Power MOSFET with overcurrent and over-temperature protection

摘要

A power integrated circuit is pin-compatible with a three-terminal power MOSFET and contains integrated circuits to turn off the device in the event of an overcurrent or an over-temperature condition. Control power voltage Vcc is applied through a first MOSFET connected between the gate pin and the gate electrode of the power device. A second control MOSFET is connected across the power device gate and source electrodes. The first control MOSFET is turned off and the second control MOSFET is turned on in response to a fault condition. The turn off of the first MOSFET limits the current sinked by the gate pin. A novel boot strap circuit is disclosed which permits the use of all N channel MOSFETs with an N channel power device, and a novel trimmable temperature shutdown circuit is provided. An integrated bipolar transistor is also integrated into the chip to prevent conduction of the P well/N epi diode formed in the device substrate.