Abstract: In the case of known switched-mode power supplies with integrated preconditioner, the control curves are largely congruent, but deviate from one another in low-load operation, whereby the unregulated intermediate circuit voltage increases. To improve efficiency in low-load operation, closed-loop control of the burst cycle is effected on the primary side of the voltage transformer. The intermediate circuit voltage is limited to a permissible limit value. The closed-loop control device in the switching stage taps the intermediate circuit voltage at a voltage divider which is arranged between the preconditioner functional unit and the switching stage. An assembly additionally monitors the output voltage, for example by means of an optocoupler. Burst mode comprises one or more burst cycles. A burst cycle is started when the intermediate circuit voltage reaches its limit value. At this time, the voltage transformer is switched off. A burst cycle ends when the output voltage reaches a minimum value.

Abstract: A power supply includes a power supply unit having an input end for receiving an oscillating voltage, and an output end for outputting a steady state voltage from the oscillating voltage according to a feedback signal, and a control circuit having a micro-controller having a first input port for receiving a measuring signal from a load, and decision logic for generating a control voltage according to the measuring signal, and a feedback controller having a first input end electrically connected to the output end of the power supply for receiving the steady state voltage, a second input end electrically connected to the micro-controller for receiving the control voltage from the micro-controller, and a output end for outputting the feedback signal according to the control voltage and the steady state voltage.

Abstract: A PFC-PWM controller with a power saving means is disclosed. A built-in current synthesizer generates a bias current in response to feedback voltages sampled from the PWM circuit and the PFC circuit. The bias current modulates the oscillation frequency to further reduce the switching frequencies of the PWM signal and the PFC signal under light-load and zero-load conditions. Thus, power consumption is greatly reduced. The PFC and the PWM switching signals interleave each other, so that power can be transferred more smoothly from the PFC circuit to the PWM circuit. The saturation of the switching components can be avoided by limiting the maximum on-time of the PWM signal. Further, an external resistor is used to start up the PFC-PWM controller and provide an AC template signal for PFC control.

Abstract: A power factor correction circuit structure is described. The circuit connects a bridge rectifier and a first capacitor in series. The first capacitor, a winding and a first switching device are also connected in series. The first switching device is the low-side switching device in a bridge converter. The first switching device, a second switching device and a second capacitor are also connected in series, The second switching device is the high-side switching device in the bridge converter and the second capacitor is the boost capacitor in the PFC circuit. The winding can be one additional winding of the main transformer in the bridge converter or an independent inductor.

Abstract: A switching power source device can enhance the power factor by increasing the conduction angle of an input current in a wide input voltage range, while obviating the increase of size and the increase of cost thereof, and lower the switching loss by removing higher harmonic waves from the input current. The device includes at least first, second, and third series circuits constituted of a rectifying circuit, at least first and second primary windings, a plurality of diodes, a smoothing capacitor, and first and second switching elements.

Abstract: A power converter having a primary circuit (e.g. full bridge) and a secondary circuit (e.g. current doubler) has switches in the secondary circuit that are controlled by a drive circuit. The drive circuit is connected to a swing node in the primary circuit, and is powered by the swing node. The drive circuit has an isolation device such as a transformer to provide electrical isolation between the primary circuit and secondary circuit. The drive circuit provides a current source for driving the secondary switch gates, thereby reducing power consumption. The present drive circuit provides clean gate drive signals without noise and oscillations. The drive circuits of the invention are simple, and require only a few components.

Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.

Abstract: A switched mode power supply includes a primary coil, a switch element, a secondary circuit, and a control circuit. The switch element is wired in series with the primary coil, for applying a DC voltage to the primary coil according to a control signal. The secondary circuit is coupled to the primary coil with output terminals providing an output voltage. The control circuit prepares the control signal with a feedback signal dependent on the output voltage supplied to the control circuit. The control circuit includes a signal generation circuit to create the control signal and a protection circuit. The protection circuit has the effect that no control signal is delivered to the switch element, if the feedback signal reaches the value of a first reference signal after a first period after starting the control circuit.

