Abstract: An electric drive apparatus and method for controlling medium-voltage alternating current motors wherein a multi-phase power transformer having multiple secondary windings provides multi-phase power to multiple power cells, each of which have a single-phase output and are controllable by a modulation controller. The primary and secondary windings in the power transformer may be star- or mesh-connected; the secondary windings may be shifted in phase. Because the power cells are connected in series, the maximum output voltage for each cell may be less than the maximum line-to-line voltage. The power cells can have a tri-state output which can be controlled using pulse-width modulation techniques. AC input power is converted to DC output power for each output phase. Output power modulation can be produced by interdigitating a selected number of carrier signals so that harmonic components reflected back to the input are attenuated.

Abstract: A power conversion circuit has a port for connection to a power source; a transformer having a primary winding, a secondary winding, and an effective secondary leakage inductance L2e; and a capacitance C connected on a secondary side of the transformer. A first switching device is connected to be opened and closed to transfer energy from the power source via the effective leakage inductance to charge the capacitance during energy transfer cycles having a characteristic time scale of pi*sqrt(L2e*C). Control circuitry controls precharging of the capacitance at selected times other than during the forward energy transfer cycle.

Abstract: An installation for transmission of high-voltage direct current comprises a first and a second converter (SR1, SR2, respectively), each one controlled by a separate piece of control equipment (CE1, CE2, respectively). Each one of the pieces of control equipment comprises a current controller (CC). The current controller of the second converter is supplied with a second current reference value (IOL2) and a current margin (IOM). The control equipment of the second converter comprises a function-forming member (11), which in dependence on an applied measured value (UD) of the direct voltage forms the current margin such that, when the direct voltage exceeds a first preselected voltage level (Udf), it assumes a first value (IOMf) and, when the direct voltage is lower than the first voltage level, it assumes a second value (IOMs), the magnitude of the second value being greater than the magnitude of the first value.

Abstract: A power supply is disclosed which is compatible with modern thin film technology which has an overall size compatible with modern miniaturized electronic components. Input power having an oscillating component in the 50/60 Hz 120/220 volt range is immediately switched to high frequency current exceeding 100 KHz and preferably switched with a frequency in the megahertz range. The switched current, otherwise unaltered from its current having an oscillating component, is then transduced in voltage at a thin film transformer, passed through thin film mounted electronic components for rectification and filtering. A regulator circuit modifies the semi-conductor switch duty cycle to control the rectifier output voltage. All transformer, rectifier, and filter components are of thin film variety and mounted to attain efficient heat dissipation together with size reduction comparable to the powered components driven by the power supply.

Abstract: In a switch mode power supply of a video apparatus, a capacitor develops a supply voltage that is coupled to a main current conducting electrode of a driver transistor. The driver transistor drives a switching power transistor. An arrangement charges the charging capacitor when the video apparatus operates in standby mode. A delay circuit introduces a delay time between a time when the capacitor begins to be charged and the time when a switching control signal is applied to the driver transistor for operation in a run mode. Consequently, the capacitor develops sufficient voltage that insures sufficient base current to turn on the power transistor in to saturation prior to the time the switching control signal is applied to the driver transistor. Thus, a possible damage to the power transistor is prevented.

Abstract: The invention provides for an autotransformer for converting three-phase AC power to nine-phase AC power. The autotransformer includes three coils each having a plurality of serial windings and a plurality of stub windings. The serial windings form a delta and the stub windings are magnetically coupled with the serial windings from the same coil. Three terminals are provided at the apices of the delta and the three-phase AC source may be directly connected to the respective apex terminals. A plurality of direct outputs are interposed between respective serial windings and a plurality of indirect outputs are electrically connected with the second ends of the stub windings. The voltage magnitude of each of the direct outputs is preferably equal to the voltage magnitude of each of the indirect outputs. The voltages of the direct outputs and indirect outputs are out of phase with the voltages at the apex terminals.

