Abstract: Disclosed is a new single-phase passive harmonic filter for one or more nonlinear loads. The filter improves the total system performance by drastically reducing the line side current harmonics generated by nonlinear loads. The filter includes two inductive portions across one of which is connected a tuning capacitor. The parallel combination of one inductive portion with the tuning capacitor forms a series tuned filter configuration while the second inductive portion is used for harmonic attenuation. A shunt capacitor is employed for shunting higher order harmonic components. A single-phase passive voltage regulator provides the needed voltage bucking to prevent over voltage at the load terminals of the filter. The filter provides an alternate path for the harmonic currents generated by nonlinear loads. The over voltage caused by the increased capacitive reactance is controlled by either capacitor switching or by the use of the passive voltage regulator or a combination of the two.

Abstract: A circuit used to convert a DC input to an AC output includes a pair of series circuits. Each of the series circuits is in parallel with the DC input and includes a switch and a transformer primary. A capacitor couples the two series circuits, and is attached to each series circuit at a node between the respective transformer primary and switch. A secondary on the transformer provides the AC output. Optionally, multiple transformers may be utilized. Similar topologies may be used for rectification instead of inversion.

Abstract: A power supply circuit has: a power supply filter including a coil which is inserted in series into an input line; a DC--DC converter which is connected to an output of the power supply filter and which converts an input voltage into an arbitrary output voltage; a detecting section which detects a potential difference between ends of the coil; and a control section which controls the output voltage of the DC--DC converter based on the detected potential difference.

Abstract: A temperature monitoring circuit with thermal hysteresis in CMOS circuitry utilizes bipolar transistors which are parasitic to standard CMOS circuitry. A concept of band-gap circuitry is used to provide a proportional to absolute temperature (PTAT) current, which is used as a reference. An output signal is produced above a predetermined temperature by comparing current changes between the PTAT current and a PTAT controlled current in a single current path. The PTAT controlled current decreases faster with temperature increase than the change in the PTAT current. The thermal hysteresis is accomplished by inverting the output signal to control a hysteresis transistor for selectively shorting out a hysteresis resistor. In the preferred embodiment, a start circuit is attached to the temperature monitoring circuit with thermal hysteresis to provide an initial current to activate the present invention. The start circuit is quickly shorted out once the devices of the present invention are turned on.

Abstract: A switched-mode power supply includes a transformer (TR) provided with a primary winding (P) having a first primary terminal (1), coupled to receive a voltage (U) with respect to a ground terminal (GND), and a second primary terminal (2); a controllable switch (SM) coupled between the second primary terminal (2) and the ground terminal (GND); and a start-up circuit (ST) for starting up the switched-mode power supply. The start-up circuit (ST) includes a field effect transistor (T) of the normally-on type having a drain coupled to the second primary terminal (2), a source, and a gate. The start-up circuit (ST) further includes a voltage stabilizer (VS) for supplying an internal supply voltage to an internal supply terminal (VINT), the voltage stabilizer (VS) being coupled to the source.

Abstract: A CMOS voltage regulator uses clock signals from an adaptive swing clock generator to control the output voltage of a charge pumping circuit. A divided portion of the output voltage is fed to a differential amplifier, where it is compared to a pre-set reference voltage. A negative feedback signal is generated from the differential amplifier and inputted to the adaptive swing clock generator, where it causes the clock signals to change amplitude in an inverse relationship to changes in the output voltage. When the divided portion of the output voltage equals the pre-set reference voltage, a steady-state output voltage condition is achieved.

Abstract: A 5V generator circuit is disclosed that generates a reliable 5V signal for use in integrated circuits from the available VPP or VCC supplies for a wide range of VPP and VCC voltages. When VCC is greater than approximately 4V, the generator circuit generates the 5V signal directly from VCC. When VCC is less than approximately 4V and VPP is greater than approximately 4V but less than about 9V, the generator circuit generates the 5V signal directly from VPP. When VCC is less than approximately 4V and VPP is greater than approximately 9V, the generator produces the 5V signal at approximately half of the voltage level of the VPP signal. When both VCC and VPP are less than about 4V, the 5V signal is generated at the too-low VCC level.

