An enabling circuit including a comparison circuit, a switching circuit, and
an
output decision circuit. The comparison circuit compares a first comparison signal
representative of a charge on a capacitor of a DC to DC converter with a second
comparison signal representative of a reference charge and provides a comparison
output signal in response to the comparison. In response to the comparison output
signal, the switching circuit provides a first switching signal in a first state
if the charge on the capacitor is less than said reference charge. Finally, the
output decision circuit accepts at least the first switching signal and provides
an enabling signal to enable the DC to DC converter to be controlled by a control
signal in response to the first switching signal in the first state.