Abstract: A direct current boost converter which has a simple structure using only one coil, and which can apply a driving voltage to a capacitive load which reciprocates in polarity is discussed. A first direct current branch circuit composed of first and second transistors is connected in parallel to a second direct current branch circuit composed of the third and fourth transistors. A coil is connected between the intermediate nodes of the transistors of these direct current branch circuits, and these nodes are further connected to both terminals of an EL panel through first and second diodes. The nodes between the first and second diodes and the EL panel are grounded through fifth and sixth transistors, respectively. A clock signal is applied to the first and third transistors, and a gate signal with an opposing phase is applied to the second and fourth transistors.

Abstract: A method and apparatus for operation of an electrical power conversion system having first and second partial systems connected in parallel. Each partial system includes an inductor and an electronic switch for controlling electrical power transferred through the partial systems. A control circuit controls operation of the electronic switches. The control circuit includes devices for generating a first control signal error and a second control signal error as a function of a reference and current flowing in the inductors. Hysteresis devices receive the first and second control signal errors and provide first and second outputs, respectively, upon intersection of the first and second control signal errors with selected threshold values. Delay devices coupled to the electronic switches receive and delay transmission of the first and second outputs to the electronic switches.

Abstract: In a power supply unit, AC energy is converted to DC energy and stored into a first capacitor to which a first winding of a transformer is connected. An anti-parallel circuit of a first transistor and a diode is connected between the first capacitor and the first winding. An anti-parallel circuit of a second transistor and a diode is connected between a second winding of the transformer and a second, battery-charging capacitor. A current is induced in a third winding of the transformer for charging a third capacitor when a current is produced in the first winding in a particular direction or when energy stored in the second winding is released into the third winding. The first and second transistors are alternately switched on so that energy is transferred from the first capacitor to the second and third capacitors when the AC energy is normal and energy is transferred from the battery to the third capacitor when the AC energy fails.

Abstract: A digitally controlled switched-mode voltage converter having conversion circuit (CMS) including a switching device (SW) for the purpose of converting an input voltage (U.sub.i) into an output voltage (U.sub.o); and a control device (CM) for controlling a duty cycle of the switching device (SM) in steps having discrete values (D.sub.c1,D.sub.c2). The control device (CM) include a change-over device (SO) for continually switching the duty cycle between at least two discrete values (D.sub.c1,D.sub.c2) in such a manner that the average value of the duty cycle corresponds to a target duty cycle (T.sub.dc).

Abstract: A three-phase boost converter having wye-connected input capacitors and a method of operating the same. The boost converter includes first, second and third phase inputs and an output. In one embodiment, the boost converter includes first, second and third inductors coupled to the first, second and third phase inputs, respectively, and operable in a discontinuous conduction mode (DCM). The boost converter further includes first and second switches coupled between corresponding rails of the output. The boost converter still further includes first, second and third capacitors coupled between the first, second and third phase inputs, respectively, and a node between the first and second switches. The first and second switches cooperate progressively to employ a voltage across the rails less a voltage across the first, second and third capacitors to discharge currents through the first, second and third inductors, respectively, and thereby reduce input current THD on all three of the phase inputs.

Abstract: A transformer assembly in which an isolation transformer and two additional inductor elements of a series/parallel resonant converter are physically integrated in a cost and space-efficient design. The transformer and two inductors are integrated through the simultaneous control of the leakage inductance and the magnetizing inductance of the assembly. The primary and secondary windings of the transformer are wound in a prescribed manner on a closed-path ferromagnetic core, the magnetizing inductance of the unit being determined by the desired inductance of second inductor, and the leakage inductance of the unit being determined by the inductance of the first inductor, which predominates the total series inductance of the tank circuit. The desired magnetizing inductance is achieved by controlling an air gap disposed in the magnetic flux path of the core, while the desired leakage inductance is achieved by winding a certain portion of the secondary turns on a loosely coupled leg of the core.

