Abstract: An AC-DC voltage conversion integrate circuit that integrates all the control and protection circuits, as well as the power transistors, into a single module. Passive components, such as the transformer and capacitors, are very small, as the switching frequency is in the KHz or MHz range. Including one or more integrated switched mode power supply ICs in every wall outlet allows for providing a plurality of DC voltages from such outlets.
Abstract: Method of control of a three-phase or multi-three-phase invertor (1) supplied from a DC voltage source (2) and controlled by a processor (5) for deriving, in the course of successive slaving periods, signals for pulse-width-modulation control of the transistors of the invertor. It consists, from measuring the power supply current of the invertor and from taking account of the switching states of the transistors, in reconstituting the phase currents.
Abstract: A MOSFET, an op-amp, a comparator circuit, and voltage dividers with capacitors are employed in combination to effectuate a soft-start switch with current limiting. The transconductance of the MOSFET is employed so that no sense resistor is required. The MOSFET and op-amp are configured as a closed-loop feedback circuit in which the output of the op-amp is coupled to the gate of the MOSFET and the inverting input of the op-amp is coupled to the output of the soft-start switch via a voltage divider. A first RC circuit provides a voltage to the non-inverting input of the op-amp which can be triggered to gradually rise from a value close to zero to some reference voltage so as to soft-start a load. Current limiting means are effectuated by a comparator circuit and voltage dividers with capacitors.
Abstract: Switched-mode power supplies require a power factor correction circuit in order to comply with anticipated regulations for the harmonic load on the line network. In its second current path, which produces a connection between a rectifier element and a tap on the primary winding of a transformer, the switched-mode power supply contains a capacitor which produces current limiting for an inductance in this current path. When the switching transistor is in the switching mode the inductance is charged, when the switching transistor is switched on, in the sense of an energy store until the capacitor is charged. When the switching transistor is switched off, the inductance and the capacitor are discharged via a diode in the direction of an energy-storage capacitor.
Abstract: An improved print mode and system for alleviating wait-banding is disclosed. In the disclosed print mode, the delay between print scans may be increased or decreased at the full swath boundaries. Within a full swath, the delay between passes is set at a standard default delay. At the full swath boundary, if a low-memory condition is sensed or if there is a need to perform a service routine, the delay is ramped up. If there is currently not a low-memory condition or if there is not a need for a pen service, the delay is ramped down. This print mode provides that the print passes are more uniformly distributed in time, thus alleviating wait-banding. This print mode is particularly advantageous for glossy medium and transparencies.
Abstract: The invention relates to a voltage regulator connected between first and second voltage references and having an output terminal for delivering a regulated output voltage. The voltage regulator includes at least one voltage divider, connected between the output terminal and the second voltage reference, and a serial output element connected between the output terminal and the first voltage reference. The voltage divider is connected to the serial output element by a first conduction path which includes at least one error amplifier whose output is connected to at least one driver for turning off the serial output element. The voltage regulator includes, between the voltage divider and the serial output element, at least a second conduction path for turning off the serial output element according to a value of the regulated output voltage in advance of the action of the first conduction path.
May 29, 1997
Date of Patent:
August 31, 1999
SGS-Thomson Microelectronics S.r.l., Consorzio per la Ricerca sulla Microelettronica nel Mezzogiorno
Abstract: A power device circuit comprises a power semiconductor device (MPWR) in series with a load (LD) between a power supply line (1) and a return line (2), and a short-circuit detector (R1, R2, . . . R1', R2', . . . CP) for determining whether the load (LD) is short-circuit. The short-circuit detector examines the distribution of the supply-to-return voltage (Vbg) between the device (MPWR) and the load (LD) by comprising a comparator (CP) which has a first input (+) coupled to a series node (11) between the device and load and a second input (+) from circuit means (R1, R2, . . . , R1', R2', . . . ) coupled between the supply and return lines (1 and 2) to provide the second input (-) with a voltage supply signal (Vbg') which is a predetermined function of the supply-to-return voltage (Vbg).
Abstract: An adaptive battery charger for charging batteries used in portable electronic devices. The battery charger monitors power provided from an AC adapter to the portable electronic device, and adaptively utilizes all available power from the AC adapter for charging the batteries, both when the portable electronic device is off, and when it is in use. As the power required for the portable electronic device increases, the power provided to the batteries decreases. As the power required to power the portable electronic device decreases, the power available to charge the batteries increases.
Abstract: A power electronic circuit arrangement is specified, having a first power converter, which is connected to a first supply system, and a second power converter, which is connected to a second supply system. The first and second power converters are connected via a voltage intermediate circuit. According to the invention, a further filter is provided in addition to the so-called 33 Hz filter (supply-system filter) in the voltage intermediate circuit, which further filter serves to suppress the undesirable in-antiphase and in-phase current components flowing in the intermediate circuit. The additional filter can be realized either in split fashion, i.e. with two subfilters, in each case one for the in-antiphase current components and one for the in-phase current components, or in combined fashion with a common filter for both current components.
Abstract: In a semiconductor device comprises an internal circuit and which is supplied with an external voltage, the internal circuit is operated in an internal voltage having a high internal level and a low internal level. A voltage decreasing circuit decreases the high internal level of the internal voltage. A controlling circuit controls decrease of the internal voltage in response to an external control signal OEB.