Abstract: A power supply protecting the electric device circuit when over-voltage is applied, is provided. The power supply has a rectifying unit rectifying AC power externally supplied, into first and second DC power and outputting the first and the second DC power; a main power supply transformer boosting the first DC power and supplying the boosted first DC power to the electric device circuit; a switching controlling unit driven by the second DC power, performing the operation on the main power supply transformer that causes the first DC power to be boosted when the second DC power is received; and a controlling unit determining whether the second DC power is to be supplied to the switching controlling unit, wherein the controlling unit senses the voltage supplied to the electric device circuit and interrupts supplying the second DC power to the switching controlling unit if the sensed voltage exceeds a given value.

Abstract: The coupling device comprises a transformer having a primary winding in series with a two-way switch controlled via an optocoupler and a three-position selector switch by a control circuit. In standby mode, the switch is connected to an oscillator defining a switching frequency (49 kHz) ensuring power supply of the control circuit, which circuit is able to detect the presence of a carrier on the transformer secondary winding. In receipt mode, the switch is closed and the control circuit analyzes the modulated information received on the transformer secondary winding. In transmission mode, the control circuit causes switching of the switch at the information modulation frequency (132 khz), performing both power supply of the control circuit and transmission of the information.

Abstract: An isolated switching-mode power supply with a volt-second clamp circuit is provided. A control circuitry for an isolated switching-mode power supply includes a transformer having a primary winding electrically connected to voltage supply terminals and a secondary winding for providing an output voltage, a volt-second clamp circuit electrically connected to the primary winding for controlling conduction and non-conduction states of the primary winding so as to achieve a maximum volt-second product limit of an input voltage at the primary winding, and a voltage feedback controller electrically connected to the volt-second clamp circuit for generating a feedback signal with reference to a magnitude of the output voltage and then modulating the volt-second product of the input voltage at the primary winding to stabilize the output voltage.

Abstract: Continuous alternating current is derived from a differential operational amplifier supplied by direct current. The differential operational amplifier produces alternating current located on the positive input of the differential operational amplifier. Output of the differential operational amplifier is received by a transformer to produce alternating current. Voltage from the transformer is fed back to the negative input of the differential operational amplifier to provide feedback for the differential operational amplifier. Whereby direct current provided to a differential operational amplifier is transformed to continuous alternating current.

Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.

Abstract: A switching power supply unit includes a control output circuit, a non-control output circuit, and a regulator circuit. With this switching power supply unit, it is no longer necessary to set the voltage of the non-control output to be greater than a required value when the control output circuit is unloaded or lightly loaded. The regulator circuit is connected to the non-control output circuit and includes a first transistor defining a first impedance element connected in series to the non-control output circuit, a second transistor defining a second impedance element connected between the control output circuit and the base of the first transistor, and a voltage control circuit controlling the impedance of the second transistor such that the output voltage of the regulator circuit is maintained constant.

Abstract: A universal switching power supply for generating one or more output voltage levels wherein the power supply is operable over a range of AC and DC input supply voltages. The universal switching power supply achieves a ratio between the highest voltage and lowest voltage of at least 27. The universal switching power supply also features an intrinsically safe output. The intrinsically safe output circuitry comprises a multi-layer PCB with a planar core transformer.

Abstract: A photocoupler semiconductor device comprises a light receiving device (12) for generating electric current; a control circuit (16); and a constant current circuit (14) having a resistor (20′) for detecting the generated current to provide the control circuit (16) with a current command. The resistor (20′) allows the electric current to increase with the amount of current received.

