An overvoltage protection circuit adapted for a switching power supply is provided. The overvoltage protection circuit can use the time difference of the start of the overvoltage protection to distinguish that the overvoltage of the output voltage of the switching power supply is caused by the failure of the internal feedback or by the internal power supply, thereby avoiding a short and harmless external power supply to affect the normal operation of the switching power supply but can immediately stop the switching power supply to achieve protection when the switching power supply has an internal feedback failure.

A device comprises a gate drive bridge coupled between a bias voltage of a power converter and ground and a transformer connected to the gate drive bridge, wherein the transformer comprises a primary winding connected to two legs of the gate drive bridge respectively and a plurality of secondary windings configured to generate gate drive signals for low side switches, high side switches and secondary switches of the power converter.

A power converter controller includes a primary controller and a secondary controller. The primary controller is coupled to receive one or more request signals from the secondary controller and transition a power switch from an OFF state to an ON state in response to the received request signals. The secondary controller is coupled to transmit the request signals to the primary controller and control the amount of time between the transmission of each of the request signals. The secondary controller includes a timing circuit that sets a minimum amount of time between the transmission of the request signals. The secondary controller also includes a secondary switch control circuit coupled to trigger the timing circuit in response to transmitting a request signal.

A power converter controller includes a primary controller and a secondary controller. The primary controller is coupled to receive one or more request signals from the secondary controller and transition a power switch from an OFF state to an ON state in response to the received request signals. The secondary controller is coupled to transmit the request signals to the primary controller and control the amount of time between the transmission of each of the request signals. The secondary controller includes a timing circuit that sets a minimum amount of time between the transmission of the request signals. The secondary controller also includes a secondary switch control circuit coupled to trigger the timing circuit in response to transmitting a request signal.

The power supply control unit includes an on trigger signal generating unit arranged to generate an on trigger signal for turning on the switching element on the basis of a feedback signal of flyback voltage, a first timer arranged to measure a predetermined minimum OFF time, a second timer arranged to measure time based on an ON time, a minimum OFF time setting unit arranged to compare the predetermined minimum OFF time measured by the first timer with the time measured by the second timer so as to set a longer time as a minimum OFF time, and an on timing determining unit arranged to determine timing for turning on the switching element on the basis of the set minimum OFF time and the on trigger signal.

A flyback converter includes a primary side circuit, a secondary side circuit and a controller. The primary side circuit includes a primary winding and a main switch electrically connected to the primary winding. The secondary side circuit includes a secondary winding and an output diode electrically connected to the secondary winding and having a parasitic electrical parameter. The controller generates a correcting parameter for counteracting an effect on an output voltage of the flyback converter from the parasitic electrical parameter, wherein the parasitic electrical parameter is an equivalent series-connection resistance R.sub.d of the output diode and the secondary side circuit, and the correcting parameter is calculated based on the formula

[00001]$\frac{n_p}{n_s}.Math.I_{\mathrm{ini}}.Math.R_d,$

wherein n.sub.p denotes a turns number of the primary winding, n.sub.s denotes a turns number of the secondary winding, and I.sub.ini denotes an initial current value which is detected when the main switch is conducted.

An embedded magnetic component transformer includes first, second, and auxiliary electrical windings in an insulating substrate including conductive vias joined together by conductive traces. The first electrical windings are divided by a tap terminal into first and second winding portions, which are interleaved with one another and energized by separate transistors. Heat generated by the first and second winding portions is transferred more equally to the separate transistors. Equal or substantially equal path lengths between each of the transistors and the first electrical windings improve flux balance allowing the transistors to conduct for equal or substantially equal times during a switching cycle. Thus, the switching cycle of the embedded transformer is more symmetric with respect to each of the transistors and winding portions, improving the electrical characteristics of the transformer.

An apparatus that includes resonant tanks, switches, control logic and one or more non-resonant capacitors. The control logic that generates two or more sets of control signal inputs applied to the inputs of the switches so that for each set of control signals one or more sub-circuit loops are formed, and wherein the one or more sub-circuit loops for a first set of control signals is different from the one or more sub-circuit loops for a second set of control signals, and each of the sub-circuit loops includes one or more of the resonant tanks, and at least one of the sub-circuit loops includes a non-resonant capacitor.

A converter includes a DC input; a transformer including first and second primary windings, first and second secondary windings, and first and second feedback windings; a first field-effect transistor; a second field-effect transistor; and a drive circuit connected to the first and second field-effect transistors. The drive circuit includes a bias circuit that applies a bias voltage to gates of the first and second field-effect transistors via the first and second feedback windings during start-up of the converter, wherein the bias voltage is reduced to zero or substantially zero after start-up of the converter; and a reset circuit that resets the bias circuit when the converter is turned off. The converter is a self-oscillating push-pull DC-DC converter.

An overvoltage protection circuit adapted for a switching power supply is provided. The overvoltage protection circuit can use the time difference of the start of the overvoltage protection to distinguish that the overvoltage of the output voltage of the switching power supply is caused by the failure of the internal feedback or by the internal power supply, thereby avoiding a short and harmless external power supply to affect the normal operation of the switching power supply but can immediately stop the switching power supply to achieve protection when the switching power supply has an internal feedback failure.