A clock circuit. The clock circuit includes a phase detector and an output unit. The phase detector is coupled to receive a reference clock signal and an output clock signal, and is configured to provide a phase signal indicative of a phase difference between the reference and output clock signals. The output unit is configured to provide the output clock signal, and is coupled to a first supply voltage node and a second supply voltage node. The output unit includes a biasing circuit and a voltage-controlled element. The biasing circuit is coupled to receive a control voltage based on the phase signal and is configured to generate a bias voltage based on the received control voltage. The voltage-controlled element is configured to adjust a parameter of the output clock signal based on the bias voltage. A supply-independent output clock is attained using this configuration.