Abstract: A switching power supply unit includes a control circuit including a turn-off circuit for turning of a first switch element Q1, which has been in an ON state, and an off-period control circuit for, based on a feedback signal from an output-voltage detecting circuit, controlling the turning-on of the first switch element to be further delayed as a load is lighter. The off-period control circuit includes a transistor as a second switch element which is provided in series between a feedback winding and the control terminal of the first switch element and which is controlled to be turned on and off based on the feedback signal from the output-voltage detecting circuit. A switching frequency is set to be lower as the load is lighter, such that power consumption at the light load is reduced.

Abstract: A voltage regulator module includes a power supply circuit for supplying power to an integrated circuit, the power supply circuit including semiconductor switching devices and a drive circuit for driving the semiconductor switching devices; and charge storage means for smoothing an output of the power supply circuit, wherein charge storage unit having a smoothing capacitor includes an electric double-layer capacitor, wherein the electric double-layer capacitor includes a plurality of positive electrodes terminals and a plurality of negative electrode terminals, and wherein the plurality of positive electrode terminals and the plurality of negative electrode terminals are disposed on a surface identical to a surface of the electric double-layer capacitor.

Abstract: The coupling device comprises a transformer having a primary winding in series with a two-way switch controlled via an optocoupler and a three-position selector switch by a control circuit. In standby mode, the switch is connected to an oscillator defining a switching frequency (49 kHz) ensuring power supply of the control circuit, which circuit is able to detect the presence of a carrier on the transformer secondary winding. In receipt mode, the switch is closed and the control circuit analyzes the modulated information received on the transformer secondary winding. In transmission mode, the control circuit causes switching of the switch at the information modulation frequency (132 khz), performing both power supply of the control circuit and transmission of the information.

Abstract: In a configuration which is provided with a voltage control circuit 2 for supplying a DC voltage control signal created on the basis of the voltage detecting signal 44 to an terminal of an auxiliary coil L3, wherein the voltage control circuit 2 controls the oscillating amplitude of a transistor Q1 for oscillation using the voltage control signal to stabilize the voltage of the secondary output, and the secondary output is led to a high voltage applying portion of a toner system printing section, a detecting signal creating circuit 5 rectifies the output from the voltage detecting coil L4 at the same timing as the rectifying/smoothing circuit rectifies the output from the secondary coil L2.

Abstract: A switching power supply unit and an electronic apparatus including the same, has a photocoupler that is used for providing feedback from the secondary side to the primary side. The photocoupler is shielded by a heat sink so that incorrect operation of the photocoupler caused by electromagnetic waves emanating from cellular phones or other electronic apparatuses is prevented, thereby preventing incorrect operation of the switching power supply unit and the electronic apparatus.

Abstract: A power supply includes an operating power circuit outputting an operating voltage, a standby power circuit outputting a standby voltage, a starting switching circuit having a first remote control receiver for receiving a first remote control signal and supplying a starting power to the standby power circuit in response to the first remote control signal, a controller having a second remote control receiver for receiving a second remote control signal and performing a function corresponding to the second remote control signal, and a feedback circuit processing a control signal to switch the starting switching circuit to either of a standby mode and a power saving mode in response to a power off signal from either of the second remote control receiver and a power switch.

Abstract: The power supply device includes a DC-DC converter circuit having a power switch and a driving stage. The driving stage has a compensation terminal on which a compensation voltage is present, and which receives a biasing current. The driving stage includes a control circuit having an output terminal connected to a control terminal of the power switch and disconnection-detecting circuitry connected to the compensation terminal and generating a signal for permanent turning-off of the power switch when the biasing current drops below a current-threshold value. The driving stage moreover includes over-voltage detecting circuitry connected to the compensation terminal and generating a signal for temporary turning-off of the power switch when the compensation voltage exceeds a voltage-threshold value.

Abstract: A universal switching power supply for generating one or more output voltage levels wherein the power supply is operable over a range of AC and DC input supply voltages. The universal switching power supply achieves a ratio between the highest voltage and lowest voltage of at least 27. The universal switching power supply also features an intrinsically safe output. The intrinsically safe output circuitry comprises a multi-layer PCB with a planar core transformer.

