Abstract: The control apparatus for controlling a voltage transforming apparatus having a transformer, power switching elements disposed in a primary side, and synchronous-rectifying switching elements disposed in a secondary side includes a judging circuit making a judgment as to whether or not an output current of the voltage transforming apparatus is smaller than a specified current on the basis of a primary-side current of the transformer and an inhibition circuit inhibiting the synchronous-rectifying switching elements from performing their synchronous-rectifying control operation when the judging circuit judges that the output current is smaller than the specified current. The judging circuit makes the judgment with compensating for a variation of a relationship between the primary side-current and the output current due to variation of duty ratio of the power switching elements, and variation of at least one of the DC output voltage and the DC input voltage of the voltage transforming apparatus.

Abstract: An exemplary embodiment of an apparatus for supplying and switching power may include a power source, a transformer, a full bridge rectifier and a control switch. The transformer has a first winding and a second winding, the first winding being connected to the power source, the second winding having a first tap and a second tap, with the first tap being connected to a first load output. The full bridge rectifier includes four nodes, the first being connected to the second tap of the second winding, the second being connected to a second load output, the third being connected to a reference voltage source. The control switch is connected between a fourth of the four nodes and the reference voltage source.

Abstract: A method for controlling a rectifier, connected to an AC power network, of a drive converter which is provided with a load-end pulse-controlled rectifier is disclosed. An electronically controlled switch is electrically connected in parallel to every diode of the rectifier. The switching operations of the switches are produced in a manner synchronized with the conduction phases of the associated network-commutated phase voltages and independently of the phase voltages of the supply network. Every switching operation produced is released upon arrival of the next zero value at the rectifier end. The network-end switching operations are linked with the load-end zero values, thereby allowing switching operations to be carried out in a currentless manner.

Abstract: An apparatus method and system are provided for power conversion, to supply power to a nonlinear load such as a plurality of light emitting diodes. An exemplary apparatus comprises a first power converter stage, a second power converter stage, a plurality of sensors such as first and second sensors, and a controller. The first power converter stage includes a power switch and a first inductor having a first inductance. The first and second sensors are both coupled to a common reference node, with the first sensor adapted to sense a first parameter of the first power converter stage, and the second sensor adapted to sense the output current level. The second power converter stage includes a second inductor having a second inductance, and is coupleable to provide an output current to the nonlinear load such as LEDs.

Abstract: A power factor correction (PFC) circuit includes a coupled split boost choke having at least two windings, at least two boost diodes and at least two power rails. Each power rail includes one of the windings and one of the boost diodes. The PFC circuit further includes a current balancing circuit coupled between the power rails for substantially balancing currents in such power rails.

Abstract: The voltage stabilizer for stabilizing a voltage of a circuit includes a first resistor, a second resistor, a voltage controller, and a current supply unit. The voltage controller keeps a voltage of the first resistor constant. The current supply unit supplies a first current to between the first resistor and the second resistor when a second current in the circuit becomes equal to or larger than a predetermined value.

Abstract: A semiconductor switch interrupts output when a microcomputer or an external IC operates abnormally is connected to a control device such, and is turned on or off depending upon a control signal from the control device. The semiconductor switch has feed voltage-monitoring means for monitoring whether the voltage fed to the control device lies within a predetermined range, and is turned off when it is so judged that the voltage is not within the predetermined range.

Abstract: A device that includes an active rectifier (14) having control gates controllable to produce an output voltage on a DC bus (20), a gate control circuit (16) for producing gate control signals for controlling the active rectifier control gates, a first circuit (18) connected to the gate control circuit (16) and producing a command current magnitude signal and a power factor signal for use by the gate control circuit (16), a current line (30) providing a current related to the DC load current to the first circuit (16), and a voltage line (32) providing a voltage related to the DC bus voltage to the first circuit (16), the first circuit (16) including a peak detector (64) detecting current peaks on the DC bus (20), a command current magnitude signal generator (34) commanding a current as a function of the detected peaks, and a power factor controller (33, 40) varying the power factor signal (42) to control the voltage on the DC bus (20).

Abstract: Apparatus and method for a power converter with feed-forward voltage compensation to enable a PFC circuit are proposed. A voltage divider and a feedback unit output a compensation voltage and a feedback voltage in response to an input voltage and an output voltage, respectively. The feedback voltage is compensated by the compensation voltage through an operation unit. A comparator activates the PFC circuit within a predetermined input power range based on the already compensated feedback voltage. The proposed power converter can always activate the PFC circuit before the input power reaches 75 W regardless of any variation of the input voltage.