Abstract: Main power supply circuit includes an inrush current suppressing circuit serially connected between its rectifying circuit and a load, this inrush current suppressing circuit being composed of a current limiting resistor and an FET switch that is serially connected to this resistor. An auxiliary power supply circuit provides power for a control circuit of the main power supply circuit, and, after the power supply switch is closed, a delay circuit monitors rise of a charge voltage of a smoothing capacitor within the main power supply circuit as well as rise of control circuit voltage of the auxiliary power supply circuit and establishes a delay time. After the elapse of the delay time, the FET switch is turned ON and the inrush current suppressing circuit is closed. The inrush current suppressing circuit is then short circuited within a short time period and the load operation is continued.

Abstract: A multi-channel single stage high power factor AC to DC converter comprising a pair of input terminals for connecting to an a.c. supply voltage, a bridge rectifier connected across the input terminal, for converting the a.c. supply voltage to a d.c. voltage, and a D.C. to D.C. converter connected to the bridge rectifier and including a high frequency switch for converting the d.c. voltage to high frequency intermittent pulses, a transformer having a primary winding connected to the high frequency switch and having at least two secondary windings each connected to a respective rectifier for producing a d.c. output voltage thereacross. A pair of capacitors are connected in the input of the DC to DC converter so that when the switch is OPEN a first one of the capacitors receives energy from the a.c.

Abstract: A circuit and method for an integrated multifunction voltage regulator is disclosed. The integrated circuit features a voltage preregulator having a battery input and a Vcc output, a voltage bus for distributing the Vcc voltage, and a plurality of function blocks which are connected to the Vcc buss and are driven by the Vcc voltage. The function blocks include voltage regulators, protected battery switches, band gap voltage references, and reset circuits.

Abstract: A current mirror (100) has an input stage (104) and an output stage (106), both preferably employing FET's. (Field Effect Transistors) An amplifier (102) equalizes drain-to-source voltages between FET's in the input and output stages to provide a higher output impedance. A resistance (R1), coupled in series with an FET in the output stage (106), provides degenerative feedback. A reference current generator (400) is constructed of two such current mirrors, one being the compliment of the other, to provide one or more stable reference currents. Loop gain of the reference current generator (400) is greater than one at start-up, but degenerative feedback reduces the loop gain to one at a predetermined stable operating point.

Abstract: A converter employs a comparator sensing the current through an output diode, for generating a confirmation signal of an OFF state of the switch until the discharge current of the inductor toward the user circuit and the external filter capacitance has become null, thus ensuring the operation in a discontinuous mode under any condition. A turn-off signal of the switch is provided by another comparator which, instead of the voltage on a sensing resistance connected in series with the switch, may sense the voltage across the switch itself. This latter embodiment is particularly suited in case of an output MOS transistor and the circuit comprises means for masking for a preset period of time the turn-off signal produced by said comparator, in order to allow a predefined turn-on phase of the switch. Enabling of the turn-on of the switch is conventionally provided by a dedicated (third) comparator of the output voltage.

Abstract: An automatic regulating circuit gradually regulates an output voltage to a reference value in synchronism with a clock signal, and has a binary search controller changing the value of a control signal across a final value corresponding to said reference value until a convergence at the final value; the control signal is supplied to a level shifting system so as to converge the output voltage at the reference value, and the automatic regulating circuit quickly completes the voltage regulation.

Abstract: A power converter has two switched capacitor circuits each including at least a plurality of sets of capacitors and switching elements, first of which circuits is provided for supplying a DC power to a load while second of which accumulates a power in a period receiving a higher input voltage, and the first switched capacitor circuit being made to receive, in a period receiving a lower input voltage, a power supplied from a DC power source and also the power supplied from the second switched capacitor circuit for supplying to the load the DC power of a constant voltage, in which an input current collectively taken up by the two switched capacitor circuits is made similar in the waveform to the input voltage to eliminate any harmonics distortion of the current drawn from the source, for attaining the supply of the DC power of the constant voltage to the load, whereby the power converter is rendered not to require any large inductor to be capable of being minimized in size and restraining any noise radiation fr

Abstract: A current reference circuit producing a reference current without temperature dependence and operating at a low supply voltage, which includes a first current source for producing a first constant current having a positive temperature coefficient, a second current source for producing a second constant current having a negative temperature coefficient, and an adder for adding the first and second constant currents to cancel their positive and negative temperature coefficients. The second current source contains first and second bipolar transistors and a resistor connected between a base and an emitter of the first bipolar transistor, and a bias subcircuit for supplying the reference current to the first bipolar transistor. The emitter of the first bipolar transistor is connected to an emitter of the second bipolar transistor, and a collector of the first bipolar transistor is connected to a base of the second bipolar transistor.

