Abstract: The present invention discloses a switching regulator, including: a power stage including at least one power transistor which switches according to a switch control signal to convert an input voltage to an output voltage; a pulse width modulation (PWM) signal generator generating a PWM signal according to the output voltage; an over current detection circuit comparing a current sensing signal with a reference signal to generate an over current signal indicating whether an over current is occurring; and a signal adjustment circuit adjusting the PWM signal or a clock signal to generate the switch control signal for controlling an ON time of the power transistor of the power stage.

Abstract: Disclosed herein is a switching converter capable of preventing a period in which a switch SW of a primary side is turned on and a period in which a synchronous rectifying switch SR SW of a secondary side is turned on from being overlapped with each other. The switching converter includes: a transformer T inducing primary energy to secondary side; a switch SW connected to a primary coil of the transformer T to switch a primary voltage; a synchronous rectifier SR connected to a secondary coil of the transformer T to rectify a secondary voltage; and a delay locked loop connected between the secondary coil and the synchronous rectifier SR, wherein the delay locked loop generates a signal synchronized with a turn-on control signal of the switch SW and outputs the generated signal to the synchronous rectifier SR to control a turn-off operation of the synchronous rectifier SR.

Abstract: A secondary controller for use in a synchronous flyback converter includes a comparator, a drive circuit, and logic circuitry. The comparator is coupled to generate a compare signal in response to a comparison of a threshold to an input signal representative of a secondary winding voltage of the synchronous flyback converter. The drive circuit is coupled to generate a drive signal to control a first switch to be coupled to a primary side of the synchronous flyback converter. The drive signal is coupled to be generated by the drive circuit in response to a feedback signal representative of an output of the synchronous flyback converter. The logic circuitry is coupled to the drive circuit and coupled to the comparator. The logic circuitry is also coupled to generate a control signal to control a second switch in response to the drive signal and in response to the compare signal.

Abstract: A receive circuit for use in a power converter controller includes a first amplifier coupled to receive an input pulse. A second amplifier is coupled to a first output of the first amplifier. The first output is coupled to be responsive to the input pulse and to a second output of the second amplifier. An output circuit is coupled to generate an output signal in response to the second output.

Abstract: An energy recovery snubber circuit for use in switching power converters. The power converters may include a switch network coupled to a primary winding of an isolation transformer, and rectification circuitry coupled to a secondary winding of the isolation transformer. The energy recovery snubber circuit may include clamping circuitry that is operative to clamp voltage spikes and/or ringing at the rectification circuitry. The clamped voltages may be captured by an energy capture module, such as a capacitor. Further, the energy recovery snubber circuitry may include control circuitry operative to return the energy captured by the energy capture module to the input of the power converter. To maintain electrical isolation between a primary side and a secondary side of the isolation transformer, a second isolation transformer may be provided to return the captured energy back to the input of the power converter.

Abstract: The power supply includes a transformer, a first switching element for performing a switching operation of turning on and off a voltage input to a primary side of the transformer, a second switching element to be connected to a secondary side of the transformer so as to be turned on and off in accordance with a voltage generated in the secondary side of the transformer, and a control unit for controlling an operation of the first switching element so that an output voltage of the secondary side of the transformer becomes a predetermined voltage. A conductive state period of the second switching element is adjusted to be longer as a frequency of the switching operation of the first switching element is higher.

Abstract: A control circuit of a power converter and a method for controlling the power converter are provided. The control circuit of the power converter comprises a switching circuit and a temperature-sensing device. The switching circuit generates a switching signal in response to a feedback signal, and the switching circuit generates a current-sensing signal for regulating an output of the power converter. The temperature-sensing device generates a temperature signal in response to temperature of the temperature-sensing device.

Abstract: A switching power converting apparatus is capable of converting an input voltage to an output voltage, and includes a transformer, a primary side control module, and a secondary side control module. The secondary side control module utilizes voltage clamping techniques or current-drawing techniques to stop self-excited conversion from the input voltage to the output voltage when the output voltage is greater than a predetermined target voltage, or utilizes a non-self-excited conversion architecture.

