A fault handling system of a solid-state transformer, including a first power unit and a second power unit that are cascaded and connected is provided. The first power unit includes a first auxiliary supply, a first control module, and a first communication module. The first auxiliary supply and the first control module are both electrically connected to two ends of a first busbar capacitor. The first control module is configured to detect a voltage of the first busbar capacitor. The second power unit includes a second auxiliary supply and a second control module. The second auxiliary supply and the second control module are both electrically connected to two ends of a second busbar capacitor. The first communication module outputs fault information to the second control module when the first control module detects that the voltage of the first busbar capacitor is greater than a threshold.

A switching converter and a low-voltage startup circuit is provided. The low-voltage startup circuit includes a comparator and a substrate voltage control module. The comparator performs a comparison between an input voltage and a reference voltage and obtain a voltage detection signal according to a result of the comparison. The substrate voltage control module adjusts a substrate voltage of a main switching transistor according to the voltage detection signal, wherein when the voltage detection signal indicates that the input voltage is lower than/equal to the reference voltage, the substrate voltage control module increases the substrate voltage of the main switching transistor, and then a turn-on threshold voltage of the main switching transistor can be reduced, so that the main switching transistor may be normally turned on when the input voltage is low, and the low-voltage startup capability of the switching converter is improved.

The control system includes a PFC circuit and a sampling control circuit, and the PFC circuit includes an inductor, a first power supply drive circuit, and a first bridge arm and a second bridge arm that are connected in parallel, and a first bridge arm midpoint is a serial connection point between a first upper bridge arm and a first lower bridge arm of the first bridge arm. The sampling control circuit is configured to control, based on voltages of two ends of an alternating current power supply, the first lower bridge arm to be turned on, so that the first power supply drive circuit starts charging. The sampling control circuit is further configured to: when charging duration of the first power supply drive circuit reaches first target duration, control the first lower bridge arm to be turned off, so that the first power supply drive circuit completes charging.

In some examples, a device includes a selector circuit configured to deliver power to a first driver circuit, where the first driver circuit is configured to activate and deactivate a first switch of a postregulator. The device also includes a startup regulator and a controller configured to cause the selector circuit to deliver power from the startup regulator to the first driver circuit. The controller is also configured to determine that a boost regulator is operational after delivering power from the startup regulator to the first driver circuit. The controller is further configured to cause the selector circuit to deliver power from the boost regulator to the first driver circuit in response to determining that the boost regulator is operational.

A bootstrap gate driver charging circuit arranged to drive the gate of an upper switch (Q.sub.U) and a lower switch (Q.sub.L) connected in series to provide an AC output voltage (400) voltage by alternatively turning on and off according to a predetermined duty cycle of alternate upper switch turn-on and lower switch turn-on phases, the bootstrap gate driver charging circuit comprising: an input terminal; an output terminal; an H-bridge inverter with an inverter input and an inverter output; a charging path; and a bootstrap capacitor. The input inverter is electrically connected to the input terminal, the inverter output is electrically connected to a first end of the bootstrap capacitor, the charging path is electrically connected between a second end of the bootstrap capacitor and a gate driver supply voltage; wherein in response to the lower switch being turned ON and providing a path to ground with respect to the supply voltage.

A gate drive circuit, which drives a gate of a first transistor, includes a first switch on a high potential side and a second switch on a low potential side connected in series at a second connection node between a high potential end and a low potential end of a series connection structure, constituted of a first voltage source and a second voltage source connected in series at a first connection node; and a third switch and an inductor connected in series between the first connection node and the second connection node. The gate of the first transistor can be electrically connected to the second connection node.

A driving circuit for a switched capacitor converter having first and second switched capacitor branches, where the first switched capacitor branch includes first and second switch groups connected between an input voltage and a reference ground, the second switched capacitor branch includes third and fourth switch groups connected between the input voltage and the reference ground, and where each switch group includes an upper power switch and a lower power switch, the driving circuit comprising: a plurality of drivers configured to correspondingly drive each power switch in the switched capacitor converter; a bootstrap capacitor that provides a power supply voltage for each driver that is configured to drive the upper power switches that are connected to the input voltage of the switched capacitor converter; and where a charging voltage for charging the bootstrap capacitor is not greater than the input voltage of the switched capacitor converter.

An isolation circuit for electrically isolating a first circuit operating at a first voltage from a second circuit operating at a second voltage that is different than the first voltage is provided. The isolation circuit includes: a first voltage source that operates at the first voltage, the first voltage source having a first supply rail and a second supply rail; an isolation device having a first input, a second input, a first output and a second output, the second input coupled to a first ground potential and the second output coupled to a second ground potential that is electrically isolated from the first ground potential by the isolation device; a first resistor coupled between the first supply rail and the first input of the isolation device; a second resistor coupled to the first input of the isolation device and the second input of the isolation device; and wherein the first output of the isolation device is coupled to the second circuit.

A power supply controller used in a DC/DC converter includes a feedback control unit that generates a pulse-shaped PWM signal having a first level that is one of a high level and a low level and a second level that is the other of the high level and the low level, on the basis of a feedback voltage based on an output voltage of the DC/DC converter; a low voltage detection unit that detects a low voltage of the feedback voltage; and a selection unit that chooses, as a chosen clock signal, a first clock signal having a high duty when the low voltage is not detected by the low voltage detection unit, and chooses a second clock signal having a low duty when the low voltage is detected by the low voltage detection unit. The feedback control unit includes a reset signal generation unit that generates a pulse-shaped reset signal having the first level and the second level, based on the feedback voltage, and a PWM signal generation unit that generates the PWM signal at the first level during a period that is an overlap between a period during which the reset signal is at the first level and a period during which the chosen clock signal is at the first level.

A power supply circuit for powering components of a facility are disclosed. The power supply circuit may include a power transformer, a power input terminal, a power output terminal, a bridge, a relay, and a control circuit. The relay is connected between the power input terminal and the power output terminal. A primary side of the power transformer is coupled between the relay and the power output terminal. The bridge is coupled to the secondary side of the power transformer. In a normal power mode, the control circuit closes the relay and operates the bridge as a rectifier. In an emergency power mode, the control circuit opens the relay and operates the bridge as a pulse width modulator. In this manner, the bridge and the power transformer can be used both to charge a battery during normal operation and generate emergency AC power from the battery.