Abstract: A switched-mode power supply with a control loop and a microprocessor has a normal mode and a low-power mode with a burst mode. The microprocessor is connected via an output to the control loop and uses this to control the burst mode of the switched-mode power supply directly. The control loop of the switched-mode power supply monitors, in particular, a secondary output voltage, so that the output of the microprocessor is connected to the control loop, for example via a simple resistor network or a transistor stage. The clock frequency and the duty cycle of the burst mode are permanently stored in the microprocessor and can be defined for the switched-mode power supply directly, for example using TTL logic.

Abstract: A power supply apparatus is provided with a power supply transformer; excitation circuit portions provided at a primary side of the power supply transformer, for exciting the power supply transformer by means of a commercial power supply; and control circuit portions provided at a secondary side of the power supply transformer, for starting operation by the power supply transformer having entered an excited state and for intermittently operating the excitation circuit portion 50. Thereby, power in a waiting state can be suppressed at maximum and energy saving can be executed further efficiently.

Abstract: A switching power supply unit and an electronic apparatus including the same, has a photocoupler that is used for providing feedback from the secondary side to the primary side. The photocoupler is shielded by a heat sink so that incorrect operation of the photocoupler caused by electromagnetic waves emanating from cellular phones or other electronic apparatuses is prevented, thereby preventing incorrect operation of the switching power supply unit and the electronic apparatus.

Abstract: An intermittent switching power supply circuit prevents excessive output power on a secondary side of a circuit. An intermittent oscillator is alternately switched on and off to maintain output voltage and/or current roughly constant, to An output power monitoring circuit monitors output power from a rectifying/smoothing circuit. A control circuit outputs a stop control signal to an control terminal of the intermittent oscillator when the output power monitoring circuit determines that the output voltage and/or current exceeds a reference value. The protection circuit and a photocoupler receiver element are connected in parallel with the control circuit. Where a circuit error occurs and the photocoupler receiver element fails to cycle the intermittent oscillator between active and inactive conditions for a predetermined time, the protection circuit provides a backup which outputs a stop control signal to stop oscillation of the intermittent oscillator element.

Abstract: A switch mode power supply (200, FIG. 2; 600, FIG. 6) includes a transformer (208), a transistor (212) that drives the primary winding of the transformer, and a controller (210, 610). The controller senses whether or not the transformer is reset and applies a switching control signal to a control terminal (220) of the transistor, accordingly. The signal is produced at a switching frequency, and the signal has a duty cycle that is limited based on whether or not the transformer is reset.

Abstract: The present invention provides electronic equipment that can shut off and supply power to a primary power supplying circuit by automatic operations, directly shut off power to the primary power supplying circuit by easy manual operations based on the operator's will, and never fails to zero power consumption of the primary power supplying circuit during no use.

Abstract: A switching power supply unit includes a control output circuit, a non-control output circuit, and a regulator circuit. With this switching power supply unit, it is no longer necessary to set the voltage of the non-control output to be greater than a required value when the control output circuit is unloaded or lightly loaded. The regulator circuit is connected to the non-control output circuit and includes a first transistor defining a first impedance element connected in series to the non-control output circuit, a second transistor defining a second impedance element connected between the control output circuit and the base of the first transistor, and a voltage control circuit controlling the impedance of the second transistor such that the output voltage of the regulator circuit is maintained constant.

Abstract: Control circuitry for controlling the delivery of power from a source voltage to a load in a transformer coupled power converter. The control circuitry includes a power switch having an input coupled to the source, an output, and an activation gate, the power switch, when cycled ON and OFF, defining a pulses of power at the load. A pulse generator is coupled to the power switch, the pulse generator producing a train of constant frequency, constant ON time switching pulses for driving the power switch activation gate. A pulse rate controller responsive to an error signal is coupled between the pulse generator and the power switch, the pulse rate controller regulating an output voltage at the load by controlling the rate of switching pulses delivered to the power switch activation gate over time. The error signal is derived by estimating the output voltage at each switching cycle from the primary side current, while compensating for the expected loss between the source and the load for each power switch cycle.

