjustment by monitoring its own output and the actual gate voltage, automatically compensating for voltage drops without requiring external intervention or complex external regulation circuits.
Data Source
AI summary
A power supply output device converts an input from a DC-DC converter into a bipolar voltage output of a gate driver circuit driving a power switch. The power output supply device includes an adjusting circuit to measure an output of the gate driver circuit at the gate of the power switch, and to adjust the bipolar voltage output in order to maintain the output of the gate driver circuit at a predetermined voltage. The power supply output device provides a cost-effective technique to regulate the peak positive voltage input into the gate of the power switch at a required voltage, regardless of any fluctuations or losses.