Methods, systems, and circuits for providing compensation for voltage variation are disclosed. A system includes: a voltage comparator configured to assert a control signal in response to detecting that one or more of power supply voltages droops below a threshold amount; a phase locked loop (PLL) configured to divide an output frequency for the PLL 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.