Abstract: A power converter circuit may convert alternating current signals into direct current signals. A load may be powered from output terminals that are provided with the direct current signals. The power converter circuit may have a transformer with primary and secondary sides. A transistor on the primary side may be controlled using a pulse width modulation controller. A diode may be coupled in series with the secondary side of the transformer and the load. To improve efficiency at larger load currents, a synchronous rectifier control circuit may modulate a transistor on the secondary side that is coupled in parallel with the diode. The synchronous rectifier control circuit may monitor voltage pulses on the transistor on the secondary side or may make direct load current measurements to ascertain how much load current is flowing. Under low or no load conditions, synchronous rectification can be inhibited to improve efficiency.

Abstract: A power supply device controls drive of a synchronous rectification switch unit by converting a voltage into a current, and comparing a voltage obtained by current-to-voltage conversion with a predetermined value.

Abstract: A flyback converter involves a bipolar transistor (BJT) and a parallel-connected diode as the rectifying element in the secondary side of the converter. The transformer of the converter has a primary winding, a first secondary winding, and a second secondary winding. A first end of the first secondary winding is coupled to the BJT base. A first end of the second secondary winding is coupled to the BJT collector and to the anode of the diode. The first and second secondary windings are wound such that when primary winding current stops, pulses of current flow out of the first ends of the first and second secondary windings. These currents are such that the BJT is maintained in saturation throughout at least most of the time current flows through the rectifying element, thereby achieving a low forward voltage across the rectifying element, reducing conduction loss, and increasing converter efficiency.

Abstract: A flyback power converter with multiple outputs is disclosed. The flyback power converter has a transformer, a first output circuit, a second output circuit, and a secondary side synchronous rectification controller. The transformer has a primary side winding, a first output winding, and a second output winding. The first output circuit has a first output capacitor for storing electric energy from the first output winding. The second output circuit has a second rectifying switch and a second output capacitor. The second output capacitor is utilized for storing the electric energy from the second output winding. The secondary side synchronous rectification controller controls the conduction time of the second rectifying switch according to a detecting signal of a secondary-side conduction period. The electric energy in the first output capacitor may be transferred to the second output capacitor through the second output winding and the second rectifying switch and vice versa.

Abstract: A flyback power converter is disclosed. The flyback power converter includes a voltage transformer, a main switch, a synchronous rectification switch, a synchronous rectification control circuit, a sampling circuit and an operation circuit. A control end of the main switch receives a main switch signal so as to control the main switch. The synchronous rectification control circuit transmits control signal to control end of the synchronous rectification switch according to sensing signal received. The sampling circuit samples the state of the synchronous rectification switch so as to generate first logic signal and second logic signal. The operation circuit executes timing for charging/discharging according to the first and the second logic-signal, so as to output switch cut-off pulse signal to a voltage-dividing circuit. If voltage of the sensing signal is lower than predetermined threshold voltage, the synchronous rectification switch enters into cut-off state according to the control signal.

Abstract: The invention relates to a DC-DC voltage converter (1), having a transformer (2) having a primary winding (2a) and a secondary winding (2b, 2c) having a centre tap, an output inductor (3), which is connected to the centre tap and to a first output connection (9a), a synchronous rectifier circuit (4) having two synchronous rectifier switches (14a, 14b), each of which is connected to the terminal taps of the secondary winding (2b, 2c), and which are designed to produce a rectified output voltage on a second output connection (9b), and a snubber circuit (5) that is switched by means of the synchronous rectifier circuit (4).

Abstract: A method and apparatus for power conversion. In one embodiment, the apparatus comprises at least two power stages, each power stage of the at least two power stages capable of converting DC input power to DC output power; and a controller for dynamically selecting, based on a first DC power, one or more power stages of the at least two power stages for converting the first DC power to a second DC power.

