Abstract: A current limiter of a voltage/frequency type inverter which comprises a comparator for comparing an output current to an applied reference value to generate a current comparator output signal; a delay circuit, coupled to the comparator, for delaying the timing of the current comparator output signal for a predetermined time duration to generate a current limiting signal based on the result of the comparison; and a pulse output circuit for outputting a predetermined pulse based on the current limiting signal.

Abstract: Individual devices of a redundant array of independent devices (RAID) are coupled to an electrical power supply. For devices having widely varying load impedances, such as disks, incident with the coupling of electrical power thereto, the replacement or addition of a device in the system, while the system is in operation, causes unacceptable power transients in the power supply. To minimize such power transients, a transient suppression circuit is employed to isolate the load impedance of the device from the power supply. Isolation is achieved in the transient suppression circuit by employing an active circuit element, such as a MOSFET power transistor, as the power coupler. A capacitor controlled voltage divider circuit, incident with the coupling of electrical power thereto, couples a time varying gate voltage, which changes as a function of the rate of charge of the capacitor, to the MOSFET power transistor.

Abstract: A power supply which serves to convert an alternating voltage supplied by an electric mains, into a DC voltage, having a rectifier with input terminals for receiving the alternating voltage and output terminals for supplying a pulsating direct voltage. A first capacitor is connected parallel to the output terminals. An inverter has input terminals connected to the first capacitor. A current limiting circuit is connected between one of the rectifier output terminals and an electrode of the first capacitor in order to limit the inrush current occurring when the power supply is switched on. The current limiting circuit includes a parallel connection of a first resistor and a first switching element, with the first switching element being operative to be in an electrically non-conductive state upon switching on of the power supply and to change over to an electrically conductive state some time after the power supply is switched on.

Abstract: A control circuit for a stove, cooktop or oven utilizing at least one electrical radiant heating element. The circuit effectively compares a controlled voltage and internally generated saw-tooth voltage wave to control the percent power to the radiant element. Also included is a slow start feature to minimize power surge when first energizing the element.

Abstract: A method and apparatus for preventing current inrush upon the application of power to a load includes the steps of applying a first increasing DC voltage from a voltage source to the load through a single signal path which includes a transistor having a control electrode coupled to the voltage source and a second electrode coupled to the load. The transistor has a first operating region with an ON resistance characteristic which decreases between first and second applied control voltages. The transistor has a second operating mode in which the transistor has a relatively low on resistance R.sub.ON. The transistor is thus disposed in the single signal path to both limit inrush current and to provide a low loss signal path between the voltage source and the load.

Abstract: An AC/DC voltage converter achieving a relatively low loss of power includes a rectifier circuit connected directly to a step-up converter circuit. The voltage converter further includes a storage capacitor and a resistor connected to outputs of the step-up converter circuit. One electrode of the storage capacitor is connected through the resistor to one output of the step-up converter circuit.

Abstract: A method and apparatus for preventing current inrush upon the application of power to a load includes the steps of applying a first increasing DC voltage from a voltage source to the load through a negative temperature coefficient device having a first terminal coupled to the voltage source and a second terminal coupled to the load and after a preselected period of time, bypassing said first and second terminals via a bypass circuit and coupling the increasing voltage to the load through the bypass circuit.

Abstract: An incandescent lamp bulb which is driven by an electronic control module (ECM) and method of manufacture characterized in that an inductor comprising a magnetic spool and a winding thereon is disposed within a screw shell base of the lamp bulb and surrounds the lamp exhaust tube therein. One end of the winding on the magnetic spool is connected to a filament wire within the screw shell base and the other end of the inductive winding is connected to an output terminal of the ECM control module. In this manner, the inductor significantly reduces the di/dt rise time of voltage and current when a TRIAC within the ECM module is driven to conduction on each one half cycle of the applied AC line voltage. This operation in turn produces a substantial reduction in radio frequency interference, both of radiation transmitted into space from the lamp bulb and by direct DC coupling back into the AC line voltage source.

Abstract: An incandescent lamp bulb which is driven by an electronic control module (ECM) and method of manufacture characterized in that an inductor comprising a magnetic element and a winding thereon is disposed within a screw shell base of the lamp bulb and surrounds the lamp exhaust tube therein. One end of the winding on the magnetic element is connected to a filament wire within the screw shell base and the other end of the inductive winding is connected to an output terminal of the ECM control module. In this manner, the inductor significantly reduces the di/dt rise time of voltage and current when a triac within the ECM module is driven to conduction on each one half cycle of the applied AC line voltage. This operation in turn produces a substantial reduction in radio frequency interference, both of radiation transmitted into space from the lamp bulb and by direct DC coupling back into the AC line voltage source.

