Abstract: Occurrence of power supply noise arising in connection with a step-down action at the time of turning on power supply is to be restrained. A step-down unit is provided with a switched capacitor type step-down circuit and a series regulator type step-down circuit, and stepped-down voltage output terminals of the step-down circuits are connected in common. The common connection of the stepped-down voltage output terminals of both step-down circuits makes possible parallel driving of both, selective driving of either or consecutive driving of the two. In the consecutive driving, even if the switched capacitor type step-down circuit is driven after driving the series regulator type step-down circuit first to supply a stepped-down voltage to loads, the switched capacitor type step-down circuit will need only to be compensated for a discharge due to the loads, and a peak of a charge current for capacitors can be kept low.

Abstract: A time domain voltage step down capacitor based circuit has an oscillating circuit for generating a clock signal. The circuit also has a capacitor based charge pump circuit for receiving the clock signal and an input voltage signal having an input current and generates an output voltage signal, less than the input voltage signal and an output current greater than the input current. The circuit further comprises a comparator circuit for receiving the output voltage signal, as a first input signal thereto, and a reference voltage signal as a second input signal thereto and compares the first input signal to the second input signal and generates a control signal in response thereto.

Abstract: A hysteretic mode controller for controlling a capacitor voltage divider which has a flying capacitor. In one embodiment, the hysteretic mode controller includes an amplifier, a gain circuit and a hysteretic comparator circuit. The amplifier has an input for coupling to the flying capacitor and an output providing a fly voltage. The gain circuit has an input for receiving the input voltage and an output coupled to a reference node providing a reference voltage. The hysteretic comparator circuit has a first input coupled to the output of the amplifier, a second input receiving the reference voltage, and an output for providing a PWM signal to control the capacitor voltage divider. The fly voltage is compared to voltage limits of a hysteretic voltage window for switching the PWM signal. The switching frequency is increased with higher load current to maintain high efficiency.

Abstract: A power conversion circuit capable of varying an output voltage within a range from a negative voltage lower than a ground voltage to a positive voltage higher than a supply voltage, and a driving method and a drive unit are provided. A power conversion circuit includes a transformer with a 1:1 ratio between the primary winding and secondary winding, a voltage outputting capacitor, and four switches. The power conversion circuit can be operated as a DC-DC converter of a step-up type, a step-up-and-down type, a step-down type, an inverted-output step-up-and-down type, or an inverted-output step-up type by selecting two switches used for control from among the four switches and alternately turning the two switches on. By switching the operating modes of the power conversion circuit, the output voltage can be varied within a range from a negative voltage to a positive voltage higher than a supply voltage.

Abstract: There are provided transducers, transmission pulse generators for transmitting pulses to the transducers, a transmission power source for supplying power to the transmission pulse generators, and an output side capacitor 7 for stabilizing a voltage of the transmission power source. The transmission power source includes a plurality of mode-specific power sources 1A and 1B for outputting a constant voltage, and a mode changeover switch 6 provided between the mode-specific power sources and the output side capacitor. The transmission power source further includes a power supplying power source 2 connected to the mode-specific power sources for supplying power, and a power regeneration capacitor 4 with a larger capacity than that of the output side capacitor, one electrode terminal of which is connected to a connection point between the power supplying power source and the mode-specific power sources and the mode changeover switch, and the other electrode terminal of which is connected to ground.

Abstract: In general, in one aspect, the disclosure describes a switched capacitor voltage regulator to generate a regulated output voltage based on varying input voltages. The regulator is capable of operating at one of a plurality of voltage conversion ratios and selection of the one of a plurality of voltage conversion ratios is based on an input voltage received. The switched capacitor voltage regulator provides a lossless (or substantially lossless) voltage conversion at the selected ratio. The ratio selected provides a down converted voltage closest to the regulated output voltage without going below the regulated output voltage. The down converted voltage is adjusted to the regulated output voltage using a resistive mechanism to dissipate excess power (lossy). Selection of an appropriate conversion ratio limits the resistive regulation and losses associated therewith and increases the efficiency of the switched capacitor voltage regulator.

Abstract: A step-down DC-to-DC converter includes an input terminal, an output terminal, a switching transistor, and a rectifying transistor. The switching circuit is connected between the input terminal and the output terminal and is configured to reduce an input voltage down to a predetermined voltage and to output the predetermined voltage from the output terminal to an external load. The series circuit includes a switching transistor and an inductor. The switching transistor is connected between the input terminal and the inductor, and is configured to perform a switching operation. The inductor is connected between the switching transistor and the output terminal. The rectifying transistor includes a P-type transistor and connected between a connected point between the switching transistor and a common ground. The rectifying transistor has a gate connected to the connected point.

