Abstract: For use with a power converter couplable to a source of electrical energy, the converter having a power switch that conducts intermittently to transfer energy from the source to an inductive element, and a freewheeling diode that alternately conducts with the power switch to transfer energy to an output of the converter, an active clamp and a method of operating the active clamp. In one embodiment, the active clamp includes: (1) an inductor, coupled in series with the freewheeling diode, and (2) a series-coupled capacitor and clamping switch, coupled in parallel with the inductor, that cooperate therewith to mitigate adverse effects of reverse recovery currents associated with the freewheeling diode and enable substantially zero voltage switching of the power and clamping switches.

Abstract: The novel current-mode switching regulator does not determine the load current by picking off a measurement voltage at a measuring resistor, as in the conventional prior art. Instead, the voltage drop across the inductor which is required in any case is picked off as the measurement voltage. A regulating signal derived from the load current is determined, by integration with respect to time, with a voltage-controlled current source. The regulating signal is fed back, as a regulated variable, into regulators of the inner control loop. In this way, it is possible to dispense with the measuring resistor. An additional compensation device makes it possible, moreover, to compensate for a regulation deviation in the desired potential of the outer control loop.

Abstract: A multi-phase power supply utilizes a current sensor including a sensor inductor winding connected in parallel with a filter inductor winding at the output of each phase for sensing the phase currents and balancing the current by adjusting the duty cycle of each phase through feedback control. In addition, in a multi-module power supply configuration, current between power supply modules is balanced through use of the same current sensor and current sharing technique. Each phase of the power supply includes at least one input power source and a current sensor. The sensor inductor winding and the filter inductor winding have the same number of turns and are wound about a magnetic core also present at each phase. A differential amplifier at each phase senses and amplifies any voltage difference between the outputs of the sensor inductor winding and the corresponding filter inductor winding.

Abstract: A drive circuit comprises an output terminal for connection to a signal line 1002. An inductor 1012 is coupled between the signal line 1002 and a reference voltage node 1010. A switch 1008 is coupled between the signal line 1002 and the reference voltage node 1010. When the switch 1008 is closed, the inductor 1012 is coupled between the reference voltage node 1010 and the signal line 1002. When the switch is open, the inductor 1012 is not coupled between the reference voltage node 1010 and the signal line 1002.

Abstract: It is an object of the present invention to provide a step-down DC/DC converter which is resistant to common-mode noise, there are no significant restrictions on a main transistor used, on its energizing circuit and the frequency of the on and off cycles of the main transistor, etc., and is capable of generating a low DC output voltage from a high DC input voltage.

Abstract: An electronic switching circuit wherein a first switch has first and second terminals communicating respectively with a supply voltage and with a first terminal of an inductive load; and a second switch has first and second terminals communicating respectively with the first terminal of the load and with a second terminal of the load. A recirculating diode is located parallel with the second switch; the circuit generates a control signal related to the derivative of the recirculating current flowing in the diode; and the control signal is processed to prevent the closing signal from being applied to the first switch when the control signal exceeds a threshold value due to reverse conduction (recovery) of the diode.

Abstract: The invention provides buck switching regulator circuits that include voltage slew rate limiting circuitry and current slew rate limiting circuitry. The specification describes current-mode and voltage-mode control implementations that provide efficient low-noise switching regulator circuits.

Abstract: A circuit and method for controlling a switching voltage regulator having (1) a switch including one or more switching transistors and (2) an output adapted to supply current at a regulated voltage to a load including an output capacitor. The circuit and method generates a control signal to turn said one or more switching transistors OFF under operating conditions when the voltage at the output is capable of being maintained substantially at the regulated voltage by the charge on the output capacitor. Such a circuit and method increases the efficiency of the regulator circuit particularly at low average current levels.

Abstract: A switching element is controlled by a control circuit. When the switching element is in an ON state, a coil current I.sub.L ramps up. When the switching element is in an OFF state, the coil current I.sub.L ramps down. If an output voltage V.sub.out is smaller than a predetermined output voltage value, a control circuit is informed of it. If the coil current I.sub.L rises to a peak current I.sub.LP set by a setting circuit, the control circuit is informed of it. The setting circuit sets the peak current I.sub.LP proportional to an input voltage V.sub.in. The control circuit sets the switching element in the ON state when the output voltage V.sub.out is smaller than the predetermined output voltage value, and sets the switching element in the OFF state when the coil current I.sub.L rises to the peak current I.sub.LP.

