Power Integrations, Inc.

Potentia Semiconductor Corporation

Rajko Duvnjak

Arthur Brian Odell

Balu Balakrishnan

David Michael Hugh Matthews

Yan-Fei Liu

David Alan Brown

Raymond Kenneth Orr

Roland Sylvere Saint-Pierre

Roger Colbeck

Munadir Aziz Ahmed

Jinyuan Tian

Fast turn-on protection of a cascode switch is presented herein. A cascode circuit includes a depletion mode field effect transistor and an enhancement mode field effect transistor electrically coupled in cascode. During turn-on, a protection circuit detects an overcurrent fault by observing a plateau of a cascode node voltage. An overcurrent fault may be detected in response to the plateau existing for greater than a threshold time duration.

Fast turn-on protection of a cascode switch

A primary controller configured for use in a power converter comprising a control circuit configured to determine a mode of operation of the power converter in response to a drive signal of a power switch. The control circuit further configured to generate a control signal in response to a signal representative of the mode of operation of the power converter, wherein the control signal represents a delay time to enable a turn on of the power switch after a turn off of a clamp switch. The control circuit further configured to generate a clamp drive signal to control the clamp switch. The primary controller further comprises a drive circuit configured to generate a drive signal to enable the power switch to transfer energy from an input of the power converter to an output of the power converter.

Mode operation detection for control of a power converter with an active clamp switch

A controller configured for use in a power converter. The controller includes a control circuit coupled to receive an input line voltage sense signal representative of an input voltage of the power converter. The control circuit is configured to generate a control signal in response to a request signal representative of an output of the power converter. The control signal represents a delay time to turn on a power switch after a turn on of a clamp switch in response to the input line voltage sense signal. The control circuit can further generate a clamp drive signal to control a clamp driver and a drive circuit configured to generate a drive signal to control the power switch to transfer energy from an input of the power converter to the output of the power converter.

Input line voltage operation for a power converter

A power converter comprising an energy transfer element is coupled between an input of the power converter and an output of the power converter. A cascode circuit generates a first sense signal and a second sense signal. A controller controls the switching of the cascode circuit to transfer energy from the input of the power converter to the output of the power converter. The controller comprising a current sense circuit generates a current limit signal and an overcurrent signal in response to the first sense signal and the second sense signal. A control circuit generates a control signal in response to the current limit signal and the overcurrent signal. A drive circuit comprising a first stage gate drive circuit generates a drive signal in response to the control signal to reduce EMI, and a second stage of gate drive circuit to enable accurate current sensing of the cascode circuit.

Multiple stage gate drive for cascode current sensing

A controller for a power converter comprising a drive signal generator and drive strength control and a variable strength multi-stage gate driver. The drive signal generator and drive strength control outputs a drive signal to control switching of a power switch and a strength signal to control drive strength of the power switch. The variable strength multi-stage gate driver is configured to turn ON the power switch in response to the drive signal with a first drive strength then a second drive strength when the strength signal is not asserted. The variable strength multi-stage gate driver is configured to turn ON the power switch in response to the drive signal with a third drive strength then the second drive strength when the strength signal is asserted. The second drive strength is stronger than the first drive strength and the first drive strength is stronger than the third drive strength.

Variable drive strength in response to a power converter operating condition

A power converter includes an energy transfer element coupled between an input of the power converter and an output of the power converter. A control switch is coupled to a normally-on switch. The normally-on switch is coupled to the energy transfer element. A controller is coupled to control switching of the control switch to control a transfer of energy from the input of the power converter to the output of the power converter. The controller includes a drive circuit coupled to generate a drive signal in response to a control signal to control switching of the control switch. The drive signal in a first stage of a multiple stage gate drive is coupled not to fully enhance the control switch. The drive signal provided by a second stage of the multiple stage gate drive is coupled to fully enhance the control switch.

An LLC resonant converter controller comprising an overcurrent protection circuit coupled to receive a current sense signal representative of current in a primary winding, wherein the overcurrent protection circuit outputs an overcurrent signal when the perturbed current sense signal is above a low threshold for a number of consecutive switching cycles. The LLC resonant converter controller further includes a control circuit coupled to generate a high side drive signal and a low side drive signal in response to a feedback signal representative of an output of an LLC resonant converter is further coupled to receive the overcurrent signal and is operable to disable switching of the first power switch and second power switch in response to the overcurrent signal.

