Hon Hai Precision Industry Co., Ltd.

Hong-fu Jin Precision Industry (shenzhen) Co., Ltd.

Yuan-Xi Chen

Ya-Jun Pan

Ying-Bin Fu

A circuit for providing a dummy load includes first to fifth resistors, a comparator, and first to fifth electronic switches. When a power good signal from a power supply is at a low level signal, the first electronic switch is turned off. The second to fourth electronic switches are turned on. The fifth electronic switch is turned off. When the power good signal from the power supply is at a high level signal, the first electronic switch is turned on. The second to fourth electronic switches are turned off. The fifth electronic switch is turned off.

Circuit for providing dummy load

A control circuit for controlling a soft-start time of a DC power supply includes a digital potentiometer, a first drive circuit, and a controller. The digital potentiometer includes a first potentiometer. The first drive circuit includes a first driver, a first MOSFET, and a first charge capacitor. The first driver charges the first charge capacitor via the first potentiometer when the DC power supply is first switched on, and the first MOSFET is switched on to connect the DC power supply to the load when the first charge capacitor is fully charged. The controller regulates resistance of the first potentiometer to regulate a charge time constant of the first charge capacitor, enabling a gradual rise in voltage supplied, from approximately zero to full power, within a desired period of time.

Soft-start time control circuit

A power adapter includes a processing circuit converting mains power to another alternating current (AC) power or a direct current (DC) power, a first output outputting the converted AC or DC power, a sense resistor connected between the processing circuit and the first output for sampling current flowing through the first output and converting the sampled current to a sampled voltage, an amplifying circuit connected to the sense resistor for amplifying the sampled voltage, and a metallic oxide semiconductor field effect transistor (MOSFET). A gate of the MOSFET is connected to the amplifying circuit. A drain of the MOSFET is connected to the first output through a first resistor and grounded through a second resistor. A source of the MOSFET is grounded. A node between the first and second resistors is connected to the processing circuit. The amplifying circuit makes the MOSFET work in a variable resistance region.

Power adapter

A motherboard includes a central processing unit (CPU), a drive, and a voltage-state display system to display a voltage mode of the CPU. The voltage-state display system includes a power management chip, a first transistor, a second transistor, a first light emitting diode (LED), and a second LED. A first phase output terminal of the power management chip is connected to the first LED through the first transistor. A second phase output terminal of the power management chip is connected to the second LED through the second transistor. The LEDs indicate the voltage mode of the CPU.

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Shenzhen, China

Yuan-Xi Chen