Power Switch Arrangement With Internal Gate Resistor Temperature Sensing
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Solution Overview
Problem
Current power switch technologies face challenges in accurately measuring junction temperature and switch current in real time due to the use of external temperature sensors, which are often inaccurate and delayed, and lack internal sensors, especially in silicon carbide technology.
Innovation Solution
The implementation of a power switch arrangement with dedicated sub-switches and sensor transistor cells that can measure junction temperature and switch current using internal gate resistors, allowing for real-time monitoring without additional sensors by structuring sub-transistors with a common drain and independent gate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external temperature sensors (NTC) are used to measure junction temperature, then temperature monitoring is enabled, but measurement accuracy deteriorates and response time increases due to thermal capacitance and propagation delay
Solution Approach 1:
The patent extracts the temperature sensing function from external NTC sensors and relocates it internally by utilizing the intrinsic gate resistor of the power switch device itself. This extraction eliminates the need for separate external sensing components and their associated thermal coupling issues, directly resolving the contradiction between measurement accuracy and response time.
Solution Approach 2:
The power switch device serves its own temperature sensing needs by using its internal gate resistor as the sensing element. This self-service approach eliminates thermal capacitance delays associated with external sensors and provides direct, real-time temperature feedback from the actual junction, simultaneously improving both accuracy and response time.
2Reliability
If external NTC sensors are placed on the transistor surface, then temperature monitoring is achieved, but measurement accuracy worsens due to poor thermal coupling and the sensor's low pass filter characteristic
Solution Approach 1:
The patent removes the external NTC sensor from the system and extracts the temperature sensing function directly from the power switch's internal structure. This eliminates the thermal coupling problems and low pass filter characteristics inherent in external sensors, providing accurate real-time temperature monitoring without compromise.
Solution Approach 2:
The gate driver circuit serves as an intermediary that enables access to the internal gate resistor for temperature sensing purposes. By controlling the gate and measuring the voltage across the gate resistor, the system can monitor junction temperature in real-time without introducing external sensing components that would degrade measurement precision.
3Measurement precision
If dedicated sensor transistor cells are extracted from the main switch area, then internal temperature and current measurement is enabled, but device complexity increases
Solution Approach 1:
The patent makes the power switch device multi-functional by enabling it to perform both power switching and temperature/current sensing functions through its existing internal structures. The gate resistor serves dual purposes as both a gate control element and a temperature sensor, while the drain current path serves as both power conduction and current sensing, thereby reducing overall device complexity despite enhanced measurement capabilities.
Solution Approach 2:
The power switch structure serves its own sensing needs by utilizing its inherent components (gate resistor, drain current path) for measurement purposes. This self-service approach eliminates the need for separate dedicated sensor structures, maintaining device simplicity while achieving precise internal parameter measurement.
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 and real-time measurement of junction temperature and switch current, enhancing the accuracy and reliability of power switch monitoring without the need for external sensors, suitable for advanced technologies like silicon carbide and gallium nitride.
Implementation Method 1
dedicated sub-switches, defined by an arrangement of transistor cells, can be utilized to determine junction temperature by measurement of internal gate resistor
Implementation Method 2
the voltage drop of the main switch caused by the drain current can be directed to a low volt measurement system during turn-on time of the main switch. During turn-off time, the sub-switches, defined by dedicated transistor cells, separate the low voltage measurement system from a relatively high power system voltage applied to the drain node
Data Source
AI summary
A power device can be structured with a power switch having multiple arrangements such that the power switch can operate as a power switch with the capability to measure properties of the power switch. An example power device can comprise a main arrangement of transistor cells and a sensor arrangement of sensor transistor cells. The main arrangement can be structured to operate as a power switch, with the transistor cells of the main arrangement having control nodes connected in parallel to receive a common control signal. The sensor arrangement of sensor transistor cells can be structured to measure one or more parameters of the main arrangement, with the sensor transistor cells having sensor control nodes connected in parallel to receive a common sensor control signal. The sensor transistor cells can have a common transistor terminal shared with a common transistor terminal of the transistor cells of the main arrangement.