Abstract: A power adapter for an electronic device selectively works in different modes according to a working state signal of the electronic device. When the electronic device is powered off or on with a battery in a determined charge state, the power adapter controls a relay to turn off the relay to disconnect power to the electronic device.

Abstract: A control circuit for a switching power supply (SPS) includes power input and output interfaces, a relay, a relay driving circuit, a microprocessor, and an alternating current/directing current (AC/DC) converter. The power input interface receives an external alternating current (AC) power signal, and transmits the AC power signal to the SPS via the power output interface. The AC/DC converter transforms the AC power signal into a direct current (DC) power signal to supply for the relay, the relay driving circuit, and the microprocessor. When a computer is turned on, the microprocessor sends a first control signal to control the relay driving circuit to drive the relay to connect the power input and output interfaces. When the computer is turned off, the microprocessor sends a second control signal to control the relay driving circuit to drive the relay to cut off connection between the power input and output interfaces.

Abstract: A phase adjusting system includes a controlled element, a multi-phase pulse-width modulation (PWM) controller comprising default and non-default phases, and a microprogrammed control unit (MCU). The PWM controller provides phases to the controlled element. The MCU is connected to the controlled element via the multi-phase PWM controller. The MCU detects the work voltage level of the controlled element and controls the multi-phase PWM controller to provide a corresponding number of phases to the controlled element. The MCU determines whether work time of the default phases of the multi-phase PWM controller is greater than a predetermined value in response to the MCU being initialized. The default phases are changed to non-default phases and a corresponding number of the plurality of non-default phases are changed to default phases in response to the work time of the plurality of default phases of the multi-phase PWM controller being greater than the predetermined value.

Abstract: A power adapter for an electronic device selectively works in different modes according to a working state signal of the electronic device. When the electronic device is powered off or on with a battery in a determined charge state, the power adapter controls a relay to turn off the relay to disconnect power to the electronic device.

Abstract: A control circuit for a switching power supply (SPS) includes power input and output interfaces, a relay, a relay driving circuit, a microprocessor, and an alternating current/directing current (AC/DC) converter. The power input interface receives an external alternating current (AC) power signal, and transmits the AC power signal to the SPS via the power output interface. The AC/DC converter transforms the AC power signal into a direct current (DC) power signal to supply for the relay, the relay driving circuit, and the microprocessor. When a computer is turned on, the microprocessor sends a first control signal to control the relay driving circuit to drive the relay to connect the power input and output interfaces. When the computer is turned off, the microprocessor sends a second control signal to control the relay driving circuit to drive the relay to cut off connection between the power input and output interfaces.