Abstract: A circuit and method for compensating for parasitic elements of a transistor. A transistor, a controller, and a compensation element are mounted to a printed circuit board. The transistor includes parasitic drain and source inductors. The compensation element may be a discrete inductor that has an inductance value equal to about the sum of the inductance values of the parasitic drain and source inductors. The magnitudes of the compensation voltage and the sum of the voltages across the parasitic drain and source inductances are substantially equal. Thus, the compensation voltage developed across the compensation inductor is used to adjust a reference voltage within the controller. A drain-to-source voltage is applied to one input of a comparator within the controller and the adjusted reference voltage is applied to another input of the comparator. An output signal of the comparator is input to drive circuitry that drives a gate of the transistor.

Abstract: In various embodiments a method is provided for determining a demagnetization zero current time for a switched mode power supply having a transformer, a first side and a second side being galvanically separated from each other and a switched mode power supply controller, the method including: determining a first voltage being applied to one side of the transformer; determining a second voltage provided at the other side of the transformer; determining a time the first voltage is provided to a winding of the transformer; and determining, by a circuit located on the same side of the transformer as the switched mode power supply controller, the demagnetization zero current time using the determined first voltage, the determined second voltage and the determined time.

Abstract: Disclosed herein are control and drive circuits and methods for synchronous rectification switching power supply bias voltage generating circuits configured for a switching power supply. In one embodiment, a control and drive circuit can include: (i) a primary side switch controller configured to generate a primary side switch control signal; (ii) a logic circuit configured to generate a first control signal based on the primary side switch control signal; (iii) a converting circuit configured to generate a second control signal based on the first control signal; and (iv) a synchronous rectifier switch controller configured to generate a synchronous rectifier switch control signal based on the second control signal such that phases of the primary side switch control signal and the synchronous rectifier switch control signal are the same or inverse based on a topology of the synchronous rectification switching power supply.

Abstract: A DC to DC converter for controlling the on time and off time of a pair of synchronous switches, which reside in the position of output rectifiers in a half bridge transformer type circuit is provided. The circuit is actually two identical circuits, one for each half of the transformer output. The circuits consist of a voltage reference, a dual comparator, a bias switch, and drive buffer as well as biasing means for proper set up of the various parameters.

Abstract: A power converter circuit may convert alternating current signals into direct current signals. A load may be powered from output terminals that are provided with the direct current signals. The power converter circuit may have a transformer with primary and secondary sides. A transistor on the primary side may be controlled using a pulse width modulation controller. A diode may be coupled in series with the secondary side of the transformer and the load. To improve efficiency at larger load currents, a synchronous rectifier control circuit may modulate a transistor on the secondary side that is coupled in parallel with the diode. The synchronous rectifier control circuit may monitor voltage pulses on the transistor on the secondary side or may make direct load current measurements to ascertain how much load current is flowing. Under low or no load conditions, synchronous rectification can be inhibited to improve efficiency.

Abstract: A switching circuit including a transformer having a primary and a secondary side; a first MOSFET switch coupled with the primary side; a primary current sensing device; a second MOSFET switch coupled with the secondary side; a secondary current sensing device; and a control circuit for driving the first and second MOSFET switches, wherein first and second switch are complementarily driven and wherein switching of the first and second MOSFET switches is controlled by the primary and secondary current sensing devices

Abstract: A method and apparatus for bi-directional current sensing for a synchronous rectifier bi-directional converter system is disclosed. A first current is measured through a first synchronous rectifier via a first transformer to provide a first signal. A second current is measured through a second force synchronous rectifier via a second transformer to provide a second signal. The first signal and the second signal are DC restored to provide a first DC restored signal and a second DC restored signal respectively. A first correction current is added to the first DC restored signal to produce a first corrected signal, and a second correction current is added to the second DC restored signal to produce a second corrected signal. The first corrected signal and the second corrected signal are added to produce a combined signal.

Abstract: A controller, power converter, and a related method for secondary side control of a switch are disclosed herein. An embodiment of the present invention includes a controller. The controller comprises a drain to source voltage (VDS voltage) input configured to receive the VDS voltage of a transistor, a gate drive output configured to output a gate drive voltage to a gate of the transistor, and control logic configured to initiate a minimum on time signal independent of triggering the gate drive voltage to activate the transistor. A related method comprises comparing a VDS voltage of a transistor to a plurality of voltage threshold levels, driving a gate of the transistor when the VDS voltage crosses a predetermined voltage threshold, and asserting a minimum on time signal when the VDS voltage crosses another predetermined voltage threshold independent of driving the gate of the transistor.

