Abstract: A boost converter for converting an input voltage received at an input thereof into first and second output voltages provided at first and second outputs thereof, respectively, a method of power conversion and a power converter employing the boost converter or the method. In one embodiment, the boost converter includes: (1) a first switching circuit coupled to a first rail of the input and having a first switch and a first capacitor coupled in parallel, (2) a second switching circuit coupled to a second rail of the input and having a second switch and a second capacitor coupled in parallel and (3) a boost inductor, coupled in series between the first switching circuit and the second switching circuit, that provides a conductive path for the input DC voltage to flow serially through the first switching circuit and the second switching circuit to charge the first and second capacitors, respectively.

Abstract: For use in a split-boost converter having a DC input, first and second outputs, a power train interposed between the DC input and the first and second outputs, a damped electromagnetic interference (EMI) filter circuit and method of reducing the EMI. In one embodiment, the EMI filter circuit includes (1) an EMI filter interposed between the power train and the second output, the EMI filter subject to oscillation from line disturbances arriving at the DC input and (2) a conductive path, coupling a rail of the second output to the DC input, that routes at least a portion of the line disturbances from the DC input directly to the second output to damp the oscillation of the EMI filter.

Abstract: A family of DC-to-DC converters includes a multi-resonant snubber network connected in parallel with a power switching device. The multi-resonant snubber network includes an auxiliary switch that is connected to transfer the energy from a parasitic capacitance of the power switching device into a resonant inductor and to achieve zero-voltage turn-on of the power switching device. An additional resonant path is included in the snubber network to achieve zero-voltage turn-off of the auxiliary switch and the power switching device.

Abstract: The invention relates to a voltage control means provided with a first and a second transistor T1 and T2 constituting a differential pair, the base of the first transistor T1 being intended to receive a reference voltage Vref, the base of the second transistor T2 being intended to receive a predetermined fraction Vs of a voltage applied to a power supply terminal VDD, and also provided with a first current mirror M1 and a second current mirror M2, each having its input connected to the collector of one of the transistors and its output connected to the collector of the other transistor, the output current of each mirror being K times larger than the input current.

Abstract: A device for converting direct voltage into a three phase alternating voltage having a two level converter connected to a direct voltage network and to an alternating voltage network. A control apparatus for performing pulse width modulation determines the pulse width modulation pattern for each phase by comparing a triangular wave for each phase with a reference alternating voltage. The triangular wave is inverted an even number of times during a fundamental oscillation of the reference alternating voltage and the time position of the inversions of each triangular wave is always such that two triangular waves are half a period displaced with respect to the third.

Abstract: A boost converter, a method of operating the same and a power converter employing the boost converter or the method.

Abstract: A voltage reference arrangement is known for deriving a number of voltages from an input reference voltage. The known arrangement utilizes a rigid resistive voltage divider. A flexible voltage reference arrangement is provided in which inaccuracies in the input reference voltage are eliminated, and a plurality of accurate voltages can be easily derived from an obtained reference voltage. The arrangement comprises a digitally controlled potentiometer having a slider coupled to a multiplexer for multiplexing the slider to an input of a differential amplifier and to outputs. The voltage reference arrangement may be used in a voltmeter and in a battery subtractor in a telephone handset so as to share hardware.

Abstract: A voltage regulator circuit that minimizes the bias current flowing between a first voltage terminal and a second voltage terminal. The circuit receives input signals via a first and a second input terminal, and provides an output signal via an output terminal. The circuit includes a differential input stage, an output stage, a first sub-circuit for reducing the current flowing through the output stage between the first voltage terminal and the output terminal, and a second sub-circuit for reducing the current flowing through the output stage between the output terminal and the second input terminal. An alternative embodiment combines the power reduction circuitry with additional circuitry decoupling the input and output stages to provide enhanced design flexibility.

Abstract: A capacitor arrangement across a direct current bus provides a high ripple current capability and high capacitance at a low cost. The circuit is used in electronic power conversion devices such as electric motor drives and inverters. A combination of film capacitors and electrolytic capacitors are used in the circuit and are placed across the dc bus. The film capacitors carry substantially all of the ripple current, while the electrolytic capacitors provide the majority of the capacitance. A resistor and a diode are used to isolate the electrolytic capacitors from the ripple current. This results in a low cost compact bus capacitor configuration.

Abstract: A motor controller inverter circuit with resistive shunts for sensing the current flowing through individual legs of the motor controller. The circuit of the invention allows the use of a single monolithic three-phase driver by providing, in addition to a shunt resistor between the emitter pin of each low side IGBT and ground, an emitter return resistor between the emitter pin of each low side IGBT and the common V.sub.SO pin of the three-phase driver. The respective voltages developed across the shunt resistors can be sensed to determine the current flowing through the individual legs of the motor controller circuit.

Abstract: A buck regulator circuit provides a low voltage, e.g., about 15 V, power source, directly from a variable high-voltage dc bus voltage that varies from 250 V to about 450 V. A monolithic gate driver circuit is used to drive the switching device, e.g., a MOSgate transistor, which delivers the high voltage dc to the load output node via a charging inductor for controlled time periods. The control principle for controlling the on and off times of the transistor (with the monolithic gate driver circuit) relies on turning on the transistor for fixed time periods that are equal to the intrinsic delay of the gate driver circuit. In contrast, the off period of the switching device is varied to regulate and maintain the output voltage at a constant value, independent of the input dc bus voltage or of the output current.

