Abstract: A switching mode power supply reduces switching losses during standby mode by alternately enabling and disabling the switching operation of a main switch during standby mode. When the main switch is enabled, it is forced to operate at a duty cycle which is greater than the minimum duty cycle. Therefore, the average switching frequency is reduced during standby mode, and switching losses are reduced accordingly. The switching mode power supply includes a current supply circuit which provides a first amount of current to a feedback capacitor when the main switch is operating, and a second, lower amount of current when the main switch is not operating. In standby mode, when the main switch is not operating, the reduced current from the current supply circuit causes the voltage across the feedback capacitor to be held at an artificially low level compared to normal mode, thereby causing the main switch to remain off even though the output voltage is below the setpoint level.