Abstract: Disclosed are synchronous rectifying control methods and circuits for an isolated switching power supply. In one embodiment, a method can include: (i) generating a ramp voltage based on a power terminal voltage, where the power terminal voltage includes a voltage between first and second power terminals of a synchronous rectifier in the isolated switching power supply; (ii) determining whether the power terminal voltage starts declining; (iii) comparing the ramp voltage to a threshold voltage when the power terminal voltage starts to decline, where the threshold voltage substantially matches a minimum conduction time of the synchronous rectifier; (iv) reducing the ramp voltage and controlling the synchronous rectifier in an off state when the ramp voltage is lower than the threshold voltage; and (v) reducing the ramp voltage and controlling the synchronous rectifier in on state when the ramp voltage is higher than the threshold voltage.

Abstract: Techniques and corresponding circuitry and drivers are disclosed for improving power factor (PF) and total harmonic distortion (THD) of a flyback power factor correction (PFC) topology operating in transition-mode. In one or more embodiments, the PF and THD are improved by correcting the on-time of the switching element of the flyback PFC topology to actively shape the wave of the PFC input current. In some embodiments, the on-time is corrected using a phase-lock-loop module that synchronizes with the rectified input line voltage signal and a output regulator module that corrects the switch on-time. The control may be implemented using a digital or an analog controller.

Abstract: A control circuit and a method for controlling a power converter are provided. The method for controlling the power converter includes the following steps. A detection signal is received from the secondary side of the power transformer and a first switching signal is generated in accordance with the detection signal. A second switching signal is generated in accordance with the first switching signal. A voltage signal is generated in accordance with the second switching signal. A comparison signal is generated in accordance with the first switching signal and the second switching signal. The voltage signal and the comparison signal are compared for outputting a comparison result. A gate signal is generated in accordance with the detection signal and the comparison result to control on and off states of a synchronization switch.

Abstract: A control circuit for a switching power converter is provided. The control circuit is installed between a secondary side and an output of the power converter and coupled to control a switching device. The control circuit includes a linear predict circuit, a reset circuit, a charge/discharge circuit, and a PWM circuit. The linear predict circuit is coupled to receive a linear predict signal from the secondary side for generating a charging signal. The reset circuit is couple to receive a resetting signal for generating a discharging signal. The charge/discharge circuit is coupled to receive the charging signal and the discharging signal for generating a ramp signal. The PWM circuit is coupled to receive the linear predict signal for enabling a switching signal and receive the ramp signal for resetting the switching signal.

Abstract: In one embodiment, a synchronous rectification control circuit in a flyback converter, can include: a first control circuit that receives a drain-source voltage signal of a synchronous rectifier switch and a flyback converter output voltage, and generates a first control signal based on a conduction time of a primary-side power switch; a second control circuit configured to receive the drain-source voltage signal, and to generate a second control signal; when the primary-side power switch is turned off, and the first control signal is greater than a threshold value, the second control signal controls a switching operation of the synchronous rectifier switch; and when the primary-side power switch is turned off, and the first control signal is less than the threshold value, the synchronous rectifier switch is configured to stop operation, before the primary-side power switch is turned on again.

Abstract: A synchronous rectification switching power source device accurately determines the timing of the turning off of a synchronous rectifier switching element regardless of the state of the load, and a synchronous rectification period is utilized to the maximum. The switching power source device is configured of a main FET connected to a primary winding of a transformer, a snubber circuit connected to the primary winding, a synchronous rectifier FET connected to a secondary winding of the transformer, a diode connected to the synchronous rectifier FET, a synchronous rectifier FET drain voltage detection unit, an output voltage detection unit, and a drive control unit. The drive control unit accurately determines the timing of the turning off of the synchronous rectifier switching element using a unit that detects the on/off state of the main FET, a variable pulse generator unit, a count value generated by a counter unit, and a threshold value.

