An apparatus, comprising: a charge-pump; a sampler that samples an optical signal, including: a black sampler; a video sampler; and an analog to digital converter. The first aspect further provides a single clock that is coupled to and provides clocking signals to: a) the charge-pump logic that is coupled to the charge-pump; and b) the sampler logic that is coupled to the sampler that samples the optical signal, wherein if the clock for the charge pump is running faster than an analog front end (“AFE”) video sampling clock, a state-machine control is configured to: skip the charge pump clock period right before a video sample signal falling edge, thereby recovering to a normal operation the next charge-pump clock period, wherein this duty cycle modulation of charge pump clock will not substantially impact charge pump output.