Abstract: An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load int

Abstract: A switching power source which enables a continuous operation of an apparatus even under an overvoltage test such as a ring wave test. In a case where the sensed voltage (Vb) of the secondary winding (5b) through a diode (D6), the Zener diode (ZD3), and a resistor (R21) to the non-inverting input terminal (+) of a comparator (31), and a high-level signal is inputted to a flip-flop (35) from the comparator (31). As a result, a high-level signal outputted from the Q output terminal is held and outputted to a flip-flop (15) as a reset signal via an OR circuit (37), so that a drive signal kept outputted from the Q output terminal of the flip-flop (15) switches to a low-level one to continue the off-control of the switching element (Q1).

Abstract: Capacitors (4, 6) are connected in series across a DC power supply (2). IGBTs (8, 10) are connected in series across the DC power supply (2), too. The IGBTs (8, 10) are rendered conductive alternately. A transformer (12) is connected between the junction of the capacitors (4, 6) and the junction of the IGBTs (8, 10). Snubber capacitors (32, 38) are connected in parallel with the IGBTs (8, 10), respectively. Diodes (34, 40) are connected in series with respective ones of the snubber capacitors (32, 38) in such a manner that said snubber capacitors (32, 38) can be charged when the IGBTs (8, 10) are rendered nonconductive. A secondary winding (54SA) of a transformer (54) is connected between the DC power supply (2) and the junction of the snubber capacitor (32) and the diode (34), and converts a secondary voltage of the transformer (12) and returns the converted voltage to the DC power supply (2) when the IGBT (8) is conductive.

Abstract: A switching power supply control-circuit according to the present invention uses bleeding resistors to charge a start-up capacitor and discharge an EMI filter. No extra discharge device is needed to accelerate the discharge of the input capacitor, since the start-up capacitor is charged up by the AC input source. A latch circuit of the power supply can be quickly reset after the AC input source is shut off. After the control-circuit begins to operate, the auxiliary winding of the transformer will power the control-circuit. To further reduce power consumption, the auxiliary winding generates a bias voltage to enable line-voltage detection. This allows the power supply to perform line-voltage detection and startup, without having to connect resistors or transistors to the input capacitor.

Abstract: A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is comprised of two half bridges (S1 A, S2A and S1B, S2B). Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes first and second rectifiers (D1, D2) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined first and second voltage, the respective rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

Abstract: A dc-to-dc converter includes a transformer having a primary winding connected to an input rectifying and smoothing circuit via an FET or like switching device, and a secondary winding connected to an output rectifying and smoothing circuit. A resonance capacitor is connected in parallel with the switching device. A switch control circuit cyclically turns the switching device on and off so as to keep constant the output voltage of the output rectifying and smoothing circuit by feedback control. The switch control circuit drives the switching device in light load mode when a flyback voltage developed by the transformer terminates earlier than each clock pulse, and in heavy load mode, in which each on-off cycle of the switching device is longer than in the light load mode, when the flyback voltage terminates later than each clock pulse.

Abstract: An inverter module for an electric railcar includes an inverter composed of three 2 in 1 IGBTs, a breaker composed of semiconductor line breaker, and a dry filter capacitor, wherein one inverter corresponds to a single motor. The inverter is a snubberless inverter omitting a snubber capacitor, and a main circuit connecting the output of the inverter to the motor is a coaxial cable. The main circuit and the interior of the inverter is connected via a connector instead of a conventional terminal block.

Abstract: A current-powered converter includes a current source, a switching section connected to the output of the converter, a dispersed inductance being provided between the switching section, and the converter output. A clamping circuit limits the voltage at the input of the switching section. The clamping circuit comprises a capacitor in which energy is stored during at least one phase of the switching cycle of the switching section, and an inductance by means of which the energy stored in said capacitor is returned to the output of the converter.

Abstract: An inverter circuit includes an input section configured to receive voltage from a voltage source and to input the voltage to the circuit. A switching network is connected to receive the input voltage from the input section. A controller controls operation of the switching network and load connections are connected to the resonant switching circuit. A variable capacitance network is series-connected to the load connection to provide a variable capacitance during circuit operation. A method includes passing a supplied voltage to a switching network which is controlled by a controller, and which delivers a lamp voltage to a lamp. A voltage in a capacitor series-connected to the lamp is clamped at predetermined levels, acting to remove a fixed capacitor from the circuit or at least a portion of a cycle of operation of the circuit, wherein an effective variable circuit capacitance is obtained by operation of the clamping action.

