Abstract: A power factor correction circuit in which an inductor current is detected separately as a charging current indication signal and a discharging current indication signal by using a current sense resistor and a current sense circuit. A scaled-down output DC voltage is compared with a predetermined reference DC voltage by using an error amplifier which serves to produce an output voltage error signal. The output voltage error signal is then multiplied with a divided-down rectified input line voltage through the use of the multiplier to generate a sinusoidal reference signal. The sinusoidal reference signal is used by peak and valley comparators which also receive the charging and the discharging current indication signals. The outputs from the peak and the valley comparators are used to control a FET transistor which controls the input line current. As a result, the power factor correction circuit is capable of effectively eliminating a dead time and thereby achieving a near unity power factor.

Abstract: In an electronic circuit having a voltage supply means, a load means, and a regulating means, in order to limit the current flowing through a load, a supply voltage/current regulator is provided which comprises a voltage dividing circuit for dividing the supply voltage of a voltage supply, a reference voltage generator for generating a reference voltage, and a differential amplifier for comparing the divider output voltage and the reference voltage and for producing an output signal in accordance with the difference. The output signal is provided to the base of a transistor connected between the voltage supply and the load. The transistor is effective limit the current flow through the load such that the supply voltage does not decrease below a predetermined limit. By limiting the flow of current through the load such that the supply voltage does not decrease below a predetermined limit, the load may be driven continuously without the problem of lock-up common in ordinary voltage regulators.

Abstract: Size reduction in a clamped power converter can be achieved, and stability of the converter under no-load and transient loads can be substantially improved, by operating the converter in a continuous flyback mode.

Abstract: A voltage multiplier for relatively high output current has its design output voltage stabilized and rendered independent of process spread, temperature, supply voltage and output current level, by a stabilization loop driving the switch that cyclically connects to ground a charge transfer capacitance of the functional voltage multiplier circuit. The feedback loop comprises an integrating stage, stabilized by creating a low-frequency zero in the transfer function for compensating one of two low-frequency poles of the transfer function of the whole circuit.

Abstract: A power supply system for a subsystem in a weapons system, having a filtering arrangement divided into three stages, the first stage providing coarse filtering for the subsystem, a second stage providing filtering for each of a plurality of sub-areas of the subsystem for filtering signals to individual devices within a given subarea.

Abstract: A EMI filter for an electric vehicle propulsion system, comprising a first and second capacitive element electrically connected in parallel with first and second power conductors, an inductive element electrically connected in series with the first power conductor and separating the first and second capacitive elements, and first and second junctions electrically connecting the second capacitive element to an electronic switch, wherein the sum of intrinsic inductances of the first and second junctions is less than the intrinsic inductance of the second capacitive element.

Abstract: A boost converter includes a snubber with finite but limited losses to minimize active power switching losses and minimize turn-off losses of the boost diode without generating any additional circulating energy losses. An inductor is connected so as to slow turn off of the boost diode and minimize reverse recovery losses. This inductor additionally minimizes the turn-on switching losses of the active power switch of the converter by providing for zero-current turn-on. A series connection of a finite resistor and a second diode is connected in shunt with the inductor/boost diode connection to prevent excessive voltage ringing across the active power switch by clamping its voltage during turn-off. A third diode is connected to the junction of the inductor and boost diode to prevent the voltage across the boost diode from ringing during the on interval of the active power switch.

Abstract: The power supply modules, together feeding a load (between the terminals 13 and 12) with the voltage V.sub.0, comprise blocking diodes D.sub.1 (or D.sub.2). A feedback loop controls the output voltage (controller 14 and comparator 15 which receives V.sub.ref1 (or V.sub.ref2)). Two output voltage terminals are used for locking, on the two electrodes of D.sub.1, the voltages V.sub.1 and V.sub.0 (or D.sub.2 with the voltage V.sub.2 and V.sub.0), and are connected to inputs of output voltage selection means (31) which are suitable to supply either the voltage kV.sub.0 (k.ltoreq.1) when D.sub.1 (or D.sub.2) is conductive, or the voltage kV.sub.1 =V.sub.ref1 (or kV.sub.2 =V.sub.ref2) when D.sub.1 (or D.sub.2) is blocked.

Abstract: A voltage regulator employs a PNP output transistor of vertical construction, which operates as a linear control element in a feedback controlled circuit which is formed in a substrate. A differential amplifier has one input coupled to a voltage reference and another input coupled via feedback from a resistive voltage divider connected between common and the output of the voltage regulator. A parasitic NPN transistor, which is merged physically and thermally with the structure of the PNP output transistor, senses the onset of output transistor saturation and re-routes the majority of the excess base current drive to a feedback control node. The feedback control node retards total excess drive via a reduction in drive amplifier gain and bandwidth thereby assuring good stability of feedback loop operation during all phases of saturation, without the need for additional frequency compensating elements.

Abstract: Due to the intermittent nature of electrical connection through moving contacts on electrically propelled vehicles, electrical power converters such as power supplies and inverters are subject to large voltage transients. For compactness and low weight, a high-frequency power converter comprised series-connected high-speed switching circuits, so that an input voltage with voltage transients is split between the switching circuits. As a result, lower-rated switching elements such as IGBT's and MOSFET's can be used while maintaining resistance to input-voltage transients.

Abstract: Method for the parallel connection of inverters by reference to extreme current values. The method achieves an equalizing regulation of the currents of several parallelly connected inverters each time the inverter with the highest current value is switched and that the instant of switching of all inverters, apart from the one switched first, depends on a comparison of its respective current value with the current value of at least one earlier switched inverter.