Abstract: The present invention relates to a method to generate at least a supply voltage to supply energy to a hearing device, whereas the ratio between the supply voltage and the source voltage is adjustable. The hearing device substantially comprises a source (Q), at least a switching element (S1, . . . , Sn), at least an energy transfer element (EUE), at least an energy storing element (ES), a load (Z) and a control unit (CTRL), whereas the method consists in that, in a first step, the control unit (CTRL) acts on the switching elements (S1, . . . , Sn), such that energy is transferred from the source (Q) to the energy transfer elements (EUE), that, in a second step, the control unit (CTRL) acts on the switching elements (S1, . . . , Sn), such that at least a part of the energy stored in the energy transfer elements (EUE) is transferred to the energy storing elements (ES) to build a supply voltage across the load (Z).

Abstract: A bilateral switch (302) plus inductance (304) to drive a capacitive load (306 plus 350) by resonant charging and discharging the load.

Abstract: A new linear power control topology coupled with simple control techniques are presented which virtually eliminate the flicker problem as well as providing excellent power quality over a wide range of power levels. A modified one dimensional LMS control system similar to the standard LMS algorithm with multiple operating points and gain scheduling is also described which when combined with the new power control topology yield a dramatic reduction in flicker while yielding a universal voltage interface for world wide use.

Abstract: A chopper-type switching power-supply circuit having a DC high-potential input terminal, a DC low-potential input terminal, a DC high-potential output terminal, and a DC low-potential output terminal. The power-supply circuit has one terminal of an inductor connected to the DC high-potential input terminal and a capacitor connected to other terminal of the inductor. The output circuit contains the DC high-potential output terminal and the DC low-potential output terminal. A first input terminal is coupled to the other end of the capacitor and a second input terminal coupled to the DC low-potential input terminal. An N-channel MOSFET has a drain electrode connected to the other terminal of the inductor and a source electrode connected to the high-potential output terminal.

Abstract: A circuit and method for controlling a switching voltage regulator having (1) a switch including one or more switching transistors and (2) an output adapted to supply current at a regulated voltage to a load including an output capacitor. The circuit and method generates a control signal to turn said one or more switching transistors OFF under operating conditions when the voltage at the output is capable of being maintained substantially at the regulated voltage by the charge on the output capacitor. Such a circuit and method increases the efficiency of the regulator circuit particularly at low average current levels.

Abstract: A process for the fuzzy control of switching power supplies which have at least one inductor and at least one switching device, and a device for performing this control, the particularity whereof resides in the fact that it comprises the following steps: measuring the value of the current on the inductor; measuring the value of the input voltage of the switching power supply; measuring an error generated between a reference voltage and an output voltage of the power supply; defining fuzzy membership functions for the value of the current on the inductor, for the input voltage value, and for the error; defining an output membership function for the value of the duty cycle of the power supply; defining multiple fuzzy inference rules to which the measured values and the membership functions are applied calculating the corresponding weight functions of the membership functions; defuzzifying the results obtained by means of the weight function calculation and the application of fuzzy rules so as to obtain a real v

Abstract: A DC/DC converter includes a control unit for outputting a control signal on the basis of a voltage difference between a DC output voltage and a reference voltage; a switching element which is connected to a line of the DC input voltage, and which becomes ON-state or OFF-state in accordance with the control signal; and a minimum ON-state duration setting unit, e.g., a monostable multivibrator, which defines the minimum ON-state duration of the switching element, when a necessary output electric power is low. Preferably, the converter includes a charge-pumping circuit having two diodes and two capacitors, so as to obtain from one capacitor a driving voltage source for driving an N-channel type field-effect transistor as the switching element.