Abstract: The present invention is an apparatus for controlling a water delivery system utilizing an instant flow tankless water heater. It includes a programmable microprocessor with support circuitry to achieve control of the outlet temperature of a varying flow rate and varying inlet temperature stream. The system senses a water outlet temperature and controls AC power through an on/off mechanism to regulate power to heating elements embedded in the water stream. The capabilities of the heating elements are improved through the application of using a microprocessor to perform a proportional (P), integrating (I) and derivative (D) calculation. The calculations are used to determine the operating characteristics of the heating system and to control the heating system.

Abstract: An IC type stabilized power source circuit being provided with n pieces of output transistors, each outputting to a common terminal; n pieces of over current detection circuits provided for the n pieces of the respective output transistors and outputting respective detection signals when the output currents flowing through the respective corresponding output transistors exceed predetermined rated current values set for the respective corresponding output transistors. N pieces of control circuits are provided for the n pieces of the over current detection circuits and when receiving the respective corresponding detection signals, each limiting the output currents to the respective corresponding output transistors in relation to the over current detection circuits from which the detection signals are received to respective values equal to or less then the respective predetermined rated current values.

Abstract: A transformer is energized from an a.c. source by initially applying the . voltage to the transformer during small but progressively increasing fractions of a succession of initial half-cycles. This is continued until the rated voltage is achieved or until the reactive current exceeds a predetermined value below that which would cause tripping of the transformer. In the event that the reactive current reaches the predetermined value, the remanence of the transformer is set at a selected level by applying the a.c. voltage to the transformer during an additional half-cycle. The length of exposure of the transformer to the a.c. voltage during the additional half-cycle depends upon the circumstances. Once the remanence has been set, operation of the transformer proceeds normally.

Abstract: A method of connecting an IC card to a motherboard involves first connecting the ground busses, then the power busses and finally the general signal busses. When the power busses are connected, a low current is allowed to flow initially, then, a predetermined period of time is allowed to elapse for equalization of IC card and motherboard voltages, then a full current is allowed to flow. A method of disconnecting an IC card from a motherboard involves first disconnecting the general signal busses, then the power busses and finally the ground busses.

Abstract: An AC powered field mounted process control transmitter includes an inrush current limiter which prevents excessive current flow to other circuitry in the transmitter. The transmitter senses a physical parameter, such as flow, and comprises a source of current, a current driven sensing circuitry, the inrush current limiter and measurement electronics for converting the sensed parameter into a transmitter output. The limiter includes a reference voltage source and is in series between the current source and the current driven sensing circuitry. When inactive (i.e. not limiting current), the limiter responds to the series current through itself so that when such current exceeds a predetermined maximum level the limiter becomes active and prevents further current flow. The limiter remains active until the voltage across itself is less than the reference voltage, at which time the limiter becomes inactive.

Abstract: A power supply circuit limits the voltage on a filter capacitor driven by rectified half-cycles of an input AC waveform. A FET switch in series with the current charging the filter capacitor is opened as soon as the charge on the filter capacitor is adequate. A voltage triggered latch circuit is responsive to the rectified AC input applied through a decoupling diode to the filter capacitor, and supplies a control signal to the FET switch. A further sensing circuit can monitor the current charging the filter capacitor, and can trigger the latch to open the FET switch as needed to limit initial in-rush current during the initial application of AC power. The decoupling diode decouples the rectified peaks provided by the rectifiers from the voltage on the filter capacitor.

Abstract: A circuit for protecting a MOSFET power transistor, the circuit having a variable input impedance in which the rate of rise of voltage is to be increased and thus the switching time reduced. For this purpose, a second MOSFET auxiliary transistor is connected by its bulk electrode to the source of the MOSFET power transistor. The source of the second MOSFET auxiliary transistor is connected to the gate of a third MOSFET auxiliary transistor and to the gate of the MOSFET power transistor. The drain of the second MOSFET auxiliary transistor is connected to a circuit input terminal which is coupled by a resistor to the gate of the MOSFET power transistor. The gate of the second MOSFET auxiliary transistor is connected to the drain of the second MOSFET auxiliary transistor as well as to the source of the third MOSFET auxiliary transistor.

