Patent ID: 6473280
Filing Date: 2002-10-29
Classification: H02M

Abstract:
A switching voltage regulator failure detection circuit, said failure detection circuit comprising:a clock generator which outputs a periodic clock signal, a driver circuit which, during each cycle of said clock signal, drives an output transistor of a switching regulator on and off to conduct current to an output inductor to provide a regulated output voltage, a decision circuit connected to sense a parameter which, when said switching regulator is operating normally, transitions above and below a predetermined threshold during each cycle of said clock signal as said output transistor is driven on and off, and to produce a decision circuit output which toggles from a first state to a second state and back to said first state for every cycle of said clock signal as long as said sensed parameter transitions above and below said predetermined threshold during said clock cycle, and a counter having a clock input connected to receive said clock signal, a reset input connected to receive said decision circuit output, and a counter output, said counter arranged to count the clock cycles received at said clock input and to toggle said counter output when said counter has counted from an initial value to a predetermined count value, said counter reset to said initial value when said decision circuit output toggles from said first state to said second state, said counter toggling its output when said decision circuit output fails to toggle for a consecutive number of clock cycles equal to said predetermined count minus said initial value, said counter output thereby indicating when said sensed parameter failed to transition above and below said predetermined threshold during a clock cycle for a consecutive number of clock cycles equal to said predetermined count minus said initial value.