Temperature Detection Diode and Current Amplifier for Power Transistor Protection
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Solution Overview
Problem
Existing temperature detection circuits for power transistors suffer from low detection accuracy and speed, which can lead to potential breakdowns due to inadequate overheating detection, particularly in high-current applications.
Innovation Solution
A semiconductor apparatus with a temperature detection diode and current amplifier that amplifies the backward leakage current, converting it into a voltage for high-speed and accurate temperature detection, including a gating circuit for control signal gating and a driver circuit for power transistor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the forward bias voltage of a diode is used for temperature detection, then the temperature detection function is achieved, but the detection accuracy is low due to small voltage change rate with temperature
Solution Approach 1:
The patent changes the detection parameter from forward bias voltage to backward leakage current. The backward leakage current has a much higher rate of change with temperature compared to forward bias voltage, enabling both high detection accuracy and high detection speed. This parameter transformation resolves the contradiction between measurement precision and productivity.
2Productivity
If the backward leakage current is directly used for temperature detection, then the detection speed is improved, but the detection signal is too weak for accurate measurement
Solution Approach 1:
The patent introduces a current amplifier as an intermediary device between the temperature detection diode and the detection circuit. The current amplifier amplifies the weak backward leakage current signal to a level suitable for accurate measurement and processing, while preserving the high detection speed characteristic of backward leakage current. This resolves the contradiction between detection speed and detection accuracy.
3Reliability
If a temperature detection circuit is added to protect the power transistor, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The temperature detection diode serves multiple functions: it detects temperature through its backward leakage current characteristics, and it can be integrated with the power transistor structure. The detection circuit processes the current signal and controls the power transistor switching. This multi-functional design achieves reliable overheating protection while minimizing additional circuit complexity.
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
Enables fast and accurate temperature detection of power transistors, improving overheating protection by amplifying the backward leakage current with a high rate of change, thus preventing thermal breakdown.
Implementation Method 1
a current amplifier that outputs a detection current generated by amplifying a backward leakage current flowing from the cathode to the anode of the temperature detection diode
Data Source
AI summary
Provided is a semiconductor apparatus which includes a power transistor that is placed between an input terminal and an output terminal, a temperature detection diode that has a cathode connected to the input terminal and an anode connected to the output terminal, a current amplifier that outputs a detection current generated by amplifying a backward leakage current flowing from the cathode to the anode of the temperature detection diode, a first conversion resistor that outputs an overheat detection signal generated by converting the detection current into a voltage, a gating circuit that performs gating of a control signal according to the overheat detection signal, and a driver circuit that outputs a drive signal to a control terminal of the power transistor based on an output signal of the gating circuit.