Abstract: An energy transfer assembly includes first and second windings wound around a bobbin. The first winding has a first number of layers proximate to a first end and a second number of layers proximate to a second end of the bobbin. The second winding has a third number of layers proximate to the first end and a fourth number of layers proximate to the second end. At least a portion of one of the first and second windings overlaps at least a portion of the other one of the first and second windings. A degree of overlap between the first and second windings is non-uniform. An isolation barrier is between the first and second windings and around the bobbin. A distance between the isolation barrier and an axis of the bobbin varies along the length of the bobbin.

Abstract: A power supply controller includes a switching signal generator, a zero crossing detection (ZCD) circuit, first and second logic gates, and an interval generator. The switching signal generator generates a switching signal and the ZCD circuit generates a ZCD signal that pulses each zero-crossing of an ac input voltage. The first logic gate generates a first output when the ZCD signal pulses while the output of the power supply is below a threshold reference. The second logic gate generates a second output when the ZCD signal pulses while the output of the power supply is above the threshold reference. The interval generator is enabled in response to the first output and disabled in response to the second output. The interval generator allows the switching signal to pass through the interval generator to the switch when enabled and does not allow the switching signal to pass when disabled.

Abstract: A power supply controller includes a switching signal generator, a zero crossing detection (ZCD) circuit, first and second logic gates, and an interval generator. The switching signal generator generates a switching signal and the ZCD circuit generates a ZCD signal that pulses each zero-crossing of an ac input voltage. The first logic gate generates a first output when the ZCD signal pulses while the output of the power supply is below a threshold reference. The second logic gate generates a second output when the ZCD signal pulses while the output of the power supply is above the threshold reference. The interval generator is enabled in response to the first output and disabled in response to the second output. The interval generator allows the switching signal to pass through the interval generator to the switch when enabled and does not allow the switching signal to pass when disabled.

Abstract: An energy transfer assembly includes first and second windings wound around a bobbin. The first winding has a first number of layers proximate to a first end and a second number of layers proximate to a second end of the bobbin. The second winding has a third number of layers proximate to the first end and a fourth number of layers proximate to the second end. At least a portion of one of the first and second windings overlaps at least a portion of the other one of the first and second windings. A degree of overlap between the first and second windings is non-uniform. An isolation barrier is between the first and second windings and around the bobbin. A distance between the isolation barrier and an axis of the bobbin varies along the length of the bobbin.

Abstract: An energy transfer assembly with tuned leakage inductance and common mode noise compensation is disclosed. An example energy transfer assembly for use in a resonant power converter includes a first winding wound around a bobbin mounted on a magnetic core. The first winding has a first number of layers proximate to a first end along a length of the bobbin and a second number of layers proximate to a second end along the length of the bobbin. The energy transfer assembly also includes a second winding wound around the bobbin. The second winding has a third number of layers proximate to the first end along the length of the bobbin and a fourth number of layers proximate to the second end along the length of the bobbin. The first and second windings are wound around the bobbin such that at least a portion of one of the first and second windings overlaps at least a portion of an other one of the first and second windings around the bobbin.

Abstract: An example controller for use in a power supply includes a zero crossing detection (ZCD) circuit, a threshold detection circuit, and a punctuated switching control circuit. The ZCD circuit generates a ZCD signal that pulses each zero-crossing of an ac input voltage. The threshold detection circuit receives and compares an output of the power supply with a threshold reference. The punctuated switching control circuit generates a switching signal to control a switch to regulate the output of the power supply. The switching signal is generated to have intervals of switching and intervals of no switching, where each interval of switching begins responsive to the output of the power supply dropping below the threshold reference and each interval of no switching begins responsive to the output rising above the threshold reference. Each interval has a beginning that is synchronized with a pulse of the ZCD signal.

Abstract: A method of controlling an LLC resonant converter includes programming a burst stop frequency and a burst start frequency in response to a maximum switching frequency of the LLC resonant converter. The burst stop frequency and the burst start frequency are fractions of the maximum switching frequency. The LLC resonant converter is switched in response to a feedback signal to regulate an output of the LLC resonant converter. The steps of switching the LLC resonant converter in a run state in response to the feedback signal reaching a value corresponding to the programmed burst start frequency, and stopping the switching of the LLC resonant converter in a stop state in response to the feedback signal reaching a value corresponding to the programmed burst stop frequency are repeated.

Abstract: A controller for use in an LLC resonant converter is disclosed. An example controller is controlled by detecting a maximum frequency signal to set a maximum switching frequency of the LLC resonant converter. A burst stop frequency and a burst start frequency are programmed in response to the maximum switching frequency. The burst stop frequency and the burst start frequency are fractions of the maximum switching frequency. The LLC resonant converter is switched in response to a feedback signal to regulate an output of the LLC resonant converter. The steps of switching the LLC resonant converter in a burst mode in response to the feedback signal reaching a value corresponding to the programmed burst start frequency and of stopping the switching of the LLC resonant converter in the burst mode in response to the feedback signal reaching a value corresponding to the programmed burst stop frequency are repeated.

Abstract: An example controller for use in a power supply includes a zero crossing detection (ZCD) circuit and a punctuated switching control circuit. The ZCD circuit is coupled to generate a ZCD signal in response to a zero-crossing of an ac input voltage of the power supply. The punctuated switching control circuit is coupled to the ZCD circuit to generate a switching signal to control a switch to regulate an output of the power supply. The punctuated switching control circuit generates the switching signal having an interval of switching and an interval of no switching in response to the ZCD signal, where the interval of switching has a beginning that is synchronized with the zero crossing of the ac input voltage and where the interval of no switching has a beginning that is synchronized with another zero crossing of the ac input voltage.