Abstract: A resonant switching-type capacitive charging power conditioner circuit includes a trap switch assembly to prevent the energy initially delivered to the circuit by an electrical energy source, from returning to the source. Once trapped, all of the energy is transferred to a capacitive store over a number of cycles. The period for each cycle is a function of the state of charge of the capacitive store, and the period decreases for each successive cycle as the charge on the capacitive store increases to its final value. Switches are turned on and off in response to the absence of certain currents in the circuit, to match the decreasing period of each successive energy transfer cycle throughout the entire energy transfer process. This adaptive clocking prevents energy from returning to the energy source, and eliminates dead time for each cycle.

Abstract: Capacitors (4, 6) are connected in series across a DC power supply (2). IGBTs (8, 10) are connected in series across the DC power supply (2), too. The IGBTs (8, 10) are rendered conductive alternately. A transformer (12) is connected between the junction of the capacitors (4, 6) and the junction of the IGBTs (8, 10). Snubber capacitors (32, 38) are connected in parallel with the IGBTs (8, 10), respectively. Diodes (34, 40) are connected in series with respective ones of the snubber capacitors (32, 38) in such a manner that said snubber capacitors (32, 38) can be charged when the IGBTs (8, 10) are rendered nonconductive. A secondary winding (54SA) of a transformer (54) is connected between the DC power supply (2) and the junction of the snubber capacitor (32) and the diode (34), and converts a secondary voltage of the transformer (12) and returns the converted voltage to the DC power supply (2) when the IGBT (8) is conductive.

Abstract: A power source including a transformer having a primary coil, a secondary coil, and a feedback coil; a resonance capacitor connected in parallel with the primary coil of the transformer in parallel, a switching unit having an input terminal which receives an input voltage input from the feedback coil of the transformer and which controls a current through the primary coil of the transformer according to the input voltage; and a current detection unit which detects the current in order to turn off the switching unit when the detected current is higher than a predetermined current. An output voltage stabilization circuit controls the input voltage at the input terminal of the switching unit, proportional to a voltage output by the secondary coil of the transformer.

Abstract: A switching power supply unit includes a first switching control circuit, which has a first ON-time control circuit, and a second switching control circuit, which has a second ON-time control terminal. The first ON-time control circuit controls the ON-time of the first switching element such that, at light load, before a voltage generated across a first drive winding causes a first switching element to be turned on, a first control transistor is brought into conduction to prevent the first switching element from being turned on and to thereby stop oscillation. The second ON-time control circuit controls the ON-time of the second switching element such that, at light load, after the end of the ON-time of the second switching element, energy release from a secondary winding is completed.

Abstract: A power conversion apparatus has a circuit configuration in which a collector voltage of an IGBT is divided. It also has a unit which protects the IGBT against overvoltages applied to the collector by outputting a potential of a voltage dividing point to a gate of the IGBT. A case of a resistor on the high-voltage side of the voltage dividing point is fixed to an emitter potential of the IGBT.

Abstract: A power conversion apparatus has a circuit configuration in which a collector voltage of an IGBT is divided. It also has a unit which protects the IGBT against overvoltages applied to the collector by outputting a potential of a voltage dividing point to a gate of the IGBT. A case of a resistor on the high-voltage side of the voltage dividing point is fixed to an emitter potential of the IGBT.

Abstract: The invention replaces a snubber resistor with a two diodes and a load. The electric charge stored in the snubber capacitor on each cycle of the switch is then caused by a first diode to flow through the load, rather than to flow through a snubber resistor. A second diode provides a charging path for the snubber capacitor. The load uses the electric power which would be wasted in the snubber resistor.

Abstract: A circuit for controlling the welding power of a welding power supply includes a control circuit, a switch, and an isolation circuit. The control circuit is configured to generate a command signal. The isolation circuit has a flyback transformer and is configured to receive the command signal and to provide a switch drive signal to the switch in response to the command signal. The switch provides welding power in response to the switch drive signal.

Abstract: A power converter apparatus, such as a DC—DC converter, includes a switch that controls current transfer between an input port and an inductance. A control circuit is operative, while current is being transferred between the inductance and a clamping circuit, to control the switch responsive to a current in the inductance. For example, the control circuit may include a current sensor configured to be coupled in series with the inductance and a switch control circuit operative to control the first switch responsive to a current sense signal generated by the current sensor. The switch control circuit may be operative to prevent transition of the switch from the first state to the second state until the current sense signal meets a predetermined criterion, e.g., a signal state indicative of a desired current condition, such as a current approximating zero or a current reversal. Related operating methods are also discussed.

Abstract: A universal switching power supply for generating one or more output voltage levels wherein the power supply is operable over a range of AC and DC input supply voltages. The universal switching power supply achieves a ratio between the highest voltage and lowest voltage of at least 27. The universal switching power supply also features an intrinsically safe output. The intrinsically safe output circuitry comprises a multi-layer PCB with a planar core transformer.

