Abstract: 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.

Abstract: A controller for use in a power converter comprising a comparator, request control, and foldback control. The comparator configured to receive a feedback signal representative of an output of the power converter and a first regulation reference representative of a target value for the output, and in response to the comparison of the feedback signal and the first regulation reference, generate a first regulation signal. Request control configured to receive the first regulation reference, and output a request signal with request events. Foldback control configured to receive the first regulation signal to generate the first regulation reference, the foldback control further configured to sense a foldback or fault condition if the feedback signal is less than the first regulation reference for a threshold duration of time, the foldback control further configured to vary the first regulation reference in response to the sensed foldback or fault condition to reduce the output.

Abstract: A transformer structure is disclosed to reduce common mode noise on an output load. The transformer structure includes a bobbin mounted on a magnetic core, a plurality of windings wound around the bobbin. The plurality of windings include a primary winding coupled to receive an input voltage, a secondary winding coupled to an output load; and a floating auxiliary winding located between the primary and secondary winding. The floating auxiliary winding includes a first terminal and a second terminal coupled to a pair of external float wires extended towards an isolation mounting sheet placed adjacent to an exterior top surface of the transformer structure. The pair of external float wires forms parallel adjacent and open-ended conductive traces with a predefined pattern on the isolation mounting sheet placed above the exterior surface of the transformer structure.

Abstract: An integrated circuit package includes a lead frame and an encapsulation that substantially encloses the lead frame. The lead frame further includes a first conductor comprising a first conductive loop and a second conductor galvanically isolated from the first conductor, proximate to and magnetically coupled to the first conductive loop to provide a communication link between the first and second conductor. The second conductor includes a first conductive portion, a second conductive portion, and a wire coupling together the first conductive portion and the second conductive portion.

Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.

Abstract: 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.

Abstract: 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.

Abstract: An electronic circuit for sensing a temperature rise in a power transistor device, the temperature rise caused by a current flow in the power transistor device. The power transistor device and a sense-FET are disposed on a substrate. The sense-FET senses a fractional portion of the current flow and outputs a current signal. A JFET has its drain connected to the drain of the power transistor device. The gate of the JFET is connected to the source of the power transistor device, such that when the power transistor device is on, the JFET is also turned on, and a drain voltage signal of the power transistor device is output at a second node of the JFET. A detection circuit receives the drain voltage signal and the current signal and outputs an alarm signal when the drain-source resistance of the power transistor device exceeds a combined threshold limit.

Abstract: Apparatus and methods for sensing resonant circuit signals to enhance control in a resonant converter are described herein. A buffer circuit coupled in parallel with or across a resonant component (e.g., a transformer) input port avails a buffered primary port signal for use in resonant conversion. The buffered primary port signal is a comprehensive signal including information relating to both input voltage and input power; and it may be used to advantageously enhance switching and power conversion in an inductor-inductor capacitor (LLC) converter. Additionally, the LLC converter uses a sense interface circuit to provide a scaled replica of the buffered primary port signal. In one example the scaled replica can advantageously be used with a secondary side controller to control output power based on the comprehensive information contained within the buffered primary port signal.

Abstract: A controller to regulate a power converter includes a terminal coupled to receive an enable signal including enable events representative of an output of the power converter. A drive circuit is 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 the output of the power converter. The drive circuit is coupled to turn on the power switch when an enable event is received in the enable signal. A current limit threshold generator is coupled to the drive circuit to generate a current limit threshold signal. The current limit threshold signal varies each switching cycle of the power switch. A time between consecutive enable events in the enable signal is the switching cycle of the power switch.

Abstract: A controller for a multiple output power converter, including an error amplifier configured to generate an error signal based on a difference between an output signal of a multiple output power converter and a reference signal. A switch request circuit is configured to generate a request signal in response to the error signal. The switch request circuit is further configured to control a switching of a power switch of the multiple output power converter to transfer energy from an input of the multiple output power converter to an output of the multiple output power converter. A power limit fault circuit is configured to receive the request signal and the error signal, the power limit fault circuit further configured to generate a first fault signal in response to detection of an output overload or short circuit.

