Power Integrations, Inc.

Semiconductor Components Industries, LLC

Fairchild Semiconductor Corporation

Zhao-Jun Wang

Giao Minh Pham

David Michael Hugh Matthews

Stefan Bäurle

Qing McIntosh

Roland Sylvere Saint-Pierre

Balu Balakrishnan

Alex B Djenguerian

Kent Wong

Vikram Balakrishnan

William B Smith

Lance M Wong

Dibyendu Rana

Tiziano Pastore

Sundaresan Sundararaj

Li Kuei Lin

Zhibo Tao

Chih-Hsien Hsieh

A control circuit comprising an output controller coupled to an output side of a power converter. The output controller comprises a switch control signal generator to receive a feedback signal representative of an output of the power controller and to communicate a control signal to an input controller coupled to an input side to control a turn ON of a power switch. The control signal is generated in response to the feedback signal and is communicated in response to an enable signal. The output controller comprises an extremum locator to generate the enable signal in response to a winding signal representative of an instantaneous voltage on an output terminal of an energy transfer element and the extremum locator enables the switch control signal generator such that the transition of the power switch from the OFF state to the ON state occurs substantially when the winding signal reaches an extremum.

Output-side controller with switching request at relaxation ring extremum

A controller comprising a regulation circuit and a frequency request circuit. The regulation circuit configured to receive a signal representative of an output and a reference representative of a desired value of the output, the regulation circuit configured to output a regulation signal in response to a difference between the signal and the reference. The frequency request circuit configured to receive the regulation signal and outputs an increment signal representative of a request to increase a switching frequency and a decrement signal representative of a request to decrease the switching frequency in response to the regulation signal. The frequency request circuit configured to assert the increment signal when the output is less than the desired value for a duration longer than a first period and assert the decrement signal when the output is greater than the desired value for a duration longer than a second period.

Controller with frequency request circuit

A signal amplifier for use in a power converter includes a variable reference generator coupled to generate a reference signal in response to a dimming control signal. A variable gain circuit is coupled to receive the reference signal, the gain signal, and a feedback signal representative of an output of the power converter. The variable gain circuit is coupled to output a first adjusted signal in response to the reference signal and the gain signal. The variable gain circuit is coupled to output a second adjusted signal in response to the feedback signal and the gain signal. An auxiliary amplifier is coupled to output the gain signal in response to the first adjusted signal and a set signal.

Signal amplifier with calibrated reference

A method of providing an input switching request signal to an input side switch includes determining a switching request window indicative of relaxation ringing during a first switching cycle. It is determined that the input side switch is operating in a discontinuous conduction mode (DCM) mode of operation during a second switching cycle. It is determined that the switching request window is open during the second switching cycle. The input switching request signal is enabled in response to determining the switching request window is open.

Apparatus and methods for sensing a variable amplitude switching signal from a secondary winding in a power conversion system are disclosed herein. By using a comparator with an adaptable reference, variable amplitude secondary winding signals in phase with primary winding signals may be detected in the presence of ringing. Detection of the in phase secondary winding signals, in turn, allows for secondary side control with power factor correction and discontinuous mode operation.

Apparatus and methods for sensing a variable amplitude switching signal from a secondary winding in a power conversion system

A controller for use in a power converter comprising a request control circuit coupled to receive a feedback signal representative of an output of the power converter. The request control circuit is coupled to generate a request signal for controlling a power switch. The request signal can include a synchronization signal in response to the feedback signal and a jitter average signal. The synchronization signal is generated by the request transmitter circuit and corresponds to an average on time for controlling the power switch.

Frequency jitter for a power converter

A driver circuit for use in a controller includes a signal generator coupled to generate a first control signal and a second control signal in response to a drive signal that is coupled to control switching of a secondary switch that is to be coupled to the driver circuit and referenced to a reference voltage that is greater than a ground reference voltage. A second switch is coupled to be controlled by the second control signal such that the reference voltage is substantially applied to a control of the secondary switch when the drive signal controls the secondary switch to be off. A first switch is coupled to be controlled by the first control signal such that the sum of the reference voltage and a first voltage is substantially applied to the control of the secondary switch when the drive signal controls the secondary switch on.

