Integrated circuit and method of soft thermal shut down for power devices

A thermal control circuit for an integrated power transistor comprises a current generator, controlled by a turn on signal, a sensing resistance in series to the power transistor, a current limiter acting when the voltage drop on the sensing resistance overcomes a certain value, a current amplifier coupled to the output node of the controlled current generator, outputting a drive current that is injected on a control node of the power transistor, and a soft thermal shut down circuit whose conduction state is enhanced as the temperature increases for reducing the drive current. [0002] The circuit controls the voltage on the power transistor in a more effective manner than known devices because the current amplifier has a variable gain controlled by the state of conduction of the soft thermal shut down circuit. [0003] The improvement substantially consists in reducing progressively the gain of the current amplifier as the temperature of the integrated circuit increases, until a thermal equilibrium is reached.