Patent ID: 7583062
Filing Date: 2009-09-01
Classification: H02H

Abstract:
1. A method for protecting voltage regulator driver circuitry during a short circuit condition of an alternator field coil, the method comprising: passively detecting a drop in field coil voltage during an on-portion of a duty cycle of the field coil voltage, wherein the passive detection of the drop in field coil voltage signifies an interrupt event; and responsive to the interrupt event, changing a logical state of a driver enable control signal so as to deactivate driver circuitry associated with a switching device used to pass field current through the field coil, wherein the driver circuitry, when deactivated, prevents the switching device from passing current regardless of the state of a pulse width modulation (PWM) control signal applied to the driver circuitry, wherein the PWM control signal and the driver enable control signal are generated by a microcontroller included within a voltage regulator, and wherein the passive detection of a drop in field coil voltage is implemented through an input pin of the microcontroller; the voltage regulator further comprising a first resistor coupled between a positive side of the field coil and the input pin of the microcontroller, and a diode configured between a first output pin of the microcontroller corresponding to the PWM control signal and the input pin of the microcontroller.