Patent ID: 7826237

Claim:
A system for providing one or more selectable modulation modes, the system comprising: a pulse-frequency-modulation (PFM) component configured to adjust a pulse frequency; a pulse-width-modulation (PWM) component configured to adjust a pulse width; and a selection component coupled to the PFM component, the PWM component, and a switch; wherein the selection component is configured to: receive a feedback signal related to an output of a power system, the power system including a primary winding; process information associated with the received feedback signal; select a modulation mode based on at least information associated with the received feedback signal; and output a modulation signal in response to at least the selected modulation mode; wherein: the selected modulation mode is a PWM mode, if the received feedback signal satisfies a first condition, the PWM mode corresponding to the PWM component; the selected modulation mode is the PFM mode, if the received feedback signal satisfies a second condition, the PFM mode corresponding to the PFM component; the PWM mode and the PFM mode are different; and the first condition and the second condition are different; wherein the switch is configured to adjust a current flowing through the primary winding based on at least information associated with the outputted modulation signal.