Abstract: An input redundant circuit according to the present disclosure may include: a core power supply unit; a first input port connected to a first input voltage; a second input port connected to a second input voltage; a relay unit connected to the first input port and the second input port to supply one of the first input voltage and the second input voltage to the core power supply unit; and a surge current limiting unit coupled to the relay unit, configured to limit a surge current generated when the relay unit is switched between the first input voltage and the second input voltage.

Abstract: An example switched-mode power supply includes an input for receiving an input voltage from a voltage source, an output for providing an output voltage to a load, and a transformer having a primary winding, a secondary winding, and a conductive shield disposed between the primary winding and the secondary winding. The power supply also includes a neutralization signal generator circuit coupled to the conductive shield to apply a neutralization signal to the conductive shield to reduce a common mode noise between the primary winding and the secondary winding of the transformer. The neutralization signal has an adjustable amplitude and/or phase. Other example power supplies and methods are also disclosed.

Abstract: According to some aspects of the present disclosure, circuit board assemblies are disclosed. Example circuit board assemblies include a printed circuit board having a first surface and a second surface, and defining an opening having at least one side extending from the first surface to the second surface. The assembly also includes a bus bar having a first surface, a second surface, and at least one side. The bus bar is secured in the opening of the printed circuit board via a press-fit, such that a slot is defined between the at least one side of the bus bar and the at least one side of the opening defined by the printed circuit board. The assembly further includes an electrical lead positioned in the slot, and solder disposed between the electrical lead and the bus bar to electrically couple the electrical lead and the bus bar.

Abstract: Example isolated AC-DC power supplies include a PFC converter coupled to an AC input, a DC-DC converter coupled between the PFC converter and a DC output, and a controller configured to control switching operation of the DC-DC converter. A pulse modulator is coupled to an output of the PFC converter to receive a signal representative of voltage ripple at the output of the PFC converter, and is configured to modulate a pulse signal based on an amplitude of the voltage ripple. A pulse demodulator is coupled to the pulse modulator to receive the modulated pulse signal, and is configured to demodulate the modulated pulse signal and provide a demodulated signal to adjust switching operation of the DC-DC converter. Also disclosed are methods for controlling isolated AC-DC power supplies.

Abstract: A power converter for converting an input power at an input of the converter to an output power at an output of the converter includes a power conversion circuit and a snubber circuit coupled to the power conversion circuit. The power conversion circuit includes a switching device coupled to a reference potential, and an inductance coupled to the switching device. The snubber circuit includes a snubber switching device, a capacitance coupled to the snubber switching device, and an auxiliary inductance coupled to the inductance of the power conversion circuit and the snubber switching device. The snubber switching device and the capacitance are coupled across the switching device of the power conversion circuit. The capacitance is adapted to store leakage energy output from the power conversion circuit and discharge at least a portion of the stored leakage energy via the snubber switching device. Other example power converters are also disclosed.

Abstract: A multi-stage switching power supply includes a first DC-DC power converter, a second DC-DC power converter and a control circuit. The control circuit is coupled to the DC-DC power converters for providing a first control signal to the first DC-DC power converter and a second control signal to the second DC-DC power converter. The control circuit is configured to vary a duty cycle of the first control signal to regulate an output voltage of the power supply, maintain a frequency of the second control signal at a fixed frequency, and in response to the duty cycle of the first control signal reaching a duty cycle threshold or an input voltage of the first DC-DC power converter reaching a voltage threshold, vary a frequency of the second control signal to regulate the output voltage of the power supply. Other example power supplies, control circuits, etc. are also disclosed.

Abstract: A DC-DC power converter includes an input, an output, a transformer, a primary field-effect transistor (FET), and a synchronous rectifier. The synchronous rectifier includes a drain that experiences multiple resonant voltage valleys during each dead-time period of the converter. The converter further includes a synchronous rectifier drive circuit configured to turn on and turn off the synchronous rectifier, and a primary control circuit. The primary control circuit is configured to operate the primary FET in a valley skipping mode, and to transmit a drive signal to the synchronous rectifier drive circuit to turn on the synchronous rectifier during a specified one of the multiple resonant voltage valleys to generate a negative current through the synchronous rectifier. Methods of operating a DC-DC power converter are also disclosed.