Abstract: The present invention is associated with a power adapter capable of simultaneously providing a low-level DC voltage and a high-level DC voltage. The power adapter includes a transformer having a primary winding for storing energy when a main switch coupled therewith is turned on and transferring the stored energy to the secondary side of the transformer when the main switch is turned off. The transformer includes a first secondary winding and a second secondary winding connected in series with each other. A first rectifier/filter circuit is connected across the first secondary winding for generating a low-level DC voltage by rectifying and filtering the energy received by the first secondary winding, and a second rectifier/filter circuit is connected across the first secondary winding and the second secondary winding for generating a high-level DC voltage by rectifying and filtering the energy received by the first secondary winding and the second secondary winding.

Abstract: A power supply operable from a plurality of alternating current inputs had having protection from abnormal operation. The power supply includes a switchable rectifier and a voltage to voltage converter. Protection circuits switch off at least one of the rectifier and the converter if the rectified voltage exceeds a predetermined voltage value and/or a current through the converter exceeds a predetermined current value. The protection circuits include latch circuits to prevent cyclic operation.

Abstract: A rectifier includes a switching circuit and a controller. The switching circuit is coupled between positive and negative buses and a plurality of input voltage sources. The switching circuit includes a plurality of pairs of switching devices. Each pair is associated with one of the input voltage sources. The controller includes first and second control loops operable to generate control signals for operating the pairs of switching devices to generate a potential across the positive and negative buses. The controller is further operable to estimate a line inductance seen by the rectifier based on at least one of the control signals and generate an inductance compensation gain factor for applying to the control loops based on the estimated line inductance.

Abstract: Power flow models of Interline Power Flow Controllers (IPFC) for large-scale power systems are studied, in details. Mathematical models of the IPFC, using the d-q axis decompositions of control parameters are derived. In this framework, for each IPFC, only two control parameters are added to the unknown vector in the iteration formula and the quadratic convergence characteristic is preserved. Simulations results from several practical large-scale power systems embedded with multiple Convertible Static Compensators (CSCs) demonstrate the effectiveness of the proposed models. Comparisons with existing models are made to elucidate the performance of the convergence.

Abstract: In one embodiment, a power supply controller uses a ramp signal to form current sense ramp compensation.

Abstract: A device includes an active rectifier (14) having control gates controllable to produce an output voltage on a DC bus (20), a gate control circuit (16) for producing gate control signals for controlling the active rectifier control gates, a first circuit (18) connected to the gate control circuit (16) for producing a command current magnitude signal and a power factor signal for use by the gate control circuit (16), a current line (30) providing a signal related to the DC load current to the first circuit (18), and a voltage line (32) providing a signal related to the DC bus voltage to the first circuit (18). The first circuit (18) includes a command current magnitude signal generator (34) producing the command current signal based on the DC load current and a power factor controller (44, 48) producing the power factor signal. The power factor controller (44, 48) includes a feed forward circuit (52, 56) for increasing the power factor signal in response to current fluctuations on the current line (30).

Abstract: A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on/off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's.

Abstract: A power supply circuit comprises a bridge circuit that has four rectifier elements connected and produces a rectified voltage between a positive side output terminal and a negative side output terminal of the power supply circuit, two of the four rectifier elements being connected to the negative side output terminal, a current detection element with which to detect a current, a first switching element that is connected in series to the current detection element and together with the current detection element is connected in parallel with one of the two rectifier elements, and a second switching element that is connected in series to the current detection element and together with the current detection element is connected in parallel with the other of the two rectifier elements. Based on a result of detecting with the current detection element, switching timings of the first and second switching elements are controlled.

Abstract: A method for constant-current generation by means of a rotational energy source, a generator and a control circuit connected to the generator. Mechanical rotational energy is generated by the energy source and the mechanical rotational energy is transmitted to the generator rotor. The magnetic field distribution produced in the generator is controlled by the control circuit that controls the current distribution in the generator between load current and generator current by feedback control by generating an opposing magnetic field. The power uptake and the current output are adapted without losses and the alternating current generated by the generator is transferred to an averaging direct-current circuit. A suitable device for carrying out the method is also provided.