Abstract: A buck-topology switching power supply (100) combines a plurality, n, of signals (111, 121, 131) from a like number (n) of substantially direct-current power sources by means of a single inductor (150). As k varies from 1 to n, a controller (170) acts to couple each signal.sub.k in sequence to the inductor input (140) for an"on" duty period t.sub.k at a predetermined switching frequency, f, thus forming at the inductor output (160) an output signal having an output voltage V.sub.o and an output power P.sub.o. Under static load conditions, the controller holds the corresponding duty period t.sub.k for each signal.sub.k at a substantially constant value. Under dynamic load conditions, however, the controller dynamically adjusts the corresponding duty period t.sub.k in order to maintain the fractional power contribution P.sub.k for each signal.sub.k relative to the output power P.sub.o at a predetermined value.

Abstract: A circuit arrangement provided with a switch mode power supply energized with a pulsatory input current generated by means of high-frequency switching of the main switching means HS (3) provided in turn with a drive circuit (6) having at least drive switching means SS (60) and connected to a return current line (7).A self-inductance element (61) is included in the drive circuit, preferably between the main switching means HS and the drive switching means SS. This arrangement results in a rapid level shifter of compact construction.

Abstract: A power transistor driving circuit for use in an electromagnetic induction heating device comprises an induction coil circuit and a driving circuit. The induction coil circuit is provided with an induction connected with an oscillating circuit made up of capacitances and resistances. The oscillating circuit is provided with at least one power transistor for producing a high frequency switching. The driving circuit comprises at least one quick switching circuit provided with two transistors between which a resistance and an inductance are connected therewith in series. One end of the inductance is connected with the gate of the power transistor for accelerating the reverse current flow of the gate so as to shorten the switching time of the power transistor and to reduce the switching power loss of the power transistor at the time when the power transistor is turned off.

Abstract: A transformer isolated circuit for driving a semiconductor power switch includes a transformer which is driven with a high frequency Pulse Width Modulated (PWM) signal in such a way that the constantly present PWM carrier supplies the power needed for high gate current pulses, while different duty cycles determine the "on" or "off" state of the power device under control. Transformer saturation is prevented by sensing primary current and returning it to zero once per PWM cycle. Because of the high PWM carrier frequency used, the average transformer power is low, yet the secondary side is able to deliver high pulse currents for fast "on-off" switching of the gate of even the largest N- or P-channel device, without need for auxiliary power supplies. Also included are provisions for extremely fast output current limiting, for use where short circuit protection is necessary. Discussion of a monolithic implementation is included.

Abstract: A pulse-controlled circuit for an insulate gate power transistor (Tp) comprises an auxiliary MOS transistor (T1) connected between the gate and a reference terminal of the power transformer in parallel with a pulse transformer secondary (W2). This circuit comprises two controlled unidirectionally conductive paths in parallel (D1, M1; D2, M2) between one terminal of the transformer secondary and the auxiliary transistor gate, these paths being alternatively rendered conductive when a positive or negative pulse is applied to the secondary of the transformer.

Abstract: A switching power source comprising a pair of output terminals, a first switch element, a reactor and a filter which are connected to each other in series between one of the terminals of an input DC power source and one of the output terminals; a second switch element connected between a connecting node for the reactor and the filter and the other terminal of the input DC power source; and means for causing energy stored in the reactor to be fed back for regeneration to the input DC power source when the switch elements are turned off, wheein the switching power source is characterized by that the first and second switch elements are alternatively actuated for ON-OFF actions at a prescribed time ratio.

Abstract: A power converter unit includes a pair of switching DC/DC converter secti for positive and negative voltages which incorporate a MOSFET switching arrangement in which a pair of MOSFETs are forced to share the output load current equally, a current limiting arrangement which activates shutdown whenever the current threshold limit is exceeded, and an internal grounding arrangement which minimizes output of current spikes by isolating the switching spikes from the input and output.

Abstract: A current mode switching regulator power supply with an improved regulator system achieves a constant operating period by predetermining the off time of the switching transistor. The off time is programmed by the input and output voltages acting on a resistor-capacitor timing circuit enabled by a current mode controller.

Abstract: A direct coupled switched mode power supply designed for the AC to DC power conversion in for example CAT TV systems and equipment. The power supply is constructed to have a conversion efficiency of between 85 and 90%. It achieves these efficiencies by utilizing a pulse transformer having a duty cycle of greater than 50% in conjunction with an output control circuit, a driver circuit and an output filter circuit all designed to work together to effect increased efficiency.

