Infineon Technologies Austria Ag

Dialog Semiconductor Gmbh

Dialog Semiconductor (uk) Limited

Integrated Device Technology, Inc.

Advanced Energy Industries, Inc.

Iwatt Inc.

Andrey B Malinin

Renato Bessegato

John William Kesterson

Yong Siang Teo

Qiu Sha

Xiaowu Gong

Milan Zarko Ilic

Kalyan N C Siddabattula

Mingsheng Peng

Horst Knoedgen

Pengju Kong

Guang Feng

Xuecheng Jin

Bryce L Hesterman

Enzhu Liang

Soichiro Ohyama

Anders Lind

Klaus Strohmayer

Yuwen Wang

Jiandong Zhang

Lasse Harju

Qifeng Shi

Hidechika Yokoyama

Athar Zaidi

Wessel Lubberhuizen

Tino Lin

Anatoly Cherepakhin

Eric Allan Larson

Kalyan NC Siddabattula

A multi-phase PFC (power factor correction) system, controller, and method of controlling the multi-phase PFC system are described. The method includes operating the phases under variable frequency control to interleave current delivered by the plurality of phases to a load. During a switching cycle for the phases, a phase synchronization correction indicator is activated if a predetermined crossing point along a rising or falling slope of the current delivered by a second phase is misaligned with the same predetermined crossing point along the opposite slope of the current delivered by a first phase. During the next switching cycle, a switching period of the second phase is adjusted if the phase synchronization correction indicator was activated during the previous switching cycle.

Power factor correction system, controller and method of controlling a power factor correction system

An LLC (inductor-inductor-capacitor) converter, including: a primary current sensing circuit operable to sense a primary current of the LLC converter; and a protection circuit coupled between the primary current sensing circuit and power switches of the LLC converter, and operable to increase a switching frequency of the LLC converter when an amplitude of the primary current falls below a predefined low current reference value after a predefined blanking time after a phase transition of the LLC converter.

LLC converter with protection circuit

A multi-phase PFC (power factor correction) system, controller for the multi-phase PFC system and method of controlling the multi-phase PFC system are described. The controller includes a digital circuitry configured to calculate a delay value based on a positive current slope and a negative current slope for a first phase of the plurality of phases which is enabled for all load current conditions. In response to an increase in an average current reference, the digital circuitry is configured to enable a second phase of the plurality of phases such that a current output by the second phase is out of phase with a current output by the first phase by an amount corresponding to the delay value as referenced to a beginning of a boost charging portion of a switching cycle for the first phase.

Multi-phase power factor correction system, controller and method of controlling a multiphase power factor correction system

A power supply includes a primary winding, a secondary winding, a switch, and a controller. The secondary winding is magnetically coupled to the primary winding. The switch is coupled to the secondary winding and controls a state of current through the secondary winding. The controller controls the state of the switch based on an integrator voltage derived from monitoring a voltage from the secondary winding. For example, the controller activates the switch to an ON state in response to detecting a condition in which the magnitude of the monitored voltage of the secondary winding crosses a threshold value such as a magnitude of an output voltage produced from the secondary winding.

Power supply and winding switch control via an integrator voltage

Techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter, without the need for a separate, isolated communication channel. The power converter of this disclosure may send digital information from secondary side to the primary side through a power transformer while the power converter operates in a mixed mode scenario, e.g. critical conduction mode (CRCM) and discontinuous conduction mode (DCM). In CRCM, a controller circuit for the power converter may encode digital information by modulating the diode conduction time in a switching cycle. In DCM, the controller circuit may encode digital information by modulating the period of time for each switching cycle, e.g. increased period, decreased period or no change to the period.

Method of communication through a flyback power transformer using a zero voltage switching pulse in CRCM mode

A synchronous rectifier includes: an integrator configured to integrate a voltage across a secondary side winding of a transformer over an integral period having an expected zero integral value; a first comparator configured to detect an end of a demagnetization phase of the secondary side winding based on diode detection; and a digital circuit configured to adjust a channel gain of the synchronous rectifier based on an integration error at the end of the integral period, the integration error corresponding to the difference between the integrated voltage at the end of the integral period and the expected zero integral. Corresponding methods of gain tuning and a power converter are also described.

