Abstract: A controller for use in a power converter that includes a current limit generator coupled to receive a feedback signal representative of an output of the power converter and generate an initial current limit signal. The controller includes a modulation circuit coupled to output a modulation signal which is a percentage of the initial current limit signal. An arithmetic operator is coupled to receive the initial current limit and selectively receive the modulation signal and output a current limit. A comparator is coupled to receive a current sense signal representative of a switch current conducted by a primary switch. A drive circuit is coupled to generate a drive signal to control switching of the primary switch to regulate the output of the power converter in response to the comparator output signal, and the drive circuit turns off the primary switch when the switch current has reached the current limit.

Abstract: A controller for use in a power converter includes a power switch including a drain, a source, a control input, and a tap. The power switch includes a first transistor coupled to a second transistor, a drain of the first transistor is coupled to the drain of the power switch and the source of the first transistor is coupled to the tap. A tap sense circuit is coupled to the tap. A drive circuit is coupled to receive an indicator signal from the tap sense circuit. The indicator signal is indicative of a voltage at the tap or the current through the first transistor. The drive circuit is coupled to receive a feedback signal representative of an output quantity of the power converter. The drive circuit is coupled to generate a drive signal to control switching of the power switch in response to the indicator signal and the feedback signal.

Abstract: 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.

Abstract: A high-voltage field effect transistor a heterojunction is disposed between the first and second semiconductor material. A first composite passivation layer includes a first insulation layer and a first passivation layer, and a second composite passivation layer includes a second insulation layer and a second passivation layer. The first insulation layer is disposed between the first passivation layer and the second passivation layer, and the second passivation layer is disposed between the first insulation layer and the second insulation layer. A gate dielectric disposed between the second semiconductor material and the first passivation layer. A gate electrode is disposed above the gate dielectric. A first gate field plate is disposed between the first passivation layer and the second passivation layer. A source electrode and a drain electrode are coupled to the second semiconductor material.

Abstract: A controller for use in a power converter comprising a feedback reference circuit coupled to receive a feedback signal representative of an output voltage of the power converter. A feedback reference circuit generates a drive signal in response to the feedback signal and the drive signal is used to control switching of a power switch of the power converter to regulate the output voltage. The controller further comprises an output power control circuit coupled to receive a current sense signal representative of an output current of the power converter and a power signal representative of a desired value of an output power of the power converter. The output power control circuit generates an adjust signal to adjust the feedback signal such that the controller modifies the output voltage to regulate to the desired value of the output power.

Abstract: A controller for use in a power converter includes a jitter generator circuit coupled to receive a drive signal from a switch controller and generate a jitter signal. The switch controller is coupled to a power switch coupled to an energy transfer element. The switch controller is coupled to receive a current sense signal representative of a drain current through the power switch. The switch controller is coupled to generate the drive signal to control switching of the power switch in response to the current sense signal and the jitter signal to control a transfer of energy from an input of the power converter to an output of the power converter.

Abstract: A controller for a power converter includes a driver circuit that generates a control signal to switch a power switch in response to an output, and a control circuit that controls the switching of the power switch. The control circuit includes a storage time reference circuit generates a storage time reference signal responsive to an input. A first comparator generates a collector off signal in response to a comparison of a switch current sense signal and a collector off reference signal. A storage time regulator circuit generates a base off reference signal in response to the storage time reference signal and the collector off signal. A second comparator generates a base off signal in response to a second comparison of the switch current sense signal and the base off reference signal. The driver circuit is coupled to discontinue and start charging a base terminal of the BJT power switch.

Abstract: A method for controlling an output of a power converter with a control circuit includes generating a drive signal to control switching of a switch to regulate the output of the power converter. It is detected if a switching period of one switching cycle of the drive signal exceeds a threshold switching period. The drive signal is disabled when a period of a switching cycle of the drive signal exceeds the threshold switching period for a threshold consecutive number of switching cycles.

Abstract: A switch having a first terminal, a second terminal and a control terminal. The switch includes a normally-on device with a first terminal, a second terminal, and a control terminal. The first terminal of the normally-on device is the first terminal of the switch. The control terminal of the normally-on device is coupled to the second terminal of the switch. A normally-off device includes a first terminal, a second terminal, and a control terminal. The control terminal of the normally-off device is coupled to the control terminal of the switch. The second terminal of the normally off-device is the second terminal of the switch. The first terminal of the normally-off device is coupled to the second terminal of the normally-on device. A clamp circuit is coupled across the normally-off device. The clamp circuit is coupled to clamp a voltage of the first terminal of the normally-off device to a threshold.

Abstract: A controller for use in a power converter includes a first terminal to provide a turn on signal to initiate turning on of a power switch and a second terminal to provide a turn off signal to initiate turning off the power switch. A detection circuit is coupled to detect a turn off time delay. The turn off time delay is the duration of time between an initiating of a turn off of the power switch by the turn off signal and an actual turn off of the power switch. A control circuit is coupled to control the turn on signal to regulate the turn off delay time to a target time value. The control circuit controls the turn on signal by controlling an amount of charge delivered to turn on the power switch.