Abstract: A temperature sensor circuit of a power semiconductor component comprises temperature-sensitive elements, some (Q1, and R1 to R3) of which are located in the vicinity of an active area of the component where heat is generated by the power semiconductor device (MPWR), whereas others (such as R4, R') are located more remote from the heat-generating active area and so are in a cool location. Hot-location elements (Q1, and R1 to R3) with different temperature coefficients are present in a first comparator circuit for indicating device temperature (Tabs) in the vicinity of the heat-generating active area. Both hot-location and cool-location elements (R2 and R4) are present in a second comparator circuit for indicating when a temperature gradient (Tdiff) threshold occurs.

Abstract: A voltage/current (v/c) conversion circuit is designed for use in integrated circuit devices. Conventional designs of v/c conversion circuits require a relatively high value of load resistor, i.e. a steep v/c conversion slope, to generate high levels of output current. In place of the high load resistor which is expensive to fabricate with IC fabrication techniques, the source-drain resistance in an n-type MOSFET is utilized, and the output current level is adjusted by adjusting the potential of a bias input circuit supplied from the gate potential in an n-type MOSFET. The proposed configuration is ideally suited to IC fabrication processes, and the circuit is useful in a many applications requiring a wide range of high current levels from a conversion circuit having a low v/c conversion factor.

Abstract: For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across the primary winding, a voltage clamp circuit for, and method of, resetting the transformer and a power converter employing the clamp circuit or the method. In one embodiment, the clamp circuit includes: (1) first and second reset windings coupled between the first and second power switches, (2) first and second energy storage devices coupled between the primary winding and the first and second reset windings, respectively, and (3) first and second switching circuits, coupled to the first reset winding and the second reset winding, respectively, that provide an electrical path from the primary winding to the converter input through the first and second reset windings, respectively, when the first and second power switches are not conducting.

Abstract: A switch mode power converter achieving high efficiency through zero voltage switching (ZVS) by using an auxiliary switch, a capacitor, an auxiliary winding and an inductor. The technique can be applied to a boost, buck-boost, buck, isolated forward or isolated flyback converter. The auxiliary switch is turned on before the main power switch turns on, and the capacitor provides voltage to energize the inductor and force current to flow into the auxiliary winding. The current is transformed by the main winding and discharges the capacitance across main power switch to zero volts before the main switch turns on. Hence ZVS is obtained and can greatly reduce the switching loss of the main power switch.

Abstract: Two parallel regulator stages, each comprising a transistor (T1, T2, respectively), are provided. The transistor (T2) forms part of the indirect parallel regulator stage and acts directly on the rectifier. It is capable of taking up comparatively large currents and hence is comparatively slow. The transistor (T1) forms part of the direct regulator stage and operates in parallel with the sustaining capacitor. Because of the coarse control provided by the transistor (T2), it need take up small currents only and can hence have a very fast control behavior. Because of the coarse control by the transistor (T2), the alternating voltage on the antenna terminals (LA and LB) quickly breaks down when the RF signal is interrupted; consequently, the transmission rate can be increased in the case of pause interval modulation. Static discharges are also dissipated by the transistor (T2), so that no additional protective circuitry is required for this purpose.

Abstract: An improved power supply apparatus for controlling electrical elements of a vehicle which is used for a vehicle using 12 volts as well as a vehicle using 24 volts. The apparatus includes a mode selection switching unit which is selectively switched in accordance with a voltage level inputted from a battery, a first voltage transformation unit, which is not operable when the mode selection switching unit is in the turned-on mode and is operable when the mode selection switching is in the turned-of mode, for dropping an input voltage from the battery to a predetermined level, and a second voltage transformation unit for dropping a voltage from the battery when the mode selection switching unit is in the turned-on mode and dropping an output voltage from the first voltage transformation unit to a predetermined level when the mode selection switching unit in the turned-off mode.

