Power Conversion MOSFET Layout for Accurate Chip Temperature Sensing
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Solution Overview
Problem
Existing power conversion devices face challenges in accurately measuring chip temperature without increasing the chip size or cost, particularly when using a freewheeling diode method, which requires a special power device with a freewheeling diode on the same chip and is limited in observation time for MOSFETs.
Innovation Solution
A power conversion device configuration that includes an insulated gate type first transistor, an insulated gate type second transistor connected in parallel, and a diode formed on the semiconductor substrate, allowing for current and temperature measurement without additional bonding pads, using a current measurement circuit and temperature measurement circuit to detect the chip temperature by causing a forward current to flow through the diode when the first transistor is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensing diode is formed on the semiconductor substrate to measure chip temperature, then temperature measurement capability is improved, but the chip area increases and product cost increases due to additional bonding pads and manufacturing processes
Solution Approach 1:
The invention uses the freewheeling diode, which already exists in the power device for its primary function of providing a current path during freewheeling mode, to also serve as a temperature sensor. By measuring the forward voltage drop across the diode during freewheeling operation, the chip temperature can be determined without adding any dedicated temperature sensing components, bonding pads, or manufacturing processes.
Solution Approach 2:
The freewheeling diode is made multi-functional by utilizing it for both its original purpose (providing current path during freewheeling) and as a temperature sensor. The diode's forward voltage characteristic, which varies with temperature, is exploited to measure chip temperature during the freewheeling period, eliminating the need for separate temperature measurement infrastructure.
2Measurement precision
If a temperature sensing diode is formed on the semiconductor substrate to measure chip temperature, then temperature measurement capability is improved, but manufacturing process complexity increases and manufacturing cost increases
Solution Approach 1:
The invention uses the freewheeling diode, which already exists in the power device for its primary function of providing a current path during freewheeling mode, to also serve as a temperature sensor. By measuring the forward voltage drop across the diode during freewheeling operation, the chip temperature can be determined without adding any dedicated temperature sensing components, bonding pads, or manufacturing processes.
Solution Approach 2:
The freewheeling diode is made multi-functional by utilizing it for both its original purpose (providing current path during freewheeling) and as a temperature sensor. The diode's forward voltage characteristic, which varies with temperature, is exploited to measure chip temperature during the freewheeling period, eliminating the need for separate temperature measurement infrastructure.
3Area of stationary object
If a freewheeling diode method is used to measure chip temperature, then chip size increase is suppressed, but the method requires a special power device with freewheeling diode on the same chip and observation time is limited
Solution Approach 1:
The control device measures the forward voltage drop across the freewheeling diode during freewheeling mode and uses this feedback information to determine the chip temperature. This temperature information is then fed back to adjust the gate signal timing, extending the effective observation period and enabling accurate temperature measurement without requiring special power device configurations.
Solution Approach 2:
The invention dynamically adjusts the gate signal timing based on the measured chip temperature to extend the observation period. By making the control timing adaptive to the actual temperature conditions, the system can accurately measure temperature over a longer effective period even during PWM operation, not just during freewheeling mode.
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
Enables accurate and cost-effective chip temperature observation without increasing the chip size or number of bonding pads, allowing for high-accuracy temperature measurement while maintaining a compact design and reducing manufacturing costs.
Implementation Method 1
causing a forward current to flow through the diode when the first transistor is off
Data Source
AI summary
Provided is a power conversion device capable of observing a chip temperature with high accuracy without increasing a cost of the power conversion device mounted with a current sense element for observing a main current of a power device. A main control MOSFET 11, a current MOSFET 12, and a diode 13 connected to a source electrode 8 of the main control MOSFET 11 and a source electrode 9 of the current MOSFET 12 are mounted in a chip of a power device, a temperature measurement circuit 3 is connected to the source electrode 9 of the current MOSFET 12, and when the main control MOSFET 11 is in an off state, a forward current (If) is caused to flow through the diode 13, and an anode potential is observed to measure the chip temperature.