Abstract: A switching regulator (18) for use in a switching power supply (10) detects a fault condition by looking for presence of feedback signals during a timer period. If feedback is present but less than a threshold value during the timer period, then the switching power supply (10) is operating normally. If feedback is not present during the timer period, then the switching power supply is in a fault condition. One way of implementing the timer is to charge and discharge by-pass capacitor (23). The timer period is the time for the VCC voltage to drop from a maximum value to a predetermined threshold. When a fault is detected, the gate drive signal from the switching regulator is disabled for a period of time before attempting auto-restart.

Abstract: The power supply device comprises a DC-DC converter circuit including a power switch and a driving stage. The driving stage has a compensation terminal on which a compensation voltage is present and which receives a biasing current, said driving stage comprising a control circuit having an output terminal connected to a control terminal of the power switch and disconnection-detecting means connected to said compensation terminal and generating a signal for permanent turning-off of said power switch when the biasing current drops below a current-threshold value. The driving stage moreover comprises over-voltage detecting means connected to the compensation terminal and generating a signal for temporary turning-off of said power switch when said compensation voltage exceeds a voltage-threshold value.

Abstract: A power supply includes an operating power circuit outputting an operating voltage, a standby power circuit outputting a standby voltage, a starting switching circuit having a first remote control receiver for receiving a first remote control signal and supplying a starting power to the standby power circuit in response to the first remote control signal, a controller having a second remote control receiver for receiving a second remote control signal and performing a funtion corresponding to the second remote control signal, and a feedback circuit processing a control signal to switch the starting switching circuit to either of a standby mode and a power saving mode in response to a power off signal from either of the second remote control receiver and a power switch.

Abstract: A signal PWR is driven into a low level in response to a power-off command from the computer, then the low level PWR signal is entered to an input terminal 36 of a switching circuit 130 and regulators 152 to 156 respectively. Consequently, the regulators come to rest and thereby the power supply to the computer is shut off. Receiving the low level PWR signal, a photo-coupler 134 and a transistor 132 in the switching circuit 130 are turned off respectively, as well as the operation of a power factor correction circuitry is stopped. Consequently, an AC power factor correction circuitry comes to rest when the power supply to the computer is shut off, and thereby the power consumption of the computer can be reduced.

Abstract: Providing a power supply system having a plurality of power supply apparatuses connected in parallel to each other, each of which is not affected by a voltage fluctuation of a reverse flow-preventive diode provided in an output line thereof, and can provide a stable output voltage controlled with high accuracy. Each of the power supply apparatuses includes a positive output terminal 33 connected to a load 13, a reverse flow-preventive diode 31 connected to the positive output terminal 33, a VF correcting circuit 46 for detecting a forward voltage of the reverse flow-preventive diode 31 and providing a controlling unit with the detected voltage in a feedback manner, an output current detecting/correcting circuit 45 for detecting a forward current of the reverse flow-preventive diode 31 and providing the controlling unit with the detected current in a feedback manner, and the controlling unit for controlling the anode potential of the reverse flow-preventive diode 31.

Abstract: A power supply apparatus is provided with a power supply transformer; excitation circuit portions provided at a primary side of the power supply transformer, for exciting the power supply transformer by means of a commercial power supply; and control circuit portions provided at a secondary side of the power supply transformer, for starting operation by the power supply transformer having entered an excited state and for intermittently operating the excitation circuit portion 50. Thereby, power in a waiting state can be suppressed at maximum and energy saving can be executed further efficiently.