Abstract: A flyback converter includes input terminals and output terminals. A transformer with a first winding and a second winding are inductively coupled. A first switching element is connected in series with the first winding and a first series circuit with the first switching element, the first winding being coupled between the input terminals. A rectifier arrangement is connected in series with the second winding and a second series circuit with the rectifier arrangement, the second winding being coupled between the output terminals. The rectifier arrangement includes a second switching element. A control circuit is configured in one drive cycle to switch on the first switching element for a first time period. After the first time period the second switching element is switched on for a second time period. A third time period is determined between an end of the second time period and the time at which the transformer assumes a predetermined transformer state.

Abstract: A switching mode power supply (SMPS) includes a transformer having a primary winding, a secondary winding for providing an output voltage, and an auxiliary winding. The SMPS also includes a power switch coupled to the primary winding. A first control circuit is coupled to the secondary winding, and is configured to provide a first electrical signal to the secondary winding when the output voltage of the SMPS is less than a reference voltage during a discontinuous time, whereupon a second electrical signal is induced in the auxiliary winding. A second control circuit is coupled to the auxiliary winding and the power switch. The second control circuit is configured to regulate the output of the SMPS by controlling the power switch in response to a feedback voltage signal from the auxiliary winding, and is further configured to turn on the power switch in response to the second electrical signal.

Abstract: A power conversion apparatus includes main circuits, in which switching elements are connected in parallel with diodes, respectively. An auxiliary circuit, which is formed of a series-connected second switching element and a capacitor, is connected in parallel with the diode operating as a freewheeling diode. The switching element of the main circuit, which is opposite to the auxiliary circuit, is set to turn on at a reference time. The second switching element of the auxiliary circuit is set to turn on in advance of the reference time by an interval of a discharging time period of the capacitor in a dead time period.

Abstract: A predictive synchronous rectification controller for controlling at least one synchronous rectification switch is provided. The synchronous rectification controller has a ramp generator, a peak sampling unit, and an output control unit. The ramp generator receives a synchronous signal and generates a ramp signal accordingly. The peak sampling unit generates a predicted reference voltage signal by retrieving a peak voltage of the ramp signal. The output control unit compares the ramp signal with the predicted reference voltage signal to generate a synchronous rectification control signal to control a conducting state of the switch.

Abstract: A flyback converter uses primary side sensing to sense the output voltage for regulation feedback. Such sensing requires a predetermined minimum duty cycle even with very light load currents. Therefore, such a minimum duty cycle may create an over-voltage condition. In the flyback phase, after a minimum duty cycle of the power switch at light load currents, a synchronous rectifier turns off approximately when the current through the secondary winding falls to zero to create a discontinuous mode. If it is detected that there is an over-voltage, the synchronous rectifier is turned on for a brief interval to draw a reverse current through the secondary winding. When the synchronous rectifier shuts off, a current flows through the primary winding via a drain-body diode while the power switch is off. Therefore, excess power is transferred from the secondary side to the power source to reduce the over-voltage so is not wasted.

Abstract: A switching power-supply apparatus includes a first converter 3, a second converter 4, an output smoothing capacitor Co1, a series resonance circuit 1 and a control circuit 11. The first converter 3, in which switching elements Q11 and Q12 are connected to both ends of a direct-current power-supply Vin in series, and a capacitor Ci1 and a primary winding Np1 of a transformer T1 including an auxiliary winding Na1 are connected to both ends of the switching element Q12 in series, includes diodes D11 and D12 that rectify voltages generated in secondary windings Ns11 and Ns12 of the transformer T1. The second converter 4, in which switching elements Q21 and Q22 are connected to the both ends of the direct-current power-supply Vin in series, and a capacitor Ci12 and a primary winding Np2 of a transformer T2 are connected to both ends of the switching element Q22 in series, includes diodes D21 and D22 that rectify voltages generated in secondary windings Ns21 and Ns22 of the transformer T2.

