Patent ID: 7821328

Claim:
A regulator, comprising: an output switch having a power input, a power output and a control input; a charge pump having a clock input and an output, the output being coupled to the output switch control input; an oscillator having a control input and a clock output, the clock output being coupled to the charge pump clock input; a voltage divider having an input and an output, the input being coupled to the output switch power output; an amplifier having a first input, a second input and an output, the first input being coupled to the output of the voltage divider, the second input being coupled to a reference voltage; a transistor having a drain coupled to the charge pump output, a source coupled to a current mirror input and a gate coupled to the output of the amplifier; a Zener diode having a cathode and an anode, the cathode being coupled to the charge pump output; a second transistor having a source coupled to the anode of the Zener diode, and a gate coupled to the output switch power output; a current mirror comprising a third transistor and a fourth transistor, the third transistor having a drain and a gate both coupled to a drain of the second transistor and having a source coupled to the ground, the fourth transistor having a gate coupled to the drain and gate of the third transistor and a source coupled to the ground; a current source coupled to the oscillator control input and to a drain of the fourth transistor; wherein the oscillator is adapted to operate at a lower frequency when a voltage at the charge pump output is at a breakdown voltage of the Zener diode and the current minor steals current from the current source away from the oscillator control input, and wherein the oscillator is adapted to operate at a higher frequency when the voltage at the charge pump output is less than the breakdown voltage of the Zener diode.