Abstract: A synchronous rectifying control circuit for utilizing in a forward topology of rectifying circuit. The circuit controls a first current switch and a second current switch provided on both ends of a secondary of a transformer. Two sets of the same of control circuits are utilized to control and adjust respectively the post and future periods of the conductive time and the driving synchronous rectifying switches are extended to replace the conventional of rectifier diodes rectifying method. An improved synchronous rectifying control circuit comprises pulse interruptive protection circuit to prevent the cross-conduction between two current switches and an anti reversing protection circuit to prevent a reverse current from flowing back to the ground.

Abstract: Provided is a DC-DC converter circuit which is stably operated without being affected by a size of an output capacitor (111) and a cost thereof. When a switching element is turned on so that a charge current that was flowing into an output capacitor flows into the switching element, the current is converted into a voltage to be added to an output voltage, and a resultant voltage is fed back to a control system.

Abstract: A circuit arrangement for operating at least one light source. Cost-effective power factor correction of the system input is achieved by a combination of a charge pump and a valley-fill circuit. According to the invention, the voltage (UN2) produced by the charge pump is fed into the valley-fill circuit with a lag, for example via an inductor (L2).

Abstract: An isolated circuit of low-voltage supply of a control circuit of a high-voltage load, in or upstream of a fullwave three-phase rectifying bridge, comprising a first low-voltage capacitor having a first electrode connected to one of the rectified output terminals of the bridge, and at least one second capacitor providing said low voltage, a first electrode of the second capacitor being connected to one of the A.C. input terminals of the bridge, the respective second electrodes of the capacitors being connected by a high-voltage diode having its cathode connected to the second capacitor.

Abstract: In a circuit arrangement for operating light sources, inexpensive technologies for power factor correction can be used in combination. A resonant capacitor in a reactance network for coupling the light source is of dual design (C51, C52). A degree of freedom is thus produced which makes it possible to optimize the costs of the circuit arrangement.

Abstract: An active-power filter includes control circuitry to combine an integrated output-voltage feedback signal, an input-voltage sense signal and an output-load feedforward signal to generate a control signal. An output-load subsystem draws the output current from the active-power filter and the output-load feedforward signal indicates when current drawn by an output-load subsystem changes. In some embodiments, the output-load subsystem may draw output current from the power converter having an output current ripple at a nominal frequency, which may range, for example, between about 35 and 100 Hz. The control circuitry may include an integrator to integrate the output-voltage feedback signal. The integrator may have a control loop bandwidth significantly less than the nominal ripple frequency to loosely regulate the output voltage while the input current drawn by the active-power filter is tightly regulated.

Abstract: Active power filters and methods control and regulate the input current drawn from an electric power bus to a DC level. Load current fluctuations and ripple current reflected back to the electric power bus are significantly reduced or substantially eliminated. A switch mode power converter with a very low bandwidth output voltage regulation control loop uses input voltage feedforward, output load feedforward, and output voltage feedforward to provide a regulated DC input current significantly attenuating input ripple current drawn from the electric power bus.

Abstract: A power factor correction (PFC) circuit (10) includes a latch (16) having an output that initiates a coil current (ICOIL) in response to a transition edge of a clock signal (CLOCK) to generate a PFC signal (VOUT). An input receives a control signal (TERM). A current modulation circuit (14) has a first input (36) coupled for receiving the PFC signal to establish a charging time (TCH) of the coil current. A second input senses the coil current to establish a duty cycle of the coil current over a period of the clock signal, and an output (38) provides the control signal as a function of the charging time and the duty cycle.

Abstract: A method of controlling a half-controlled rectifier, and a rectifier structure, which comprises an n-phased half-controlled converter bridge, a DC intermediate circuit and a capacitor of the DC intermediate circuit. The converter structure further comprises an auxiliary intermediate circuit and a non-controlled n-phased diode rectifier bridge which feeds the auxiliary intermediate circuit and is connected to the DC intermediate circuit by isolating diodes.

Abstract: An apparatus for and a method of controlling standby power to minimize energy consumption in a standby mode. The standby power control apparatus includes a control unit, a power supply unit, a constant voltage unit, and a standby power generation unit. The control unit controls an overall operation of the system. The power supply unit converts an alternating current (AC) power into a direct current (DC) voltage and outputs the DC voltage to a load. The constant voltage unit drops the output DC voltage of the power supply unit and provides the control unit with the dropped output voltage. The standby power generation unit drops the output voltage of the power supply unit from a first value to a second value lower than the first value if the system is switched to a standby mode.

