Semiconductor Components Industries, LLC

Igo, Inc.

Mobility Electronics, Inc.

Bryan Wayne McCoy

Ajay Karthik Hari

Jason Walter Swanson

Thomas Ciccone

Richard Garrison Dubose

John C Ciccone

Thomas Duffy

Alan David Finkel

Agus S The

Arthur Kenneth Dewyer

William E Davis

Andrew Christopher Stirling

Timothy Kaske

Anthony Michael Nasir

Selvarajan Shanthosh

An active clamp flyback (ACF) converter can be used to convert AC voltages to DC voltages and offers the ability to reuse leakage energy and a negative magnetizing current to achieve zero-volt-switching. The leakage energy can vary with system design and therefore may be difficult to control, but the negative magnetizing current can be controlled by adjusting a switching frequency of the ACF converter. The adjustment can be determined by comparing the negative magnetizing current to a threshold. Using a fixed threshold may not be optimal because variations in system operating conditions, such as load current, line voltage, and output voltage, can affect the amount of negative magnetizing current required for zero-volt-switching (i.e., can affect the threshold). Additionally, a range of possible switch technologies can affect the threshold. The present disclosure describes an adaptable threshold for a variable frequency ACF converter that allows for efficient switching.

System and methods for switching an active clamp flyback converter

In one form, a method for generating a drive signal for a switch in a switched mode power supply includes receiving a feedback signal, generating a feedback voltage in response to the feedback signal, modulating a pulse width of the drive signal in response to the feedback voltage and a mode signal, generating a modulate signal in response to a magnitude of the feedback voltage crossing a first level in a first direction, generating the mode signal in response to the magnitude of the feedback voltage crossing a second level different from the first level in a second direction, and varying a gain between the feedback signal and the feedback voltage in response to the mode signal.

Switched mode power supply with multi-mode operation and method therefor

An ACF power converter uses a soft start operation to reduce overheating and stress on components. The power converter includes a first transistor and second transistor. A high side driver controls the first transistor, and low side driver controls the second transistor. A first operating potential is provided to the low side driver during a first period of time. The second transistor switches based on an oscillator signal having a first rate of frequency change to generate a second operating potential for the high side driver, while attempting to hold the first transistor in the non-conductive state during a second time period. The first and second transistors switch based on the oscillator signal having a second rate of frequency change during a third time period. The power converter is held in ACF mode and inhibited from changing state for a period of time post soft start.

Active clamp power converter and method of reducing shoot-through current during soft start

A power converter has a power transistor and inductor coupled in a conduction path with the power transistor. A switching frequency of the power transistor is reduced during a light load condition. A pulse width of a drive signal to the power transistor is controlled to select a current through the inductor and power transistor corresponding to the switching frequency to maintain a fixed output power of the power converter, and further to vary the current through the inductor and power transistor to maintain the fixed output power of the power converter over a range of switching frequencies. A first number of pulses of the drive signal to the power transistor during a first time period sets the fixed output power of the power converter. No pulses of the drive signal are provided during a second time period after the first time period.

Power converter and method of entering skip at a fixed output power in a light load condition independent of magnetizing inductance

In one form, a switched mode power supply controller with frequency foldback includes a pulse width modulator responsive to a clock signal to generate a drive signal having a pulse width that varies in response to a feedback signal, and a variable frequency oscillator having a first input for receiving the feedback signal, a control input for receiving a control signal defining a foldback starting frequency, a foldback ending frequency, a foldback starting voltage, and a foldback ending voltage, and an output for providing the clock signal having a variable frequency that varies over a range between the foldback starting frequency and the foldback ending frequency as the feedback signal varies between the foldback starting voltage and the foldback ending voltage, respectively. The control signal is user programmable for at least one of the foldback starting frequency, the foldback ending frequency, the foldback starting voltage, and the foldback ending voltage.

Switched mode power supply with dynamic frequency foldback

Active clamp flyback power converter. At least some of the example embodiments are methods including: activating a main FET and thereby inducing positive current flow in a primary winding, the positive current flow resulting in reverse biasing of a rectifier of a secondary circuit; deactivating the main FET and thereby forward biasing the rectifier in the secondary circuit and causing current flow in the secondary winding; activating a clamp FET and thereby coupling a clamp capacitor to a leakage inductance of a transformer, the primary circuit having initially a positive current flow through the primary winding and then a negative current flow through the primary winding; and regulating the negative current flow through the primary winding.

Systems and methods of active clamp flyback power converters

In one form, a switched mode power supply controller with frequency foldback includes a pulse width modulator responsive to a clock signal to generate a drive signal having a pulse width that varies in response to a feedback signal, and a variable frequency oscillator having a first input for receiving the feedback signal, a control input for receiving a programmable control signal defining a foldback starting frequency, a foldback ending frequency, a foldback starting voltage, and a foldback ending voltage, and an output for providing the clock signal having a variable frequency that varies over a range between the foldback starting frequency and the foldback ending frequency as the feedback signal varies between the foldback starting voltage and the foldback ending voltage, respectively. In another form, a switched mode power converter uses such a switched mode power supply controller with an inductive element, switch, and feedback circuit.

A switched mode power supply includes an active clamp flyback converter having an input for receiving an input voltage, and an output for providing a regulated voltage, the active clamp flyback converter having a first switch for controlling a flow of current through a primary winding of a flyback transformer, and a second switch for clamping a switch node on a primary side of the flyback transformer, and a controller for controlling the first and second switches to operate the active clamp flyback converter in an active clamp flyback mode when a load current is above a first predetermined level, and for controlling the first and second switches to operate the active clamp flyback converter in a discontinuous conduction mode with a variable switching frequency when the load current is below a second predetermined level.

Switched mode power supply with efficient operation at light loads and method therefor

A semiconductor component that includes a current limit circuit and a method for limiting current in the semiconductor component. An input/output pin is connected to the gate of a transistor and a control resistor is connected between the gate of the transistor and its source. One terminal of the control resistor is connected to the input/output pin and the other terminal is connected to another input/output pin. A current source is connected to the input/output pin. A reference voltage is generated between the two input/output pins and compared with a drain-source voltage that is between one of the two input/output pins and another input/output pin. A control voltage is set in accordance with the comparison. The control voltage then controls the voltage on another of the pins that is not common to the reference voltage and to the drain-source voltage.

Method for limiting current and circuit therefor

A power converter having an aircraft power source detector configured to limit the amount of power that can be drawn by the power converter when utilized in an aircraft. The power converter may detect an artifact of the aircraft power source, such as the 400 Hz ripple noise on an aircraft power line, or existing in the aircraft cabin, such EMI or aircraft lighting.

Power converter having airplane power source frequency detector

A method for reducing a temperature rise of a magnetic material is provided. The method includes applying force to the magnetic material to reduce a dimensional change of the magnetic material during a first part of an operation cycle, such as due to magnetostriction. The force is removed from the magnetic material during a second part of an operation cycle, allowing magnetostrictive dimensional changes to occur.

Magnetostriction aided switching

A power converter having an aircraft power source detector adapted to limit the amount of power that can be drawn by the power converter when utilized in an aircraft. The power converter may detect an artifact of the aircraft power source, such as the 400 Hz ripple noise on an aircraft power line, or existing in the aircraft cabin, such EMI or aircraft lighting.

Growing community of inventors

Chandler, AZ, United States of America

Bryan Wayne McCoy