The synchronous rectifier controller includes a voltage regulator to provide a control voltage to the control terminal of the rectifier switch. The synchronous rectifier controller compares the channel voltage of the rectifier switch with a threshold voltage to generate a comparison result signal. When the channel voltage is greater than the threshold voltage, the comparison result signal has a first logic value, and when the channel voltage is less than the threshold voltage, the comparison result signal has a second logic value. An inverted comparison result signal is generated according to the comparison result signal. When the channel voltage is less than the threshold voltage, the inverted comparison result signal enables a pull-up power supply to pull up the control voltage; and when the channel voltage is greater than the threshold voltage, the comparison result signal enables a pull-down power supply to pull down the control voltage.

Disclosed are a power circuit and an automated external defibrillator including the same. The power circuit may include a battery-driven power source, and a transformer comprising a primary winding and N secondary windings, wherein N is an integer greater than or equal to 2, and wherein the primary winding is electrically coupled to the power source. The power circuit may include N charging and discharging branches, wherein the N charging and discharging branches are respectively connected to the N secondary windings and are cascaded in sequence. The power circuit may include a plurality of electrode plates configured to be connected to an external load, wherein electrode plates of the plurality of electrode plates are electrically coupled to one or more output nodes of the N charging and discharging branches.

A power converter includes a switch control circuit for driving a high side switch of the power converter comprising the high side switch and a low side switch connected in series. The switch control circuit may have a first terminal for receiving an input signal, a second terminal used as a reference ground terminal of the switch control circuit, and a third terminal used as an output terminal to provide a driving signal, the switch control circuit can draw power from the input signal and may be configured to control a logic state of the driving signal based on a logic state of the input signal relative to a reference ground signal at the second terminal or based on a current flowing through the first terminal.

A secondary side controller for a flyback converter includes an integrated circuit (IC), which in turn includes: a synchronous rectifier (SR) sense pin coupled to a drain of an SR transistor on a secondary side of the flyback converter; a capacitor having a first side coupled to the SR sense pin, the capacitor to charge or discharge responsive to a voltage sensed at the SR sense pin; a diode-connected transistor coupled between a second side of the capacitor and ground; a first current mirror coupled to the diode-connected transistor and configured to receive, as input current, a reference current from a variable current source; and a peak detect transistor coupled to the diode-connected transistor and to an output of the first current mirror. The peak detect transistor is to output a peak detection signal in response to detecting current from the capacitor drop below the reference current.

A bridge converter converts an input voltage into an output voltage, and includes a switching circuit, a transformer, a rectifying circuit, and a control module. The switching circuit includes a first switch and a second switch. The control module sets a first time period and a second time period. The control module provides a first control signal and a second control signal to control the switching circuit based on the output voltage. The control module fixes an operation frequency of the first control signal and the second control signal at the maximum frequency based on that the control module is set in a standby mode, and provides the first control signal and the second control signal in the first time period, and shields the first control signal and the second control signal in the second time period.

A secondary controller applied to a secondary side of a power converter includes a control signal generation circuit and a gate control signal generation circuit. The gate control signal generation circuit generates a gate control signal, and generates an injection signal according to the gate control signal. When a superposition voltage is less than a reference voltage, the control signal generation circuit generates a gate pulse control signal, wherein the gate pulse control signal corresponds to an output voltage of the power converter and the injection signal, the gate control signal generation circuit is further used for generating a gate pulse signal according to the gate pulse control signal, and the gate pulse signal is used for making a primary side of the power converter turned on.

A transformer includes first and second primary windings serially electrically connected in a primary-side series combination. The transformer further includes a secondary winding disposed between the first primary winding and the second primary winding. The transformer further includes first and second shielding windings serially electrically connected in a shielding series combination. The first shielding winding is disposed between the first primary winding and the secondary winding, and the second shielding winding is disposed between the second primary winding and the secondary winding.

Various embodiments are directed to a voltage clamp system comprising: a rectifier; a protected node, a reference node, and one or more internal nodes, coupled to the rectifier; a power converter, coupled to the rectifier via the one or more internal nodes; and one or more output nodes coupled to the power converter and configured to couple to a power sink. The rectifier and the power converter are configured to output power via one or more output nodes coupled to the rectifier, and to limit a component of the voltage between the protected node and the reference node.

A controller of a power converter is coupled to a switch assembly and configured to perform a hold-up time procedure that causes the controller to control first and second switching elements into opposite conducting states during a first period of time of a pulse cycle and into alternate opposite conducting states during a second period of time of the pulse cycle. The hold-up time procedure also causes the controller to control a first pair of synchronous rectifier switching devices into a conducting state during a third period of time overlapping less than all of the first period of time and into the conducting state during a fourth period of time overlapping less than all of the second period of time. A second pair of synchronous rectifier switching devices is controlled into a non-conducting state during the first and second periods of time.

A flyback converter is provided that includes a high-side synchronous rectifier switch transistor. A secondary-side synchronous rectifier controller powered by a power supply voltage controls a cycling on and off of the high-side synchronous rectifier switch transistor. An active control of the charging of the power supply voltage uses an auxiliary capacitor that is charged from a charge source while a power switch transistor in a first switching state. When the power switch transistor is in a second switching state that is the complement of the first switching state, the active control coupes the auxiliary capacitor to a power supply capacitor that stores the power supply voltage.