A power control system comprising: at least one point-of-load, POL, regulator (106 to 114, 200) having a power conversion circuit (142, 230) adapted to convey power to a load and a digital controller (34, 146, 246) coupled to the power conversion circuit through a feedback loop (232,234,236), the digital controller (34, 146, 246) being adapted to provide a pulse width modulated control signal (PWMk) to said power conversion circuit responsive to a feedback and voltage error measurement (VEd k) from an output of the power conversion circuit, said digital controller (34, 146, 246) further comprising a digital filter (34, 234) having a transfer function G(z) defined by plural filter coefficients, the digital controller (34, 146, 246) periodically storing a successive one of a plurality of samples of said feedback and voltage error measurement; a serial data bus operatively connected to said at least one POL regulator (106 to 114, 200); and a system controller connected to said serial data bus and adapted to communicate with said at least one POL regulator (106 to 114, 200) via said serial data bus, said system controller retrieving each said successive stored sample from said digital controller (34, 146, 246) via said serial data bus; a summer within the POL regulator (106 to 114, 200) combining the pulse width modulated control signal (PWMk) with a deterministic noise signal from a loop response detection circuit coupled to the feedback loop, and providing the combined signal to the power conversion circuit; wherein, after retrieving a pre-determined number of said samples, said system controller uses at least a portion of said samples to calculate optimized filter coefficients for said digital filter (34, 234) based on the calculated feedback loop transfer function G(z) and communicates said optimized filter coefficients to said digital controller (34, 146, 246) via said serial data bus, said digital controller (34, 146, 246) thereafter using said optimized filter coefficients in said digital filter (34, 234); so as to adapt the POL feedback loop to variations of its open loop response, such as due to ageing of components, temperature induced variation of component performance, or load characteristic changes. at least one point-of-load, POL, regulator (106 to 114, 200) having a power conversion circuit (142, 230) adapted to convey power to a load and a digital controller (34, 146, 246) coupled to the power conversion circuit through a feedback loop (232,234,236), the digital controller (34, 146, 246) being adapted to provide a pulse width modulated control signal (PWMk) to said power conversion circuit responsive to a feedback and voltage error measurement (VEd k) from an output of the power conversion circuit, said digital controller (34, 146, 246) further comprising a digital filter (34, 234) having a transfer function G(z) defined by plural filter coefficients, the digital controller (34, 146, 246) periodically storing a successive one of a plurality of samples of said feedback and voltage error measurement; a serial data bus operatively connected to said at least one POL regulator (106 to 114, 200); and a system controller connected to said serial data bus and adapted to communicate with said at least one POL regulator (106 to 114, 200) via said serial data bus, said system controller retrieving each said successive stored sample from said digital controller (34, 146, 246) via said serial data bus; a summer within the POL regulator (106 to 114, 200) combining the pulse width modulated control signal (PWMk) with a deterministic noise signal from a loop response detection circuit coupled to the feedback loop, and providing the combined signal to the power conversion circuit; wherein, after retrieving a pre-determined number of said samples, said system controller uses at least a portion of said samples to calculate optimized filter coefficients for said digital filter (34, 234) based on the calculated feedback loop transfer function G(z) and communicates said optimized filter coefficients to said digital controller (34, 146, 246) via said serial data bus, said digital controller (34, 146, 246) thereafter using said optimized filter coefficients in said digital filter (34, 234); so as to adapt the POL feedback loop to variations of its open loop response, such as due to ageing of components, temperature induced variation of component performance, or load characteristic changes.