Abstract: A DC-DC power converter includes an input, an output, a transformer, and a primary FET coupled to selectively conduct current though a primary winding of the transformer. The primary FET includes a drain that experiences multiple resonant voltage valleys during each dead-time period of the converter. The converter further includes a synchronous rectifier coupled to selectively conduct current through a secondary winding of the transformer, and a control circuit. The control circuit is configured to operate the primary FET in a valley skipping mode by turning on the primary FET during a second or subsequent one of the multiple resonant voltage valleys, and to allow a negative current in the secondary winding of the transformer before turning off the synchronous rectifier during one or more of the multiple resonant voltage valleys. Methods of operating DC-DC power converters are also disclosed.

Abstract: Example isolated AC-DC power supplies include a PFC converter coupled to an AC input, a DC-DC converter coupled between the PFC converter and a DC output, and a controller configured to control switching operation of the DC-DC converter. A pulse modulator is coupled to an output of the PFC converter to receive a signal representative of voltage ripple at the output of the PFC converter, and is configured to modulate a pulse signal based on an amplitude of the voltage ripple. A pulse demodulator is coupled to the pulse modulator to receive the modulated pulse signal, and is configured to demodulate the modulated pulse signal and provide a demodulated signal to adjust switching operation of the DC-DC converter. Also disclosed are methods for controlling isolated AC-DC power supplies.

Abstract: According to some aspects of the present disclosure, automatic transfer switch circuits and control methods are disclosed. Example automatic transfer switch circuits include a first voltage input having a line terminal and a neutral terminal, a second voltage input having a line terminal and a neutral terminal, a voltage output having a line output terminal and a neutral output terminal, a first relay coupled to the line terminal of the first voltage input and the line terminal of the second voltage input, a second relay coupled to the neutral terminal of the first voltage input and the neutral terminal of the second voltage input, a third relay coupled between the line output terminal and at least one of the first relay and second relay, a fourth relay coupled between the neutral output terminal and at least one of the first relay and the second relay, and a controller.

Abstract: A control circuit for controlling a power circuit having a power switch includes a control loop configured to generate a control signal for the power switch of the power circuit based on an error signal determined by comparing a sensed parameter of the power circuit and a reference signal, and a positive offset signal and a negative offset signal each configured to adjust the control signal. The control circuit is configured to detect a change in an output current of the power circuit and selectively apply only one of the offset signals based on the change in the output current to adjust the control signal thereby enhancing a dynamic response to the change in the output current. Additional example control circuits, example power supplies and/or power converters including a control circuit for controlling a power switch, and example control methods are also disclosed.

Abstract: According to some aspects of the present disclosure, example interleaved power supplies and corresponding control methods are disclosed. Example interleaved power supplies include an input terminal, an output terminal, and a first phase circuit coupled between the input terminal and the output terminal. The first phase circuit includes a first inductor and a first switch. The power supply also includes a second phase circuit coupled between the input terminal and the output terminal. The second phase circuit includes a second inductor and a second switch. The power supply further includes at least one current sensor, and a controller operable to control the first phase circuit and the second phase circuit in an interleaved mode when the sensed output current is below a current threshold and to control the first phase circuit and the second phase circuit in an in-phase mode when the output current is above the current threshold.

Abstract: A switching shunt regulator circuit includes a current source having an input for receiving an input voltage and an output for providing a DC current, and a shunt voltage regulator coupled to the output of the current source. The current source is configured to provide DC current to a DC load and DC current to the shunt voltage regulator when the DC load is coupled to the output. The DC current to the shunt voltage regulator regulates a voltage at the output. The shunt voltage regulator has a current carrying capacity greater than the sum of the DC current to the DC load and the DC current to the shunt voltage regulator.

Abstract: A switch mode power supply includes an input, an output, and a power converter coupled between the input and the output. The power converter includes a transformer having a primary side and a secondary side, and a clamping circuit. The clamping circuit has a switching device coupled to the primary side of the transformer. The power supply further includes a control circuit coupled to the switching device. The control circuit includes at least one isolation component. The control circuit is configured to receive a signal from the secondary side of the transformer via the at least one isolation component, and control the switching device coupled to the primary side of the transformer in response to the signal received from the secondary side of the transformer via the at least one isolation component. Other example power supplies, power converters, control circuits, etc. are also disclosed.

