Patent ID: 8885363

Claim:
A dual-mode switching power control device for converting an input power with an input voltage into an output power with an output voltage supplied to an external load, comprising: an electric transformer having a first side inductor and a second side inductor, the first side inductor having a first end connected to a positive end of the input power; a PWM (pulse width modulation) driving controller being a single chip device selected from a group consisting of a MCU (microcontroller) and a CPU (central processing unit); a switching transistor having a gate driven by a first terminal of the PWM driving controller, a drain connected to a second end of the first side inductor and a source connected to a negative end of the input power; an isolation element having a first terminal connected to the output voltage for converting the output voltage into a feedback signal transmitted through a second terminal of the isolation element to a second terminal of the PWM driving controller, the feedback signal being correlated with loading power of the external load through a lookup table stored in the PWM driving controller; an output diode having a positive end connected to a first end of the second side inductor and a negative end connected to the first terminal of the isolation element; and an output capacitor connected in parallel with the external load and having a first end connected to the negative end of the output diode and a second end connected to a second end of the second side inductor; wherein the PWM driving controller determines whether a loading state of the external load is light loading or heavy loading based on the feedback signal, the loading state is light loading if the feedback signal is smaller than a threshold value, and the loading state is heavy loading if the feedback signal is larger than the threshold value, and the PWM driving controller performs DCM (Discontinuous Conduction Mode) to drive the gate of the switching transistor in case of the light loading, and performs CCM (Continuous Conduction Mode) in case of the light loading.