Astec International Limited

Arlaindo Vitug Asuncion

Vijay Gangadhar Phadke

Gordon Currie

Israel Gomez Beltran

Richard Daniel Cabbab Caubang

Evan M Espina

Yancy Fontanilla Boncato

Hong Mao

Melvin Co

Geof Potter

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 method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load is disclosed. The method includes sensing the output voltage and sensing the load current. The method further includes controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level. The method also includes adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

Fast transient step load response in a power converter

A switching power converter includes an input for receiving an input voltage, an output for providing an output voltage, a controller, and a power circuit coupled between the input and the output and including at least one switch. The controller is configured to determine a duty cycle for the switch to regulate the output voltage and control the switch with a PWM drive signal having an on-time and an off-time. The PWM drive signal has a constant frequency and a duty cycle equal to the determined duty cycle when the determined duty cycle is greater than or equal to a minimum duty cycle. The PWM drive signal has a variable frequency and a duty cycle equal to the minimum duty cycle when the determined duty cycle is less than the minimum duty cycle.

Switching power converter and controller

A switching power converter has at least one electronic power switch. To minimize switching losses and optimize efficiency, the gate drive voltage level used to drive the electronic power switch is optimized. In an aspect, a digital controller generates optimizes the gate drive voltage using efficiency optimization algorithms, which in an aspect are programmed in the digital controller. In accordance with an aspect of the present disclosure, the switching power supply has at least two electronic power switches coupled in parallel. Optimization algorithms are used to determine the optimum number of switched electronic power switches that are actively being switched at a given time in order to achieve optimized efficiency for condition changes, such as input voltage variation, load and environmental temperature changes. In an aspect, the algorithms are programmed in a digital controller chip. In an aspect, both gate drive voltage level and the number of electronic power switches being actively switched at a given time are optimized.

Switching power converter with reduced switching losses

A power converter includes a controller and at least one output terminal for providing an output voltage and an output current to a load. The controller is configured for monitoring the output voltage and the output current and calculating an efficiency of the power converter based on the monitored output voltage and output current. The controller is also configured to generate a fault signal after detecting a degradation in the power converter efficiency.

Power converters with operating efficiency monitoring for fault detection

A power converter includes a controller having at least one input for monitoring a rate of change of an operating parameter of the power converter. The controller is configured for comparing the monitored rate of change of the operating parameter with an allowable rate of change for the operating parameter, and for generating a fault signal when the monitored rate of change of the operating parameter deviates from the allowable rate of change for the operating parameter. The operating parameter for which the rate of change is monitored may be, for example, a temperature, a current and/or a voltage in the power converter.

Power converters with rate of change monitoring for fault prediction and/or detection

A circuit for controlling the operation of synchronous rectifiers. The circuit delays the turn-off of the synchronous rectifiers in accordance with the load current. The magnitude of the load current is examined to determine which of a plurality of delay elements is selected to delay turn-off of the synchronous rectifiers. Delay is accomplished by holding up for a predetermined time period one of a plurality of control signals utilized to determine when the synchronous rectifier should be turned-off.

Method and apparatus for reducing body diode conduction of synchronous rectifiers

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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Parañaque, Philippines

Arlaindo Vitug Asuncion