Abstract: Multiple controllers connected in parallel to control external circuits such as dc-dc converters so that the external circuits supply power equally to a load such as a microprocessor. All of the controllers are connected and each controller includes an oscillator and a pulse width modulation circuit to synchronize the frequency of all of the oscillators such that the duty cycle of all the oscillators are equal. Each controller includes an over-current protection circuit and an over-voltage protection circuit which will cause the controller with a fault to discontinue supplying power to the load. Each controller further includes a circuit to adjust the duty cycle of the non-faulty controllers when a controller with a fault is caused to discontinue supplying power to the load.