Abstract: A voltage drop compensating circuit is disclosed which compensates for unwanted voltage drops along a DC current conductor connected to an integrated circuit. The compensating circuit includes a differential amplifier connected between a voltage supply and the conductor form the integrated circuit which is marred by the voltage drop. One input terminal of the amplifier is connected to the supply lead and an output terminal of the amplifier is connected to the conductor. A feedback network is connected between another input terminal of the amplifier and the integrated circuit. A potential difference between the two input terminals on the amplifier will lead to the amplifier adjusting a potential on the output terminal until the unwanted voltage drop along the conductor is compensated for.

Abstract: A power supplying device in a primary side of a power circuit is provided, including: a main power transformer including a coil for receiving DC output from a first rectifier, to be turned on/off according a PWM pulse output from a PWM IC, thereby inducing current, and for separately supplying the induced current; a power transistor for receiving DC power output from a second rectifier according to power off mode, to drop voltage, the second rectifier receiving and rectifying the current output from the main power transformer in DPMS mode operation; and a third rectifier for receiving and rectifying current induced through the coil inserted into the main power transformer in the normal operation, to supply power to the primary side of a power circuit.

Abstract: A power supply with a programmable voltage slew rate is disclosed for generating a regulated voltage at a predetermined set-point. The power supply includes a programmable current source for generating a controllable level of current flow and a capacitive element coupled to the current source. The capacitive element is responsive to the current flow to establish a reference voltage that varies linearly with respect to variations in the current flow. The power supply additionally includes a power device having a control element disposed in sensed communication with the reference voltage and an output for driving a load. The output is operative to generate an output voltage following that of the reference voltage.

Abstract: For use with a power converter coupled to a regulation circuit and having a power switch and an auxiliary switch coupled thereto, a controller, method of operating the power switch and auxiliary switch and a power converter employing the controller and method. In one embodiment, the controller includes a voltage conditioning network, parallel-coupled to the power switch, capable of sensing a voltage across the power switch and developing a conditioned voltage. The controller further includes a drive circuit, coupled to the voltage conditioning network, adapted to provide a drive signal to control the auxiliary switch as a function of the conditioned voltage and a regulation control signal from the regulation circuit.

Abstract: An energy-efficient power inverter is disclosed which changes direct current provided at a pair of source terminals to alternating current at load terminals. The power inverter comprises a switch device and snubber circuit including a resistance, a capacitance and a saturable core device for selectively removing the resistance from the snubber circuit. At saturation the core device effectively shorts the resistance out of the circuit, and upon coming out of saturation the device effectively reinserts the resistance for improved reduction in power losses during the switch operation.

Abstract: A converter system, in particular for supplying electrical drives with direct current or DC voltage, or with alternating current or AC voltage, at a specifically matched frequency or for dynamic power factor correction. The converter system has at least one converter which has power semiconductors which can be switched on and/or off. It is possible to influence the current flow through the power semiconductors by adjusting the times at which the power semiconductors are switched on and off. It is also possible to influence the desired overall voltage or the desired overall current at the output of the converter by suitably controlling the times at which the individual power semiconductors of the converter are switched on and off.

Abstract: A method and apparatus for controlling current flow in current sources includes a current source FET (18), a control FET (20), and a driver circuit which includes complementary logic (310). The use of complementary logic for control advantageausly allows commonly available logic functions to control the current flow in individual current sources while maintaining a substantially constant bias voltage on the gate of the current source FETs. A chip-wide bias generator can be maintained substantially constant while controlling individual current sources.

Abstract: A method and apparatus for power factor correction. The present invention provides passive power factor correction for power supplies that supply more than 200 Watts. In one embodiment, power factor correction is provided for over 500 Watt power supplies. A diode bridge circuit provides a rectified voltage output from an alternating current input. A correction circuit receives the rectified voltage and provides power factor correction. The output of the correction circuit is the input to a load circuit, such as an alternating current to direct current circuit.

Abstract: A voltage control unit is provided to continuously monitor a reference output voltage by using a voltage monitoring circuit. When the reference output voltage is lower than a predetermined value, a pair of series transistors are turned ON by a detection output to thereby pull up the reference output voltage to the power supply voltage, and further to pull up the reverse phase input voltage to the reference output voltage. Then, the control is carried out in such a way that the reverse phase input voltage exceeds the normal phase input voltage. As a result, a reference voltage generating circuit is capable of providing a smooth ramp up voltage at power up or during any time the supply voltage is below the predetermined voltage.

Abstract: A capacitive element is charged with no excessive flow of current so that a potential to effect the operation of a switching element can be obtained with stability. A capacitor (30) is charged with a circulating current from a load (40). On the charging path, a resistor (21) is provided in series to prevent an excessive flow of the charging current. Between terminals (V.sub.B, V.sub.S) of an upper-arm driving circuit (25) which receive a voltage to effect the operation of an IGBT (34) of an upper arm, the capacitor (30) and the resistor (21) are provided to suppress a decrease in potential (V.sub.B) at the terminal (V.sub.B).

