A drive circuit for an electric machine is disclosed. In one example, the drive circuit utilizes a bootstrap capacitor and a bootstrap diode, followed by a regulator, as a basis for driving a gate of a power stage of an inverter. The regulated voltages from the bootstrap capacitor and bootstrap diode eliminate the need for using a transformer for driving the gate of the power stage of the inverter.

A power control device includes a mode setter configured to effect a change from a normal mode to a low-power mode upon detecting a light load in a burst operation, and a minimum on-period setter configured to, in response to a change to the low-power mode, change the minimum on-period of the switching transistor from a first minimum on-period to a second minimum on-period longer than the first minimum on-period.

Quasi-Constant On-Time Controller. At least one example embodiment is a method of operating a power converter, comprising: charging an inductor of a switching power converter, each charging has an on-time; and then discharging the inductor while providing current to the load; and repeating the charging and the discharging at a switching frequency. During the repeating, the example method may comprise: adjusting the switching frequency proportional to a voltage difference between an output voltage and a setpoint voltage; generating an on-time reference proportional to a frequency difference between the switching frequency and a setpoint frequency, the on-time of each charging of the inductor is based on the on-time reference; and modifying the on-time proportional to the voltage difference.

A holdup energy arrangement can include a motor control module configured to connect to motor power electronics to operate an inverter to control a motor. The motor control module can operate at a lower voltage than the motor power electronics. The arrangement can include a power supply operatively connected to the motor control module and configured to provide power the motor control module and a converter operatively connected to the power supply and configured to be electrically connected to a DC link capacitor of the motor power electronics. The arrangement can also include a logic control module configured to control the converter to selectively allow energy to flow from the DC link capacitor, through the converter, and to the power supply to provide holdup energy to the power supply with energy from the DC link capacitor.

The invention relates to a switching power supply converter, which comprising a transformer including a primary winding and a secondary winding, a power switch circuit and a voltage input circuit, a voltage output circuit, an auxiliary winding, a control circuit, and a voltage sensing circuit; the control circuit performs that in a first turn-off period of the power switch circuit, acquiring a first time duration from a preset delay after the power switch circuit turning off until the sensed voltage corresponding to a preset condition, and acquiring a difference between the first time duration and a preset time duration as a second time duration; in a second turn-off period of the power switch circuit, acquiring the sensed voltage at the time point corresponding to the end of the second time duration starting from the preset delay after the power switch circuit turning off as an effective sample.

An assembly for powering a first circuit, including at least one ferrite bead in series with a diode between a first terminal of application of a first voltage and a first terminal of said first circuit.

Systems and methods for reducing auxiliary transformer winding turns are disclosed. In one aspect, a circuit includes a transformer having a primary winding, a secondary winding and an auxiliary winding having a first end and a second end, a diode having a cathode and an anode, the anode coupled to the first end of the auxiliary winding, and a capacitor having a first terminal coupled to the second end of the auxiliary winding, and a second terminal coupled to the cathode.

A switched capacitor converter circuit includes: a conversion capacitor; an output capacitor; and switches configured to switch the coupling configurations of the conversion capacitor and the output capacitor according to a level of the first power supply voltage of the switched capacitor converter circuit, to generate the second power supply voltage at the output capacitor according to the first power supply voltage. The second power supply voltage provides power to control the power converter circuit. When the first power supply voltage is higher than a high threshold, the switched capacitor converter circuit controls the second power supply voltage to be lower than the first power supply voltage. When the first power supply voltage is lower than a low threshold, the switched capacitor converter circuit controls the second power supply voltage to be higher than the first power supply voltage.

In one example, a switched circuit includes first and second transistors. The first transistor has a first gate and a first source/drain path. The second transistor has a second gate and a second source/drain path. The first and second source/drain paths are coupled in series between an input terminal and an output terminal. A first drive circuit has a first drive input and a first drive output. A second drive circuit has a second drive input and a second drive output. The first drive output is coupled to the first gate, and the second drive output is coupled to the second gate. Switching circuitry is coupled between: at least one of first or second power supply circuits; and at least one of the first or second drive circuits.

A power supply circuit having a first capacitor, a transformer including a primary coil having a voltage of the first capacitor applied thereto, a secondary coil and an auxiliary coil, a second capacitor having a voltage from the auxiliary coil applied thereto, a transistor controlling an inductor current flowing through the primary coil, a control circuit outputting a first control signal when supply of the input voltage is unstopped, or is stopped yet a voltage of the second capacitor reaches a first level, and outputting a second control signal thereafter when the voltage of the second capacitor further reaches a second level, a first drive circuit outputting a first drive signal for switching control of the transistor in response to the first control signal, and a second drive circuit outputting a second drive signal for controlling on-resistance of the transistor to discharge the first capacitor, in response to the second control signal.