Semiconductor Gate Drive Circuit for Miller-Period Overheat Detection
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Solution Overview
Problem
Existing methods for detecting chip temperature in voltage-controlled semiconductor elements, such as using thermistors or temperature detection diodes, face challenges like inaccurate detection of Miller effect periods and increased drive device size, and are inefficient in monitoring abrupt temperature changes.
Innovation Solution
A drive device with a delay circuit, one-shot circuit, comparator, and AND circuit that detects the Miller effect period and outputs an overheat signal based on the gate voltage's transition during this period, allowing for accurate chip temperature monitoring without additional electrodes or enlarged chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature detection diode is integrally formed on the chip to directly measure chip temperature, then measurement precision is improved, but the active area of the semiconductor chip is reduced
Solution Approach 1:
The patent uses the gate voltage during Miller effect period as an intermediary parameter to indirectly measure chip temperature. Instead of directly measuring temperature with a detection diode on the chip, the system measures the gate voltage which has temperature-dependent characteristics during the Miller effect period, and converts this voltage measurement into temperature information. This intermediary approach avoids occupying chip area while maintaining temperature measurement capability.
Solution Approach 2:
The patent replaces the physical temperature detection diode structure with an electrical measurement method. Instead of using a dedicated temperature sensing component that occupies physical space on the chip, the system substitutes this with measurement of electrical parameters (gate voltage) that exhibit temperature-dependent behavior, thereby eliminating the need for additional physical detection structures on the chip.
2Device complexity
If a thermistor is provided inside the semiconductor device to detect temperature, then device complexity is reduced, but measurement precision deteriorates due to inability to follow abrupt temperature changes
Solution Approach 1:
The patent utilizes the periodic switching operation of the semiconductor element to obtain temperature information. By measuring the gate voltage during each switching cycle's Miller effect period, the system can continuously track temperature changes including abrupt variations. This periodic measurement approach enables real-time temperature monitoring without requiring continuous physical contact with the chip, overcoming the thermistor's inability to follow rapid temperature changes.
3Measurement precision
If additional electrodes are formed on the chip for temperature detection, then measurement precision is improved, but the active area of the chip is reduced
Solution Approach 1:
The patent makes the existing gate electrode serve multiple functions: it is used both for normal gate control of the semiconductor element and for temperature detection during the Miller effect period. By utilizing the gate voltage that already exists during switching operations, the system eliminates the need for separate temperature detection electrodes, thereby maintaining full chip active area while achieving temperature measurement capability.
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 real-time, accurate chip temperature monitoring with a compact circuit configuration, effectively preventing overheating in voltage-controlled semiconductor elements.
Implementation Method 1
a delay circuit connected to the drive circuit, the delay circuit being configured to delay a drive signal output from the drive circuit by a predetermined period of time until a gate voltage of the voltage-controlled semiconductor element enters a Miller effect period, the Miller effect period being a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the voltage-controlled semiconductor element
Data Source
AI summary
A drive device for driving a voltage-controlled semiconductor element. The drive device includes: a drive circuit connected to the gate of the semiconductor element via a gate resistor; a delay circuit connected to the drive circuit, for delaying a drive signal output from the drive circuit until a gate voltage of the semiconductor element enters a Miller effect period, which is a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the semiconductor element; a one-shot circuit connected to the delay circuit, for outputting a pulse signal with a pulse width shorter than the Miller effect period; a comparator that compares the gate voltage with a reference voltage; and an AND circuit that outputs an overheat detection signal in response to the gate voltage exceeding the reference voltage.