Patent ID: 9634676
Date: 2017-04-25
CPC Classifications: H03B,H03L

Claim:
1. A system, comprising: a voltage comparator configured to receive a plurality of power supply voltages and to assert a control signal in response to detecting that one or more of the power supply voltages droops by a threshold amount; a phase locked loop (PLL) configured to enter an open-loop mode of operation in response to the control signal, the PLL including a frequency divider configured to divide an output frequency for the PLL and a multiplexor configured to select an output of the frequency divider in response to the assertion of the control signal; a plurality of voltage sensors corresponding to the plurality of power supply voltages, the voltage sensors configured to output respective digital signals indicative of a voltage level of its corresponding power supply voltage; and a control circuit configured to control an oscillator frequency in the PLL during the open-loop mode responsive to the respective digital signals.