Astec International Limited

Israel Gomez Beltran

Vijay Gangadhar Phadke

Arlaindo Vitug Asuncion

Siu Lun Wu

Zhizhi Li

Gordon Currie

Melvin Co

Siu Wu

A multi-phase switched-mode power supply includes first and second interleaved phase circuits coupled between input and output terminals. The first phase circuit includes a first inductor coupled with a first switch, and the second phase circuit includes a second inductor coupled with a second switch. A control circuit is configured to output first and second PWM signals to the first and second switches. An on time of the second PWM signal is equal to an on time of the first PWM signal plus a fixed offset time period. The control circuit is configured to determine a period between rising edges of the first PWM signal in order to determine an off trigger PWM signal, and change the second PWM signal to a logical low value when a falling edge of the off trigger PWM signal occurs while the second PWM signal has a logical high value.

Multi-phase switched-mode power supplies

A switched mode DC-DC power supply includes a power circuit having an input for receiving an input voltage, an output for providing an output voltage, and four power switches coupled between the input and the output. The four power switches are arranged in a full bridge configuration. The power supply further includes a control circuit coupled to the power circuit for providing a plurality of control signals to the power switches. The plurality of control signals have a variable frequency. The control circuit is adapted to vary the frequency of the plurality of control signals, and to vary a parameter of only two of the plurality of control signals to regulate the output voltage. The parameter is a duty cycle or a phase of said two control signals. Other example switched mode DC-DC power supplies are also disclosed.

Power supplies having power switches controllable with a varying frequency, duty cycle and/or phase to regulate outputs

A method of operating a switching power converter having at least one power switch controlled by a drive signal having a switching frequency is disclosed. The method includes monitoring an output power of the switching power converter, determining whether the output power has decreased below a threshold level and, in response to the output power decreasing below the threshold level, changing the switching frequency of the drive signal from a first switching frequency to a second switching frequency when an operating condition of the switching power converter is satisfied. Also disclosed are controllers and switching power converters (including PFC converters).

AC-DC switching power converters with frequency variation in response to load changes

A two-stage converter including a buck converter and a DC-DC converter that receives power from the buck converter. The DC-DC converter generates an output voltage of the two-stage converter. A buck control circuit generates a drive signal for the buck converter. The drive signal is based on a first signal representing the output voltage, a second signal representing load applied to the buck converter, and a compensation signal. A characteristic of the compensation signal varies based on the drive signal.

Duty cycle dependent non-linear slope compensation for improved dynamic response

A circuit for reducing power loss for a soft switching full bridge converter at light loads and enabling very high frequency operation without using a cold plate approach. The circuit preferably includes a resonant inductor and blocking inductor on the converter's primary side arranged so as to provide reduced losses for a zero voltage switching bridge converter. The circuit provides these benefits even for converters having a power transformer with very low leakage inductance. The circuit is not dependent on the presence of a high leakage inductance for the power transformer. The circuit can also be used in soft switching half bridge converters. The circuit can also be used in a hard switching full bridge or half bridge converter for achieving zero voltage switching at reduced cost with reduced losses at light load, if the duty cycle of the converter is set near fifty percent.

Circuit for reducing losses at light load in a soft switching full bridge converter

A soft switched zero voltage transition full bridge converter for reducing power loss at very light loads for zero voltage switching (ZVS) converters operating at high frequency. The converter has four switches in two switching legs, each having two switches connected in series between two input voltage terminals. Junction points of the legs are coupled to a primary winding of a transformer. The transformer has a secondary winding from which an output voltage of the converter is derived by rectifying and filtering. A pair of capacitive voltage dividers are connected between the input terminals, each formed by two small capacitors, each having a parallel-connected diode. The output voltage is regulated by phase shift control of the switches. The capacitors are selected small enough for storing only enough energy to enable ZVS in conjunction with two resonant inductors. The converter enables reduced component size of the inductors and energy storage capacitors.

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Antipolo, Philippines

Israel Gomez Beltran