Abstract: A circuit and method protects an emergency head-retract capacitor that regulates initial charge current using a constant current source. The initial charge current is applied at power-up to the capacitor until a charging voltage having a desired threshold level is attained in the capacitor. The charging voltage is monitored through an analog-to-digital converter by an overall controller that, upon detecting the presence of the desired threshold level in the capacitor, deenergizes the constant current source. A voltage pump, which includes a voltage multiplier (doubler), is then activated to selectively apply regulated charging voltage to thereafter maintain the desired threshold level. The pump includes a voltage pump controller that is controlled by a voltage comparator having a reference voltage set to a desired threshold level. That voltage comparator is also in communication with the capacitor to measure its present input charging voltage.