Push-Pull MOSFET Gate Drive With Temperature-Corrected Switching
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Solution Overview
Problem
Existing gate drive circuits for power semiconductor elements, such as those connecting N-channel and P-channel MOSFETs in a push-pull manner, suffer from temperature-dependent response delays and increased losses due to fixed gate voltage, especially during high-frequency switching at elevated temperatures.
Innovation Solution
Incorporating a temperature correction circuit with a transistor and thermistor circuit between the N-channel and P-channel MOSFETs, which lowers the gate voltage of the P-channel MOSFET as ambient temperature rises, thereby reducing delay differences in turn-on and turn-off times and preventing increased losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed gate voltage is applied to MOSFETs, then circuit simplicity is maintained, but temperature-dependent response delays and increased losses occur
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gate voltage of the P-channel MOSFET based on temperature. A thermistor detects temperature changes, and a transistor modifies the gate voltage accordingly - lowering it at high temperatures to compensate for threshold voltage shifts, thereby maintaining consistent turn-on and turn-off delays across temperature variations.
2Device complexity
If fixed gate voltage is used, then device structure remains simple, but simultaneous ON time increases causing higher losses
Solution Approach 1:
The patent reduces switching losses by changing the gate voltage parameter dynamically. At elevated temperatures, the thermistor-transistor circuit lowers the P-MOSFET gate voltage, preventing premature turn-on and reducing the simultaneous ON time of both MOSFETs during switching transitions, thereby minimizing conduction losses.
3Ease of operation
If gate voltage is not corrected for temperature, then circuit operation is straightforward, but turn-on and turn-off delay times vary with temperature
Solution Approach 1:
The patent maintains ease of operation while compensating for temperature effects through automatic parameter adjustment. The thermistor-transistor temperature correction circuit continuously modifies the P-MOSFET gate voltage in response to temperature changes, equalizing turn-on and turn-off delay times across the temperature range without requiring complex external control.
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 temperature correction circuit ensures consistent turn-on and turn-off times across temperature variations, reducing losses and maintaining efficient high-frequency switching performance by adjusting gate voltage based on temperature changes.
Implementation Method 1
The thermistor circuit includes a thermistor element connected between a base and an emitter of the transistor
Data Source
AI summary
In a gate drive circuit of which an N-channel MOSFET and a P-channel MOSFET are connected in a push-pull manner to amplify an input pulse signal and drive an output element, a temperature correction circuit is connected between gate terminals of the N-channel MOSFET and the P-channel MOSFET. The temperature correction circuit lowers each of gate voltages of the N-channel MOSFET and the P-channel MOSFET as ambient temperature rises.