Charge pumps and methods of operating charge pumps

A method for operating a charge pump, comprising:

• monitoring a level of a first supply voltage of a charge pump;
• and
• turning off an oscillator of the charge pump responsive to the level of the first supply voltage dropping below a certain level, wherein turning off the oscillator comprises setting an inverter of a plurality of inverters in a ring oscillator loop of the oscillator to a steady state output;
• wherein the oscillator is configured to receive a second supply voltage higher than the first supply voltage during normal operation of the charge pump;
• and
• wherein a voltage level of the first supply voltage is independent of a voltage level of the second supply voltage.

A charge pump, comprising:

• a delay element;
• a plurality of inverters;
• and
• a flip flop, the delay element, the plurality of inverters, and the flip flop coupled in series, and an output of a one of the plurality of inverters coupled in a feedback loop to the delay element;
• wherein the charge pump is configured to monitor a level of a first supply voltage, and to turn off an oscillator of the charge pump responsive to the level of the first supply voltage dropping below a certain level;
• wherein the delay element, the plurality of inverters, and a feedback line coupled from the output of the one of the plurality of inverters to an input of the delay element comprise a ring oscillator loop, and wherein the oscillator includes the ring oscillator loop;
• wherein the oscillator is configured to receive a second supply voltage higher than the first supply voltage during normal operation of the charge pump;
• and
• wherein a voltage level of the first supply voltage is independent of a voltage level of the second supply voltage.