A method involves determining that a power converter is in a no-load or ultra-light load mode of operation. In response to determining that the power converter is in a no-load or ultra-light load mode of operation, a voltage amplitude of a feedback signal of the power converter is allowed to rise towards a voltage amplitude that is greater than or equal to a first threshold voltage level. Upon determining that the voltage amplitude of the feedback signal is greater than or equal to the first threshold voltage level, a first sequence of enabling pulses are issued to a primary side switch of the power converter to reduce a voltage amplitude of the feedback signal. Upon determining that the voltage amplitude of the feedback signal is greater than or equal to a second threshold voltage level, a normal mode of operation of the power converter is entered.

Various embodiments provide a parallel arrangement of discontinuous conduction mode (DCM) voltage regulators to provide a regulated voltage to a load. The individual DCM voltage regulators may be triggered (e.g., switched to a charge state) when the regulated voltage falls below a lower threshold. Different DCM voltage regulators in the parallel arrangement may have different lower thresholds. In some embodiments, different DCM voltage regulators may include different inductance and/or transistor size (e.g., to tune the DCM voltage regulators to different current handling capabilities). Other embodiments may be described and claimed.

In a DC/DC converter, in first power transmission in which power is transmitted from a first DC power source to a second DC power source, on/off drive of a positive electrode-side switching element and a negative electrode-side switching element is stopped in a third bridge circuit on the power-receiving side. When a power transmission amount by the first power transmission is smaller than a first reference value, a control circuit lowers the switching frequency of the switching elements of a first bridge circuit and a second bridge circuit on the power-transmitting side and a fourth bridge circuit on the power-receiving side, compared with when the power transmission amount is equal to or greater than the first reference value.

A direct current-to-direct current (“DC-DC”) converter includes: a first converter which outputs a first power voltage in a normal mode or a power saving mode based on a inductor current generated therein, where the first converter operates in a first driving manner in the normal mode, and operates in a second driving manner in the power saving mode; a second converter which outputs a second power voltage based on a inductor current generated therein, where the second converter operates in a third driving manner in the power saving mode, and a magnitude of the second power voltage in the power saving mode is different from that in the normal mode; and a mode selector which supplies a mode control signal to the first and second converters, where the first and second converters are driven in the normal mode or the power saving mode based on the mode control signal.

Circuit embodiments for a switched-capacitor power converter, and/or methods of operation of such a converter, that robustly deal with various startup scenarios, are efficient and low cost, and have quick startup times to steady-state converter operation. Embodiments prevent full charge pump capacitor discharge during shutdown of a converter and/or rebalance charge pump capacitors during a startup period before switching operation by discharging and/or precharging the charge pump capacitors. Embodiments may include a dedicated rebalancer circuit that includes a voltage sensing circuit coupled to an output voltage of a converter, and a balance circuit configured to charge or discharge each charge pump capacitor towards a target steady-state multiple of the output voltage of the converter as a function of an output signal from the voltage sensing circuit indicative of the output voltage. Embodiments prevent or limit current in-rush to a converter during a startup state.

Embodiments herein describe control circuitry for operating a PFC converter in an AC-DC power supply under light loading conditions. The embodiments herein improve the power factor by identifying an optimized phase offset (γ) between an AC reference voltage and an AC reference current used to control the PFC converter. In one embodiment, the control circuitry iteratively changes the phase offset between the reference voltage and current and measures its impact on the power factor. The control circuitry then selects the phase offset that results in the best power factor to use when operating the PFC converter under light loading conditions.

Aspects of hybrid modulation control for DC-to-AC converters are described. In one embodiment, a hybrid modulation pattern is generated. The hybrid modulation pattern separates switch gating control into multiple control regions for a half cycle of the waveform. A first control region modulates according to a first modulation technique and a second control region modulates according to a second modulation technique. The switches of a resonant converter are controlled according to the hybrid modulation pattern to generate the waveform.

A display device includes a diode bridge configured to rectify input power; a power factor correction (PFC) circuit configured to control a power factor of the input power rectified by the diode bridge; a direct current (DC)/DC converter configured to change voltage of the input power received through the PFC circuit; and a PFC controller connected to the diode bridge and configured to selectively turn on or off the PFC circuit based on terminal voltages of lower diodes included in the diode bridge.

The invention discloses a converter adaptable to a wide range output voltage and a control method thereof. The converter comprises a PWM half-bridge circuit. The control method comprises the steps of: controlling the PWM half-bridge circuit to enter into a discontinuous conduction mode by regulating a switching frequency; when the PWM half-bridge circuit is operated in the discontinuous conduction mode, oscillation occurs among the output inductor, a magnetizing inductor of the transformer and a parasitic capacitor of the PWM half-bridge circuit, and when a center point voltage of the primary switching bridge arm reaches a valley or a peak, turning on the corresponding power switch. The invention reduces switching loss by controlling the corresponding power switch in the PWM half-bridge circuit to turn on when a voltage across the power switch is oscillated to valley.

The invention discloses a flyback switching power supply, including a power input and rectifying circuit; a DC-DC switching circuit, the DC-DC switching circuit comprising a PWM control integrated circuit; and a voltage and current feedback circuit. The PWM control integrated circuit comprises a chip working frequency setting pin for setting a working frequency of the PWM control integrated circuit, the flyback switching power supply further comprises a frequency adjustment circuit connected between the chip working frequency setting pin of the PWM control integrated circuit and the voltage and current feedback circuit, and the frequency adjustment circuit is configured to decrease the working frequency when the flyback switching power supply is under a low load condition, and increase the working frequency when the flyback switching power supply is under a high load condition.