Abstract: An inverter with a self-commutated pulse converter connected to the power mains and at least one self-commutated pulse converter connected to a load. The line-side converter is electrically connected to the load-side converter through a DC intermediate circuit. A line filter can also be connected before the self-commutated pulse converter on the line side. The disconnectable converter valves of the line-side and load-side converters are implemented as semiconductor switches with different circuit topologies and can operate at different pulse frequencies. Each of the line-side and load-side converters can be optimized for a desired pulse frequency, which saves cost and space.

Abstract: The present invention discloses a power apparatus with the output voltage thereof made variable, which allows harmonics to be suppressed while an enhanced power factor being maintained. The power apparatus comprises an alternating current power source, a bridge rectifier circuit to subject alternating currents from the alternating current power source to full-wave rectification, a reactor connected between the alternating current power source and the alternating current input end of the bridge rectifier circuit and a capacitor connected via a bi-directional switch between the alternating current input end and the direct current end of the bridge rectifier circuit, further comprising a smoothing capacitor, a zero-crossing detecting means, a bi-directional switch drive signal generating means and a bi-directional switch driving means.

Abstract: A power line communication MODEM includes a rectification circuit for converting an AC power source to a DC power source, a MODEM circuit to which a DC voltage is supplied from the rectification circuit, a USB connector connected to the MODEM circuit, and a signal overlapping circuit for overlapping a signal processed by the MODEM circuit with the AC power source, wherein the rectification circuit supplies the DC voltage to the USB connector.

Abstract: The invention relates to a rectifier circuit matched for power factor correction, comprising a first diode (D1), a second diode (D2), a third diode (D3) and a fourth diode (D4) in bridge arrangement, an inductance (L1) and a capacitance (C1), with a first pole (10) and a second pole (12) of the bridge arrangement being connected to a source (U) which has at least one AC voltage component, and the inductance (L1) being arranged in series with the third pole (14) or the fourth pole (16), where the capacitance (C1) is connected between the first pole (10) and the second pole (12), and two of the four diodes (D1, D2, D3, D4) are in the form of fast diodes.

Abstract: Methods and apparatus are disclosed for suppressing or eliminating nonlinear current drawing characteristics, while at the same time substantially eliminating high order current harmonics. In accordance with various aspects of the present invention, an energy transfer system, for example a pulse width modulator (PWM) flyback converter (22), comprises an inductor (L) interposed between the AC line voltage and the load (Rload), with a controllable switch (26) provided between the inductor (L) and the negative supply leg of a rectifier circuit (10). The duty cycle of the converter switch (26) is suitably controlled to produce a substantially constant DC output from the converter (22). Proper synchronization of the converter switch (26) ensures that the current through the inductor (L) and the output current through the load (Rload) remains in phase with the AC supply voltage. Thus, a power factor on the order of unity is maintained while substantially eliminating nonlinear current drawing characteristics.

Abstract: A Power Factor Correction (PFC) circuit according to the present invention includes a boost converter which outputs a predetermined voltage according to control of a switch. The switch is coupled to a resistor and a capacitor which, by forming a current detector, detect the current flowing through an inductor of the boost converter. The output voltage of the boost converter is divided by resistors, and the voltage difference between the divided voltage and a reference voltage is amplified by an error amplifier. The output voltage of the error amplifier and a reverse sawtooth waveform provided from an oscillator are input in a multiplier so as to be multiplied by a gain, and output voltages of the multiplier and of the current detector are provided to a switching driver. The switching driver turns off the switch when the output voltages of the current detector and of the multiplier are equal, and turns on the switch when the state of the reference clock signal is changed.

Abstract: Disclosed is a Power Factor Correction (PFC) controller which comprises a boost converter, an error amplification unit, a calculator, and a switching driver. The error amplification unit reduces the error voltage of the output voltage of the boost converter to a specific reference voltage. The calculator receives first and second input voltages proportional to the input power of the converter and the output voltage of the error amplification unit, and outputs the voltage proportional to the first input voltage and the output voltage of the error amplification unit and inversely proportional to the second input voltage. The switching driver controls the switch to OFF when the voltage which detects the current flowing to switch of the boost converter becomes equal to the output voltage of the calculator, and controls the switch to ON when the zero current of the coil of the boost converter is detected.

