Patent ID: 8471540
Filing Date: 2013-06-25
Classification: H02M

Abstract:
1. A DC-DC converter controlling direct current power comprising: a switching element switching on and off an input direct current; a control circuit periodically switching said switching element on for an ON time and off for an OFF time; and a resistor dividing an output voltage of the DC-DC converter by a variable division ratio, the divided output voltage being fed back to the control circuit, wherein the ON time is determined by a pulse width of a one-shot circuit, and under both light and heavy load conditions, said control circuit applies a pulse frequency modulation (PFM) and controls the ON time, wherein the PFM is applied by varying said OFF time in accordance with a pulse frequency modulation control, and the ON time is controlled to increase when said pulse width is increased in accordance with one of a rise in the output voltage or a drop in the variable division ratio of the output voltage of said DC-DC converter.