Abstract: Methods of regulating an output voltage of a switched mode power supply having a variable input voltage and a power switch include adjusting a reference voltage to adjust a duty cycle of a control signal for the power switch. The reference voltage may be adjusted as a function of the duty cycle, in response to the duty cycle of the control signal being outside a defined range and/or in the response to a temperature within the switched mode power supply being above a threshold temperature. Other methods include selecting a reference voltage from a plurality of reference voltages based on a determined input voltage and generating a control signal for the power switch as a function of the selected reference voltage to adjust the duty cycle of the control signal. Switched mode power supplies and control circuits for implementing the methods are also disclosed.

Abstract: A power supply system includes a flyback power converter and a control circuit coupled to the flyback power converter. The power converter includes an input, an output, a transformer having a plurality of windings coupled between the input and the output, a first power switch coupled to the transformer and a clamping circuit having a capacitor, a diode, and a second power switch coupled to one of the plurality of windings. The capacitor and the diode are coupled in parallel between the winding and the second power switch. The control circuit is configured to operate the power converter in a discontinuous conduction mode and control the first power switch and the second power switch at a fixed frequency to achieve substantially zero voltage switching during turn on of the first power switch. Various other example power supply systems, power converters, and methods for controlling a power converter are also disclosed.

Abstract: According to some aspects of the present disclosure, isolated power supplies and corresponding control methods are disclosed. Example isolated power supplies include a transformer, at least one power switch coupled to the transformer, a controller, an output terminal, and a feedback circuit coupled to the output terminal to sense the output voltage and compare the sensed output voltage to a voltage reference. The power supplies include a fault detection circuit to sense the output voltage, compare the sensed output voltage to a fault reference, and modify a feedback signal when the sensed output voltage exceeds the fault reference. The power supplies also include a single isolation device coupled between the feedback circuit and the controller. The controller is operable to control the power switch based on the feedback signal and to detect a fault condition when a slew rate of the feedback signal exceeds a fault threshold slew rate value.

Abstract: A control circuit includes a first integrator circuit corresponding to a first mode and a second integrator circuit corresponding to a second mode. The control circuit is configured to transition control of the power converter between the first mode and the second mode such that one of the first mode and the second mode is a controlling mode for a period of time and the other one of the first mode and the second mode is a non-controlling mode for the period of time, and set an output of the first integrator circuit or the second integrator circuit corresponding to the non-controlling mode to equal an output of the first integrator circuit or the second integrator circuit corresponding to the controlling mode. Other example control circuits, power converters including a control circuit, and methods for controlling a power converter are also disclosed.

Abstract: According to some aspects of the present disclosure, open loop bi-directional converters and corresponding control methods are disclosed. Example open loop bi-directional converters include a transformer, one or more primary switches coupled to a primary side of the transformer, one or more secondary switches coupled to a secondary side of the transformer, an input capacitor coupled to an input terminal, an output capacitor coupled to an output terminal, and a primary side controller operable to control the one or more primary switches in an open loop mode at a fixed frequency and a fixed duty cycle. The open loop bi-directional converter is coupled to provide current from the secondary side of the transformer to the primary side of the transformer automatically when the voltage of the input capacitor is reduced below the voltage of the output capacitor.

Abstract: A multiphase DC/DC power converter includes an input, an output, at least a first converter and a second converter coupled in parallel between the input and the output, an inductor coupled to the first and second converters, an output capacitor coupled between the first and second converters and the output, and a control circuit coupled to the first converter and the second converter. The first and second converters each include a power switch. The control circuit is configured to switch the power switches at a frequency with a phase shift therebetween, and to vary the frequency to regulate a voltage at the output. Additionally, the control circuit may be configured to switch power switches at a fixed frequency with substantially no phase shift therebetween during startup of a multiphase DC/DC power converter, and at a variable frequency with a defined phase shift therebetween after startup.