Abstract: A circuit for limiting inrush current in a DC power supply is disclosed. The inrush limiting circuit should be placed between an input AC power line and a power supply input capacitor bank. A thermistor is located between the capacitor bank and the input diode bridge to limit the initial inrush current. Once the input capacitor bank is fully charged, an insulated-gate bipolar transistor or IGBT switches the rectified line voltage to a boost power factor correction converter circuit, which utilizes an inductor and diode along with a field effect transistor to boost the input to a high DC voltage. This high DC voltage blocks the thermistor through use of a diode and keeps it cold to maintain high resistance in case of a new off/on cycle. The IGBT can be replaced with a silicon control rectifier, a triac, or a field effect transistor.

Abstract: The live insertion circuit of the present invention comprises a movable magnetic body for changing an inductance of a variable inductor, and the movable magnetic body is moved toward a supporting member by a rod at the time of inserting the package into the unit. At this time, an inductance of the variable inductor is changed according to the connection condition of terminals for connecting the package and the unit, thus suppressing a surge current.

Abstract: In the case of a method and a device for triggering an electromagnetic consumer (1), which is connected in series to a switching means (2), the voltage applied to the switching means (2) is fed to a voltage comparison means (12) and compared there to the voltage of a reference voltage source (13). Dependent upon this voltage comparison, an output signal is produced at the output terminal of the voltage comparison means (12), which serves to switch over a suppressor device (4).

Abstract: An inrush current limiting circuit contains an FET as an active component which is controlled by a network of passive components. The network includes a gate control circuit for controlling the operation of the FET and a negative feedback circuit which responds to the load voltage during the transient state. The current limiting circuit is fast acting during momentary power interruptions and has low power losses.

Abstract: In order to reduce the switch-on surge in current in the operation of an inductive load provided with a magnetizable core at an alternating mains current, in particular in pulse group operation, a switch-off-reset impulse is applied to this load following switching-off of the inductive load from the alternating current mains. This impulse has a polarity phased opposite to the last pulse group halfwave. In this way the remanent induction of the transformer core is shifted in a defined manner to lower values so that a defined remanence state of the iron core can be assumed when starting the next pulse group. This permits peak-current-free switching-on under any load and pulse period conditions. The remanent induction of the transformer core can also be maintained in the sector occurring immediately following switching-off of the inductive load, thus at the end of a pulse group.

Abstract: A transistor overcurrent protection circuit using an error amplifier to make a voltage comparison between a threshold voltage and the collector voltage of a current sensing transistor. The current sensing transistor is arranged in a circuit such that the collector current of the current sensing transistor is a measure of the collector current of an output transistor. A driver transistor has its emitter connected to the base of the output transistor. A source of control current to the drive transistor is coupled to the output of the error amplifier. When the collector voltage of the current sense transistor falls below the threshold voltage, the error amplifier causes the control current to the drive transistor to be reduced so as to reduce the collector current of the output transistor.

Abstract: This overload protection circuit capable of sustaining high capacitive load or any other load which may create an important inrush current, comprises a differential bridge composed of high impedance measuring resistors (R1, R1' R3, R3'), a low impedance sensing resistor (R2), and a timing and control circuit (20) including a transistor (T2), a capacitor (C1) and resistors that controls a switch (T1) and limits the inrush current of the subcircuit capacitor by slowing the closing of the switch. In case of defaults, the switch will be opened fast enough to minimize the fault transient transfer from down-stream to up-stream of the protection circuit. In addition, a comparator (32) associated to a resistor (R31) providing an hysteresis enables to avoid the oscillations in the region of the system transition from on to off states and vice versa. This circuit can be used in a system which comprises a secondary power supply unit (9) which powers a plurality of subcircuits (22).

Abstract: A power supply maintains a rectifier circuit in a non-doubler mode configuration when the power supply is attached to a 110-120 volt AC power source, until bulk capacitors in the rectifying circuit are charged to a combined potential of (.sqroot.2)*110-120 volts. The power supply then switches to a doubler mode configuration and the capacitors charge separately to a combined potential of (.sqroot.2)*220-240 volts. The two step charging procedure reduces the inrush current, over that developed in charging the capacitors from a zero volt potential to a combined potential of (.sqroot.2)*240 volts. It thus limits the current through a switch which configures the power supply in the doubler mode. If the power supply operates only with a 110-120 volt AC power source, which is common in high power industrial applications smaller diodes may be used in the rectifier circuitry since the inrush current is reduced.

