Power Circuit Junction Sensing via Shared Drive Input Line
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Solution Overview
Problem
Existing power semiconductor device circuits face challenges in monitoring junction temperature and current, especially in high-power multi-chip modules, due to the complexity and impracticality of implementing additional sense elements and connections for temperature and current sensing.
Innovation Solution
Incorporating temperature-sensitive current sources and sense circuitry that are thermally coupled to power switching devices and freewheel diodes, allowing for the monitoring of temperature and current without additional external terminals, and using drive circuitry to determine operational conditions based on sense signals received on the drive input line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sense elements and numerous connections are implemented for temperature and current sensing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines temperature sensing and current sensing functions into a single integrated sense circuit that shares common connections with the power semiconductor device. The sense circuit is thermally coupled to the device and electrically connected through shared terminals, eliminating the need for separate sense elements and numerous additional connections while maintaining accurate measurement of both temperature and current parameters
Solution Approach 2:
The sense circuit is designed to perform multiple functions simultaneously: it measures both temperature (through thermal coupling) and current (through electrical connection), and can provide monitoring for both the power semiconductor device and the freewheel diode. This multi-functional approach replaces what would traditionally require separate dedicated sense circuits for each parameter and each device
2Reliability
If additional sense elements and connections are added for monitoring, then reliability is improved through early failure detection, but ease of manufacture deteriorates
Solution Approach 1:
The sense circuit is designed to be integrated with the power semiconductor device in a single assembly step. The thermal coupling is established through direct physical contact during manufacturing, and electrical connections are made through shared terminals that are already part of the device structure, eliminating the need for separate assembly operations for temperature and current sensing elements
3Measurement precision
If numerous external terminals are used for sense connections, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sense circuit utilizes the existing control terminal and power terminals of the power semiconductor device for its connections. The control terminal serves both as the gate control input and as a connection point for the sense circuit, while the power terminals serve dual purposes for both power conduction and sense signal extraction, thereby eliminating the need for additional external terminals
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
This solution provides reliable, accurate, and cost-effective monitoring of power device circuits, enabling early detection of potential failures and improving the reliability and lifetime of power circuits by eliminating the need for extra connections and complex calibration.
Implementation Method 1
sense circuitry including at least one temperature sensitive current source coupled to at least one the conduction terminal, the sense circuitry to provide at least one sense signal from the temperature sensitive current source to the drive input line, the sense signal to indicate at least one temperature
Implementation Method 2
the temperature sensitive current source is thermally coupled to the power switching device, the temperature indicated by the sense signal is of the power switching device
Data Source
AI summary
A power circuit has a power switching device (PSD) to, when in an ON state, conduct current from its first to second terminal; a diode anti-parallel to the PSD that, when in a non-blocking state, conducts current from its anode to its cathode; a drive input line coupled to a device control terminal of the PSD to control its switching; and sense circuitry, having a temperature sensitive current source (TSCS) coupled to a conduction terminal, providing a sense signal from the TSCS to the drive input line to indicate temperature. The TSCS is thermally coupled to the PSD, the temperature indicated is of the PSD, and the conduction terminal is the first or second terminal of the PSD; and/or the TSCS is thermally coupled to the diode, the temperature indicated by the sense signal is of the diode, and the conduction terminal is the anode or cathode of the diode.