Abstract: An automatic polarity conversion circuit for providing output signals having predetermined output polarities. The automatic polarity conversion circuit includes first and second input terminals for receiving first and second input signals, respectively. Also included is a converter converting the first and second input signals into first and second output signals having predetermined first and second output polarities, respectively, regardless of the polarities of the first and second input signals. Further, a first output terminal outputs the first output signal, and a second output terminal outputs the second output signal.

Abstract: An apparatus for a controlled supply of current to an electric consumer, including a turn-on function. The apparatus including a circuit board having conductor paths, a subordinated phase control circuit mounted on the circuit board and having a triac switching in both directions of an AC supply voltage and a trigger circuit for triggering the triac, the triac being connected in series with the consumer, a contact point mounted to the board, and a springing metal tongue having a first end mounted to the board and a second end that extends above the contact point at a distance from the board. The metal tongue and the contact point form electric contacts with the conductor paths on the board so as to define a switch. The electric contacts lead to connection points in the trigger circuit of the triac.

Abstract: A switching bandgap reference circuit with compounded .DELTA.V.sub.BE includes an amplifier having an output, an inverting input and a non-inverting input; a first PN junction connected to the non-inverting input; a second PN junction connected to the inverting input through an input capacitor; a low current source and a high current source; a switching device for applying in the auto zero mode the low current source to a first terminal of the first PN junction and the high current source to a first terminal of the second PN junction for establishing the V.sub.BE, of the first junction at both the inputs of the amplifier and for applying in the valid reference mode the high current source to the first terminal of the first PN junction and the low current source to the first terminal of the second PN junction for establishing the positive .DELTA.V.sub.BE, of the first PN junction to both the inputs of the amplifier and applying the negative .DELTA.V.sub.

Abstract: AC/DC power converter device comprising a full-wave rectifier (R) the output of which is applied to a direct current module which has two outputs: the main output is connected to the load via a capacitor (C1) which transfers a first power level (P1), and the auxiliary output is formed by a capacitor (C2) and a direct current converter (DC) which stores a second power (P2) and transfers it to the load during the full cycle of the input power wave (PE). As a result the second power level (P2) is continuously topping up the first power level (P1).

Abstract: This invention provides an absolute value voltage to current conversion circuit which realizes multiple outputs of the current obtained by the conversion of a voltage. For an input voltage of positive polarity, an inverting voltage to current conversion circuit is formed by means of an operational amplifier and a multiple output current mirror circuit. In that case, currents which are 1/n of a converted current are obtained by setting the ratio of the input current to the output current of the current mirror circuit to n:1. For an input voltage of negative polarity, a noninverting voltage to current conversion circuit is formed by means of the operational amplifier and a plurality, n, of bipolar transistors. The converted current is distributed among n bipolar transistors to obtain an output current per transistor which is 1/n of the converted current. As a result, an absolute value voltage to current conversion circuit with multiple outputs can be realized.

Abstract: An apparatus for controlling rescue operations and for improving power efficiency in which an Auto Landing of Power failure ALP device is provided with an active power filter for supplying a compensation current to a control unit when the ALP device is in a stand by condition that a power failure does not occur.

Abstract: An improved ink stick supply assembly is provided for a solid ink color printer which reliability feeds solid ink sticks from an ink stick loading bin to ink stick melt plates which melt the ink sticks on demand and guide the molten ink into individual color ink reservoirs in the printer print head. Low ink and empty ink level sensors are provided which advise the printer operator when to replenish the ink stick supply. A low friction material and spring loaded pusher blocks facilitate travel of the inks through the ink stick feed chutes to the melt plates.

Abstract: A current source includes a first current mirror and a second current mirror that share a common current path. The current in the common current path mirrors a current of a current reference connected to the first current mirror. A current in an output current path of the second current mirror mirrors the current of the common current path. A first feedback loop controls the current in the common current path and a second feedback loop matches a voltage of the common current path with an output voltage. The cooperation of the first and second feedback loops ensures that the output current replicates the current of the current reference even when an voltage of the current source is close to the supply voltage. Thus, the voltage swing of the current source output voltage is increased and a precision current source is provided even when the output voltage is close to the supply voltage.