Transient or fault conditions for a switched capacitor power converter are detected by measuring one or more of internal voltages and/or currents associated with switching elements (e.g., transistors) or phase nodes, or voltages or currents at terminals of the converter, and based on these measurements detect that a condition has occurred when the measurements deviate from a predetermined range. Upon detection of the condition fault control circuitry alters operation of the converter, for example, by using a high voltage switch to electrically disconnect at least some of the switching elements from one or more terminals of the converter, or by altering timing characteristics of the phase signals.