Abstract: An inrush current limiting circuit includes a power FET switch connected between power source and load and a control circuit. The power FET switch includes one or more parallel-connected power FETs, each having low individual conductive resistances. The control circuit, connected between the power inputs and the gate of power FET switch, includes a voltage supply for providing sufficient voltage to turn the power FET switch on and a time constant circuit for controlling the rate at which the power FET means is turned on. With the voltage supply connected to an optional enable terminal, a DC enable signal can control powering of the load. A second time constant circuit controls the rate of power down.

Abstract: Control pulses having a first frequency are supplied to the switches of an inverter by a controller. During initial operation of the inverter, however, a softstart circuit supplied pulses to the inverter switches of the inverter wherein the soft-start pulses have a second frequency. The second frequency is constant and higher than the first frequency.

Abstract: An apparatus for converting single phase input power to three phase output power supplied to a motor includes a pair of input lines, and a pair of DC bus lines, a pair of capacitors, a pair of diodes, and a pair of controlled switching devices which are each connected between the DC bus lines. One of the input lines is connected to the node between the capacitors and the other input line is connected to the node between the diodes. Two output lines are connected to the input line and a third output line is connected to the node between the two switching devices, with the three output lines being connected to a motor to supply three phase power to the motor. The switching devices are switched in a pulse width modulated manner to provide a voltage between the third output line and the other two output lines which provides the three phase power. During motor startup, at least one startup capacitor is switched in between one or both of the input lines and the output lines to provide startup torque for the motor.

Abstract: A hot plug circuit insuring that the plugging of cards to a board is performed in the hot-plug mode when the cards are supplied from a common power supply located on one of the cards or on the board. This circuit (62) limits the surge current generated at the interconnection of first circuits (30) arranged on a first card (1) and powered by a supply device (2) providing a first supply voltage (ground) on a first supply line (36) and a second supply voltage (+V) on a second supply line (34), with second circuit (24) on a second card powered by the supply device (2) through a third supply line (74) and fourth supply line (76). The surge current results from the charge of a decoupling capacitor of capacitance Cd arranged on the second card between the third and fourth supply lines when the cards are interconnected through an interconnecting arrangement (14, 12, 22).

Abstract: A turn-on transient overcurrent response suppressor is connected to an exing electrical circuit having a regulator circuit that includes an overcurrent protection mechanism. A first charging circuit is connected to the power supply for simultaneous charging therewith. A second charging circuit is connected to the first charging circuit for delayed charging therewith. Connected between the first and second charging circuits is a circuit to create a low impedance discharge path for the second charging circuit while preventing discharge of the first charging circuit when the power supply is no longer providing the input voltage. First and second transistor circuits are connected to turn on during the charging and discharging of the second charging circuit and turn off when the second charging circuit is fully charged. In this way, turn-on transients caused by loss of AC power are prevented from falsely triggering the regulator circuit's overcurrent protection mechanism.

Abstract: A heater activating apparatus includes a power source, a heater heated to which is applied to voltage from the power source, and a current regulating element. The voltage from the power source is applied to the heater through the current regulating element when the heater is initially to energized, and thereafter, the voltage is applied to the heater without passing through the current regulating element.

Abstract: The invention concerns a device for a.c. cut-in limitation of a power-sup unit with inductive reactance. The device has a series-connected first a.c. switch and a phase-angle control circuit by means of which a time lag can be introduced in the connection between the primary winding and the mains a.c. voltage at the point in time that cut-in takes place. The control electrode of the first a.c. switch of the floating phase-angle control circuit is connected to the output of a control circuit by means of which a trigger voltage, which is synchronized with the mains a.c. voltage, is generated, when the power-supply unit is switched in, at a selectable phase angle between 90 and 0 degrees before a zero passage of the main a.c. voltage. The trigger voltage can be suppressed before the zero passage of the mains a.c. voltage is reached in order to switch off the power-supply unit.

Abstract: A solid state circuit interruption arrangement monitors a current path to provide protection to both a load and a solid state switch. The arrangement includes an energy absorber for absorbing energy from the current path in response to the solid state switch interrupting the current path, and a control circuit for periodically generating the interrupt signal to interrupt the current path for prescribed intervals and to control the current supplied to the load between a maximum current level and a minimum current level.

Abstract: A current limiting circuit for limiting current surges caused by device turn-on and by input line voltage surges. The circuit has a current sensor for sensing current surges and causing the current to be routed through a current limiting device, such as a resistor. The current sensing circuit senses both over current and normal current conditions and resets the current limiting switch as appropriate. The use of a current sensor as opposed to a sensor for turn-on conditions or voltage levels provides actual control of the current thereby protecting the electrical device during the first application of power and from AC line voltage surges.

