The present invention discloses a power factor correction circuit. The power factor correction circuit includes: a first bridge arm having a first switch and a second switch; a second bridge arm having a third switch and a fourth switch; a first inductor and a second inductor; a first capacitor and/or a second capacitor connected with a common point between the second inductor and the first inductor; and a third capacitor and/or a fourth capacitor, the third capacitor connected in parallel to the third switch based on an arrangement of the second capacitor and having a capacitance value same as that of the second capacitor, the fourth capacitor connected in parallel to the fourth switch based on an arrangement of the first capacitor and having a capacitance value same as that of the first capacitor.

Embodiments of this application disclose power feeding equipment and a power supply method, which relate to the field of power supply technologies, and resolve a problem that power supply efficiency of an existing power architecture is low, and high efficiency and energy saving cannot be implemented. A specific solution is power feeding equipment, including a power interface, a control unit, and N first power units. The power interface is coupled to each first power unit, and each first power unit is further coupled to a powered system. The control unit is coupled to each first power unit, and output power of the N first power units is greater than or equal to maximum required power of the powered system.

A printer system includes a first apparatus including a first voltage source for converting an inputted AC voltage to a first DC voltage and for outputting the converted first DC voltage, and a first controller operable by a voltage based on the first DC voltage outputted from the first voltage source; and a second apparatus including a second voltage source for converting an inputted AC voltage to a second DC voltage and for outputting the converted second DC voltage, and a second controller operable by a voltage based on the first DC voltage outputted from the first voltage source. The second apparatus includes a first switching portion for switching a state thereof between a connection state in which the AC voltage is supplied to the second voltage source and a non-connection state in which supply of the AC voltage is cut off.

An apparatus includes a control circuit and a voltage regulator circuit coupled to a regulated power supply node. The voltage regulator circuit is configured to generate a power signal on the regulated power supply node using a reference voltage level. The apparatus further includes a control circuit that is configured to determine an operating mode using results of a comparison of a threshold value and a load current being drawn from the regulated power supply node by a load circuit. The control circuit may be further configured to set, in a first operating mode, the reference voltage level independently of the load current, and set, in a second operating mode, the reference voltage level using the load current.

A power supply can include a main power converter, a standby converter, and control circuitry that operates the standby converter in a constant voltage regulation mode when a load current of the power supply is below a standby threshold and operates the standby converter in a constant current regulation mode when the load current of the power supply is above the standby threshold. The control circuitry can operate the standby converter in a constant voltage regulation mode to produce a voltage higher than a regulated output voltage of the main power converter. The control circuitry can idle the main power converter when a load current of the power supply is below the standby threshold. The standby threshold can correspond to a constant current limit of a constant current control loop of the standby converter. The control circuitry can employ hysteresis to the standby threshold/constant current control loop.

A power conversion apparatus includes a converter circuit converting AC voltage output from an AC power supply into DC voltage. The converter circuit includes unit converters. The power conversion apparatus includes a low current-oriented controller the unit converters to cause current corresponding to a single phase to flow through a current detector, and a high current-oriented controller controlling operation of the unit converters based on a result of comparison between a duty command and a carrier signal, where the duty command is generated based on detection values detected by the current detector and a voltage detector. When the detection value detected by the current detector is less than or equal to a first threshold, the low current-oriented controller is activated, and when the detection value detected by the current detector is greater than the first threshold, the high current-oriented controller is activated.

An OLED driving power source includes a power supply board connected to main board and OLED screen, power supply board includes standby circuit, power supply circuit, first conversion module, second conversion module and switch; after powering on, standby circuit supplies mainboard and power supply circuit, power supply circuit starts first conversion module to output first voltage and second voltage to power mainboard and output HVDC to second conversion module, switch converts first voltage to first enabling voltage to supply OLED screen according to first enabling signal from mainboard; power supply circuit starts second conversion module to convert HVDC into second enabling voltage to power and light up OLED screen, first conversion module comprises bridgeless PFC circuit and auxiliary path LLC control circuit integrated into same semiconductor chip encapsulation, and omitting specific standby circuit, circuit structure is simplified, area of power supply board is reduced, and production cost is reduced.

A circuit includes an output node and an amplifier and first and second branches coupled between power supply and reference nodes. The first branch includes a first switching device coupled between a first amplifier input and the reference node, the second branch includes a second switching device coupled between the output node and a second amplifier input, and a third switching device is coupled between the power supply and output nodes. Responsive to a first voltage level on the power supply node, each of the first and second switching devices is switched off and the third switching device is switched on, and responsive to a second voltage level on the power supply node greater than the first voltage level, each of the first and second switching devices is switched on and the third switching device is switched off.

A driving circuit for driving a light source and a projection device are provided. The driving circuit includes a power converter, a detection circuit, and a control circuit. The power converter provides a driving power to the light source. The detection circuit provides a feedback signal according to a current value of the light source. The control circuit receives an operation command and the feedback signal. The control circuit determines whether the driving circuit enters a light-load state according to at least one of the operation command and the feedback signal. When the driving circuit is determined to enter the light-load state, the control circuit controls the power converter to decrease a current value of the driving power and controls the power converter to increase a switching frequency of the driving power. The driving circuit and the projection device may prevent the light source from flickering under the light-load state.

The present disclosure describes various aspects of adaptive current control in switching power regulators for fast transient response. In some aspects, a clock of a switching power regulator is prevented, in response to detecting a transient load, from affecting application of current to an inductor of the regulator. A first switch device applies current to the inductor of the regulator until inductor current reaches a maximum current level. A second switch device then enables the current to flow through the inductor until the inductor current reaches a current control signal based on an output voltage of the switching power regulator. In some aspects, an offset is also applied to the current control signal to further increase average inductor current. These operations may be repeated without interruption from the clock to quickly increase the inductor current, and thus current provided to the regulator output in response to the transient load.