Power Switch Temperature Detection via Paired Current Voltage Measurements
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Solution Overview
Problem
Conventional techniques for detecting temperature in power switch circuits are imprecise and delayed, often using external components that measure housing temperature rather than the switch itself, leading to delayed reactions to temperature-related issues.
Innovation Solution
The implementation of a power switch circuit with a temperature-dependent circuit element, such as a resistor, electrically coupled to the power switch, and a driver circuit that performs paired measurements of current and voltage to accurately determine the temperature, allowing for precise control of the power switch through local or system-level techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external temperature sensors (NTC thermistors or semiconductor-based sensors) are mounted close to the power switch, then temperature measurement is enabled, but measurement precision deteriorates because these sensors measure housing temperature or nearby temperature with intrinsic delay rather than the switch temperature itself
Solution Approach 1:
The patent extracts the temperature-dependent circuit element (Rds(on) of the power switch itself) from the external environment and uses it as the sensing element. By measuring the on-resistance of the power switch directly through paired voltage and current measurements, the system obtains direct temperature information from the switch rather than inferring it from external sensor readings, thereby eliminating measurement delay and improving precision.
Solution Approach 2:
The patent introduces paired voltage and current measurements as intermediaries to indirectly measure the temperature-dependent on-resistance of the power switch. By measuring voltage across and current through the switch during its on-state, the system calculates Rds(on) which serves as a mediator to determine switch temperature without requiring direct thermal contact sensors.
2Reliability
If external temperature sensors are used to detect power switch temperature, then temperature detection is achieved, but reliability deteriorates due to delayed reaction to temperature-related problems
Solution Approach 1:
The patent performs preliminary temperature monitoring by continuously measuring the on-resistance of the power switch during normal operation. By detecting temperature changes before they lead to failure conditions, the system can take preventive actions such as adjusting duty cycle, modifying switching frequency, or triggering cooling mechanisms, thereby improving reliability through early intervention.
Solution Approach 2:
The patent implements a feedback mechanism where the measured on-resistance (and inferred temperature) is fed back to the control system, which then adjusts operating parameters accordingly. This closed-loop control enables real-time adaptation to temperature conditions, improving system reliability by preventing operation under excessive temperature conditions.
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 approach enables precise temperature detection and control of power switches, reducing the risk of temperature-related problems by providing real-time and accurate temperature measurements, thereby enhancing the reliability and efficiency of power delivery.
Implementation Method 1
The temperature-dependent circuit element may comprise a temperature-dependent resistor
Data Source
AI summary
This disclosure is directed to circuits and techniques for detecting or responding to temperature of a power switch based on paired measurements of current and voltage. A driver circuit for a power switch may be configured to perform a current measurement and a voltage measurement associated with a temperature-dependent circuit element and control the power switch based at least in part on the current measurement and the voltage measurement. In some examples, the current and voltage measurements may be used to determine the temperature of the power switch.