Abstract: The variation of the time (t2) in which current flows from the chock (n1) of the switching power supply to the load (C3, RL), which variation is necessary for the regulation of the output voltage (Ua), is accomplished by means of a threshold switch (S) short-circuiting the coil of the choke.

Abstract: A multi-loop controller for controlling a quasi-resonant converter having a power switch, a filter inductor and an output voltage. The controller includes a sensor circuit for sensing the output voltage of the converter. A detector monitors the filter inductor current of the converter. The output voltage is compared with a known reference voltage to develop a control error voltage when the output voltage exceeds the reference voltage. A comparing circuit then compares the inductor current with the control error voltage and produces a control signal when a predetermination relationship has been detected. Finally, an activating circuit responsive to the control signal turns the power switch on.

Abstract: A nonlinear resonant switch for power conversion devices and a converter using the switch are described. The switch optimizes converter efficiency by switching only when current is zero and by limiting the peak current to a value near that provided by conventional PWM converters. A nonlinear reactor having a winding in series with the switch and a tank circuit is biased to saturation at low currents but is driven into an unsaturated condition by high currents so that a resultant high series inductance mitigates further current increase. Several converter topologies incorporating this improvement are shown.

Abstract: A PWM inverter including a saturable core and a main circuit comprising a series circuit of a main winding and a resistor in which switching means applies a DC voltage across the main circuit by time ratio control with the polarity inverted alternately, and the on-off control of the switching means is accomplished by using a saturable transformer with a saturable core.

Abstract: A FET switching regulator has a FET switch which is periodically turned on to couple an unregulated DC input voltage to an output filter which develops a regulated output DC voltage. Regulation of the output DC voltage is determined by the on time or duty cycle of the FET switch. A periodic waveform is developed by a pulse-width modulator. The pulse-width modulator compares the input and output DC voltages to a reference voltage to pulse-width modulate the periodic waveform to determine the duty cycle. When the periodic waveform goes high, it triggers a first regenerative circuit which drives the gate of the FET switch into saturation within 20-30 nanoseconds. When the periodic waveform goes low, a second regenerative circuit is triggered to return the FET switch to an off state within 20-30 nanoseconds. Accordingly, the FET switch may be operated at frequencies approaching 500 kHz without excessive power losses within the FET switch in the transitory states between cutoff and saturation.

Abstract: A switching regulator for supplying current to a load in order to maintain a selected voltage across the load. Current is supplied to the load from a coil which receives a train of spaced trapezoidal current pulses from an energy source. The spacing between current pulses is maintained constant while the duration of the current pulses is varied to compensate for changes tending to vary the load voltage.

Abstract: A main switch consisting of a switching transistor and a current transformer is triggered at the leading edge of a main switch drive pulse. The switching transistor then starts a positive feedback operation through the current transformer and is turned on at high speed. Upon activation of the switching transistor, the magnetic core of the current transformer is saturated by the switching transistor emitter current flowing in the current transformer. Magnetic saturation of the core turns off the switching transistor with the magnetic energy stored in the current transformer. The main switch drive pulse falls after the switching transistor is turned off.

Abstract: A potential free actuation circuit for a pulse duration controlled electronic power switch having a control electrode and two major electrodes, the circuit including a driver stage having a control input and two major electrodes, and a pulse transformer connected for supplying control pulses to the driver stage for turning the power switch on and off. The driver stage and pulse transformer are connected and operated so that when the power switch is being turned off, its control electrode is placed at the potential of one of its major electrodes to thereby achieve greater freedom from disturbance, and so that the power switch is actuated with very low resistance by the driver stage, resulting in very short switching times which lead to low switching losses.

Abstract: In an impressed current cathodic protection system for a boat and/or its propulsion system the boat battery is connected to a switching type power converter which supplies the anode higher current at lower voltage than taken from the battery. The voltage on the anode is regulated to be constant or to be fixed relative to the voltage at a reference half cell. With either arrangement, the voltage drop across a reference resistor can be applied to an op amp to turn on a transistor to connect an alternate power source to the anode. The voltage across the resistor is regulated by the power converter chip so the chip also regulates the alternate source to prevent excessive voltage on the anode.

