Method and system for efficient power control with multiple modes. According to an embodiment, the present invention provides a power system with selectable power modes. The power system includes a first terminal for outputting energy, and the first terminal is electrically coupled to a load. The system also includes a pulse-frequency modulation (PFM) component that is configured to adjust a pulse frequency based on the load. The system additionally includes a pulse-width modulation (PWM) component that is configured to adjust a pulse width based on the load. The system further includes a switch that is electrically coupled to the first terminal. Also, the system includes a control component, the control component being configured to provide a control signal that is capable of causing the switch to be turned on or off. The control signal is associated with an output of the PWM component and the pulse width if an output is greater than a predetermined value. The control signal is associated with an output of the PFM component and the pulse frequency if an output is lower than a predetermined value.