Icergi Limited

Texas Instruments (cork) Limited

Texas Instruments Corporation

Commergy Technologies Limited

George Young

Andrew Bernard Keogh

Seamus Martin O'Driscoll

Colin Gillmor

Trong Tue Vu

Peter Michael Meaney

William James Long

Garry Trevor Tomlins

Garry Tomlins

Michael John Barry

Jacobus Marthinus Barnard

Brian Gaynor

Patrick Walsh

Bernard Keogh

The present application related to switching circuits as employed in power supplies and more particularly to a method of controlling same. More specifically, the present application relates to current shaping circuits for use in power supplies and provides a method for controlling them which provides for stable operating conditions and fast transient response.

Method of controlling a current shaping circuit in a converter with power factor correction

The present application relates to switching power supplies and in particular to AC to DC switch mode power supplies, to methods of power factor correction for same and to devices and circuits that may be used generally in same. The application describes a number of multi-level approaches and circuits.

Power factor correction stages in power conversion

The present application relates to the field of switching power supplies and in particular to switching power supplies in which a primary side is isolated from the secondary side and in which a synchronous rectifier on the secondary side is controlled from the primary side. The application provides a method for minimizing body diode conduction losses.

Method of control for synchronous rectifiers

A class of switching power supplies that use a resonant isolation stage (typically LLC) fed directly or via a diode bridge from the line. Extension of the range of available gain values over frequency without material loss of efficiency is facilitated by usage of additional resonant elements. This capability allows the devices to provide narrow-range inputs to secondary-processing circuits, with the ability to achieve power factor correction if required. The conversion architecture is also compatible with optimal usage of energy storage elements suitable for use with switching power supplies.

Switched mode AC-DC converter

The present application relates to magnetic components employed in switching power supplies. The application provides a gapped magnetic core () construction in which the gap is distributed by placing gaps between the legs () of the core and the top and bottom sections (). The application also provides a bobbin construction having a reduced footprint for inductor and transformers.

Magnetic component for a switching power supply and a method of manufacturing a magnetic component

The present application relates to AC power supplies and in particular to power factor correction circuits in AC-DC converters. The application provides an active power factor correction circuit in which zero voltage switching is inherently achieved using a passive snubbing approach employing a saturable transformer.

Power factor correction circuit

The present application is directed to drive arrangement for semiconductor switches and in particular to a method of driving the gate of a switch with pulses corresponding to turn-on and turn-off commands through separate turn-on and turn-off transformers. The application provides a fail safe reset feature, a more efficient turn-on circuit and an energy recovery circuit for recovering energy from the gate upon turn-off. The application also provides a novel arrangement for assembling multiple pulse transformers on a circuit board.

Gate drive circuit for a semiconductor switch

A transformer-coupled gate-drive power regulator system is provided that includes a feedback stage that generates a PWM signal having a duty-cycle that is based on a magnitude of an output voltage in an output stage. A switch driver stage configured to provide each of a first control signal and a second control signal based on the PWM signal. A switching stage comprising a first transformer input stage, a second transformer input stage, and a control switch. The first transformer input stage activates the control switch via the first control signal while the second transformer input stage is deactivated, and the second transformer input stage activates the control switch via the second control signal while the first transformer input stage is deactivated. The control switch can be configured to provide current through an output inductor in the output stage to generate the output voltage in response to being activated.

Transformer-coupled gate-drive power regulator system

This invention relates to a control circuit for a buck power factor correction (PFC) stage. Buck PFC stages are commonly used in low cost, high efficiency power converters. These buck PFC stages are typically controlled using a very slow control loop with a crossover frequency of the order of 10 to 20 Hz. However, such a slow response is unsuitable for applications requiring overvoltage protection. The present invention overcomes the problems with the known control circuits for buck PFC stages by implementing a two stage control circuit having a fast outer loop control circuit and a slow inner loop control circuit. The fast outer loop control circuit is in operation during low load conditions and the slow inner loop control circuit is only active under load.

Control circuit for a buck power factor correction stage

A PWM modulator as might be used in a power converter, a drive signal will be generated on an output pin of an integrated circuit PWM controller device which is used to drive the output when the modulator is required to be on.

PWM controller with drive signal on current sensing pin

The present invention relates to a power converter () and a method of operating same. There are numerous advantages to operating power converters using a series resonant converter (). This approach is particularly suitable for minimizing switching losses in the power converter when it is operated at high frequency. However, there are problems with the known converters in that they are prone to generate noise in the acoustic spectrum due to the fact that the converter stages are often operating at different frequencies. The present invention relates to a power converter and a method of operating same that enables the operating frequency of the converter to be controlled by a control circuit over a predetermined range of the resonant frequency. This allows reduction in acoustic noise generation and facilitates frequency smearing that will in turn reduce spectral peaks. This is achieved while maintaining output ripple within acceptable ranges.

Power converter implementing frequency smearing

This invention relates to a power converter () comprising a converter input (), a converter output (), a power factor correction (PFC) stage () and an isolation stage (). The PFC stage () is implemented by way of a buck PFC with low side drive and low side current sensing, There is provided a third stage, an intermediate buck pre-regulation stage (), intermediate the buck PFC stage () and the isolation stage (), Control of the power converter output voltage is achieved by varying the duty cycle of the intermediate buck pre-regulation stage () and therefore the isolation stage () may be an unregulated stage operated as a fixed DCDC voltage converter. The isolation stage () is operated as a 50%-50% duly cycle double ended stage. The configuration of power converter allows for a relatively inexpensive, highly efficient converter with 90%+ efficiency and simplified control.

Power converter

A power converter for delivering power to a load at a regulated voltageincludes a regulating stage receiving an unregulated supplyand having a main transformer. Switchesandare arranged in a half-bridge connect the transformer primaryto the unregulated supplyto drive the load via a rectifying stage connected to the transformer secondary. The on-time of the switch is controlled by a controllerto effect the regulation over a range of values of the unregulated supply. An auxiliary transformerhas a secondary windingconnected in series with the main transformer primaryand a primary winding that is selectively driven via a switch. A comparatordetects a low voltage event within the regulating stage, such as a drop in the intermediate voltage at. The primary windingof the auxiliary transformeris driven during the low voltage event.

Power converters

This invention relates to a transformer () for multi-output power supplies such as those commonly found in electronic equipment. The transformer comprises a magnetic core () and a plurality of windings () at least some of which are fractional windings, arranged about the magnetic core. The transformer comprises a dual transformer structure with a pair of transformers, a main transformer () and an auxiliary transformer (). In a preferred embodiment, the main transformer and the auxiliary transformer are connected together. In this way, readily available magnetic components may be used in the construction of the transformer and the simple construction allows for a large cross-sectional area of transformer to be deployed so that reduced turn counts of windings may be used.

Transformer for multi-output power supplies

The present invention relates to a transformer assembly () and a process for manufacturing same. The transformer () comprises a primary winding () wound on a PCB () and a secondary winding () mounted adjacent to the primary winding. The primary winding comprises a spiral coil, for example of wire or insulated wire, wound on the PCB. Gate drive windings () are incorporated in the PCB () and there is therefore very close coupling between the primary winding and the gate drive windings. Furthermore, the secondary winding () is a center-tapped secondary having two halves. A flux balance winding () is provided to connect the two halves of the center-tapped secondary winding () and minimize leakage inductance thereby reducing power loss and spiking effects and obviating the need for complex control arrangements.

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Dublin, Ireland

George Young