A field effect transistor (FET) driver circuit includes an error amplifier for
providing a FET control signal and a current limiting amplifier for preventing
excessive current flow through the FET. The current limiting amplifier generates
an overcurrent signal when an excessive current is detected. In response to the
overcurrent signal, a voltage control circuit adjusts the voltage at the output
of the error amplifier to turn off the FET. Meanwhile, a pulldown circuit at an
input of the error amplifier adjusts the voltage provided to that input to cause
the error amplifier to provide an output voltage that also tends to turn off the
FET. If a buffer is present at that input to the error amplifier, a second pulldown
circuit is placed at the input to the buffer to maintain a stable unity gain across
the buffer.