Abstract: A protected, transformerless power converter for converting an AC mains power source to a low voltage DC power source is presented. The AC input voltage is rectified to supply pulsating DC voltage to a pass element resistor. An electronic switch located between the pass element resistor and an output filter capacitor interrupts the current flowing into the output filter capacitor. The output filter capacitor averages the pulse current drawn from the AC input line to provide a constant DC output voltage to a load. The instantaneous AC input voltage, the average value of the AC input voltage, and the output voltage are used to calculate the optimal times of conduction of the electronic switch. Controlling the time of conduction in this manner maximizes the power efficiency of the converter and protects the supply from an output overload or short circuit condition over a wide range of AC input voltages.

Abstract: The active capacitor regulating type controllable voltage and current power supply circuit is disclosed with a voltage reducing and current limiting rectifying circuit which is constituted by capacitors and a bridge type current rectifier device, wherein it is characterized in that the output terminals of the rectifying circuit are parallel installed with a current distributing circuit device, thereby to actively control the output voltage setting status.

Abstract: Methods and apparatus are disclosed for suppressing or eliminating nonlinear current drawing characteristics, while at the same time substantially eliminating high order current harmonics. In accordance with various aspects of the present invention, an energy transfer system, for example a pulse width modulator (PWM) flyback converter (22), comprises an inductor (L) interposed between the AC line voltage and the load (R.sub.load), with a controllable switch (26) provided between the inductor (L) and the negative supply leg of a rectifier circuit (10). The duty cycle of the converter switch (26) is suitably controlled to produce a substantially constant DC output from the converter (22). Proper synchronization of the converter switch (26) ensures that the current through the inductor (L) and the output current through the load (R.sub.load) remains in phase with the AC supply voltage.

Abstract: The disclosure concerns an electronic device, for example a radio-alarm clock, that can be powered from the mains power supply or from batteries and can operate without interruption when changing from one of these power supplies to the other. It comprises a support connected to the mains and a mobile part that can be placed in electrical contact with said support and that includes at least one electronic circuit requiring power. This electronic circuit is powered from the mains via a first diode when said mobile part is placed in electrical contact with said support, and is powered by at least one battery via a second diode when said mobile part is removed from said support.

Abstract: An integrated circuit controller for a switching power converter implementing feed-forward and synchronization features. The controller IC has pins which permit dual functionality. The feed-forward feature is implemented with a supply voltage from an unregulated auxiliary winding which additionally powers the controller. The synchronization feature is implemented by coupling an external synchronization signal to a feedback pin of the controller IC to which a feedback signal from the output of the converter is also coupled.

Abstract: The PWM control scheme is illustrated in conjunction with a power distribution control circuit (30), wherein the duty cycle of converter (32) is suitably controlled by a number of feedback loops embodying various parameters, for example a voltage error signal, an average (e.g. RMS) value of the input voltage (Vin). Circuit (30) comprises a rectifying circuit (42), a converter circuit (32), for example an AC-DC converter, a capacitor (C), an oscillator and PWM circuit (44), an error signal (46), a multiplier circuit (48), a differencing amplifier (50), and a synthesizing circuit (52). Circuit (30) appears as a resistive load to the line for feed PWM, a fixed load, and a fixed RMS input voltage. To stabilize the output voltage (Vout), the pulse width signal (44a) applied to converter suitably varies in proportion to both changes in the RMS value of the input voltage and the output voltage.

Abstract: A regulated power supply having power factor correction control which includes a state variable integrator/error amplifier that provides a low distortion error signal during steady state operation and fast transient response for tight output voltage control.

Abstract: An AC-DC converter of a type having an improved power factor having an arrangement that enlargements of loads to be borne by circuit components due to AC input voltage is prevented so that the size and cost of the AC-DC converter are reduced. A constant-current circuit is, in parallel, connected to a voltage dividing point of charge voltage of an output capacitor to be connected to an input terminal of an error amplifier of a booster converter circuit and realized by a plurality of resistors so that control of a constant-current value of the constant-current circuit is performed with the rectified output from the rectifying circuit. As a result, the loads to be borne by the circuit components of the AC-DC converter can be made constant regardless of the supplied AC voltage level so that the size and cost of the AC-DC converter are reduced.

Abstract: A power generation system is constituted by an induction generator and a converter. An output current waveform of the induction generator is determined by the magnetic flux, speed, winding impedance, DC output voltage, and load of the induction generator. In particular, the output current waveform is changed in accordance with a change in speed (i.e., change in slip). Switching elements in the converter are ON/OFF-controlled in accordance with changes in current waveform, thereby controlling power generation of the induction generator.

