A control circuit includes: a flip-flop having an output configured to be coupled to a control terminal of a transistor and for producing a first signal; a comparator having an output coupled to an input of the flip-flop, and first and second inputs for receiving first and second voltages, respectively; a transconductance amplifier having an input for receiving a sense voltage indicative of a current flowing through the transistor, and an output coupled to the first input of the comparator; a zero crossing detection (ZCD) circuit having an input configured to be coupled to a first current path terminal of the transistor and to an inductor, where the ZCD circuit is configured to detect a demagnetization time of the inductor and produce a third signal based on the detected demagnetization time; and a reference generator configured to generate the second voltage based on the first and third signals.

A power source apparatus including: a transformer including a primary coil, a secondary coil, and an auxiliary coil, and has a primary side and a secondary side which are insulated from each other; a rectifier circuit including a first output terminal and a second output terminal; a smoothing capacitor; a switching element; a first series circuit having a capacitor and a first rectification element connected in series; and a second series circuit having a second rectification element and the auxiliary coil connected in series. The number of turns of the auxiliary coil is smaller than the number of turns of the primary coil. A product a ratio between the number of turns of the auxiliary coil and the number of turns of the secondary coil and an output voltage on the secondary side of the transformer is equal to or lower than a voltage of the smoothing capacitor.

Disclosed is a power conversion circuit, comprising a three-phase inductor and a switching conversion unit, and the three-phase inductor is integrated into a magnetic assembly, the magnetic assembly comprising: two magnetic yokes relatively parallel to each other; a first, a second and a third winding column spaced apart sequentially and located between the two magnetic yokes, and three windings wound around the first, the second and the third winding column in one-to-one correspondence for forming an phase inductor of the three-phase inductor respectively, and phase differences between power frequency currents flowing in any two of the windings are 120°; wherein when a reference current is applied to each of the windings, magnetic fluxes on the first and the third winding column have a first reference direction, and a magnetic flux on the second winding column has a second reference direction opposite to the first reference direction.

The subject invention reveals new methods and structures for achieving single stage power conversion with both regulated input current and regulated output voltage processing a minimum of load power and thereby achieving higher efficiency than other singles stage power converters with both regulated input current and regulated output voltage and two stage power factor corrected power converters. The subject invention reveals power factor corrected converters that improve the efficiency of the single stage power factor corrected converters on which they are based by adding an auxiliary converter that processes a small fraction of the total load power.

A power converter circuit may include a control circuit configured to generate a drive signal for rendering a semiconductor switch conductive and non-conductive to generate a bus voltage across a bus capacitor. The control circuit may adjust a minimum operating period of the drive signal to a first value when an output power of the power converter circuit is greater than a first threshold and to a second value when the output power is less than a second threshold. The control circuit may comprise a comparator that generates the drive signal in response to a sense voltage and a threshold voltage. When operating in a standby mode, the control circuit may adjust a magnitude of the threshold voltage based on an instantaneous magnitude of an alternating-current line voltage received by the power converter circuit, such that an input current drawn by the power converter circuit is sinusoidal.

Power converters with power factor correction circuits and controllers thereof that are configured to generate frequency-adjustable first and second pulsed signals having respective and complementary phases separated by an adjustable deadtime. For example, a power converter may be configured to receive an alternating current (AC) input signal and output a direct current (DC) output signal. The power converter may include at least one DC/DC converter and a power factor correction circuit. The power factor correction circuit may include a first switching transistor comprising a first gate; a second switching transistor in series with the first switching transistor and comprising a second gate; and a controller configured to generate first and second pulsed signals having respective and complementary phases and separated by an adjustable deadtime and apply the generated first and second pulsed signals to the first and second gates, respectively.

Power factor correction circuits and controllers thereof that are configured to generate frequency-adjustable first and second pulsed signals having respective and complementary phases separated by an adjustable deadtime. For example, a controller for a power factor correction circuit may include a comparator, a frequency controller, and a deadtime controller. The controller may be configured to: receive an input signal comprising a measured output voltage of the power factor correction circuit; compare, via the comparator, the measured output voltage with a set point, resulting in a difference between the measured output voltage and the set point; feed the difference into the frequency controller and adjust a frequency of the first and second pulsed signals based on an output of the frequency controller; and provide the difference to the deadtime controller and adjust the deadtime of the first and second pulsed signals based on an output of the deadtime controller.

A controller for an AC-DC converter including a rectifier circuit that converts AC input voltage into DC output voltage uses control logic to control the rectifier circuit according to two or more operating modes. Each operating mode determines a gain of the rectifier circuit. The controller selects an operating mode from the two or more operating modes based on at least one of an AC input voltage value and a required DC output voltage value. The AC-DC converter provides a wide range of DC output voltage with power factor correction. The controller may be used with AC-DC converter topologies such as boost converter, isolated boost converter, PWM converter, LLC resonant converter, and LCC resonant converter.

A method and a control circuit for driving an electronic switch coupled to an inductor in a power converter in successive drive cycles each including an on-time and an off-time are disclosed. Driving the electronic switch includes: measuring an inductor voltage during the on-time in a drive cycle in order to obtain a first measurement value; measuring the inductor voltage during the off-time in a drive cycle in order to obtain a second measurement value; obtaining a first voltage measurement signal that is dependent on a sum of the first measurement value and the second measurement value; and adjusting the on-time in a successive drive cycle dependent on a feedback signal and the first voltage measurement signal.

The present disclosure provides a three-phase AC/DC converter aiming for low input current harmonic. The converter includes an input stage for receiving a three-phase AC input voltage, an output stage for at least one load, and one or more switching conversion stages, each stage including a plurality of half bridge modules. The switches in each module operate with a substantially fixed 50% duty cycle and are connected in a specific pattern to couple a DC-link and a neutral node of the input voltage. The AC/DC converter further includes one or more controllers adapted to vary the switching frequency of the switches in the switching conversion stages based on at least one of load voltage, load current, input voltage, and DC-link voltage. The converter can also include one or more decoupling stages, such as, inductive components adapted to decouple the output stage from the switching conversion stages.