Abstract: A switched mode power supply includes a primary coil, a switch element, a secondary circuit, and a control circuit. The switch element is wired in series with the primary coil, for applying a DC voltage to the primary coil according to a control signal. The secondary circuit is coupled to the primary coil with output terminals providing an output voltage. The control circuit prepares the control signal with a feedback signal dependent on the output voltage supplied to the control circuit. The control circuit includes a signal generation circuit to create the control signal and a protection circuit. The protection circuit has the effect that no control signal is delivered to the switch element, if the feedback signal reaches the value of a first reference signal after a first period after starting the control circuit.

Abstract: The voltage applied to a power converter is detected by a voltage detector, a function generator produces a voltage proportional to this detected voltage, and a high-pass filter detects an AC component superimposed on the voltage. An adder adds a bias voltage to this AC component, and an adder adds the output from the adder and the output from the function generator. The output from the adder is compared with a triangular wave produced from a rectangular wave generator, and a switching element is controlled to make switching operation according to the compared result. When a DC current is decreased by the AC component, a resistance current Ib is increased so that the AC components superimposed on the current and resistance current can be cancelled out.

Abstract: An intermittent switching power supply circuit prevents excessive output power on a secondary side of a circuit. An intermittent oscillator is alternately switched on and off to maintain output voltage and/or current roughly constant. An output power monitoring circuit monitors output power from a rectifying/smoothing circuit. A control circuit outputs a stop control signal to an control terminal of the intermittent oscillator when the output power monitoring circuit determines that the output voltage and/or current exceeds a reference value. The protection circuit and a photocoupler receiver element are connected in parallel with the control circuit. Where a circuit error occurs and the photocoupler receiver element fails to cycle the intermittent oscillator between active and inactive conditions for a predetermined time, the protection circuit provides a backup which outputs a stop control signal to stop oscillation of the intermittent oscillator element.

Abstract: A switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided into sub-windings with at least one tap. A capacitance is disposed in parallel with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the values of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor becomes blocked have different resonant frequencies and thereby partially cancel each other. This results in an effective damping of the resonant voltage over the switching transistor. Since the capacitors are connected in series, the effective total capacitance is low, so that the resulting discharge current at the time when the switching transistor becomes conductive is comparably low.

Abstract: A DC-DC power converter in which the voltage across the main switch due to leakage inductance of the transformer is clamped and leakage energy of the transformer is recycled instead of being dissipated so as to improve operating efficiency.

Abstract: A swinging inductor is used to achieve zero-current switching in a resonant buck-type voltage converter. The swinging inductor exhibits the property of a relatively high inductance at zero current and low current, but it swings back to the original resonant inductance value at high current. In this way the high and medium regions of the current sine wave remain effectively unchanged. Upon circuit power application, the current rises slowly due to the high swinging inductance value, but this is an innocuous parasitic effect. Using the swinging inductance placed in series with a switching device to control the transfer of energy from the input source to the output load allows for a very efficient transfer of energy and it also prevents the current from becoming negative. Moreover, the efficiency level is sustainable over a wide range of input and output voltage requirements.

Abstract: An inverter apparatus includes an inverter circuit for driving a load. This inverter circuit has at least a pair of switching elements connected in series in a forward direction between both polarity terminals of a dc supply for supplying power to a load. An inverter drive circuit is employed for driving each switching element of the inverter circuit and has at least one high withstand voltage IC wherein the signal level reference potential is different in the input signal and the output signal. A clamping circuit clamps the potential of the low voltage side reference terminal, to which a potential, that is a reference for operation of the high withstand voltage IC in the inverter drive circuit and is a reference for a signal on the low potential side of the high withstand voltage IC, is applied. The voltage is clamped to the high voltage reference terminal to which is applied a reference potential for the high potential-side signal in the high withstand voltage IC.

Abstract: In a driving apparatus of a power semiconductor element for conducting or interrupting a main current, first resistance variable for changing a first resistance according to a control voltage, and second resistance variable for changing a second resistance according to a voltage between a first and a second terminal are provided, and either one of a voltage of a control power supply or a voltage between the first and the second terminal is voltage-divided by the first resistance and the second resistance, and the divided voltage is applied to a control gate terminal at the time of conducting or interrupting the main current.

Abstract: The present invention offers a low cost, reliable, on chip implementation that takes advantage of the nature of the average current mode topology to detect phase failures within a multi-phase system. The invention further includes sensing average current to the load, generating error voltages and changing duty cycles when the sensed load current is not at the desired level.

Abstract: An inverter device and a motor driving device are arranged to have an inrush current prevention circuit for preventing an inrush current from flowing into a smoothing circuit when the power is turned on. The inrush current prevention circuit includes a current limiter for limiting the inrush current, a plurality of semiconductor switching elements, and an inrush current prevention circuit driving -circuit for driving the plurality of semiconductor switching elements, the semiconductor switching elements being connected together.

