Power Switch Evaluation Circuit With Single-Terminal Sensing
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Solution Overview
Problem
Existing power semiconductor devices face challenges in efficiently monitoring parameters such as voltage transient dV/dt, temperature, and overcurrent without increasing manufacturing cost, complexity, and degrading performance, particularly in silicon carbide (SiC) switches.
Innovation Solution
An evaluation circuit with an integrated sensor that uses a single sense and return electrical connection to monitor these parameters, incorporating a junction capacitor, pn-junction diode, and temperature-dependent resistive path to minimize complexity and cost while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate sensing connections and measurement circuits are used to monitor voltage transient dV/dt, temperature, and overcurrent, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The evaluation circuit is designed to perform multiple measurement functions (voltage transient dV/dt monitoring, temperature sensing, and overcurrent detection) through a single integrated circuit structure with shared sensing connections. The circuit selectively activates different measurement modes based on the parameter being evaluated, eliminating the need for separate dedicated sensing paths for each parameter and thereby reducing overall device complexity while maintaining comprehensive monitoring capability
Solution Approach 2:
The patent combines multiple sensing functions into a unified evaluation circuit that uses a common sense connection and return connection. The measurement circuits are merged to share infrastructure components, and the evaluation circuit integrates multiple parameter evaluation capabilities in one device, reducing the total number of connections and components required compared to separate dedicated circuits for each parameter
2Measurement precision
If multiple separate sensing connections are used to monitor different parameters, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The evaluation circuit provides multi-functional parameter monitoring through a single integrated design, allowing the same physical connections to serve multiple measurement purposes. This universality reduces the bill of materials and assembly steps required, directly lowering manufacturing cost while maintaining the ability to accurately measure multiple parameters including voltage transient dV/dt, temperature, and overcurrent
Solution Approach 2:
By merging the sensing connections and measurement circuits into a unified structure, the patent reduces the total component count and interconnection requirements. This consolidation simplifies the manufacturing process, reduces assembly time, and lowers production costs compared to implementing separate dedicated sensing paths for each monitored parameter
3Measurement precision
If additional sensing connections and measurement circuits are added, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The integrated evaluation circuit can rapidly switch between different measurement modes (voltage transient, temperature, overcurrent) using the same hardware infrastructure. This eliminates the need to physically access or activate separate dedicated circuits for each parameter, reducing the time required to evaluate multiple parameters and improving overall system productivity while maintaining accurate 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
The integrated sensor system effectively measures and evaluates voltage transient dV/dt, temperature, and overcurrent, reducing manufacturing costs and complexity while maintaining optimal control and response times.
Implementation Method 1
incorporating a junction capacitor
Implementation Method 2
pn-junction diode
Implementation Method 3
temperature-dependent resistive path
Data Source
AI summary
A method includes evaluating a first parameter, a second parameter, and third parameter of a power switch. A first evaluation mode includes receiving a first sense current at a common sensing terminal from the power switch; and measuring the first parameter during a switching event of the power switch based on the first sense current. A second evaluation mode includes outputting a second sense current from the common sensing terminal to the power switch; and measuring the second parameter, which is dependent on a current flow of the second sense current through the power switch, the current flow depending on an electrode voltage present at a drain or a collector of the power switch. A third evaluation mode includes generating a third sense current at the common sensing terminal; and measuring the third parameter, which is generated based on the third sense current and a temperature of the power switch.