Abstract: An adaptive synchronous rectification control circuit and a control method are developed. The control circuit comprises an adaptive circuit that generates a reference signal in response to a detection signal of a power converter. A clamped circuit clamps the reference signal at a threshold voltage if the reference signal equals or is greater than the threshold voltage. A switching circuit generates a control signal to control a synchronous switch of the power converter in response to the detection signal and the reference signal. The control method generates the reference signal in response to the detection signal. The reference signal is clamped at the threshold voltage if the reference signal equals or is greater than the threshold voltage. The method further generates the control signal to control the synchronous switch of the power converter in response to the detection signal and the reference signal.

Abstract: Disclosed is a light load control circuit and the method accordingly where the synchronous rectification is latched off when the light load condition is detected for several successive cycles.

Abstract: A synchronous rectification circuit for a power converter includes a power switch coupled to a transformer and an output capacitor and a switching control circuit configured to provide a control signal to the power switch in response to a first state and a second state of the voltage across the power switch. In the switching control circuit, the second state is determined prior to the first state is determined. In an embodiment, the switching control circuit includes a voltage comparing unit configured to act in response to the first and second inputs. The voltage comparing unit is also configured to output a logic signal according to the voltage difference between the sensed voltage drop across the power switch and a reference threshold voltage. A logic processing circuit is coupled to the voltage comparing unit and configured to provide the first state and the second state of the voltage across the power switch.

Abstract: A controller for a power converter having a transformer T1 with a primary winding coupled to a power switch SW and a secondary winding coupled to a synchronous rectifier switch SR. In one embodiment, the controller includes a first controller configured to control a conductivity of the power switch SW, and a first delay circuit configured to delay an initiation of the conductivity of the power switch SW. The controller also includes a second controller configured to control a conductivity of the synchronous rectifier switch SR as a function of a voltage difference between two terminals thereof, and a second delay circuit configured to delay an initiation of the conductivity of the synchronous rectifier switch SR. The controller still further includes a shutdown circuit configured to substantially disable conductivity of the synchronous rectifier switch SR before the initiation of conductivity of the power switch SW.

Abstract: A multi-voltage power supply includes a transformer, a first output circuit to generate a first output voltage using a voltage transferred to a secondary winding of the transformer, and a first output voltage controller to control a voltage supplied to the primary winding of the transformer according to the first output voltage. The multi-voltage power supply includes second through Nth output circuits to generate second through Nth output voltages using the voltage transferred to the secondary winding of the transformer, and second through Nth output voltage controllers performing control in order to linearly output the second through Nth output voltages by feeding back the second through Nth output voltages.

Abstract: A flyback converter uses primary side sensing to sense the output voltage for regulation feedback. Such sensing requires a predetermined minimum duty cycle even with very light load currents. Therefore, such a minimum duty cycle may create an over-voltage condition. In the flyback phase, after a minimum duty cycle of the power switch at light load currents, a synchronous rectifier turns off approximately when the current through the secondary winding falls to zero to create a discontinuous mode. If it is detected that there is an over-voltage, the synchronous rectifier is turned on for a brief interval to draw a reverse current through the secondary winding. When the synchronous rectifier shuts off, a current flows through the primary winding via a drain-body diode while the power switch is off. Therefore, excess power is transferred from the secondary side to the power source to reduce the over-voltage so is not wasted.

Abstract: A driver for a switch, method of driving a switch, and a power converter employing the same. The driver for the switch includes a first driver switch coupled to a terminal of the switch. The driver also includes a second driver switch inverted with respect to the first driver switch and coupled to another terminal of the switch, wherein the first and second driver switches are configured to provide a drive signal to a control terminal of the switch.

Abstract: According to one embodiment, a power conversion apparatus determines a peak value of circuit current in each pulse cycle, from a corrected output voltage value by subtracting a predetermined reference voltage from an output voltage detected by the output voltage detector, and an input voltage detected by the input voltage detector. The pulse signal output unit outputs a pulse signal to the first switch when the polarity of input voltage is positive, and outputs a pulse signal to the second switch when the polarity of input voltage is negative. A pulse signal turns on in synchronization with a clock signal input from the oscillator, and is kept on until the circuit current detected by the circuit current detector reaches the peak value. A pulse signal turns off when the circuit current reaches the peak value, and turns on again in synchronization with the next clock signal.