Abstract: A printhead includes a plurality of recording elements such as LEDs each having a light output characteristic related to a driving parameter such as current. A plurality of driver circuits establishes the driving parameter for driving the recording elements. The driver circuits are mounted on a circuit board. A flex circuit having a conductive pattern electrically connects the driver circuits to the recording elements. The driver circuits include resistors for use in regulating the driving parameter. In lieu of mounting the resistors on the circuit board, the resistors are instead advantageously mounted on the flex circuit for controlling current to the respective recording elements. This allows the resistors and recording elements to be replaced without the need to also replace or modify the circuit board in the event that more efficient recording elements are to be used.

Abstract: The present invention provides a transformer which uses bi-directional syronous rectification to transform the voltage of an input signal from one voltage level to another. The invention provides a transformer which requires less core volume, and hence mass, than conventional transformers, and includes a rectifier for transforming a first time varying input signal, such as a sinusoid or saw tooth signal, into a full-wave rectified voltage signal. A synchronous switch control generates first and second control signals in response to sampling the first time varying voltage signal. A floating drive buffer generates third control signals in response to receiving the second control signals. An AC switching stage transforms the full-wave rectified voltage signal into a first and second series of voltage pulses in response to receiving the first control signals. Each of the first and second series of voltage pulses has a pulse period, T, and a pulse width, .omega..

Abstract: A switched-mode power supply circuit having an operating mode and a stand-by mode. The switched-mode power supply circuit includes a transformer and a controllable switch connected to a primary winding of the transformer for switchably connecting the primary winding to a source of d.c. voltage. In the stand-by mode, the switched-mode power supply circuit is arranged to switchable connect the primary winding to the d.c. voltage source in bursts which occur at a low frequency. Between each of the bursts, an auxiliary capacitor, which is ordinarily charged by an auxiliary winding during switching of the controllable switch, is now charged by a start-up current source contained in a controller for controlling the controllable switch.

Abstract: The power-supply controller of a computer can minimize power-consumption as shown in the following description. The operation mode will convert to a sleep-mode reducing the power-consumption below a constant voltage if there is no input to operate a computer system for a predetermined period of time. If the condition of no input for operating a computer system persists, the power supply controller cuts off the power-supply once again. In order to achieve this object, this invention is composed of a power-supply, a power-controller, and a power-mode-controller. The power-supply includes a first rectifier that converts an AC voltage to a DC voltage, a DC/AC converter which converts a DC voltage into an AC voltage, a switching mechanism which outputs a pulse signal used to operate the DC/AC converter, a second rectifier which converts to a DC voltage from an AC voltage received from the DC/AC converter, and a driver which provides an operation voltage to operate the switching mechanism.

Abstract: In a regulated power supply circuit which includes a differential amplifier circuit and a current output circuit which receives the output from the differential amplifier circuit, wherein the current output circuit comprises a drive stage transistor which operates upon receipt of an output from the differential amplifier circuit at an input terminal thereof, a current output stage of a MOSFET which is driven by the drive stage transistor and a load resistor for the drive stage transistor connected to the output side thereof, and the load resistor and the drive stage transistor are provided between a power source line and a ground line and the MOSFET is driven by an output taken out via the load resistor.

Abstract: An alternating current power control device including a phase comparison controller for comparing a phase of an input voltage with that of a first reference voltage, a single-winding transformer for varying the input voltage, a mutual induction reactor for lowering the input voltage by a desired level in response to an output voltage from the single-winding transformer, an output voltage comparator for comparing an output voltage with a second reference voltage, an output current comparator for comparing an output current with a reference current, an OR logic controller for performing an OR operation with respect to output signals from the phase comparison controller and output current comparator, and a switch array for selectively transferring the output voltage from the single-winding transformer to the mutual induction reactor in response to output signals from the output voltage comparator and OR logic controller.

Abstract: A simplified power supply circuit includes: a primary capacitor connected across an anode and a cathode of a rectifier for rectifying an input voltage of high voltage and low current of AC current, a plurality of secondary capacitors connected in series in between a positive pole and a negative pole of the primary capacitor through a positive-pole on-off switch and a negative-pole on-off switch, each secondary capacitor having its positive and negative conductors respectively connected to an output positive terminal and an output negative terminal by an on-off switch circuit, and the secondary capacitors having their output positive and negative terminals connected in parallel for amplifying the low input current (with high voltage) to be a high output current (with low voltage) without using the heavy iron core and winding of a conventional transformer.

Abstract: In a resonant DC-DC converter for converting a d.c. input voltage into a d.c. output voltage, a main switching element (3) switches the d.c. input voltage under control of switching pulses to supply an a.c. voltage to a primary side of a transformer (4). A resonant circuit (5) is provided at a secondary side of the transformer. A clamp circuit is connected to the main switching element and comprises a first capacitor (2-1) and an auxiliary switching element (2-2) serially connected to the first capacitor. The main and the auxiliary switching elements are alternately put into an on state under control of the switching pulses.

Abstract: Methods and apparatus for uninterruptible power supply (UPS) systems are provided. The UPS systems are configured to provide the advantages of an in-line device, and operate in a quasi-standby mode. The UPS includes a rectifier unit and inverter arranged to nominally deliver a portion (e.g. up to about 20%) of the primary AC power supply to a critical load through an output transformer. The rectifier unit preferably includes internal energy storage capabilities, such as a capacitor and inductor. The remaining portion of the AC power supply is nominally supplied directly to the critical load and is controlled by a transfer switch and the output transformer. When a fault is detected in the main AC power supply, the transfer switch switches to a faulted position and power is supplied from the rectifier inductor and capacitor or from a battery to the load through the inverter.