Overcurrent protection in a power converter

A power converter includes an energy transfer element, a cascode circuit including a low voltage switch and a normally-on switch coupled to the energy transfer element, and a controller coupled to control switching of the cascode circuit. The controller includes a current sense circuit to generate a current limit signal and an overcurrent signal in response to a source signal and first and second sense finger signals from the cascode circuit, a control circuit to generate a control signal in response to the current limit signal and the overcurrent limit signal, and a drive circuit to generate a drive signal in response to the control signal to control the switching of the low voltage switch. The drive signal provided by a first stage is coupled not to fully enhance the low voltage switch, and provided by a second stage is coupled to fully enhance the low voltage switch.

A controller includes a first control circuit coupled to an input side of a power converter. The first control circuit includes a timing and delay circuit and a switch selection circuit. A second control circuit is coupled to an output side of the power converter. The second control circuit includes a valley detection circuit and a synchronous rectifier control circuit. A third control circuit is coupled to the input side of the power converter. The third control circuit is coupled to drive an auxiliary switch coupled to an input side of an energy transfer element. The first control circuit is coupled to alternately drive a main switch, which is coupled to the input side of the energy transfer element, and the auxiliary switch in response to a command signal to transfer energy from the input side to the output side of the energy transfer element to drive a load.

Peak switching and optimal SR drive timing control

A controller for use in a power converter includes a current sense circuit to generate a current limit signal and an overcurrent signal in response to a source signal, a first sense finger signal, and a second sense finger signal. A control circuit is coupled to generate a control signal in response to the current limit signal and the overcurrent limit signal. A drive circuit is coupled to generate a drive signal with a multiple stage gate drive in response to the control signal. The drive signal in a first stage of the multiple stage gate drive is a weak turn on drive signal to turn a switch on slowly to reduce electromagnetic interference (EMI). The drive signal in a second stage of the multiple stage gate drive is a strong turn on drive signal to fully turn on the switch quickly to enable accurate current sensing of the switch.

A controller includes a primary controller and a secondary controller to control switching of a power switch and a secondary switch, respectively, coupled to an energy transfer element of a power converter. A first drive circuit is coupled to generate a first drive signal to enable a first ON section of the secondary drive signal after an ON section of the primary drive signal. A second drive circuit is coupled to generate a second drive signal to enable a second ON section of the secondary drive signal to store energy in the energy transfer element. The energy stored in the energy transfer element during the second ON section is coupled to reduce a switch voltage across the power switch prior to a next ON section of the primary drive signal. The secondary drive signal is generated in response to the first drive signal and the second drive signal.

Active reduced voltage switching using secondary switch

A clock generation circuit for use in a power converter controller includes a modulation signal generator that is coupled to generate a modulation signal in response to an input sense signal representative of an input voltage of a power converter. The modulation signal is responsive to the input sense signal when the input sense signal is greater than a first input threshold. A clock modulator circuit is coupled to receive the modulation signal and a first clock signal from an oscillator. The clock modulator circuit is coupled to generate a second clock signal in response to the first clock signal and the modulation signal. An average frequency of the second clock signal is responsive to the modulation signal.

Power limiting by modulating clock

An off line resonant converter includes a boost storage inductance circuit coupled to a switcher circuit that includes stacked first and second passive switching devices coupled to the boost storage inductance circuit and stacked first and second active bidirectional switching devices coupled to the stacked first and second passive switching devices. The stacked first and second active bidirectional switching devices generate a square wave signal and alternately store energy in and receive energy from the boost storage inductance circuit such that a pulsating current is conducted between the boost storage inductance circuit and the switcher circuit. The pulsating current is bidirectional and flows in a direction responsive to a polarity of the ac input line voltage. A resonant circuit is coupled to an output of the switcher circuit to receive the square wave signal from the switcher circuit to generate an output of the resonant converter.

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Kanata, Canada

Rajko Duvnjak