An apparatus is disclosed for harvesting ringing energy. In an example aspect, the apparatus includes a bootstrap circuit. The bootstrap circuit includes a bootstrap capacitor and a bootstrap switch. The bootstrap switch includes a first terminal configured to accept an input voltage. The bootstrap switch also includes a second terminal coupled to the bootstrap capacitor. The bootstrap switch additionally includes a body diode comprising an anode coupled to the first terminal and a cathode coupled to the second terminal. The bootstrap switch is configured to be in an open state to charge the bootstrap capacitor via the body diode. The bootstrap switch is also configured to provide a voltage at the second terminal of the bootstrap switch. The voltage is greater than an average of the input voltage.

This application provides example circuit modules and example electronic devices comprising the circuit module. One example circuit module includes a power input terminal, a power output terminal, a first switching transistor, a second switching transistor, a comparison unit, a boost unit, an energy storage unit, and a direct current conversion unit, where the first switching transistor is turned on and the second switching transistor is cut off when a source voltage input by the power input terminal to the comparison unit is greater than the preset threshold, or the first switching transistor is cut off and the second switching transistor is turned on when a source voltage input by the power input terminal to the comparison unit is less than or equal to the preset threshold.

An object is to provide a technique capable of bringing a switching time point of a gate drive condition close to an appropriate switching time point. A semiconductor switching element drive circuit includes a logic circuit that inverts a level of an output signal based on a divided voltage of an output voltage of a semiconductor switching element, and a switching circuit. The switching circuit switches a gate drive condition of the semiconductor switching element during a turn-off operation from a first gate drive condition to a second gate drive condition in which a switching speed is lower than that of the first gate drive condition based on the output signal from the logic circuit.

A current path to a gate is cut off by a normally-off first switch element until start-up of a gate drive voltage generator is sensed. Furthermore, a semiconductor switching element is maintained in an off state as a normally-on second switch element short-circuits the gate to a source. As start-up of the gate drive voltage generator is sensed, the second switch element is turned off and the first switch element is turned on. As the gate is thus driven by an output from a signal amplifier in accordance with a control signal, the semiconductor switching element is turned on and off in accordance with the control signal.

A hybrid gate driver circuit includes a field effect transistor (FET) drive terminal, a switching node terminal, a transistor, and a capacitor. The transistor includes a first terminal coupled to the FET drive terminal, and a second terminal coupled to ground. The capacitor includes a first terminal coupled to the switching node terminal, and a second terminal coupled to a third terminal of the transistor.

A power supply circuit for a switching mode power supply, having: a charging capacitor coupled to an auxiliary winding; a power supply diode coupled to a power supply capacitor, wherein the charging capacitor has a connecting terminal coupled to the power supply diode, and the charging capacitor and the power supply diode are serially coupled between the auxiliary winding of the switching mode power supply and the power supply capacitor; and a power supply switch coupled between the connecting terminal and a primary ground of the switching mode power supply.

A circuit assembly for connection to a current source, preferably a 4-20 mA current loop and/or a high-impedance voltage source, preferably a high-impedance voltage source comprising an internal resistance greater than or equal to 100 ohms, includes at least one boost converter with a coil, a diode, in particular a flyback diode, which is connected in series with the coil, an output-side storage capacitor for summing an output voltage, and a switching element for connecting the coil to ground; a circuit part for dynamically controlling the switching element of the boost converter, wherein the circuit part is at least designed to control the switching element of the boost converter in a start-up phase such that the current source directly charges the storage capacitor via the coil until a predefinable reference value is reached.

A switch circuit is configured of a first semiconductor element and a second semiconductor element connected in series, and receives a DC voltage of 100 V or more. The drive circuit causes the first semiconductor element or the second semiconductor element to perform a switching operation. The isolated power supply circuit converts a predetermined power supply voltage into an isolated first power supply voltage, and outputs the first power supply voltage to the drive circuit. The isolation signal converter converts a first signal of 6 MHz or more into an isolated first drive signal, and outputs the first drive signal to the drive circuit. The single substrate mounts the isolated power supply circuit and the isolation signal converter. Both the first semiconductor element and the second semiconductor element are wide bandgap semiconductor elements.

A bleeder current control method. The bleeder current control method includes the following steps: The rectifier bridge transmits a post-bridge input signal to the power system. The shaping circuit obtains the post-bridge input signal and shapes it into a bleeder current reference signal, the bleeder current reference signal is inversely correlated with the initial post-bridge input signal. Acquiring a current sampling signal representing the bleeder current, and comparing the error of the current sampling signal with the bleeder current reference signal to obtain an error signal. The current sampling signal is controlled according to the error signal, so that the current sampling signal is output based on the waveform of the bleeder current reference signal. Thus, a reliable and full-time sine wave envelope signal is provided to the power system, so as to reduce the loss caused by the bleeder current to the power system.

A converter to convert an input voltage into a regulated output current for supplying a load includes a reverse current protection diode having an anode coupled to the input voltage and a cathode, an energy storage element coupled to the cathode of the reverse current protection diode, a high side transistor coupled to the energy storage element and responsive to a high side control signal, and a low side transistor coupled to the energy storage element and responsive to a low side control signal. A controller is configured to generate the high side control signal and the low side control signal such that the low side transistor is enabled and the high side transistor is disabled during a pre-regulation interval.