Abstract: A noncontact power transmitting apparatus which makes it possible to rapidly charge a secondary cell of a part to be charged with large electric power and realize a lightweight and compact part to be charged. A power-transmitting coil of a charging part is divided into two sets, and the power-transmitting coils of the sets are respectively wound around cores, and are formed as a first power-transmitting coil portion 26 and a second power-transmitting coil portion 27 which are separate and independent as the two sets. Meanwhile, a power-receiving coil of a part to be charged is wound around a core, and is formed as a single power-receiving coil portion 28.
Abstract: A digital potentiometer capable of being connected directly to an electronic switch is disclosed. The digital potentiometer for example may utilize a 64 step resistor array, which would then have 64 steps. Each of the steps have precise values so as to accurately attenuate a signal in logarithmic steps. The logarithmic resistor is connected to a gate device which in turn has a voltage source connected to it designed to provide the threshold or turn-on voltage for the device for each of the 64 steps and wiper points of the resistor array.
Abstract: The present invention is to provide to a charge pumping circuit capable of reducing the area of the layout by making the positive and negative charge pump in a single circuit, of enhancing the efficiency of the pump and of making the pumping speed high with the high driving voltage. The charge pumping circuit comprises: a charge pump for generating voltage amplitude which is over Vdd; a positive charge pump for transferring positive charges from the charge pump in response to a first control signal; a negative charge pump for transferring negative charges from the charge pump in response to the first control signal; and a controller for making a voltage, which is applied to the negative charge pump, to a ground voltage level at a negative charge operation, and for providing a voltage level for the negative charge pump to prevent charges from flowing to the negative charge pump.
Abstract: A power supply unit has an overdischarge detection circuit for detecting overdischarge of a power source, an overcurrent detection circuit for detecting overcurrent, and a stopping circuit for stopping overdischarge or overcurrent in accordance with an overdischarge detection signal or an overcurrent detection signal. The power supply unit is further provided with a delay circuit to prevent the overdischarge detection circuit and the overcurrent detection circuit from being activated erroneously by external noises. This delay circuit provides a variable delay time so that the delay time will be longer when overdischarge is detected than when overcurrent is detected. This makes it possible to stop overdischarge and overcurrent without fail.
Abstract: A DC to DC converter which maintains high efficiency over broad current ranges in a current mode switching regulator circuit without changing operational mode. A low ripple voltage is maintained over the entire load range and good voltage regulation is maintained with high efficiency. This is possible because the switching frequency is adjusted in accordance with the load without changing operational states, thus making it unnecessary to define plural states of operation. The timing of turning on the switch(es) varies since the switch(es) is (are) turned on when two set (ready) signals both become ready. For fixed frequency switching applications, switching pulses from a fixed frequency oscillator as a first set signal are skipped when a second set signal is not ready. On the other hand, for a variable frequency switching scheme which is implemented by driving the switching with a one-shot having a constant OFF time, the switching pulse is created after both set signals become active.
Abstract: An apparatus for controlling a switching frequency of a switching mode power supply (SMPS) for a video display appliance which can remove a switching noise generated during the switching-on and switching-off operations of an SMPS transformer by controlling the switching frequency of the SMPS transformer so that the duty of the SMPS transformer is kept in a predetermined range.
Abstract: A power supply with a power factor correction circuit for use in a display monitor controls a switching power circuit in response to a voltage induced at a secondary winding of a transformer provided in the power factor correction circuit. Further, upon receiving a power saving control signal generated from a microcomputer provided in the display monitor, the power supply operates in the stand-by mode, (i.e., the power saving mode), in which only the power saving mode power supply circuit operates to supply operational power to the microcomputer.
Abstract: A control circuit drives the coil of a contactor in response to a control voltage being applied. The control circuit includes a power supply that produces a regulated output voltage from the control voltage. The onset of the regulated output voltage starts a timer which controls the width of pulses produced by a PWM controller. The pulses control a transistor that applies the control voltage to the coil. Initially the pulses cause a high current to flow through the coil to close the contactor and after an interval of time the timer signals the PWM controller to shorten the pulses which applies lesser current to the coil to keep the contacts closed. A flyback circuit provides a relatively low reverse voltage drop path in parallel with the coil to maintain the electromagnetic field during the periods between the pulses. When the control voltage is removed to open the contactor, the flyback circuit provides a high reverse voltage drop path to promptly dampen the coil current.
February 12, 1998
Date of Patent:
June 8, 1999
James E. Hansen, Michael E. Bauer, Dale L. Gass, William J. Janutka
Abstract: A switching power source device in which recovery current can be decreased. The power source device includes a magnetic element connected one of terminals of a power source section, a switch having one end connected with the magnetic element and the other end connected with the other terminal of the power source section, a smoothing capacitor connected between the magnetic element and the other terminal of the power source section, and a diode connected between the magnetic element and the smoothing capacitor with forward direction directed to pass current from the power source section through the magnetic element to the smoothing capacitor.
Abstract: A voltage regulator (10) comprising a vertical channel transistor (12). The vertical channel transistor (12) may have a gate (16), a voltage input terminal (18), and a voltage output terminal (20). A reference voltage supply (14) may be coupled to the gate (16).
December 12, 1997
Date of Patent:
June 1, 1999
Texas Insturments Incorporated
Han-Tzong Yuan, Albert H. Taddiken, Donald L. Plumton, Jau-Yuann Yang