Abstract: The present disclosure relates to solutions for operating a flyback converter comprising an active clamp. The flyback converter comprises two input terminals and two output terminals. A first electronic switch and the primary winding of a transformer are connected in series between the input terminals. An active clamp circuit is connected in parallel with the primary winding. The active clamp circuit comprises a series connection of a clamp capacitor and a second electronic switch. A third electronic switch and the secondary winding of the transformer are connected in series between the two output terminals. In particular, the present disclosure relates to solutions for switching the first, second and third electronic switch in order to achieve a zero-voltage switching of the first electronic switch.

Abstract: An electronic device includes a circuit board that manages supply of electricity to the electronic device. The circuit board includes an integrated circuit and an external capacitor coupled to a supply terminal of the circuit board. During a startup operation of the integrated circuit, the integrated circuit supplies a first charging current to charge the capacitor to a supply voltage value. The circuit board includes a boost circuit that receives a portion of the first charging current and outputs a second charging current that augments charging of the capacitor. The second charging current is an amplification of the first charging current. The integrated circuit enables operation of the electronic device after the capacitor is charged to the supply voltage value.

Abstract: A method and apparatus for an active discharge of an X-capacitor are provided. A sensor signal, indicative of a voltage at the capacitor, is compared with a lower and upper threshold values. A first value of a smaller one of the lower and upper threshold values is increased to a first new value that is greater than a second value of a larger one of the lower and upper threshold values in response to a first control signal indicating the sensor signal is greater than the upper and lower threshold values. A third value of the greater one of the lower and upper threshold values is decreased to a second new value that is less than the value of the larger one of the lower and upper threshold values in response to a second control signal indicating the sensor signal is less than the upper and lower threshold values.

Abstract: An embodiment provides a circuit including a transformer having a primary winding coupled to an input port configured to receive an input voltage and a secondary winding configured to provide an output voltage at an output port, controller circuitry configured to switch on and off a current through the primary winding so that energy is transferred to the secondary winding while switching and supply circuitry connected to the controller circuitry, wherein the supply circuitry is coupled to an auxiliary winding of the transformer and configured to provide a supply voltage for the controller circuitry.

Abstract: The present disclosure relates to solutions for operating a flyback converter comprising an active clamp. The flyback converter comprises two input terminals and two output terminals. A first electronic switch and the primary winding of a transformer are connected in series between the input terminals. An active clamp circuit is connected in parallel with the primary winding. The active clamp circuit comprises a series connection of a clamp capacitor and a second electronic switch. A third electronic switch and the secondary winding of the transformer are connected in series between the two output terminals. In particular, the present disclosure relates to solutions for switching the first, second and third electronic switch in order to achieve a zero-voltage switching of the first electronic switch.

Abstract: An embodiment provides a circuit including a transformer having a primary winding coupled to an input port configured to receive an input voltage and a secondary winding configured to provide an output voltage at an output port, controller circuitry configured to switch on and off a current through the primary winding so that energy is transferred to the secondary winding while switching and supply circuitry connected to the controller circuitry, wherein the supply circuitry is coupled to an auxiliary winding of the transformer and configured to provide a supply voltage for the controller circuitry.

Abstract: The present disclosure relates to solutions for operating a flyback converter comprising an active clamp. The flyback converter comprises two input terminals and two output terminals. A first electronic switch and the primary winding of a transformer are connected in series between the input terminals. An active clamp circuit is connected in parallel with the primary winding. The active clamp circuit comprises a series connection of a clamp capacitor and a second electronic switch. A third electronic switch and the secondary winding of the transformer are connected in series between the two output terminals. In particular, the present disclosure relates to solutions for switching the first, second and third electronic switch in order to achieve a zero-voltage switching of the first electronic switch.

Abstract: An electronic device includes a circuit board that manages supply of electricity to the electronic device. The circuit board includes an integrated circuit and an external capacitor coupled to a supply terminal of the circuit board. During a startup operation of the integrated circuit, the integrated circuit supplies a first charging current to charge the capacitor to a supply voltage value. The circuit board includes a boost circuit that receives a portion of the first charging current and outputs a second charging current that augments charging of the capacitor. The second charging current is an amplification of the first charging current. The integrated circuit enables operation of the electronic device after the capacitor is charged to the supply voltage value.