Abstract: A full wave rectifier includes an amplifier having a minus input, a plus input and an amplifier output; an input resistor connected between a circuit input and the minus input; and a current bridge having an output terminal connected to the circuit output, a first terminal connected to the minus input and a second terminal connected to the amplifier output. The current bridge includes a first current mirror circuit and a second current mirror circuit. The first current mirror circuit includes a first current source and a second current source, a source end of each current source of the first and second current sources being connected to the first terminal, a drain end of the first current source being connected to the second terminal and a drain end of the second current source being connected to the output terminal.

Abstract: Instabilities in the output voltage provided from an AC power supply system connected to a power factor correcting load are suppressed by a stabilizer which is connected across the output lines from the power supply system to the load. The stabilizing apparatus includes a rectifier having AC input nodes connected to the power supply system output lines, and DC output nodes at which DC voltage appears. A capacitor and resistor are connected in parallel across the output nodes of the rectifier. During normal operation, where the peak AC voltage from the power supply system is substantially constant, the capacitor charges up to a voltage level near the zero to peak value of the AC voltage waveform, with the charge on the capacitor slowly dissipated through the parallel resistor at a rate that does not substantially dissipate the charge between peaks of the AC voltage waveform.

Abstract: A switching circuit can reduce switching power loss and can vary at least one of the switching frequency and the conduction rate of switching of the switching circuit with less dependency on a frequency of a resonating circuit. A converter unit employs the switching circuit for expansion of control range of an output voltage. A primary switching element forming the switching circuit is provided with a resonance circuit and an auxiliary switching element. With the auxiliary switching element, resonance operation is achieved. The switching circuit is applicable to switching portions of a DC-DC converter unit, an inverter or the like.

Abstract: A full wave rectifier includes an amplifier having a minus input, a plus input and an amplifier output; an input resistor connected between a circuit input and the minus input; and a current bridge having an output terminal connected to the circuit output, a first terminal connected to the minus input and a second terminal connected to the amplifier output. The current bridge includes a first current mirror circuit and a second current mirror circuit. The first current mirror circuit includes a first current source and a second current source, a source end of each current source of the first and second current sources being connected to the first terminal, a drain end of the first current source being connected to the second terminal and a drain end of the second current source being connected to the output terminal.

Abstract: A three phase power conditioner. The inventive power conditioner (10) converts an alternating current input signal from a three phase source (12) into a direct current output signal and includes a first circuit (20) for converting a first phase of the input signal into a first direct current output signal. A second circuit (22) is included for converting a second phase of the input signal into a second direct current output signal. Likewise, a third circuit (24) converts a third phase of the input signal into a third direct current output signal. A control circuit (30) regulates the power supplied by the first, second and third circuits to balance the loads (26) for all load values dynamically. In an illustrative implementation, the first, second and third circuits (20, 22, and 24) are implemented with boost converters and the controller (30) is implemented with a load share controller. The inventive power conditioner is adapted for use with Wye and Delta configured three phase power sources.

Abstract: A power-supply unit having a rectifier circuit, switch, first and second voltage generation circuits, a control circuit, and a capacitor. The rectifier circuit is connected to an A.C. power source. The switch opens/closes an electric line which supplies a load circuit with electric power from the A.C. power source via the rectifier circuit. The first voltage generation circuit generates a first voltage based on an output voltage of the rectifier circuit. The first voltage is a non-zero voltage. The second voltage generation circuit generates a second voltage based on the output voltage, and is larger than the first voltage. The control circuit turns the switch on when the output voltage is in a range between the first voltage and the second voltage, and turns the switch off when the output voltage is outside the range.

Abstract: The invention concerns a washing composition for washing a surface to deposit thereon substantially water-insoluble particles. The aqueous washing composition of the invention comprises an anionic surfactant, the particulate substance to be deposited and a water-soluble cationic non-cellulosic polymer which enhances the deposition of the particulate substance onto the surface but which cationic polymer does not form in the composition a water-insoluble complex with the anionic surfactant, the cationic charge density of the polymer being from 0.0001 to 0.0017; the concentration of the cationic polymer in the washing composition being from 0.0001% to 0.01% by weight; and the concentration of the surfactant in the washing composition being from 0.01% to 5% by weight.