Abstract: A switching power source in which the voltage error of a secondary side DC output is fed back to a switching circuit through an insulating element, thereby to stabilize the output voltage. In the switching power source, irrespective of the voltage of the secondary side DC output, a pulse of the level with which an error detecting circuit determines that the voltage of the secondary side DC output has been increased is applied to the error detecting circuit, whereby the switching operation of the switching circuit is changed into an intermittent operation corresponding to the pulse.

Abstract: The present invention relates to a switching power-supply circuit comprising: rectifying and smoothing means for generating a rectified and smoothed voltage and outputting the rectified and smoothed voltage as a direct-current input voltage; an insulating converter transformer for transferring a primary-side output to a secondary side; switching means for intermittently passing on the direct-current input voltage to a primary winding of the insulating converter transformer; a primary-side resonance circuit translating an operation of the switching means into voltage resonance; power-factor improvement means for improving a power factor by generating intermittently a rectified current based on the fed-back switching output voltage; a secondary-side resonance circuit on a secondary side of the insulating converter transformer; direct-current output voltage generation means carrying out a rectification operation in order to generate a secondary-side direct-current output voltage; and constant-voltage control mea

Abstract: The present invention provides electronic equipment that can shut off and supply power to a primary power supplying circuit by automatic operations, directly shut off power to the primary power supplying circuit by easy manual operations based on the operator's will, and never fails to zero power consumption of the primary power supplying circuit during no use.

Abstract: In a normal operation mode, a mode changeover controller 8 continuously operates a PWM control circuit 6 so as to operate a switching element 5 at the basic oscillation frequency. In a standby mode, the mode changeover controller 8 intermittently operates the PWM control circuit 6 so as to turn on the switching element 5 at a given repetition interval and for a given time period. This repetition interval is shorter than a time for decreasing an output voltage from a rectifying and smoothing circuit 20 down to a guaranteed load operating voltage due to power consumption of the load and the rectifying and smoothing circuit 20 in the standby mode and is longer than a time for entering a sonic frequency band. That time period is longer than a time for stabilizing an output from the rectifying and smoothing circuit 20 and is longer than a time for entering a sonic frequency band.

Abstract: The circuit arrangement for connecting a consumer to an alternating voltage source includes a switch actuator (16) connectable in series with the consumer (12) and an electronic circuit (22) associated with the switch actuator and supplied with a direct voltage by means of it. The switch actuator (16) includes a rectifier for supplying the direct voltage to the electronic circuit, a transformer (24) comprising a secondary winding (32) supplying power to the rectifier, a first low inductance primary winding (26) and a second high inductance primary winding (28) and a switching device (36,42) controlled by the electronic circuit (22) to switch between the primary windings. Another switching device (44) is connected in parallel with the first primary winding (26) in order to short-circuit it for a predetermined short-circuit duration as a function of a nominal power consumed by the consumer. The switching device (36,42) can be a relay or a semiconductor component.

Abstract: A power supply for converting an inputted oscillating voltage into an outputted steady state voltage. The power supply includes a voltage converting circuit for converting the inputted oscillating voltage into a first steady state voltage, a transformer for transforming the first steady state voltage into a second oscillating voltage, a pulse generator for generating a pulse signal so as to control on and off of the transformer, a rectifying circuit for rectifying the second oscillating voltage so as to generate the outputted steady state voltage, and a feedback circuit for controlling a duty cycle of the pulse signal according to the outputted steady state voltage and an output voltage generated by a variable power source so that the outputted steady state voltage generated by the power supply can be controlled by the variable power source.

Abstract: A power supply arrangement including a transformer and a switching element coupled to a primary winding of the transformer and a power supply. The power supply includes a capacitor having a first terminal coupled to a junction of the primary winding and the switching element and a first diode coupled between the capacitor and an output node. The power supply further includes a discharge element, such as a resistor or a diode, coupled between the junction of the first diode and the capacitor and a power supply common. A voltage regulator, such as a Zener diode, is connected to the output node to produce a regulated voltage powered by the voltage applied to the transformer primary winding, with the regulated voltage being used to power the control circuitry.