Gain tuning for synchronous rectifiers

A power converter, such as a flyback power converter, configured to send digital information from a secondary side to a primary side of the power converter and notify the secondary side that the communication has been received by the primary side. In this manner the secondary side may receive an acknowledgement (ACK) from the primary side, while maintaining isolation between the primary side and secondary side. To implement the ACK response to digital communication from the secondary side, the primary side may delay generating a PWM pulse to the primary side switch. The secondary side may detect the missing PWM pulse based on a change in the integrated secondary side current and determine that the primary side has sent an ACK response.

Reliable communication through a flyback power transformer using a zero voltage switching pulse

In some examples, a controller is configured to control a power switch electrically connected in series with a winding. In some examples, the controller is also configured to control a pass switch electrically connected between an output node of the winding and a bus out node. In some examples, the controller includes a current source configured to selectively drive a charging current from an intermediate node between the power switch and the winding to a control terminal of the pass switch to turn on the pass switch.

Control of a pass switch by a current source

A system is disclosed which provides feedback voltage DC level cancelling for a configurable output of a DC-DC switching converter. By simplifying the design, the operational amplifier can be used for a wider output voltage range. Extension of the usage case to a Boost DC-DC switching converter can give noticeable performance improvements. Offset introduction using a flying capacitor is attractive because it does not require trimming. The proposal also allows for improvements for DC-DC switching converters designed for lower supply voltages, with no decrease in the differential input signal swing.

Feedback voltage DC level cancelling for configurable output DC-DC switching converters

The disclosure describes techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter. By modulating the amount of time between zero voltage switching (ZVS) pulses initiated by a synchronous rectification (SR) transistor on the secondary side, a power converter circuit of this disclosure may communicate digital information to the primary side from the secondary side. The power converter circuit of this disclosure may include stable, accurate and reliable ZVS pulse detection techniques on the primary side to determine slight changes in the period between ZVS pulses from the secondary side. A controller circuit on the secondary side may encode digital information by modulating the ZVS period, e.g. increased period, decreased period or no change to the period.

Communication through the flyback power transformer by the usage of the zero voltage switching pulse

Techniques are provided for controlling a synchronous rectification (SR) switch within a switched-mode power converter. The SR switch rectifies an output voltage of the power converter, and incurs little power loss in doing so. An SR controller generates control signals, including a turn-off trigger, that control conductivity of the SR switch. Voltages provided to the SR controller are divided down, so that the SR controller inputs do not need to support excessively high voltage levels as may be present in the power converter. The divided voltages are integrated to create a volt-second metric that closely tracks current through a winding of the power converter and the SR switch. The volt-second metric is compared against a threshold to determine when to issue an SR switch turn-off trigger.

Synchronous rectification switch control with automatic compensation and reset

Circuits and methods are provided for supplying power to a transformer of a switching DC/DC voltage converter within a power converter. The power converter includes separate nodes that can potentially supply such power. A first of these nodes is coupled, typically directly and with no energy-storing bulk capacitor, to a rectifier that supplies rectified power from an alternating current power source. A second node is also supplied power from the rectifier, but is coupled to a bulk capacitor that can store and supply energy as needed. The techniques disclosed herein use the first node to supply power to the transformer when feasible, and use the second node, and its associated bulk capacitor, to supply power otherwise. In so doing, the energy storage requirements of the bulk capacitor may be reduced, meaning that the capacitance and associated size of the bulk capacitor may be reduced relative to other power converter circuits.

Selection control for transformer winding input in a power converter

A controller for a switching mode power converter is configured to drive a switching element to selectively connect a supply to a primary side winding of a transformer to generate a regulated voltage, current, or power at a secondary side winding of the transformer. The controller is configured to, for each switching cycle, select a peak current value from a plurality of peak current values calculated to drive an oscillating voltage at the switching element to correspond to a voltage valley and in response to determining a voltage valley is occurring at the oscillating voltage at the switching element, output an enabling signal to cause the switching element to generate a channel electrically connecting the supply to the primary side winding until current at the switching element is not less than the selected peak current value.

Valley mode switching with fixed frequency for switching mode power supply

A voltage sensing circuit for a switching power converter includes a comparator having a comparator input stage that processes a voltage from a main DAC and a current from a tracking DAC.

Low-power and compact voltage sensing circuit

An isolated switching power converter is provided wherein a secondary side is valley mode switched to transmit data to a primary side. This provides secondary side regulation without the need for an optocoupler. Data communication between the primary and secondary sides of switching power converters is presented.

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Fort Colins, CO, United States of America

Andrey B Malinin