Abstract: An electronic device includes a circuit board that manages supply of electricity to the electronic device. The circuit board includes an integrated circuit and an external capacitor coupled to a supply terminal of the circuit board. During a startup operation of the integrated circuit, the integrated circuit supplies a first charging current to charge the capacitor to a supply voltage value. The circuit board includes a boost circuit that receives a portion of the first charging current and outputs a second charging current that augments charging of the capacitor. The second charging current is an amplification of the first charging current. The integrated circuit enables operation of the electronic device after the capacitor is charged to the supply voltage value.

Abstract: A control circuit is configured to control a power factor correction (PFC) pre-regulator including a power switch and being configured to operate in a transition mode of operation and a valley-skipping mode of operation. The control circuit generates a drive signal to control a switching of the power switch based on a current threshold. A current threshold generator in the control circuit is configured to modulate the current threshold as a function of a number of valleys skipped in the valley-skipping mode of operation.

Abstract: An electronic device includes a circuit board that manages supply of electricity to the electronic device. The circuit board includes an integrated circuit and an external capacitor coupled to a supply terminal of the circuit board. During a startup operation of the integrated circuit, the integrated circuit supplies a first charging current to charge the capacitor to a supply voltage value. The circuit board includes a boost circuit that receives a portion of the first charging current and outputs a second charging current that augments charging of the capacitor. The second charging current is an amplification of the first charging current. The integrated circuit enables operation of the electronic device after the capacitor is charged to the supply voltage value.

Abstract: An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

Abstract: An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

Abstract: A control circuit is configured to control a power factor correction (PFC) pre-regulator including a power switch and being configured to operate in a transition mode of operation and a valley-skipping mode of operation. The control circuit generates a drive signal to control a switching of the power switch based on a current threshold. A current threshold generator in the control circuit is configured to modulate the current threshold as a function of a number of valleys skipped in the valley-skipping mode of operation.

Abstract: The present disclosure relates to solutions for operating a flyback converter comprising an active clamp. The flyback converter comprises two input terminals and two output terminals. A first electronic switch and the primary winding of a transformer are connected in series between the input terminals. An active clamp circuit is connected in parallel with the primary winding. The active clamp circuit comprises a series connection of a clamp capacitor and a second electronic switch. A third electronic switch and the secondary winding of the transformer are connected in series between the two output terminals. In particular, the present disclosure relates to solutions for switching the first, second and third electronic switch in order to achieve a zero-voltage switching of the first electronic switch.

Abstract: A method and apparatus for secondary side current mode control of a converter are provided. In the method and apparatus, an output voltage of the converter is detected, where the converter has primary and secondary windings that are galvanically isolated in respective primary and secondary sides. A secondary control signal is generated in the secondary side based at least in part on the output voltage and a reference voltage. The secondary control signal is converted to a primary control signal provided in the primary side. The converter is driven in the primary side based at least in part on the primary control signal and a current sense signal indicative of a current flowing through the primary winding.

Abstract: A control circuit controls a switching circuit of a resonant converter where the switching circuit includes first and second power switches. A first on time of the first power switch and a second on time of the second power switch are controlled to generate a square wave signal to drive the resonant circuit. The control circuit controls the first on time based on a zero current detection time indicating detection of a zero current crossing of a resonant current generated in the resonant circuit in response to the square wave signal and on a time shift delay time based on an output voltage of the resonant converter. The second on time of the second power switch control is based on the zero current detection time detected for the first power switch and on the time shift delay time.

Abstract: An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

Abstract: A controller circuit for an AC-DC converter includes a first controller circuit block configured to drive one or more switches at the primary side of a transformer in the AC-DC converter. A second controller circuit block is configured to sense, at a secondary side of the transformer in said AC-DC converter, a secondary side signal indicative of the output signal from said AC-DC converter. The second controller circuit block generates switching control signals for the first controller circuit block as a function of the secondary side signal. An isolator circuit block between the first controller circuit block and the second controller circuit block includes an isolated transmission channel of the switching control signals from the second controller circuit block to the first controller circuit block.

Abstract: A method and apparatus for controlling a power converter are provided. In the method and apparatus, switching from a first phase to a second phase is delayed until it is determined that both a tank current signal of the converter goes below a tank current threshold and the converter has been in the first phase for more than a first minimum time period. Then the converter determines if a resonant capacitor voltage has fallen below a first resonant capacitance voltage threshold and if a tank current signal goes above a tank current threshold. The converter switches from the first phase to the second phase in response to determining at least one of: the resonant capacitor voltage has fallen below the first resonant capacitance voltage threshold and the tank current signal goes above the tank current threshold. The converter is additionally operated in third and fourth states.