Abstract: Occurrence of power supply noise arising in connection with a step-down action at the time of turning on power supply is to be restrained. A step-down unit is provided with a switched capacitor type step-down circuit and a series regulator type step-down circuit, and stepped-down voltage output terminals of the step-down circuits are connected in common. The common connection of the stepped-down voltage output terminals of both step-down circuits makes possible parallel driving of both, selective driving of either or consecutive driving of the two. In the consecutive driving, even if the switched capacitor type step-down circuit is driven after driving the series regulator type step-down circuit first to supply a stepped-down voltage to loads, the switched capacitor type step-down circuit will need only to be compensated for a discharge due to the loads, and a peak of a charge current for capacitors can be kept low.

Abstract: Switched capacitor networks for power delivery to packaged integrated circuits. In certain embodiments, the switched capacitor network is employed in place of at least one stage of a cascaded buck converter for power delivery. In accordance with particular embodiments of the present invention, a two-stage power delivery network comprising both switched capacitor stage and a buck regulator stage deliver power to a microprocessor or other packaged integrated circuit (IC). In further embodiments, a switched capacitor stage is implemented with a series switch module comprising low voltage MOS transistors that is then integrated onto a package of at least one IC to be powered. In certain embodiments, a switched capacitor stage is implemented with capacitors formed on a motherboard, embedded into an IC package or integrated into a series switch module.

Abstract: Disclosed are apparatus and methodology for providing a capacitive voltage divider configured to reduce a relatively high level alternating current (AC) to a lower level direct current (DC). The apparatus provides a series of capacitors and diodes configured for series charging of the capacitors and parallel discharge thereof by way of a single switching element. In operation, the capacitor series is charged during the negative half cycle of the AC source and then discharged during the positive half cycle thereof.

Abstract: A semiconductor device includes a first capacitor node, a second capacitor node, a first capacitor electrode, a second capacitor electrode, a first switch and a second switch. The first switch is coupled between the first capacitor electrode and the first and second capacitor nodes such that the first switch has a first position that couples the first capacitor electrode to the first capacitor node and a second position that couples the first capacitor electrode to the second capacitor node. The second switch is coupled between the second capacitor electrode and the first and second capacitor nodes such that the second switch has a first position that couples the second capacitor electrode to the first capacitor node and a second position that couples the second capacitor electrode to the second capacitor node.

Abstract: A frequency control circuit including a controlled oscillator and an amplifier circuit is disclosed for providing a clock signal to a switched capacitor circuit which divides an input voltage to provide an output voltage. The controlled oscillator has a frequency control input receiving a frequency control signal and an output for providing the clock signal at a frequency based on the frequency control signal. The amplifier circuit has an input for receiving the output voltage and an output providing the frequency control signal based on droop of the output voltage. In one embodiment, the amplifier circuit adjusts the frequency control signal to optimize efficiency of the switched capacitor circuit over a voltage range of the output voltage, which changes based on load level.

Abstract: A method for operation of a converter circuit is specified, wherein the converter circuit has a converter unit with a multiplicity of drivable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which method the drivable power semiconductor switches are driven by means of a drive signal which is formed from reference voltages. The reference voltages are formed by subtraction of damping voltages from reference-phase connection voltages, with the damping voltages being formed from filter capacitance currents, weighted with a variable damping factor of the LCL filter. An apparatus for carrying out the method is also specified.

Abstract: A power converting circuit with an open load protection function is electrically connected to a power supply providing a first voltage level, and outputs a second voltage level to drive a load. The power converting circuit includes a DC/DC converter and a rectifying element disposed between an output node and an input node of the DC/DC converter that forms a discharging loop with the DC/DC converter. The DC/DC converter receives the power, converts the first voltage level into the second voltage level and outputs the second voltage level to the load. The rectifying element is utilized to release a surge voltage produced by the DC/DC converter in an open load condition.

