In a fast power converter with distributed output capacitors with
parasitic impedances between them, the settling time of the output
voltage is too long, making voltage unsuitable as a control input. The
charge on each of the distributed output capacitors can be measured,
preferably differentially, in a summing network in which the conductance
of each of the summing resistors is proportional to the capacitance of
the capacitor with which it is associated. The charges can be summed as a
total charge control input for the fast power converter. The total charge
control is very sensitive to changes in the output current, and is
insensitive to lags, ringing and/or oscillations of the voltages among
the distributed capacitors. If the output capacitor of a VRM is small
compared to the total capacitance, the impedance of its connector is
largely mitigated.