Abstract: A polyphase inverter employs multiple power semiconductor switches both for its operation and to distribute the current and heat loads for improved operation and cooling. The inherently high currents required for motor operation are divided among a plurality of smaller conductors and semiconductor switches, making a printed wiring board feasible both for power distribution and for control. The approach also permits shorter path lengths to the switches, reduced inductance, faster possible operation of the power switches, and reduced transient activity outside of the immediate switch area. Signals derived from various power points can enable the controller to assess actual current and power distribution and to apportion losses appropriately, or to limit total power output should the losses be deemed excessive.

Abstract: A power supply controller having a multi-function terminal. In one embodiment, a power supply controller for switched mode power supply includes a drain terminal, a source terminal, a control terminal and a multi-function terminal. The multi-function terminal may be configured in a plurality of ways providing any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, over-voltage detection and maximum duty cycle adjustment. The operation of the multi-function terminal varies depending on whether a positive or negative current flows through the multi-function terminal. A short-circuit to ground from the multi-function terminal enables the power supply controller. A short-circuit to a supply voltage from the multi-function terminal disables the power supply controller. The current limit of an internal power switch of the power supply controller may be adjusted by externally setting a negative current from the multi-function terminal.

Abstract: A protection circuit arranged in a switching power supply system for protecting the switching power supply system is provided. The protection circuit includes a detecting circuit electrically connected to a switching controller of the switching power supply system for providing a trigger signal when a supply voltage drops to an under-voltage level, and a protection circuit electrically connected to the detecting circuit for providing a signal to protect the switching power supply system when the detecting circuit provides the trigger signal to the protection circuit. A method for protecting an switching power supply system is provided. The method includes the steps of detecting that the reference voltage signal disappears when the supply voltage is smaller than a minimum of operating voltage and providing a trigger signal, and providing an protection to protect the switching power supply system in response to the trigger signal.

Abstract: A power supply controller having a multi-function terminal. In one embodiment, a power supply controller for switched mode power supply includes a drain terminal, a source terminal, a control terminal and a multi-function terminal. The multi-function terminal may be configured in a plurality of ways providing any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, over-voltage detection and maximum duty cycle adjustment. The operation of the multi-function terminal varies depending on whether a positive or negative current flows through the multi-function terminal. A short-circuit to ground from the multi-function terminal enables the power supply controller. A short-circuit to a supply voltage from the multi-function terminal disables the power supply controller. The current limit of an internal power switch of the power supply controller may be adjusted by externally setting a negative current from the multi-function terminal.

Abstract: A compact, economical and fast battery charger for Ni-CAD and Ni-MH batteries turns a current source into a controlled voltage source which keys off a signal representative of the voltage level of the battery during the charging process and turns the current source ON and OFF to assure that the battery during the charging process does not exceed a given voltage level. The apparatus includes in par a ballasting resistor in series with the battery to compensate for the low resistance of the battery and an open collector voltage comparator which establishes high and low voltage set points for turning the current source ON and OFF at the appropriate times. The method and apparatus includes a visual display responsive to a signal which produces on the visual display an indication of the state of charge of the battery during a charging cycle. A circuit board has a long U-shaped trace extending around a notch in the board, on each side of each is mounted on battery.

Abstract: A high-power modulation system includes drive circuitry that receives input signals from the signal source via a series of transformers. The drive circuitry amplifies the input signals and provides the resulting amplified signals to the high-power switch. A storage capacitor within the drive circuitry stores energy derived from the input signals, and the stored energy is used to power the drive circuitry. One embodiment takes advantage of inductive ringing to more rapidly turn off the high-power switch. A diode connected in series between two drive transistors rectifies the ringing signals, pulling a control signal to the high-power switch negative.

Abstract: In a three-level neutral point clamping type inverter circuit which includes a positive bus line (4), a negative bus line (5) and a neutral line (6), wherein first and second IGBTs (11), (12) are connected in series between the positive bus line (4) and a phase voltage output terminal (10) and third and fourth IGBTs (13), (14) are connected in series between the negative bus line (5) and the phase voltage output terminal (10), the three-level neutral point clamping type inverter circuit further includes a first snubber capacitor (21) provided between the positive bus line (4) and the neutral line (6), a second snubber capacitor (22) provided between the negative bus line (5) and the neutral line (6), a first snubber diode (23) having a cathode coupled to the positive bus line (4) and an anode coupled to the phase voltage output terminal (10), and a second snubber diode (24) having an anode coupled to the negative bus line (5) and a cathode coupled to the phase voltage output terminal (10).