Abstract: A switching power supply apparatus generates a first output voltage with a reversed polarity of an input voltage and a second input voltage of double the input voltage with the reversed polarity, and then outputs them from the first output terminal and the second output terminal. A driver circuit includes a control unit and a first switch to a sixth switch. The driver circuit repeats three charging periods in a time-division manner. The three charging periods are a first charging period during which a flying capacitor is charged with the input voltage, a second charging period in which a low-potential-side terminal of the flying capacitor is connected to a ground terminal and a first output capacitor is charged with a voltage appearing at the other end of the flying capacitor, and a third charging period in which a high-potential-side of the flying capacitor is connected with the first output terminal and a second output capacitor is charged with a voltage appearing at the other end of the flying capacitor.

Abstract: A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.

Abstract: A step-down controller has an input having a first and a second input terminal for applying an input voltage, an output having a first and a second output terminal at which an output voltage can be provided, a series circuit including a switch and an inductance which is coupled between the first input terminal and the first output terminal. The switch has a control input for applying a control signal. A first diode is coupled between a junction point between the switch and the inductance and a reference potential such that, when the inductance is freewheeling, a current flow through the first diode (D1) is possible. There is a snubber network with a snubber capacitor, a second and third diode and an auxiliary inductance, a series circuit including the snubber capacitor, the third diode and the auxiliary inductance being coupled in parallel with the inductance.

Abstract: A battery powered headworn communication device and a method for conversion of a battery voltage in a battery powered headworn communication device, which includes providing a voltage reduction to a fixed part of the input voltage and providing a variable reduction that ensures that a minimum voltage is maintained. Preferably, the fixed part reduction and the variable reduction are performed in parallel and the fixed voltage conversion is a ? conversion of the input voltage. A fixed voltage conversion and the variable conversion can be balanced according to the actual battery voltage.

Abstract: A bidirectional Trench Lateral Power MOSFET (TLPM) can achieve a high breakdown voltage and a low on-resistance. A plurality of straight-shaped islands having circular portions at both ends are surrounded by a trench arrangement. The islands provide first n source regions and a second n source region is formed on the outside of the islands. With such a pattern, the breakdown voltage in the case where the first n source regions are at a high potential can be higher than the breakdown voltage in the case where the second n source region is at a high potential. Alternatively, in the case of not changing the breakdown voltage, the on-resistance can be reduced.

Abstract: A switching power supply apparatus generates a first output voltage with a reversed polarity of an input voltage and a second input voltage of double the input voltage with the reversed polarity, and then outputs them from the first output terminal and the second output terminal. A driver circuit includes a control unit and a first switch to a sixth switch. The driver circuit repeats three charging periods in a time-division manner. The three charging periods are a first charging period during which a flying capacitor is charged with the input voltage, a second charging period in which a low-potential-side terminal of the flying capacitor is connected to a ground terminal and a first output capacitor is charged with a voltage appearing at the other end of the flying capacitor, and a third charging period in which a high-potential-side of the flying capacitor is connected with the first output terminal and a second output capacitor is charged with a voltage appearing at the other end of the flying capacitor.

Abstract: The invention relates to a buck converter comprising: a pair P—0 of switches SB, SH in series and connected to an input terminal B of the converter by the switch SB, K other additional pairs P—1, P—2, . . . , P_i, . . . P_K?1, P_K of switches in series between another input terminal A and the switch SH of the pair P—0, with i=1, 2, . . . K?1, K, the two switches of the same additional pair P_i are connected in series via an energy recovery inductor Lr_i; K input groups, Gin—1, Gin—2, . . . Gin_i, . . . Gin_K?1, Gin_K, of Ni capacitors C each in series; K output groups, Gout—1, Gout—2, . . . Gout_i, . . . Gout_K?1, Gout_K, of Mi capacitors C each in series. The switches P—0 and the K additional pairs are simultaneously controlled by first and second complementary control signals.

Abstract: A step-down circuit is provided that comprises a clock control circuit which provides a plurality of clock signals having a frequency determined based on a control signal; a charge pump circuit which reduces a first potential applied to a first terminal and then provides a second potential from a second terminal by switching the connection of a plurality of capacitors in sync with a plurality of the clock signals output from the clock control circuit; and a comparator which produces the control signal to be supplied to the clock control circuit by comparing the second potential to a reference potential.

