A power converter includes: a switching transistor, a transformer, a control circuit; the control circuit is configured to determine a target voltage in a process that the switching transistor is driven to conduct; the target voltage can represent a voltage change of an input terminal of the switching transistor; when the target voltage starts to drop but is higher than a reference voltage, drive a control terminal of the switching transistor with a first driving current; when the target voltage decreases to be lower than the reference voltage, drive the switching transistor with a second driving current; the second driving current is higher than the first driving current; the switching transistor is driven by the first driving current for part or all of the time before entering the Miller plateau stage, and is driven by the second driving current after starting to enter the Miller plateau stage.

The present invention relates to an adaptive soft start and soft stop device for a converter, and more particularly, provides an adaptive soft start and soft stop device for a converter which controls a final output voltage to be increased or decreased with a predetermined gradient by increasing a duty at a predetermined rate or increases a frequency during a start period using an input voltage Vin and an output voltage Vo and decreasing the duty at a predetermined rate or decreases a frequency during a stop period.

A motor drive system includes a direct current (DC) bus that provides a DC link voltage across a DC link capacitor, and a split DC link mid-point circuit connected in parallel with the DC link capacitor. The split DC link mid-point circuit establishes a mid-point reference based on the DC link voltage. A power inverter is in signal communication with the DC bus. The power inverter includes one or more gate driver units configured to drive one or more corresponding switches. Each gate driver unit includes a mid-point ground connection that is connected to the mid-point reference. The split DC link mid-point circuit can define a voltage divide that establishes the mid-point reference and can be used to monitor the DC link voltage.

The present disclosure provides a conversion circuit including a power supply module, positive and negative input terminals, positive and negative output terminals, a switch, an inductor, input and output capacitors, and a controller. The power supply module converts an AC power for providing three potentials on three power supply terminals respectively. The potential on the first power supply terminal is higher than the potential on the second power supply terminal, which is higher than the potential on the third power supply terminal. The positive and negative input terminals are electrically connected to the first and third power supply terminals respectively, and a voltage therebetween is an input voltage. The negative output terminal is electrically connected to the third power supply terminal. The controller is electrically connected to the positive input terminal, the second power supply terminal and the switch. A voltage across the controller is lower than the input voltage.

A control unit (4) generates a control signal. A switching device (2) performs switching according to the control signal and generates a primary side input voltage from a supply voltage. A transformer (1) converts the primary side input voltage to a secondary side output voltage. A drive circuit (7) drives a power device (8) according to the secondary side output voltage. The control unit (4) includes a table listing a correspondence relationship between supply voltages and set values of control signals for obtaining a desired secondary side output voltage, refers to the table and generates the control signal having a set value corresponding to the supply voltage.

A system includes a switching power converter, including a first transistor having a first gate, a first drain, and a first source, the first drain adapted to be coupled to a power supply. The switching power converter also includes a second transistor having a second gate, a second drain, and a second source, the second gate coupled to a second gate driver, the second source adapted to be coupled to ground, and the second drain coupled to the first source. The switching power converter also includes a third transistor having a third gate, a third drain, and a third source, the third gate adapted to be coupled to a current source, the third source coupled to a resistor, and the third drain coupled to the first gate. The switching power converter includes a capacitor coupled to the first drain and adapted to be coupled to the current source.

Embodiments of this application provide charging apparatuses, charging apparatus control methods, and charging systems, and relate to the field of terminal device charging technologies. The charging apparatus includes a rectifier circuit, a transformer, a lower bridge switch, a clamp capacitor, an upper bridge switch, and a controller. The transformer includes a primary coil and at least one secondary coil. The controller is configured to control the upper bridge switch and the lower bridge switch to be alternatively turned on. The controller is further configured to obtain a sampling waveform at a location at which the controller is electrically connected to the transformer when the lower bridge switch is turned off, and, when the sampling waveform is abnormal, turn off the lower bridge switch in a first phase of a next charging cycle. The sampling waveform includes a voltage waveform of the primary coil or a voltage waveform of the secondary coil.

A reference voltage generator configured to be supplied with a first voltage from an external device and to generate a reference voltage which is a voltage lower than a second voltage which is a voltage higher than the first voltage supplied from the external device on the basis of the second voltage through negotiation with the external device; a determiner configured to determine a magnitude relationship between the second voltage and the reference voltage; and an output configured to notify that a voltage has decreased when the second voltage is equal to or lower than the reference voltage on the basis of the result of determination are included.

This application provides a switching conversion circuit, including: a power module, supplying power to a switching conversion module and an IC controller; and the switching conversion module is an asymmetrical half-bridge flyback structure and includes at least a first switching transistor, a second switching transistor, a first capacitor, and a transformer. The transformer includes a first secondary-side winding and a second secondary-side winding, and the first secondary-side winding of the transformer is coupled to a load. The IC controller turns on the first switching transistor or the second switching transistor based on a value of a first voltage, so that the switching conversion module enters an operating state to supply power to the load; and turns off the first switching transistor and the second switching transistor based on a value of a second voltage, so that the switching conversion module stops supplying power to the load.

An active pull-up circuit which is operated between an upper voltage and a lower voltage and which pulls up an intermediate node to the upper voltage in reaction to an input voltage of the pull-up circuit falling from the upper voltage to an intermediate voltage is described. The pull-up circuit comprises a first transistor having a source terminal coupled to the upper voltage, a drain terminal coupled to the intermediate node and a gate terminal coupled to the input voltage. The pull-up circuit comprises a second transistor having a source terminal coupled to the upper voltage, a drain terminal coupled to the intermediate node and a gate terminal coupled to a control node. In addition, the pull-up circuit comprises control circuitry configured to pull the control node to a voltage level of the intermediate node, subject to the input voltage falling from the upper voltage to the intermediate voltage.