Patent ID: 9634480
Date: 2017-04-25
CPC Classifications: H01C,H02H,H03K

Claim:
1. A circuit for protecting a semiconductor element in a system for supplying power from an input node to an output node, the semiconductor element including a MOSFET in a case, the circuit comprising: an analog multiplier responsive to a voltage across the semiconductor element and a current flowing through the semiconductor element to produce an output voltage representing a product of values representing the voltage across the semiconductor element and the current in the semiconductor element, a transconductance amplifier coupled to an output of the analog multiplier for receiving the output voltage of the analog multiplier to produce an output current, an analog RC circuit coupled to the output of the transconductance amplifier and configurable to include a selected number of resistive elements having selected resistance values and a selected number of capacitive elements having selected capacitance values, the RC circuit being configurable to provide an RC thermal model that reproduces a desired thermal behavior of the semiconductor element, the RC circuit being responsive to the output current of the transconductance amplifier to produce an output voltage, a comparator for comparing the output voltage of the RC circuit with a reference voltage to produce a control signal supplied to the semiconductor element, and a sensor that senses the temperature of the MOSFET case, wherein the circuit has a configuration that