Abstract: A voltage converter having a voltage intermediate circuit and an invertor connected to the output of the voltage intermediate circuit. The invertor produces a three-phase AC voltage at its output and is connected to the output terminals of the voltage converter by a filter arrangement. The filter arrangement includes a filter inductor connected in series with the output terminal and the filter capacitor connected between the output terminal and a common capacitor star point. Attenuation of the DC system is achieved by having the capacitor star point connected to the voltage intermediate circuit by way of an RC element having a capacitor and a resistor.

Abstract: A method and apparatus for maintaining relatively low ripple current in a dc-dc converter while minimizing the size of an inductive line filter utilizes a transformer having at least a pair of secondary windings in which the secondary windings are selected to have different numbers of winding turns depending on the specific design of the ideal duty factor at which the converter will be operated. In addition, the converter is provided with an active pre-load which establishes a continuous conduction current when load current is below some selected minimum value in order to provide control stability during light load conditions without converter oscillations.

Abstract: The highly efficient multi-frequency voltage regulating circuit is capable of converting magnetic field energy to electrical energy for charging either a battery or an energy storage device such as a capacitor. The invention provides a magnetic field sensor circuit that measures the strength of incoming magnetic field energy with respect to a reference current. The invention also provides for a programmable magnetic field detection circuit which is used to adjust the detection level of the inductor-capacitor magnetic field converter circuit. A discharge expediter circuit is provided to improve the efficiency of the magnetic field converter circuit by discharging excess energy.

Abstract: A control method and apparatus for reducing transformer core volume in a power converter of the type having a switching circuit coupled to a primary winding of the transformer for selectively coupling the primary winding to a dc voltage source, a secondary winding of the transformer being coupled to an output rectifier circuit for developing a relatively high dc voltage across an output capacitor. The apparatus includes a high voltage zener diode clamp for limiting the maximum voltage on the capacitor, and the rectifier circuit includes at least a pair of zener diodes connected for blocking reverse current flow through the rectifier circuit.

Abstract: A power supply device for a discharge lamp has a rectifier for rectification of an AC voltage from an AC voltage source into an output DC voltage, a smoothing capacitor connected across the rectifier for providing a smoothed DC voltage, and an inverter which receives the smoothed DC voltage to provides a high frequency output to the lamp. The inverter includes a composite resonant circuit with first and second resonant systems each including an impedance element. The lamp is connected across the impedance element of the first resonant system. A balancing circuit is included to combine the high frequency powers fed respectively through the first and second resonant systems in a direction of canceling the high frequency powers with each other to provide a combined high frequency power.

Abstract: A power supply control device, by which a plurality of switching power supply circuits of different properties are operated under switching conditions respectively fitted therefor simultaneously with the prevention of an occurrence of what is called a low-frequency switching beat phenomenon, thereby achieving the miniaturization and the increasing of the efficiency of a power supply unit. To synchronize the timing of switching operations among control systems or units of the power supply control device, the control device of the multi-channel type or the control device having a master-slave function is used. Further, a frequency divider circuit or a frequency multiplier circuit is connected to a comparator of such a control device. Thereby, although synchronizing the timing among the switching operations, a plurality of pulse output signals of different frequencies are outputted from the control systems or the control units.

Abstract: A power supply control device, by which a plurality of switching power supply circuits of different properties are operated under switching conditions respectively fitted therefor simultaneously with the prevention of an occurrence of what is called a low-frequency switching beat phenomenon, thereby achieving the miniaturization and the increasing of the efficiency of a power supply unit. To synchronize the timing of switching operations among control systems or units of the power supply control device, the control device of the multi-channel type or the control device having a master-slave function is used. Further, a frequency divider circuit or a frequency multiplier circuit is connected to a comparator of such a control device. Thereby, although synchronizing the timing among the switching operations, a plurality of pulse output signals of different frequencies are outputted from the control systems or the control units.