Abstract: An N-channel MOS transistor is used to configure a DC—DC converter having good characteristics without providing a particular voltage circuit which outputs a voltage higher than an input voltage. An N-channel MOS transistor 11 and a choke coil 12 are connected in series between a negative side of a direct-current power supply and a negative side of the output capacitor 8. A PWM circuit 14 applies pulse signals to a gate of the MOS transistor 11 based on the input voltage divided by the capacitors 9 and 10. The pulse signal of the PWM circuit 14 is formed by the voltage corresponding to the output voltage of the output capacitor 8, and the pulse signal is inputted to the gate of the N-channel MOS transistor 11 through a photocoupler 16.

Abstract: A DC/DC converter and a series regulator are connected in parallel between an input terminal and an output terminal. At the time of a heavy load, the DC/DC converter is operated. Although the DC/DC converter has a large current consumption of its own, it has a high power conversion efficiency. Accordingly, since a load current increases at the time of a heavy load, it is effective to use the DC/DC converter whose power conversion efficiency is high, and its current consumption can be neglected since the load current is large. On the other hand, at the time of a light load, the series regulator is operated. Although the series regulator has a small current consumption of its own, it has a low power conversion efficiency. Accordingly, at the time of a light load, even when the series regulator is used, its low power conversion efficiency can be neglected because its current consumption is small.

Abstract: A device converting electric power between a voltage source and a current source, comprising several stages (8i) of switching cells (10i,k) comprising each two switches (12i,k, 14i,k), capacitors (20i,k) associated with the cells (10i,k) arranged in a row (18k) increasing from current source (4), control devices (16i,k) each connected to a cell (10i,k) and elements for monitoring the control devices (16i,k) . The stages (8i) define two end groups and at least an intermediate group of switches, the two end groups comprising switches of each cell belonging respectively to the first and last stage connected in series, the intermediate group comprising pairs of switches (12i,k, 14i?1,k) of cells belonging to two neighbouring stages connected in series. Furthermore, the capacitors (20i,k, 20n,k) of a common row (18k) are transversely connected in series between the two end groups.

Abstract: A power source inverter circuit is provided which, when a feeding unit generates enough electric power, puts a load circuit into operation while storing electric power in a storage unit and, when the power feeding unit stops generating power, efficiently uses up the electric power stored in the storage unit.

Abstract: In a power circuit, first and second voltage-dividing capacitors are connected in series between first and second power terminals in even cycles. On the other hand, the first and second voltage-dividing capacitors are connected in series between the second and first power terminals in odd cycles, which occur alternately with the even cycles.

Abstract: A DC voltage chopper contains a power switch device with a drive circuit, an LC filter circuit connected in a main circuit of the power switch device, a commutating circuit connected in parallel to the LC filter circuit, and a comparison circuit with a hysteretic function and has an output connected to the drive circuit. A first input terminal of the comparison circuit is connected to an output terminal of the DC voltage chopper, and a second input terminal of the comparison circuit is connected to a reference voltage generator that generates a reference voltage. The drive circuit has a logic circuit with a first input receiving the output signal of the comparison signal of the comparison circuit, and a second input receiving a trigger clock signal with a fixed frequency. The DC voltage chopper combines the good attributes of hysteresis control with a fixed switching frequency.

Abstract: A step-down circuit is provided that comprises a clock control circuit which provides a plurality of clock signals having a frequency determined based on a control signal; a charge pump circuit which reduces a first potential applied to a first terminal and then provides a second potential from a second terminal by switching the connection of a plurality of capacitors in sync with a plurality of the clock signals output from the clock control circuit; and a comparator which produces the control signal to be supplied to the clock control circuit by comparing the second potential to a reference potential.

Abstract: A circuit is provided that provides for the same power characteristics to an assembly of electrical resistive elements wired in parallel as to the assembly as wired in series. An input power source provides electrical resistive power to a plurality of load elements, wherein the plurality of load elements are connected in parallel to each other. A plurality of power splitters divide the power source into separate and equal power subsources such that there is one power splitter and one power subsource for each load element, wherein the power provided to each of the plurality of load elements is equal to the power of the electrical power source. Redundancy and fault tolerance is provided to the circuitry by permitting remaining load elements to continue to operate should one or more load elements fail.

Abstract: A buck converter is disclosed which prevents a voltage drop below a desired voltage when a load change occurs. The buck converter generates an override signal to turn on one or more switch devices in the circuitry. The effect of the override signal is to provide a sudden increase in the current supplied to a load, preventing the output voltage from dropping below the predetermined level. Sensing circuitry within the buck converter detects a voltage drop at the load, causing the override signal to be generated. The override signal may be a continuous signal or a one-shot pulse. Additional current sensing circuitry and the switch history of the buck converter determines the duration of the override signal for one embodiment and the number of switches activated within the buck converter.