Abstract: A power supply includes a PFC (power factor correction) converter that has an input and an output. The PFC converter input is coupled to an input of the power supply. The power supply also includes a resonant mode converter that has an input and an output. The resonant mode converter input is coupled to the PFC converter output and the resonant mode output is coupled to an output of the power supply. A control unit is also included in the power supply and is coupled to receive a feedback signal that is representative of the output of the power supply. The control unit is coupled to provide control signals coupled to control switches of the resonant mode converter at a controlled switching frequency to control the output of the power supply. The control unit is further coupled to provide a PFC control signal coupled to control a switch of the PFC converter at a switching frequency that is harmonically related to the controlled switching frequency.

Abstract: A controller for use in an LLC resonant converter is disclosed. An example controller is controlled by detecting a maximum frequency signal to set a maximum switching frequency of the LLC resonant converter. A burst stop frequency and a burst start frequency are programmed in response to the maximum switching frequency. The burst stop frequency and the burst start frequency are fractions of the maximum switching frequency. The LLC resonant converter is switched in response to a feedback signal to regulate an output of the LLC resonant converter. The steps of switching the LLC resonant converter in a burst mode in response to the feedback signal reaching a value corresponding to the programmed burst start frequency and of stopping the switching of the LLC resonant converter in the burst mode in response to the feedback signal reaching a value corresponding to the programmed burst stop frequency are repeated.

Abstract: An energy transfer assembly with tuned leakage inductance and common mode noise compensation is disclosed. An example energy transfer assembly for use in a resonant power converter includes a first winding wound around a bobbin mounted on a magnetic core. The first winding has a first number of layers proximate to a first end along a length of the bobbin and a second number of layers proximate to a second end along the length of the bobbin. The energy transfer assembly also includes a second winding wound around the bobbin. The second winding has a third number of layers proximate to the first end along the length of the bobbin and a fourth number of layers proximate to the second end along the length of the bobbin. The first and second windings are wound around the bobbin such that at least a portion of one of the first and second windings overlaps at least a portion of an other one of the first and second windings around the bobbin.

Abstract: An example controller for use in a power supply includes a zero crossing detection (ZCD) circuit and a punctuated switching control circuit. The ZCD circuit is coupled to generate a ZCD signal in response to a zero-crossing of an ac input voltage of the power supply. The punctuated switching control circuit is coupled to the ZCD circuit to generate a switching signal to control a switch to regulate an output of the power supply. The punctuated switching control circuit generates the switching signal having an interval of switching and an interval of no switching in response to the ZCD signal, where the interval of switching has a beginning that is synchronized with the zero crossing of the ac input voltage and where the interval of no switching has a beginning that is synchronized with another zero crossing of the ac input voltage.

Abstract: A DC converter comprises a half bridge supply circuit and one or more flyback or forward converter output circuits, and optionally also an LLC converter whose control can determine a common variable switching frequency. The half bridge supply circuit produces a 50% duty output alternating between two input voltages, such as zero and a voltage Vin. In each flyback or forward converter output circuit, a switch connects a transformer primary to the half bridge supply circuit output in a PWM controlled manner to regulate a respective flyback or forward converter DC output which is produced by the converter output circuit, with a duty ratio less than 50% whereby switching losses are reduced. Soft switching is further facilitated by the half bridge supply circuit having two transistors controlled in a complementary manner.

Abstract: Distributed power supply arrangements and related methods are disclosed. Voltage is sensed at least one sense point in a power plane of a power distribution network. The power plane includes distributed source points and load points through which a plurality of power sources supply power to a plurality of loads. Currents supplied to the power plane by the power sources are regulated based on the voltage sensed at each of the at least one sense point.

Abstract: An electronics product has a control unit responsive to a power-on remote control signal to enable DC power converters to supply power for normal operation of the product and to a microprocessor for responding to other remote control signals. The microprocessor controls the control unit to return to a standby mode of the product by disabling the DC power converters. The arrangement facilitates eliminating a conventional standby power supply and achieving a very low standby power consumption.

Abstract: A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second inductor inductively coupled to the first inductor, and an AC switch for selectively shorting the second inductor. A capacitor in parallel with the first inductor forms a resonant circuit tuned to the AC supply frequency when the switch is open. Each switch is opened and closed with a controlled duty cycle to provide individual control of an average current of each CCFL.

Abstract: Distributed power supply arrangements and related methods are disclosed. Voltage is sensed at least one sense point in a power plane of a power distribution network. The power plane includes distributed source points and load points through which a plurality of power sources supply power to a plurality of loads. Currents supplied to the power plane by the power sources are regulated based on the voltage sensed at each of the at least one sense point.

Abstract: A plurality of power sources (26) supply power to a plurality of loads (24) via a distribution network (20, 22). Voltage is sensed at one or more points (28) in the network to provide a closed loop for regulating current or power supplied by the power sources, thereby allowing for voltage drops due to resistance of the distribution network. The loads may be low voltage integrated circuit devices on a printed circuit board (10), the distribution network may comprise power and ground planes of the board, and the power sources may be switch mode power converters on the board and providing regulated output currents.

Abstract: A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second inductor inductively coupled to the first inductor, and an AC switch for selectively shorting the second inductor. A capacitor in parallel with the first inductor forms a resonant circuit tuned to the AC supply frequency when the switch is open. Each switch is opened and closed with a controlled duty cycle to provide individual control of an average current of each CCFL.