Abstract: A lighting device includes a power converter with an input and an output. The output connects to a load circuit that includes a lamp. An output of the power converter is regulated based on results of first and second current detectors. One end of the output and one end of the input are connected to one end of the load circuit via the first and second current detectors, respectively. Detection outputs of the current detectors are synthesized. A ground-fault current flows through a current pathway from one end of the input of the power converter to the one end of the output of the power converter via the current detectors. The current pathway is formed when a ground fault occurs at a load terminal of the load circuit. Detection signals of the current detectors result from the ground-fault current and are of additive polarities.

Abstract: A flyback converter involves a bipolar transistor (BJT) and a parallel-connected diode as the rectifying element in the secondary side of the converter. The transformer of the converter has a primary winding, a first secondary winding, and a second secondary winding. A first end of the first secondary winding is coupled to the BJT base. A first end of the second secondary winding is coupled to the BJT collector and to the anode of the diode. The first and second secondary windings are wound such that when primary winding current stops, pulses of current flow out of the first ends of the first and second secondary windings. These currents are such that the BJT is maintained in saturation throughout at least most of the time current flows through the rectifying element, thereby achieving a low forward voltage across the rectifying element, reducing conduction loss, and increasing converter efficiency.

Abstract: A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices.

Abstract: Disclosed herein are a converter, a method for controlling the same, and an inverter. The converter includes: an input terminal having power input thereto; a first converter unit converting the power input to the input terminal to thereby output the converted power to an output terminal; and a second converter unit connected between the input terminal and the output terminal while being in parallel with the first converter unit, wherein each of the first and second converter units includes an active clamp unit provided at a primary side thereof and a synchronous rectifying unit provided at a secondary side thereof.

Abstract: A pseudo-resonant switching power source device is provided which comprises a primary winding 2a of a transformer 2 and a main MOS-FET 3 connected in series to a DC power source 1, a voltage-resonant capacitor 12 connected in parallel to main MOS-FET 3, a rectification smoother 4 connected to a secondary winding 2b of transformer 2 and having a rectification MOS-FET 51 and a smoothing capacitor 6, a synchronized rectification controller 52 for turning rectification MOS-FET 51 on after turning-off of main MOS-FET 3 and turning rectification MOS-FET 51 off before turning-on of main MOS-FET 3, a pulse width elongation circuit 55 for extending on-pulse width of rectification MOS-FET 51, and a main control circuit 8 for producing main drive signals to turn main MOS-FET 3 off and on with operation frequency responsive to on-pulse width of rectification MOS-FET 51 extended by pulse width elongation circuit 55 to vary operation frequency of main MOS-FET 3 so as to restrain noise by high frequency components in main d

Abstract: A power converter circuit may convert alternating current signals into direct current signals. A load may be powered from output terminals that are provided with the direct current signals. The power converter circuit may have a transformer with primary and secondary sides. A transistor on the primary side may be controlled using a pulse width modulation controller. A diode may be coupled in series with the secondary side of the transformer and the load. To improve efficiency at larger load currents, a synchronous rectifier control circuit may modulate a transistor on the secondary side that is coupled in parallel with the diode. The synchronous rectifier control circuit may monitor voltage pulses on the transistor on the secondary side or may make direct load current measurements to ascertain how much load current is flowing. Under low or no load conditions, synchronous rectification can be inhibited to improve efficiency.

Abstract: In a power supply, a synchronous rectification switch rectifies a pulse voltage, and a current-voltage conversion unit converts a current on a voltage-input side of the synchronous rectification switch to a first voltage and converts a current on a voltage-output side of the synchronous rectification switch to a second voltage. A switching unit switches an operation state of the synchronous rectification switch based on a result of a comparison between the first voltage and the second voltage converted by the current-voltage conversion unit. A state holding unit holds an off state after the synchronous rectification switch is turned off by the switching unit.