Abstract: A voltage regulator for providing a bidirectional current and a regulated voltage to a load. The voltage regulator regulates the output voltage at one half the level of the input voltage using a voltage doubler circuit in reverse. The regulator provides current to the load when the output voltage drops and receives current from the load when the output voltage rises. The voltage regulator is particularly suited to supplying a termination voltage to multiple line drivers in a DDR DRAM system, where the line drives require an active termination voltage to reduce power. Additionally, a pair of linear regulators, one for clamping the output voltage at a predetermined low voltage level and for supplying additional current demanded by the load, and the other for clamping the output voltage at a predetermined high voltage level and for receiving additional current supplied by the load, is included.

Abstract: A DC—DC converter capable of generating an output voltage in increments of less than power supply voltage Vdd is provided. A power supply voltage Vdd is provided to a three-stage switched capacitor type DC—DC converter. A first stage of the DC—DC converter comprises two capacitors C11 and C12 and switches 61, 62 and 63, that alternate a connection of the capacitors C11 and C12. The capacitors C11 and C12 are connected in series when charging by turning the switch 61 ON, while the capacitors C11 and C12 are connected in parallel when discharging by turning the switches 62 and 63 ON. Thus a boosted voltage of 3.5 Vdd is obtained from an output terminal 40.

Abstract: An apparatus and method for compensating for a decreasing internal voltage that is generated from a higher external voltage. In response to the internal voltage decreasing in excess of a voltage margin, the amount by which the higher external voltage is reduced in generating the internal voltage is adjusted to raise the internal voltage.

Abstract: An apparatus and method for compensating for a decreasing internal voltage that is generated from a higher external voltage. In response to the internal voltage decreasing in excess of a voltage margin, the amount by which the higher external voltage is reduced in generating the internal voltage is adjusted to raise the internal voltage.

Abstract: An apparatus and method for compensating for a decreasing internal voltage that is generated from a higher external voltage. In response to the internal voltage decreasing in excess of a voltage margin, the amount by which the higher external voltage is reduced in generating the internal voltage is adjusted to raise the internal voltage.

Abstract: A voltage step-down circuit (100) that may provide an internal voltage (VINT) by reducing an external power source (VDD) has been disclosed. A voltage step-down circuit (100) may include a voltage step-down portion (10) and a compensation current source portion (20). Voltage step-down portion (10) may compare a reference voltage (VREF) with an internal voltage (VINT) and control an output current (I0) accordingly. An internal circuit (1) connected to receive internal voltage (VINT) may transition from a standby state to an active state in accordance with an activation signal. Compensation current source portion (20) may provide a compensation current (Ic) when internal circuit (1) is in a standby state. In this way, voltage step-down portion (10) may be biased to provide sufficient output current (I0) so that a response time may be improved and variations in internal voltage (VINT) may be reduced.

Abstract: This invention discloses the concept of the integration of the four terminal switcher and the capacitor pairs for the DC to DC converter or power supplier. This invention can be built by IC process as the DC to DC converter or power supply alone or used as power supply or converter module or block for distributed power in the System-on-Chip. This invention discloses the basic structure of the DC to DC converter or power supply module on standard CMOS IC process and on SOI substrates. This basic structure of the DC to DC converter or power supply module provides high current and low voltage applications for future generations of ICs.

Abstract: A DC-DC converter capable of generating an output voltage in increments of less than power supply voltage Vdd is provided.

Abstract: A charge pump receives a direct current input voltage at a first level and provides a substantially constant direct current output voltage at a second level. Variations of the input voltage level above and below the output voltage level are handled seamlessly by a continuous mode control scheme that controls a charging current of the charge pump. The charge pump includes an error amplifier which produces a control signal based on a comparison of a feedback voltage proportional to the output voltage and a reference voltage. The control signal controls a variable current source to regulate the charging current provided to a charge storage component.

Abstract: An inverter or converter by current injection, provided with a circuit whose generating frequency for the alternating voltage is adjusted by the load's resonant frequency, cycle to cycle, without lags. The inverter or converter permits avoiding power losses when transferring energy as a result of the variation in the load's resonant frequency that necessarily occurs in all fixed frequency inverters. The inverter or converter may be characterized as a frequency interlocking circuit, provided with at least one voltage scanner in the load, adapter and galvanic insulation, one lead circuit, one clipping circuit, one comparator circuit and one oscillator and coupling circuit.