Biasing circuit for switch

A method for reducing electromagnetic interference in a flyback converter includes activating a first switch to generate a primary current therein. The first switch is deactivated to generate a secondary current from a magnetic flux generated by the primary current. The magnetic flux is removed by the generation of the secondary current. A second switch is activated with a first voltage pulse to limit an excess voltage across the first switch. The excess voltage is generated in response to the deactivation of the first switch. A second switch is activated with a second voltage pulse to limit a voltage oscillation across the first switch. The voltage oscillation occurs after the removal of the magnetic flux. A first pulse width of the first voltage pulse is increased by a first jitter delay. A second pulse width of the second voltage pulse is increased by a second jitter delay.

Reduction of electromagnetic interference in a flyback converter

A method for regulating a power converter includes initiating a transition of a switch coupled to an input side of the power converter from an OFF to an ON state to regulate a transfer of energy from the input to an output side of the power converter after a switch control signal generator receives an enable signal and if a feedback signal representative of an output of the power converter indicates a change in an output of the power converter. The enable signal is generated to communicate a control signal from the output to the input side in response to a first signal representative of a voltage on an output terminal that oscillates in response to an ending of the transfer of energy. The transition of the switch from the OFF to the ON state occurs substantially at a time that the first signal reaches an extremum.

An electrical circuit for a power supply includes a primary-side controller integrated circuit (IC) that outputs a drive signal on a switch pin to control a switching operation of a switch that is coupled to a primary winding of a transformer. The primary-side controller IC places the switch pin at high impedance during a sense window and turns on the switch in response to sensing a dynamic detection signal on the switch pin during the sense window. The dynamic detection signal is induced by a secondary-side controller IC by controlling switching of a switch that is coupled to a secondary winding of the transformer when the output voltage drops below a predetermined threshold during standby or other low load conditions.

Power supply circuit with secondary side to primary side communication

A method for controlling a resonant converter includes maintaining an output current equal to an output power of the converter divided by an output voltage of the converter in response to a secondary current of a transformer being greater than or equal to a maximum output current. The output power is maintained at a constant output power in response to the output power being greater than or equal to a maximum output power, and the secondary current being less than the maximum output current. Maintaining the output current ratio and the constant output power each comprises changing the duty cycle of a primary-side switch configured to gate a primary current of the transformer. The output voltage is limited to a maximum output voltage in response to the secondary current being less than the maximum output current, and the output power being less than the maximum output power.

Primary-side control of resonant converters

An ac-dc power converter controller includes a switch driver circuit coupled to generate a drive signal to control switching of a power switch to control a transfer of energy from an input of the power converter to an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to generate a sense enable signal in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal for an extended duration of time after the power switch turns OFF.

Input voltage sensor responsive to load conditions

A control circuit for use in an isolated power converter includes an output-side first controller having a switch control signal generator and an extremum locator. The switch control signal generator communicates a control signal to a second controller on the input side of the power converter via an isolated interface to initiate a transition of a switch from an OFF state to an ON state. The extremum locator enables the switch control signal generator to communicate the control signal in response to an oscillating voltage signal at an output terminal of the energy transfer element. The extremum locator enables the switch control signal generator such that the transition of the switch from the OFF state to the ON state occurs substantially at a time that the oscillating voltage signal reaches an extremum.

A power converter controller includes a switch driver circuit coupled to generate a drive signal to control switching of a power switch to control a transfer of energy from an input of the power converter to an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to receive the drive signal to generate a sense enable signal to control the input sense circuit in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal continuously in response to a first load condition, and sense the input sense signal only during a fraction of a switching period of the power switch in response to a second load condition.

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San Jose, CA, United States of America

Zhao-Jun Wang