Multi-Threshold Over-Temperature Protection Circuit for Semiconductor Packages
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Solution Overview
Problem
Existing semiconductor packages with over-temperature protection circuits rely on a single temperature threshold value, which is not sufficiently fast or accurate for granular temperature sensing, leading to incomplete protection of power switches in multi-phase power inverter circuits.
Innovation Solution
A semiconductor package with an integrated over-temperature protection circuit utilizing multiple temperature threshold values, where a temperature sensor is placed on the leadframe to provide accurate and fast temperature sensing, allowing for reduced current through power switches based on varying temperature ranges, thereby maintaining operability without complete disabling of switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single temperature threshold value is used in the over-temperature protection circuit, then the circuit structure is simple, but the temperature sensing accuracy and response speed are insufficient
Solution Approach 1:
The temperature protection range is divided into multiple segments with different threshold values (first threshold, second threshold, third threshold). Each threshold corresponds to a specific protection level, allowing granular temperature monitoring and staged protection responses instead of a single binary threshold.
Solution Approach 2:
The protection circuit uses multiple temperature threshold parameters (first, second, and third thresholds) instead of a single threshold parameter. This enables differentiated protection levels at different temperature ranges, improving measurement precision while maintaining circuit feasibility through parameter multiplication.
2Adaptability or versatility
If a single temperature threshold is used, then the protection circuit is simple, but the operational flexibility and current control granularity are limited
Solution Approach 1:
The current protection mechanism is segmented into multiple levels: first current reduction at first threshold, second current reduction at second threshold, and complete switching disablement at third threshold. This staged approach provides operational flexibility while avoiding complete system shutdown at moderate temperature elevations.
Solution Approach 2:
The protection circuit dynamically adjusts its response based on the sensed temperature relative to multiple thresholds. The current through power switches is modulated in stages rather than being statically disabled, allowing the system to adapt to varying thermal conditions and maintain operation within safe parameters.
3Measurement precision
If discrete temperature sensor and protection circuit are used separately, then the components are easy to manufacture, but the temperature sensing speed and accuracy are insufficient
Solution Approach 1:
The temperature sensor is integrated within the leadframe structure, and the over-temperature protection circuit is coupled to receive signals directly from this integrated sensor. This merging of sensor and protection circuit into a unified assembly reduces signal transmission delays, improves thermal coupling accuracy, and simplifies the overall system while maintaining manufacturability.
Data Source
AI summary
According to an exemplary implementation, a semiconductor package includes a multi-phase power inverter having power switches and situated on a leadframe of the semiconductor package. The semiconductor package further includes an over-temperature protection circuit configured to reduce current through the power switches based on multiple temperature threshold values of the power switches and a sensed temperature of the power switches. The over-temperature protection circuit can be configured to enter first and second modes based on the multiple temperature threshold values and the sensed temperature, where the second mode reduces current through the power switches to a greater extent than the first mode.