IGBT Gate Drive Circuit with Feedback Current Regulation
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Solution Overview
Problem
Existing insulated gate semiconductor drive devices face challenges in uniformly parallel driving multiple IGBTs connected in parallel with constant current, leading to potential thermal breakdown due to current concentration and requiring complex configurations for current balance.
Innovation Solution
The device includes a constant current circuit, discharge circuit, switch circuit, current detection circuit, and current regulation circuit to regulate the constant current supplied to each IGBT, ensuring balanced current distribution and preventing thermal breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If constant current is supplied to gates of multiple IGBTs connected in parallel, then turn-on loss and noise are reduced, but current concentration occurs leading to thermal breakdown risk
Solution Approach 1:
The patent implements a feedback mechanism where the actual gate current is detected and fed back to the control circuit. The control circuit adjusts the gate drive current based on the detected current to ensure uniform current distribution among parallel IGBTs, preventing current concentration and thermal breakdown while maintaining the benefits of constant current drive.
2Power
If multiple IGBTs are driven in parallel with constant current, then power control capability is improved, but uniform current distribution becomes difficult to achieve
Solution Approach 1:
The patent uses current detection circuits to monitor the actual current flowing through each IGBT and feeds this information back to the control circuit. The control circuit dynamically adjusts the gate drive signals to compensate for variations in IGBT characteristics, ensuring uniform current distribution while maintaining high power control capability.
3Device complexity
If gate threshold voltage variations are not compensated, then device complexity is reduced, but turn-on timing uniformity deteriorates
Solution Approach 1:
The patent implements a feedback control system that detects the actual gate current and adjusts the drive signal in real-time. This feedback mechanism automatically compensates for gate threshold voltage variations without requiring complex pre-characterization or individual adjustment circuits, achieving uniform turn-on timing with moderate device complexity.
Data Source
AI summary
A drive circuit includes a constant current circuit which supplies a constant current to the gate of an IGBT and on-operates the IGBT; a discharge circuit which grounds the gate of the IGBT and off-operates the IGBT; and a switch circuit which operates one of the constant current circuit or discharge circuit in accordance with a control signal and turns on or off the IGBT. In particular, the drive circuit includes a current detection circuit which detects a current flowing through the IGBT when the IGBT is turned on; and a current regulation circuit which feeds the current detected by the current detection circuit back to the constant current circuit and controls an output current of the constant current circuit in accordance with the turn-on characteristics of the IGBT.