Abstract: A voltage conversion circuit has an improved power efficiency and a lower power consumption is described. The voltage conversion circuit includes a plurality of voltage conversion cells, each of which includes a capacitor element. A switch circuit is connected to the plurality of voltage conversion cells to selectively switch between parallel connection of a plurality of voltage conversion cells and serial connection of a plurality of voltage conversion cells. A control circuit is connected to the switch circuit to control the switch circuit to selectively perform a first voltage conversion of an input voltage by the plurality of parallel-connected voltage conversion cells and a second voltage conversion of the input voltage by the plurality of series-connected voltage conversion cells.

Abstract: An inverter or converter by current injection, provided with a circuit whose generating frequency for the alternating voltage is adjusted by the load's resonant frequency, cycle to cycle, without lags. The inverter or converter permits avoiding power losses when transferring energy as a result of the variation in the load's resonant frequency that necessarily occurs in all fixed frequency inverters. The inverter or converter may be characterized as a frequency interlocking circuit, provided with at least one voltage scanner in the load, adapter and galvanic insulation, one lead circuit, one clipping circuit, one comparator circuit and one oscillator and coupling circuit.

Abstract: A circuit and method for regulating a voltage by means of a switched capacitor circuit including multiple switches and capacitors. The circuit is operable in a plurality of modes that match the power transferred by the switched capacitors to the power drawn by a load. Advantageously, the circuit and method increase the efficiency of the regulator circuit over varying input voltage levels and output current levels. In addition, the circuit provides lower output ripple than conventional charge pumps.

Abstract: The efficiency of the DC-DC converter that the load factor varies greatly is improved.

Abstract: The power supply device has a temporary energy store, a main energy store, and a switching device. The switching device has three switching states. The temporary energy store is connected in the first switching state to a power supply input and is connected in the second switching state to the main energy store, which is connected to a power supply output. An energy discharge device is connected to the temporary energy store in the third switching state of the switching device which follows directly the second switching state.

Abstract: This invention discloses the concept of the integration of the four terminal switcher and the capacitor pairs for the DC to DC converter or power supplier. This invention can be built by IC process as the DC to DC converter or power supply alone or used as power supply or converter module or block for distributed power in the System-on-Chip. This invention discloses the basic structure of the DC to DC converter or power supply module on standard CMOS IC process and on SOI substrates. This basic structure of the DC to DC converter or power supply module provides high current and low voltage applications for future generations of ICs.

Abstract: A circuit arrangement for reducing a variable, in particular pulsed input voltage (Uein) to an operating voltage Uz, Uarb to be delivered to an evaluation circuit (10), in which the input voltage Uein can be reduced, in accordance with a division factor (F) made available by at least one voltage divider (R1, R3, T1, R4; R7, R8, R2), to obtain the operating voltage Uz, Uarb, in which the at least one voltage divider (R1, R3, T1, R4; R7, R8, R2), can be regulated in such a way that the division factor (F) can be increased with an increasing input voltage Uein and can be decreased with a decreasing input voltage Uein.

Abstract: First, second and third capacitors (11, 12, 13) having predetermined capacitance values are connected in series in a commercial alternating current line. A rectifier bridge (14, 15, 16, 17) including two diodes (14, 15) having backward characteristics adjusted to a Zener voltage is connected in parallel with the capacitor (12) in the center, and a smoothing capacitor is connected between a first end and a second end of the rectifier bridge (14, 15, 16, 17). As a result, it is possible to divide alternating current (AC) from a power input terminal into a desired voltage while insulating it, and clip it with a predetermined voltage to shape it into a voltage waveform close to a rectangular wave and smooth it. Thereby, a stabilized DC voltage with less ripples can be obtained.

Abstract: An induction furnace having a voltage source series inverter, a load circuit having a combination of an induction coil and a resonating capacitor bank, and control circuitry to phase lock the inverter frequency to the natural resonant frequency of the load. The capacitor bank can be divided into two groups, one across the output of the inverter and the other in series with the load. This arrangement allows for the division of the inverter voltage across the furnace coil according to the ratio of the two capacitances. The inverter uses pulse width modulation and is buffered from the load circuit by means of a small series connected inductor. Additionally, the system can have a common power supply system that supplies power in any desired proportion to a plurality of induction furnaces.