Abstract: A controller for use in a power converter includes a control loop clock generator that is coupled to generate a switching frequency signal in response to a sense signal representative of a characteristic of the power converter, a load signal responsive to an output load of the power converter, and a hard switch sense output. A hard switch sense circuit is coupled to generate the hard switch sense output in response to the switching frequency signal and a rectifier conduction signal that is representative of a polarity of an energy transfer element of the power converter. A request transmitter circuit is coupled to generate a request signal in response to the switching frequency signal to control switching of a switching circuit coupled to an input of the energy transfer element of the power converter.

Abstract: A controller for use in a power converter includes a comparator configured to compare a sense signal representative of an amount of energy delivered to an output of the power converter, to a target value. An update clock generator configured to receive the sense signal and to generate a clock signal having a clock frequency in response to the sense signal. A request control coupled to the comparator and to the update clock generator, the request control configured to generate a request signal having a request frequency that is responsive to an output of the comparator and that controls an operational state of a power switch of the power converter. The request control further configured to update a rate at which the request frequency of the request signal is responsive to the clock frequency of the clock signal.

Abstract: A power converter controller includes a control loop clock generator that generates a switching frequency signal in response to a sense signal representative of a characteristic of the power converter, a load signal responsive to an output load, and a limit signal representative of a maximum length of a current half cycle of the switching frequency signal. A comparator generates an enable signal in response to the load signal and a load threshold. A limit control generates the limit signal in response to the enable signal and the switching frequency signal. A rate of change of half cycles of the switching frequency signal is controlled in response to the limit signal. A request transmitter generates a request signal in response to the switching frequency signal to control switching of a switching circuit coupled to the energy transfer element and an input of the power converter.

Abstract: Methods and apparatus for continuous conduction mode operation in multi-output power converters are described herein. During a switching cycle, secondary current may be delivered via a diode to a secondary output. Prior to beginning a subsequent switching cycle, a diverting current may be provided to a lower voltage secondary output on a parallel path. In this way diode current may be reduced to substantially zero prior to the subsequent switching cycle.

Abstract: A controller to regulate an output voltage of a power converter comprising a feedback reference circuit to generate a drive signal to control a power switch in response to the feedback signal and an output power control circuit configured to generate an adjust signal in response to an output current of the power converter and a desired value of an output power of the power converter, the adjust signal adjusts the feedback signal such that the controller regulates the output voltage to achieve the desired value of the output power. The output power control circuit further comprises an analog-to-digital converter (ADC), a calculator circuit, and an update circuit. The ADC provides a measure signal which is a digital representation of the output current, the calculator circuit determines a calculated value of the output voltage, and the update circuit further outputs an update signal to update the adjust signal.

Abstract: An HFET includes a first and second semiconductor material. A first composite passivation layer includes a first insulation layer and a first passivation layer, and the first passivation layer is disposed between the first insulation layer and the second semiconductor material. The HFET includes a second passivation layer, where the first insulation layer is disposed between the first passivation layer and the second passivation layer. A gate dielectric is disposed between the second semiconductor material and the first passivation layer. A source electrode and a drain electrode are coupled to the second semiconductor material, and a gate electrode is disposed laterally between the source electrode and the drain electrode. A first gate field plate is disposed between the first passivation layer and the second passivation layer and electrically connected to the gate electrode, and a second gate field plate is disposed above first gate field plate.

Abstract: A controller for use in a power converter comprising a comparator, request control, and foldback control. The comparator configured to receive a feedback signal representative of an output of the power converter and a first regulation reference representative of a target value for the output, and in response to the comparison of the feedback signal and the first regulation reference, generate a first regulation signal. Request control configured to receive the first regulation reference, and output a request signal with request events. Foldback control configured to receive the first regulation signal to generate the first regulation reference, the foldback control further configured to sense a foldback or fault condition if the feedback signal is less than the first regulation reference for a threshold duration of time, the foldback control further configured to vary the first regulation reference in response to the sensed foldback or fault condition to reduce the output.

Abstract: A resonant converter includes a resonant transformer having a leakage inductance and a magnetizing inductance coupled in series to form a resonant transformer input port. The resonant transformer has an output that is coupled to provide an output power to a load. A primary bridge circuit is coupled to provide an input power to the resonant transformer input port. A buffer circuit is coupled in parallel with the resonant transformer input port. A control module is coupled to receive a buffered primary port signal from the buffer circuit to control the primary bridge circuit to control the output power to the load in response to the buffered primary port signal.

Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.