Abstract: A bidirectional power converter array has overall voltage feedback, an error signal generator, and plural bidirectional power converter modules. Each module of the array includes a series inductor and local feedback based upon the inductor current. Each module also has a resistive current sensor, providing wideband local feedback. A low-pass filter is coupled to the current sensing resistor to reduce switching noise. The low-pass filter also reduces the bandwidth of the local feedback signal, so interactions with the overall feedback occur, which may result in instability. A winding transformer-coupled to the series inductor generates AC signal representing high-frequency components of the inductor current, relatively free of switching noise. The AC current sample is added to the low-frequency components derived from the resistor and low-pass filter, to form a low-noise local feedback signal, with sufficient bandwidth to reduce unwanted interactions with the overall system feedback.

Abstract: An electrical power converter system having a power factor correction circuit and a switching power converter. The power factor correction circuit converts the AC line voltage into an unregulated DC voltage referred to as the PFC voltage, which supplies an unregulated DC input voltage to the switching power converter. The switching power converter converts the unregulated DC input voltage into one or more regulated DC output voltages. The PFC voltage automatically adjusts to an appropriate value for achieving the desired power factor correction, converter efficiency, and converter temperature. In a preferred embodiment, the value of the PFC voltage is adjustable in response to a control signal produced by a PFC control circuit. The PFC control circuit measures the peak value of the input line current to determine whether the power factor is acceptable. If the power factor is acceptable, the PFC voltage will be maintained at a relatively low value.

Abstract: A circuit configuration for limiting an output voltage of a clocked voltage regulator includes a control unit receiving a direct voltage to be regulated and having an output for supplying an output voltage. A voltage regulating amplifier is constructed as an integrator, receives the output voltage and a reference voltage, and supplies an output signal. A current threshold generator detects a current intensity of the integrator and supplies an output signal. A multiplier multiplies the output signal of the current threshold generator by the output signal of the voltage regulating amplifier and a signal obtained from the direct voltage to be regulated and supplies an output signal. A current regulating amplifier receives the output signal of the multiplier and a signal obtained from the direct voltage to be regulated and supplies an output signal. A driver stage converts the output signal of the current regulating amplifier into a trigger signal for the control unit.

Abstract: A control process for a voltage transformer for sine-wave line current input with a large input voltage range, includes controlling or regulating the input current of the voltage transformer as a function of a current command value. The output voltage of the voltage transformer is in the form of an actual value input quantity of a controller which supplies a control signal as a function of an output voltage command value. The above-mentioned current command value is obtained by multiplying a signal proportional to the rectified input voltage of the voltage transformer by the above-mentioned control signal, and also by a direct current voltage signal which is a reciprocal of the peak value, to the effective value or to the average value of the input voltage of the voltage transformer. Such a process is preferably used in a switched-mode voltage transformer, e.g. in an isolating transformer, a step-up transformer or a step-up/step-down transformer.

Abstract: A synchronous regulator circuit including a transformer having a secondary inductor magnetically coupled to a primary inductor, where the secondary inductor is coupled to control a synchronous power switch. The secondary inductor operates to drive the synchronous power switch using self-regeneration during a flux reversal phase of each cycle. A timing circuit or simple pulse width modulation circuit (PWM) turns on the primary switch and turns off the synchronous switch during a power phase of each cycle, and then turns off the primary switch during the flux reversal phase of each cycle. The flux reversal of the secondary inductor drives the synchronous switch on, thereby achieving synchronous operation without an expensive dual output PWM. The present invention is illustrated using both a buck and a boost topology. A third switch is preferably used to clamp the synchronous switch off during the power phase.

Abstract: A circuit configuration for supplying electrical consumers, in particular sensors in a motor vehicle, with a constant voltage required for their operation, includes a reference voltage source. A transistor is connected as an emitter follower for making a buffered reference voltage available at an output as a supply voltage for an electrical consumer.