An active gain control circuit includes a dynamic voltage divider having a variable resistance configured to attenuate a rectified input line voltage to produce a reference signal, a filter-divider circuit configured to extract a DC-level attenuated reference voltage from the reference signal, and an operational amplifier configured to receive the DC-level attenuated reference voltage and a regulation voltage, and to generate a gate control signal based on a difference between the regulation voltage and the DC-level attenuated reference voltage, the variable resistance of the dynamic voltage divider being controlled by the gate control signal, and a comparison voltage generator configured to attenuate a comparison voltage to generate the regulation voltage.

Various embodiments of the teachings herein include a rectifier. The rectifier may include: a rectifier circuit formed with current valves with microelectromechanical systems (MEMS) switches; and a switching controller driving the MEMS switches to switch and open. The switching controller opens the MEMS switches when a voltage feeding the rectifier falls below a minimum distance from a zero voltage.

Various embodiments of the teachings herein include a rectifier. The rectifier may include: a rectifier circuit formed with current valves with microelectromechanical systems (MEMS) switches; and a switching controller driving the MEMS switches to switch and open. The switching controller opens the MEMS switches when a voltage feeding the rectifier falls below a minimum distance from a zero voltage.

Provided are a power supply conversion device and a charging control method. The device includes: a transformer; a first rectifier circuit connected to a primary winding of the transformer used for converting a received alternating current into a first direct current, a voltage value of the first direct current being a first direct-current voltage, and the transformer used for converting the first direct-current voltage into a second direct-current voltage; a voltage converter connected to a secondary winding of the transformer and used for converting the second direct-current voltage to output a constant direct-current voltage or a pulsating direct-current voltage; and a controller connected to the first rectifier circuit and the voltage converter and used for controlling the voltage converter to selectably output the constant direct-current voltage or the pulsating direct-current voltage according to a desired charging mode of a device to be charged connected to the power supply conversion device.

An integrated single stage ac-dc driver for powering LED loads includes a boost converter operating in a Discontinuous Conduction Mode, DCM, comprising a half-bridge, and a Zeta Asymmetrical Half Bridge, ZAHB, integrated with the boost converter such that the boost converter and the ZAHB share the half-bridge to perform power factor control, PFC, with a fixed duty cycle and control an output voltage.

A switched mode power supply (SMPS) includes a filter (202), a power factor correction (PFC) circuit (204), and a control circuit (206, 406) configured to determine various electrical parameters of the SMPS. In some embodiments, the control circuit (206, 406) is configured to determine a power line frequency and an AC input voltage based on an AC line voltage and an AC neural voltage. In other embodiments, the control circuit (206, 406) is configured to determine an AC input current based on a reactive current flowing through the filter (202) and a PFC AC current. In further embodiments, the control circuit (206, 406) is configured to report a value of an electrical parameter if value is determined to be accurate. Other example switch mode power supplies, control circuits and methods are also disclosed.

A device for providing power to a server rack includes a first AC input port, a second AC input port, a first relay, a second relay, and an output port. The output port is electrically connected to both the first AC input port and second AC input port. The first relay is electrically between the first AC input port and the output port, and the second relay is electrically between the second AC input port and the output port. The first relay and second relay are configured to compare a first phase of a first voltage from the first AC input port to a second phase of a second voltage from the second AC input.

Structures and functions of power supplies are disclosed. In an example, a power supply includes a power factor correction circuit and a bypass circuit. The bypass circuit bypasses the power factor correction circuit when the switch of the bypass circuit is on in response to a predetermined range of input power of the power supply. The bypass circuit also includes a delay circuit to delay the activation of the bypass circuits in response to the predetermined range of input power of the power supply for a predetermined time period.

A power converter configured to be connected to three or more voltage parts, includes three or more power-conversion circuitries to be connected to respective ones of the three or more voltage parts, and a multi-port transformer connected to the three or more power-conversion circuitries at respectively different ports. The three or more voltage parts include a vehicle drive battery and a plurality of alternating-current (AC) voltage parts. Each of the plurality of AC voltage parts is configured to provide at least one of power input to a multi-port transformer side and power output from the multi-port transformer side.

A drive controller is used in a control system of a power factor correction (PFC) circuit. The control system further includes the PFC circuit. The PFC circuit includes a first bridge arm, a second bridge arm, a first switching transistor, and a second switching transistor. The driving controller includes a sampling circuit and a driving circuit. The sampling circuit is configured to obtain a target current value between the first switching transistor and the second switching transistor. The drive circuit is configured to turn off gate inputs of the first switching transistor and the second switching transistor when the target current value is greater than a current threshold, to turn off the first switching transistor and the second switching transistor and protect the control system.