Abstract: A device for protecting a direct current electrical power supply from disturbances caused by connecting to it or disconnecting from it an electronic system comprises at least one variable impedance component. The impedance of this component is controlled so that it has a very high first value when said electronic system is disconnected, a very low second value when said system is connected, a value varying slowly from said first value to said second value on changing from the disconnected state to the connected state and a value varying quickly from said second value to said first value on changing from the connected state to the disconnected state. The output current from said variable impedance component constitutes the supply current of said electronic system.

Abstract: For a preset period following application of a closing order, the semi-conductor of the static power switch, supplied with DC voltage, is controlled by a regulating circuit so as to operate as a current generator limiting the current to a value much lower than its rated value. A fuse acts as measuring shunt. The switch can comprise a circuit breaker function. In this case, the fault detection circuit measures the voltage at the terminals of the semi-conductor and supplies an opening signal when this voltage exceeds a preset threshold.

Abstract: The power supply of the present invention is designed to operate over a wide range of both ac and DC input voltages and frequencies from 0-400 Hz. The power supply also provides two DC low voltage outputs, one for devices that do not require a high degree of regulation and one for devices that do require a high degree of regulation. The power supply also includes a power-up inrush clamp to limit high start up currents to approximately two times the nominal switching current. The primary switching transistor of the power supply is controlled by a dynamic feedback circuit which works interactively to increases the switching speed of the primary switching transistor.

Abstract: According to this invention, in a power supply circuit of a switching power supply apparatus, a circuit arrangement capable of adjusting the resistance values of a plurality of resistors in accordance with an input voltage condition is realized so that the switching power supply apparatus can be applied to a wide range of input voltages.

Abstract: A drive circuit for driving a capacitive load (4) and for producing a signal (FIG. 2b, 3b, 4b, 5b) indicative of the condition of the load, the circuit comprising: a FET (26) applying current to the load; a resistance (30) sensing the level of the applied current; a differential amplifier (32) detecting when the sensed level exceeds a predetermined threshold; and a bipolar transistor producing a control signal (FIG. 2b, 3b, 4b, 5b) to limit the applied current until the load current falls below the threshold, whereby the control signal is a pulse width modulated signal whose pulse width is indicative of the condition of the load.

Abstract: A circuit for limiting the inrush current in DC to DC and DC to AC power supplies. The circuit utilizes a small capacitor for taking a charge which slowly turns on a FET transistor placed in series with a large filter capacitor; the slowly reducing resistance of the transistor provides the desired inrush current limiting.

Abstract: In an operating device for high-current loads, such as fan motors, or the like, connected to the electric system of mobile units, in particular motor vehicles, it is proposed each respective electric motor is connected to the electric system via an electronic control circuit controlling the pulse width of the pulse supply voltage supplied to the motor for the purpose of adjusting the motor to different power requirements, with nominal-value adjustment. An interference elimination circuit including a series coil and at least one capacitor of high capacitance is arranged between the electronic control system and the electric system of the mobile unit. The series coil is equipped with an iron-powder core and designed in such a manner that no saturation is obtained even under maximum current conditions so that a sufficiently high inductivity reserve remains available for pulse damping.

Abstract: A power supply circuit which includes a current limit circuit for limiting the inrush current when the power supply is switched on. The current limit circuit is coupled between a supply voltage at the input end of the power supply and a storage capacitor at the output end of the power supply. The current limit circuit includes a first semiconductor switch having a resistor in parallel with its switching path. In parallel with the control path of the first semiconductor switch is a parallel circuit that includes a first capacitor, a first resistor and the switching path of a second semiconductor switch. The control electrode of the second semiconductor switch is connected to a tap on a first voltage divider to which a second capacitor is connected in parallel. The switching path of a third semiconductor switch is connected parallel to the control path of the second semiconductor switch.

Abstract: An automotive voltage regulator is disclosed to have plural regulated outputs using a transient protected isolator output stage (TPIOS) that prevents a system fault condition on any one output from adversely affecting the other outputs. In an automotive environment employing a nominal 14-volt supply, an individual output can be taken from -4 to +26 volts without causing damage or having any significant reaction on the non-faulted outputs. The circuit employs a relatively small NPN output pass transistor and, therefore, requires a relatively low value stabilizing bypass capacitor.