Abstract: A regulator is provided for establishing asymmetrical voltage increase/decrease capability between an input node and an output node for enhanced regulation of either a voltage sag or a voltage swell within a utility system. The regulator includes an autotransformer having an input tap coupled to the input node of the regulator and an output tap coupled to the output node. The regulator further includes an electronic tap changer system coupled to the winding of the autotransformer. Together, the autotransformer and the electronic tap changer system provide the regulator with its asymmetrical voltage increase/decrease capability between the input node and the output node thereof. The regulator can be configured for voltage increase only, voltage decrease only, or both, provided an asymmetrical voltage increase/decrease capability is defined.

Abstract: In a power converter having an input coupled to a power switch and a rectifier for conducting currents from the input to an output of the power converter, a snubber circuit for, a method of, moderating reverse recovery currents associated with the rectifier and a power converter employing the circuit or the method. In one embodiment, the circuit includes a snubber inductor and snubber capacitor coupled to the rectifier. The circuit further includes a first auxiliary switch that conducts to divert a portion of the currents away from the rectifier through the snubber inductor and snubber capacitor. The circuit still further includes a second auxiliary switch, interposed between the power switch and the first auxiliary switch, that conducts to create a path to discharge the capacitor to the output of the power converter.

Abstract: For use with a power converter having a main output and an auxiliary output and an auxiliary regulating switch that regulates a voltage at the auxiliary output, a transient response network, and method of diverting energy from the main output to the auxiliary output. In one embodiment, the transient response network, includes: (1) an energy diverting switch interposed between the main output and the auxiliary output, and (2) a control circuit, coupled to the energy diverting switch, that senses a characteristic of the power converter and causes the energy diverting switch to conduct a current in response to a substantial load reduction at the main output thereby diverting energy from the main output to the auxiliary output.

Abstract: A rectifier includes a first electrically conductive cooling member having a first surface for direct contact mounting. A second surface has a first set of diode mounting locations. A diode is mounted within each diode mounting location of the first set and has a terminal extending generally normal from the first surface. An electrical insulator overlies the second surface. A second electrically conductive cooling member has a first surface overlying the insulator, and a second surface having a second set of diode mounting locations. The second electrically conductive cooling member has a plurality of slot openings formed in a radial pattern and extending through the second electrically conductive cooling member from the first surface to the second surface.

Abstract: A lossless snubber circuit is described for use with power converters, particularly asymmetric half-bridge converters. The snubber circuit provides a clamping circuit which has a clamping diode and a clamping capacitor connected across each of the rectifier diodes in the power converters output circuit. The clamping diode and clamping capacitor act to clamp the voltage across the rectifier diode and to recover the reverse recovery energy from the rectifier diode's turn-off. The reverse recovery energy is then transferred back to the input capacitors of the converter's input circuit through an energy recovery circuit. The energy recovery circuit includes a recovery switch which regulates the operation of the snubber circuit and a commutation transformer which provides the path from the snubber circuit to the input circuit. The snubber circuit allows the clamping voltage of the clamping capacitor to be adjusted to accommodate changes in the converter's conditions.

Abstract: A load device having a short-circuit protection function is disclosed which is capable of avoiding damage of a switching element such as an output transistor. The load device includes a switching element coupled to a load in series. The switching element operates in response to a drive signal. A power supply supplies a voltage across the series circuit of the load and the switching element. A voltage detection circuit detects a voltage exertion to the load and generates a voltage exertion signal. A short-circuit protection circuit interrupts supply of the drive signal to the switching element when no voltage exertion detection signal appears at the expiration of a predetermined period of time from initiation of the supply of the drive signal.