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: A resonant mode power supply includes a D.C. voltage source and switching elements for alternatively connecting an oscillating circuit, including a primary winding of a transformer, to the D.C. voltage source and to ground. A first secondary winding supplies the main output voltage of the power supply and a second secondary winding provides a control output voltage. An opto-coupler is included and has a light emitter connected to the second secondary winding, and a light sensor connected to a controller for controlling the switching of the switching elements, wherein the higher the frequency of the switching, the lower the power being supplied by the power supply. Burst mode stand-by is started by the first secondary winding being shunted to the second secondary winding causing the light emitter to emit a maximum amount of light. The controller increases the switching frequency until it exceeds a predetermined maximum frequency.

Abstract: An electronic signal conditioner (ESC) (10) that can be designed to operate a differential capacitive load (90) or a single-ended capacitive load (92). The ESC (10) is disclosed in four design configurations. In the first design, the ESC (10) employs a pair of high-frequency transformers (34,48) each having a single-ended primary winding (36,50) that is connected through a secondary winding (42,56) to a rectifying circuit (70,80) that operates a differential capacitive load (90). The second design also employs a pair of transformers (32,34) that have push-pull primary windings (36,50) which similarly operate a differential capacitive load (90). The third design employs a single transformer (34) having a single-ended primary winding (36) which similarly operates a single-ended capacitive load (92). The fourth design also uses a single transformer (32) having a push-pull primary winding (36) which operates a single-ended capacitive load (92).

Abstract: Converter equipment has two double converters (SR1, SR2), the ac terminals of which are connected to separate secondary windings (T11, T12) of a transformer (T1) and the dc terminals of which are connected to separate direct-voltage networks (LN1, LN2). Each double converter has a rectifier bridge (LR1, LR2) and an inverter bridge (VR1, VR2). Each secondary winding is connected to an inverter bridge in one double converter and to a rectifier bridge in the other double converter.

Abstract: An anode voltage of a diode for reverse current prevention provided in each power supply module is output to a current balance control terminal via a resistor. The current balance control terminals of the respective power supply modules are mutually connected, and an average level of the anode voltages in the reverse current prevention diodes of the respective power supply modules is applied to the current balance control terminals as a reference voltage level. By executing the switching control for the power MOSFET in each power supply module so as to make the anode voltage of the reverse current prevention diode in each power supply module equal to the reference voltage, the output current values of the respective power supply modules are set to be equal.

Abstract: Autotransformer design which is capable of modifying the active power flow in autotransformers connecting two different voltage systems in an electrical substation. The bus-tie autotransformers presented change the active power flow by modifying the phase-angle between the primary and secondary voltages of the autotransformer. In accordance with the two tap changers are employed allowing for independent changes in both the voltage ratio and the phase-angle values.

Abstract: Autoranging power supply apparatus may comprise a power output section having a plurality of pairs of output terminals, each of which has a maximum voltage and current rating. A switching network associated with the power output section connects and disconnects the plurality of pairs of output terminals to the external load. A control system connected to the switching network operates the switching network in response to changes in the impedance of the external load to connect and disconnect to the external load selected ones of the plurality of pairs of output terminals of the power output section to compensate for impedance variations in the external load and to prevent from being exceeded the maximum voltage and current ratings for each of the plurality of pairs of output terminals.

Abstract: The power output of a static DC--DC converter employing a current mode PWM controller is controlled upon the varying of the switching frequency, by detecting the sawtooth signal produced by the local oscillator generating a DC signal with an amplitude inversely proportional to the frequency. The power output is controlled by alternatively clamping the output voltage of the error amplifier of the PWM controller at a voltage proportional to the amplitude of the DC signal, or by offsetting the signal present on the current sensing resistor by a voltage corresponding to the difference between a constant voltage and the DC signal.

Abstract: In a circuit where a power converter (1) that is connected to a motor is also connected at its input terminals (2, 3) to a d.c. power supply system (U.sub.DC) and where at least one condenser (C) is connected in parallel to the power converter (1) connected to the motor and at least one line reactor (L) is connected in series to the condenser (C), a reduction in the harmonic currents fed back into the d.c. power supply system (U.sub.DC) by the power converter (1) connected to the motor above a predetermined minimum frequency is achieved without unnecessarily overdimensioning the condenser (C) and the line reactor (L) due to the fact that the line reactor (L) has at least one tapping point (4) to which at least one RC circuit (5) is connected in parallel to the condenser (C), where the RC circuit (5) has at least one capacitor (C.sub.1) and at least one resistor (R.sub.1) connected in series with it.

Abstract: An AC/DC power supply circuit is provided. In the AC/DC power supply circuit, output lines of a DC power supply unit including a multitap transformer are connected to output ends of a secondary winding of a multitap transformer in an AC power supply unit, or an output line of the DC power unit is connected to a leading end of a primary winding of the multitap transformer in the AC power supply unit.