Abstract: A current supply arrangement includes a power transistor (T1) driven by a control transistor (T2). The power transistor switching path is connected between a terminal (UE+) of an unregulated input direct voltage (UE) and a terminal (UA+) of a regulated supply voltage (UA). A first control amplifier (OP1), drives the control transistor via a first electrode (base) thereof and compares a voltage derived from the supply voltage (UA) with a first reference voltage (Uref). A second control amplifier (OP2) compares a measuring voltage (UM) derived at a current measuring resistor (R10) with a second reference voltage. The voltage control and current regulation results in a system having a small number of elements and a sufficient dynamic control range.

Abstract: A DC power switch (10) for a capacitive load (11) has a main transistor (Q1) in series with the load between positive and negative DC bus terminals (B.sup.+, B.sup.-). A secondary transistor (Q2) and a resistor (R.sub.1) are connected in series and this series connection is connected in parallel to the main transistor (Q1). A control circuit (20; 50) is connected to the main and secondary transistors (Q1, Q2) and controls them. In response to an enable signal (26), the secondary transistor (Q2) is initially turned on such that it and the resistor provide the initial charging current for the capacitor load (11) and subsequently the secondary transistor is turned off and the main transistor is turned on such that it provides the subsequent current required by the load. This configuration minimizes the power dissipation ratings required for the transistors while balancing this requirement with the relative rapid providing of charging current for the capacitive load.

Abstract: An inrush current limiting circuit in accordance with the principles of the present invention limits initial current flow to a highly initially reactive power load. The current limiting circuit comprises a plug in connection to a power source and two conductor paths leading from the plug in connection. A power FET has a source element to drain element path in series with one of the conductor paths and has a gate connection. A bipolar transistor is connected to shunt the gate element of the power FET to the potential at its source element when the bipolar transistor is conducting, thereby to limit the current passing through the power FET. A sense resistor is in series with one of the conductor paths for controlling a base element of the bipolar transistor to cause it to conduct when current through the sense resistor exceeds a predetermined amount.

Abstract: In a method and device for limiting the starting current of a DC converter, at least one buffer capacitor is initially charged through a load resistor. The current going through the load resistor is measured with a monitor. The monitor switches on a DC converter and bridges the load resistor once a switching threshold is reached. A predetermined minimum current is used as the switching threshold.

Abstract: A closed loop, electronic temperature control system for a tankless water heater. The control system incorporates error range comparison circuitry for comparing the difference between a water temperature selected from a temperature selection device and an actual water temperature sensed by a temperature sensing device. An error range comparison circuit operates to select a high gain when the sensed water temperature is within about +/-3.degree. Fahrenheit of the selected temperature, and a low gain when the sensed water temperature is more than +/-3.degree. Fahrenheit of the selected water temperature. A slow start network is included for applying current gradually to the heating element of the water heater when power is initially applied to the system. A master power down circuit quickly interrupts current flow to the heating element after the system has been powered down.

Abstract: There is disclosed a power regulating system for portable engine generator wherein overcurrent protection is provided by connecting the AC output of an AC generator driven by an engine to a rectifier for conversion to a DC current, supplying the DC current so obtained to an inverter to obtain an AC current of an arbitrary frequency, and providing for stopping of the driving signal to the inverter when an overcurrent state is detected in the inverter.

Abstract: A DC switch mode power supply operating from an AC input power source typically has an input stage which includes a rectifier for rectifying the AC input power waveform to provide a DC voltage to the switch mode power supply. This rectifier includes a capacitive storage circuit for storing the DC power to be supplied to the switch mode power supply. To protect the circuit against current surges during start-up, normally an open relay is provided in parallel with a current limiting resistor. This resistor can burn out under some circumstances. This invention replaces the resistor with a capacitor divider circuit containing at least one capacitor in series between the storage capacitor and one of the terminals from the input power supply. A second capacitor can also be provided in parallel with the storage capacitor and one of the diodes of the rectifier. Another diode of the rectifier is in series with the storage capacitor.

Abstract: A gate drive circuit for an insulated gate bipolar transistor initially drives the gate to a first voltage potential which causes the transistor to partially turn on. A sensor detects when the transistor saturates at which point the gate drive voltage is increased to increase the conductivity of the transistor and reduce its saturation voltage drop. If, however, a load coupled to the transistor is short circuited, the transistor will never reach saturation and will remain partially turned on at a point where it has increased short circuit current handling capability. In addition, once the transistor has been fully turned on, should a short circuit load condition occur, the transistor will drop out of saturation causing the drive circuit to reduce the gate voltage to increase the short circuit current handling capability of the transistor.