A switch mode power supply controller includes a switch terminal adapted to be coupled to an inductor that drives a load, high- and low-side switches a pulse width modulation (PWM) circuit, and a current monitor circuit. The PWM circuit is coupled to a feedback terminal for receiving a feedback signal, and alternatively drives the high-side switch and the low-side switch with a duty cycle set using the feedback signal to regulate an output voltage to a desired level in a work mode, and keeps both the high-side switch and the low-side switch non-conductive in a non-work mode. The current monitor circuit provides a current monitor signal representative of a current driven from the inductor to the load, wherein the current monitor circuit forms the current monitor signal by measuring an inductor current during a work mode, and by emulating the inductor current during a non-work mode.