Adaptive charge pump voltage supply frequency switch

A dual-oscillator circuit including:

• a first oscillator having an enable input and an output configured to output a first frequency signal;
• a second oscillator having an enable input and an output configured to output a second frequency signal higher in frequency than the first frequency signal;
• a multiplexor having a first input coupled to the output of the first oscillator, a second input coupled to the output of the second oscillator, a selector input, and an output;
• and
• a counter, including:
• a clock input coupled to the output of the second oscillator;
• a count-enable input;
• a first output coupled to the enable input of the first oscillator;
• a second output coupled to the enable input of the second oscillator and to the selector input of the multiplexor;
• wherein the counter is configured to assert a first enable signal on the first output and de-assert a second enable signal on the second output if not counting to couple the first frequency signal to the output of the multiplexor, and to assert the second enable signal on the second output if counting to couple the second frequency signal to the output of the multiplexor.

An electronic switch circuit including:

• a first oscillator having an enable input and an output configured to output a first frequency signal;
• a second oscillator having an enable input and an output configured to output a second frequency signal higher in frequency than the first frequency signal;
• a multiplexor having a first input coupled to the output of the first oscillator, a second input coupled to the output of the second oscillator, a selector input, and an output;
• a counter, including:
• a clock input coupled to the output of the second oscillator;
• a count-enable input;
• a first output coupled to the enable input of the first oscillator;
• a second output coupled to the enable input of the second oscillator and to the selector input of the multiplexor;
• a charge pump coupled to the multiplexor output, the charge pump having an output node, and configured to output an electrical charge at the output node of the charge pump, wherein the electrical charge is based on the signal coupled to the output of the multiplexor, wherein the electrical charge is greater if the output of the multiplexor is coupled to the second frequency signal than if the output of the multiplexor is coupled to the first frequency signal,
• a switch having at least one through-path comprising a pair of NFETs having conduction channels coupled in series, each NFET including a gate coupled to the output of the charge pump, each through-path coupling a corresponding input terminal to an output terminal;
• wherein the counter is configured to assert a first enable signal on the first output and de-assert a second enable signal on the second output if not counting to couple the first frequency signal to the output of the multiplexor, and to assert a control the second enable signal on the second output if counting to couple the second frequency signal to the output of the multiplexor;
• and
• wherein the counter is configured to commence counting in response to a control signal applied to the count-enable input, the control signal indicating selection of a corresponding through-path and indicating application of a control voltage to the gates of the pair of NFETs of the corresponding through-path.