Semiconductor Switching Element Overheat Protection
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Solution Overview
Problem
Existing semiconductor devices face challenges in accurately monitoring the temperature of switching elements, particularly when the temperature is highest, which hinders effective overheat protection operations.
Innovation Solution
A semiconductor device configuration that includes a switching element chip with a first sensing element for detecting operating current and a second sensing element outside the chip to detect output voltage, allowing the control circuit to accurately monitor temperature and interrupt the switching element when overheated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If temperature is measured only immediately after switching element is turned on, then measurement is simple, but temperature monitoring accuracy deteriorates because the highest temperature occurs after predetermined time elapses
Solution Approach 1:
The control circuit performs periodic temperature measurements at predetermined time intervals after the switching element is turned on. This allows the system to capture the temperature at the peak point (when it becomes highest) rather than only at the initial moment, thereby improving measurement accuracy while maintaining operational simplicity through automated periodic sampling
Solution Approach 2:
The control circuit continuously monitors temperature measurements taken at different time points and uses this feedback information to determine when the temperature reaches its highest point. Based on this feedback, the system can accurately identify the peak temperature and trigger appropriate protection operations, resolving the contradiction between simple measurement and accurate monitoring
2Reliability
If separate temperature detecting device is attached to semiconductor chip, then temperature measurement is possible, but measurement delay occurs making it difficult to accurately measure temperature
Solution Approach 1:
The patent merges the temperature detection function with the existing switching element structure by utilizing the parasitic diode that already exists within the switching element. This integration eliminates the need for separate temperature detecting devices and their associated mounting delays, allowing direct and immediate temperature measurement of the switching element without time loss
Solution Approach 2:
The switching element's own parasitic diode is utilized for temperature detection purposes. The diode's forward voltage characteristic, which varies with temperature, serves as the temperature sensing mechanism. This self-service approach allows the switching element to monitor its own temperature internally, eliminating external detection devices and associated measurement delays
3Device complexity
If parasitic diode reverse recovery current is measured for temperature detection, then no separate temperature detection structure is needed, but temperature can only be measured immediately after switching which is not when temperature is highest
Solution Approach 1:
The control circuit performs periodic measurements of the parasitic diode's forward voltage at multiple time points after the switching element is turned on. By sampling at predetermined time intervals, the system can identify when the temperature reaches its peak and capture accurate temperature data at that critical moment, maintaining structural simplicity while improving timing accuracy
Solution Approach 2:
The measurement timing is made dynamic rather than fixed. The control circuit adjusts the measurement timing based on the operational state of the switching element, performing measurements at multiple time points including immediately after turn-on and at subsequent intervals. This dynamic approach ensures temperature is captured at the highest point while maintaining the simplicity of using the existing parasitic diode structure
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 precise temperature monitoring and appropriate overheat protection by calculating the operating current and temperature using voltage measurements from both sensing elements, ensuring timely intervention during high-temperature conditions.
Implementation Method 1
a first sensing element, which is provided in the switching element chip and is configured to detect first output voltage based on an operating current of the switching element
Implementation Method 2
a second sensing element, which is provided outside the switching element chip and is configured to detect second output voltage based on the operating current of the switching element
Implementation Method 3
a control circuit, which detects the operating current based on the second output voltage and calculates temperature of the switching element based on the first output voltage and the operating current
Data Source
AI summary
A semiconductor device includes a switching element chip, in which a switching element is formed; a first sensing element, which is provided in the switching element chip and is configured to detect first output voltage based on an operating current of the switching element; a second sensing element, which is provided outside the switching element chip and is configured to detect second output voltage based on the operating current of the switching element; and a control circuit, which detects the operating current based on the second output voltage and interrupts the switching element, based on the first output voltage of the first sensing element and the detected operating current, when the switching element is overheated.