Abstract: An output circuit of a PWM inverter for PWM controlling a coil voltage of a motor includes an N channel power element, a P channel power element, a current control circuit having a current output terminal, and a second current control circuit having a current input terminal. A current flowing out from the current output terminal of the first current control circuit and a current flowing in from the current input terminal of the second current control circuit are subjected to particular control to thereby control the N channel power element and the P channel power element. The output circuit of the PWM inverter is configured inexpensively to control a voltage of a motor winding terminal with very small error and with low power consumption.

Abstract: A synchronous rectifying circuit for a switching power supply is disclosed which is arranged such that the necessity to provide a diode element in parallel with a rectifying transistor is eliminated so that a highly efficient and stable operation can be achieved. "On" drive signal of a switching transistor (Q1) is detected by a first limiter circuit (6), and a flip-flop circuit (5) causes a rectifying transistor (Q2) to be turned off in response to output of the first limiter circuit (6); turning-off operation of the switching transistor (Q1) is detected by a second limiter circuit (7), and the flip-flop circuit (5) causes the rectifying transistor (Q2) to be turned on in response to output of the second limiter circuit (7). The necessity to provide a diode element in parallel with the rectifying transistor is eliminated. Stable operation can be performed even if the switching element has an indefinite operation delay time. An enhanced efficiency can be achieved.

Abstract: A high precision DC-DC converter circuit having improved efficiency is disclosed. The DC-DC converter circuit includes a low accuracy switching regulator circuit for driving a switching field effect transistor (FET) on and off. A high accuracy output voltage regulator circuit is inserted into the feedback loop between the output of the DC-DC converter circuit and the sensing input of the switching regulator circuit such that the accuracy of the output voltage regulator circuit primarily determines the precision of the DC-DC converter. The DC-DC converter also includes a quick shut-off circuit coupled to the gate and source of the FET for driving the gate of the FET negative when the FET is switched off such that switching losses are minimized. A second embodiment of the high precision DC-DC converter is used to convert from 5.0 to 3.3 volts. The second embodiment includes a transformer, one winding of which is used as an output inductor.

Abstract: A voltage converting circuit of the charge pump step-up type includes a first circuit means for charging each of first and second capacitors with the voltage of a voltage source at a first timing. A second circuit operates to serially connect the charged first capacitor between a positive electrode of the voltage source and a positive voltage output terminal at a second timing so that a positive voltage which is a double of the voltage source voltage, is supplied from positive voltage output terminal. A third circuit operates to the charged first and second capacitors in series between a ground terminal and a negative voltage output terminal at a third timing so that a negative voltage which is a double of the voltage source voltage, is supplied from the negative voltage output terminal.

Abstract: A circuit for weighted addition which includes a transistor having a gate and a plurality of resistance elements. Each resistance element has a first and second end. The first end of each resistance element is impressed with a voltage, and the second end of each resistance element is connected to the gate of the transistor. The circuit is small in size and renders precise and various types of weighted addition possible.

Abstract: A magnetic flowmeter system provides a volumetric flow rate output and has a coil receiving a magnetic field producing coil current from the current supply circuitry. The current supply circuitry includes an H-bridge transistor circuit having first and second switches which couple one of the first and second coil wires to a supply conductor. Third and fourth switches of the bridge circuit couple the other of the first and second coil wires to a second supply conductor. A control circuit periodically alternates conduction of the first, second, third and fourth switches to reverse the polarity of the coil current. A coil current control circuit generates a non-alternating output representing the sensed alternating coil current amplitude. The control circuit modulates the conduction duty cycle of the third and fourth switches as a function of the non-alternating output to regulate the coil current amplitude to a selected level.

Abstract: This invention relates to an electric switch intended to be placed in an electric power circuit, said switch being responsive to a control signal. The switch comprises a semiconductor switch, an electromechanical switch and a signal processor. The electromechanical switch is connected in parallel to the semiconductor switch. The signal processor receives the control signal and outputs a command signal for controlling the semiconductor switch and the electromechanical switch. The invention also relates to a process for switching an electric power circuit.

Abstract: A power supply which incorporates a high frequency inverter and which is suitable for use in conjunction with a florescent lamp. The power supply comprises a full wave rectifier (10) and a reservoir capacitor (12) connected across the rectifier for the purpose of providing successive half-cycles of the voltage waveform V2 across the capacitor with a minimum instantaneous voltage level greater than zero. A solid state switching device (14) and an oscillator (15) are connected in circuit with the reservoir capacitor. The oscillator generates a gating signal to the switching device. The switching device is arranged to provide an output voltage V4 which has a frequency determined by the applied gating signal V3 and which has a peak amplitude value which varies over successive cycles with the waveform of the voltage V2 across the reservoir capacitor.

Abstract: A converter for supplying various output voltages for a television receiver includes a multi-resonant circuit, including a resonant inductor, the leakage inductance of a flyback transformer, and a charging capacitor (including the parasitic capacitance of a switching transistor). This arrangement relaxes the slope of the voltages in the converter resulting in reduced radiated EMI. In addition, the values of the inductor and the capacitor are adjusted so that the switching transistor turns on at zero voltage and zero current so that the switching transistor is less stressed and the converter is capable of high frequency operation. Finally, the switching signals applied to the switching transistor are subjected to a filter-delay to lessen the slope of the signals thereby also resulting in a reduction in the EMI radiated from the driving circuit.