Power Transistor Drive Circuit Temperature Compensation
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Solution Overview
Problem
Existing power transistor drive circuits face challenges in reducing noise and loss across varying temperatures, with known circuits either failing to suppress noise and loss at high temperatures or increasing noise and loss at low temperatures due to temperature-dependent operating resistances of FETs and IGBTs.
Innovation Solution
A power transistor drive circuit incorporating a constant current generation unit, temperature detection element, and control circuit that adjusts current flow and gate voltage based on temperature, using a diode for temperature detection and resistors with negative temperature characteristics to optimize turn-on drive capability and minimize noise and loss across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a constant current drive circuit is used to suppress noise and loss at high temperatures, then turn-on drive capability is improved at high temperatures, but noise and loss increases at low temperatures
Solution Approach 1:
The drive circuit dynamically adjusts the gate voltage based on temperature conditions. At high temperatures, it applies a higher gate voltage to ensure sufficient turn-on drive capability, while at low temperatures, it reduces the gate voltage to prevent excessive current and noise. This dynamic adjustment resolves the contradiction between optimizing performance at high temperatures and preventing noise at low temperatures.
Solution Approach 2:
The circuit changes the electrical parameters (gate voltage level) according to temperature conditions. By detecting temperature and相应地 adjusting the drive voltage parameter, the circuit achieves optimal performance across different temperature ranges, suppressing both loss at high temperatures and noise at low temperatures.
2Speed
If gate voltage is increased to improve turn-on drive capability, then switching speed is improved, but noise and loss increases
Solution Approach 1:
The circuit optimizes the gate voltage parameter based on temperature conditions. At high temperatures where switching speed may degrade, it increases gate voltage to maintain fast switching. At low temperatures where switching is already fast, it reduces gate voltage to minimize noise and energy loss. This parameter optimization resolves the contradiction between switching speed and noise/loss.
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 solution effectively reduces temperature dependence of noise and loss, optimizing turn-on drive capability and maintaining precise current characteristics from -20°C to 125°C, ensuring optimal performance and reduced noise and loss at any temperature.
Implementation Method 1
a temperature detection element, provided integrally in a semiconductor substrate in which is provided the power transistor, that generates a voltage in accordance with temperature, based on the constant current output from the constant current source
Data Source
AI summary
Aspects of the invention include a constant current source that generates a constant current, apart from a constant current circuit, and a temperature detection zener diode (a temperature detection element). The input side of the constant current source can be connected to a power source. The output side of the constant current source can be connected to the anode of the temperature detection diode. The anode of the temperature detection zener diode can also be connected to one end of a resistor provided in the constant current circuit. Further, the cathode of the temperature detection zener diode can be connected to a GND. Further, the temperature detection zener diode can be incorporated in the same semiconductor substrate as a semiconductor substrate into which an IGBT is built.