Abstract: An ac-dc power supply includes a dc-dc converter coupled to an input of the ac-dc power supply. The input of the ac-dc power supply is coupled to receive an ac input voltage and an ac input current. The dc-dc converter includes a regulated output and a reservoir output. A controller is coupled to receive sense signals from the dc-dc converter. The controller is coupled to control the dc-dc converter to regulate the regulated output in response to the sense signals. The controller is further coupled to control a waveform of the ac input current to have a substantially same shape as a waveform of the ac input voltage. A regulator circuit is coupled to the regulated output and the reservoir output. The controller is coupled to the regulator circuit to control a transfer of energy from the reservoir output to the regulated output through the regulator circuit.

Abstract: A controller for use in a power converter includes a sense circuit coupled to generate a feedback signal representative of an output voltage of the power converter. A feedback reference circuit coupled to generate a drive signal in response to the feedback signal. An output power control circuit coupled to receive a current sense signal representative of an output current of the power converter and a power signal representative of a desired value of an output power of the power converter via an interface. The controller modifies the output voltage to regulate to the output power to the desired value.

Abstract: A controller for use in a two-stage power supply is coupled to control switching of a switching element to regulate a transfer of energy from an input to an output of a flyback converter. The controller activates a boost switching element during a first interval in each line half cycle of an input voltage to boost an output voltage at an output of a boost-bypass converter. The controller deactivates the boost switching element during a second interval in each line half cycle such that the output voltage of the boost-bypass converter drops towards the input voltage during the second interval while the output voltage of the boost-bypass converter is greater than the input voltage. The controller controls the output voltage to follow the input voltage during a third interval of each line half cycle while the boost switching element remains deactivated and the input and output voltages are substantially equal.

Abstract: A controller for use in a power converter includes a control circuit coupled to generate a low side drive signal to control switching of a low side switch, and generate an ON signal and an OFF signal in response to a feedback signal representative of an output of the power converter. A high side signal interface circuit is coupled to generate a high side drive signal in response to the ON signal and the OFF signal to control switching of a high side switch. The ON signal and the OFF signal are coupled to be pulled up in response to a bypass voltage during an initial state. The high side signal is coupled to turn on the high side switch in response to the control circuit pulling the ON signal low, and turn off the high side switch in response to the control circuit pulling the OFF signal low.

Abstract: Devices are disclosed for providing heterojunction field effect transistor (HFETs) having improved performance and/or reduced noise generation. A gate electrode is over a portion of the active region and is configured to modulate a conduction channel in the active region of an HFET. The active region is in a semiconductor film between a source electrode and a drain electrode. A first passivation film is over the active region. An encapsulation film is over the first passivation film. A first metal pattern on the encapsulation film includes a shield wrap over the majority of the active region and is electrically connected to the source electrode.

Abstract: A controller includes a drive circuit that generates a drive signal to switch a power switch to control a transfer of energy to of a power converter output in response to a current sense signal, a feedback signal, and a current limit signal. A current limit generator generates the current limit signal in response to a load coupled to the output. An exclusion frequency range detection circuit generates a frequency skip signal in response to the drive signal to indicate when an intended frequency of the drive signal is within an exclusion frequency window. The current limit signal is unvarying for at least a switching cycle when the intended frequency of the drive signal is within the exclusion frequency window. A first latch generates a hold signal to control the current limit generator to hold the current limit signal in response to the frequency skip signal and the feedback signal.

Abstract: A cascode switch circuit includes a normally-on device cascode coupled to a normally-off device between first and second terminals of the cascode switch circuit. A leakage clamp circuit is coupled between first and second terminals of the normally-off device. The leakage clamp circuit is coupled to clamp a voltage at an intermediate terminal between the normally-on device and the normally-off device at a threshold voltage level. The leakage clamp circuit is further coupled to clamp a voltage between the second terminal of the normally-on device and the control terminal of the normally-on device at the threshold voltage level to keep the normally-on device off when the normally-on device and the normally-off device are off.

Abstract: An integrated circuit (IC) for sensing a current flowing through a transistor device includes a substrate and a current scaling circuit that includes first and second MOSFET devices. The first MOSFET device has a drain coupled to the switched FET at a first node and a source coupled to the substrate. The second MOSFET device has a source coupled to the substrate and a drain coupled to a second node. The first MOSFET device has a channel size that is K times larger than the second MOSFET device. Circuitry is included that equalizes a voltage across both the first MOSFET device and the second MOSFET device.

Abstract: An integrated circuit (IC) for controlling the discharge of a capacitor coupled across first and second input terminals of a power converter circuit, wherein the first and second terminals for receiving an ac line voltage. The IC includes a switching element coupled across the first and second input terminals and a detector circuit. The detector circuit including first and second comparators that produce first and second output signals responsive to a zero-crossing event of the ac line voltage. The first and second output signals being used to generate a reset signal coupled to a timer circuit responsive to the zero-crossing event. When the reset signal is not received within a delay time period, the timer circuit outputs a discharge signal that turns the switching element on, thereby discharging the capacitor.

Abstract: A controller for use in a power converter includes a comparator to compare a current sense signal with a current limit to generate a comparator output signal representative of whether a switch current has reached the current limit. A drive circuit controls switching of a power switch to regulate an output of the power converter in response to a feedback signal and the comparator output signal. The drive circuit turns off the power switch in response to the comparator output signal. A current limit generator generates an initial current limit in response to the feedback signal. The current limit is responsive to the initial current limit. A light load sense circuit outputs a light load signal in response to sensing a light load condition of the power converter. A modulation circuit outputs a modulation signal and modulates the initial current limit in response to the light load signal.