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On Wed, 27 Apr 2011 23:24:15 -0400, Dave McGuire wrote: The resistive voltage divider you refer to, is a resistive load across the capacitor, it is the R of the RC circuit. Its R must be low enough to draw enough current to produces a measureable voltage drop for the PCM logic to see. It sound like in your design, sufficent load to bleed the excess VCC of of the cap. Sometimes but not always, the internal resistive voltage divider you refer to, provides the mininum load necesssary for the Cap to bleed back down from the peak source voltage to the desired target voltage between pulses. It is this bleed down or load across the Cap, countered by the recharging pulse that preforms the regulation. But often it is not enough load and an additional external load is required to acheve stable regulation. As I said, capacitive reactance may come into play, if the cap is big enough (or bad), internal resistance may provide enough leakdown/bleedoff but I would not bet on it. Is it not bad caps we are looking for ? I did not want to start something here, but one cant get away from Ohms law, it says I=E/R or otherwise stated as E=I*R if you prefer. With infinate R (no load) there is no I, with no I and there is no drop in E, and with no drop in E and there is no regulation! With No load at all and the Cap charges nearly to the full source voltage on the first few pulses (depending on size of the cap) and never bleeds back down to the target level if there is 0 current flow. To put this back on subject, dummy loads do not need to be large to test voltage regulation. Although a well designed or controlable load will allow you to test voltage regulation at any desired current limit. Back under my rock The other Bob