Abstract: An improved rectifying network employing a semiconductor diode, a saturable reactor connected in series with the diode between a pair of terminals, and means for biasing the saturable reactor to saturate the saturable reactor core for forward diode current flow.

Abstract: In a DC-DC converter of the type in which an inductance stores energy when a main switching transistor is turned on and releases the stored energy when the main switching transistor is turned off, a semiconductor active element is used as a flywheel element which is turned off when the main switching element is turned on, but is turned on to provide the path for the current established by the release of the stored energy, and the signal which is substantially in synchronism with the switching operation of the main switching transistor is applied to the control terminal of the semiconductor active element so as to cause it to turn on and off.

Abstract: A device including a main circuit comprising a switching main transistor unit, a smoothing reactor, a smoothing condenser and a commutation diode. To control the conduction and nonconduction of said main transistor unit by means of the output obtained by detecting and amplifying the output voltage of said main circuit, the main transistor unit comprises at least two main transistors connected in parallel with each other. A secondary winding of a current transformer is connected between the bases of the main transistors. A parallel circuit comprising a diode and a condenser is connected between the neutral point of the secondary winding and the emitters of the main transistors.

Abstract: An apparatus is provided for sensing the state of high voltage contact inputs in a process control system. Lower voltage contact closure input modules cooperate with a reference bus and reference bus regulator to reduce the voltage drop across an input module when a pair of contacts is closed, thereby reducing the energy dissipated and heat created by the input module.

Abstract: A high voltage, pulse width regulator circuit wherein the input voltage may be up to twice the voltage rating of pass or switching transistors used in the circuit is disclosed. This is accomplished by dividing the input unregulated DC voltage or full wave rectified AC voltage in half. The divided voltage is placed on each of two input lines. The pulse width regulator utilizes two transistors or other semiconductor switches, each receiving one half the input voltage. To insure a properly regulated voltage on the output and to avoid the possibility of one of the transistors receiving more than one half the input voltage, means are provided for insuring that the voltage drop across either transistor will be limited to approximately one half the input voltage at all times. By utilizing the teachings of this invention, a pulse width regulator capable of handling an input voltage of at least twice the rating of the transistors employed in the regulator is obtained.

Abstract: A switching regulator which chops an unstabilized D.C. input voltage by a switching transistor and rectifies the chopped voltage to produce a stabilized D.C. output voltage is disclosed. A series circuit of a resistor, a capacitor and a coil is inserted between a stabilized D.C. output terminal and a base electrode of an exciting transistor which excites the switching transistor to suppress the increase of a ripple voltage produced when the unstabilized D.C. input voltage drops.

Abstract: A dc/dc converter for controlling the current through a load which comprises a switching transistor having its emitter-collector circuit coupled between an input voltage source and the load. A control transformer having first, second and third electromagnetically coupled windings is also provided, the second winding of the transformer being electrically connected between the base and emitter of the switching transistor. A control switching logic circuit selectively generates pulses for determining the beginning and the end of the conducting period of the switching transistor, and a control circuit coupled to the logic circuit selectively short circuits the third winding thereby reducing the voltage across the second winding and driving the switching transistor into its non-conducting state.

Abstract: A circuit for reducing the voltage of a d-c power supply with one grounded terminal comprises a chopping transistor in an ungrounded supply lead, periodically turned on and off by an electronic switch, and an L/C network downstream of that transistor along with a flywheel diode. The switch lies in series with an ancillary voltage generator, having a terminal voltage substantially lower than the supply voltage, in a grounded loop which is reactively coupled to the transistor base via a capacitor or a transformer. A control signal for opening and closing the switch may be obtained from a square-wave generator connected across the transistor output and driven by the stepped-down supply voltage.

Abstract: A half-wave and a full-wave rectifier using transistors as rectifying elements have independently controlled multiple output voltages obtained from a single power supply. The transistor used as a rectifying element has its turn-on controlled thus allowing voltage control by phase control action.

Abstract: A switching regulator circuit for utilization with power supplies supplying a high DC output current including a plurality of control rectifiers and inductive reactors with sequential gating of the rectifiers at regular intervals for providing overlapped output current pulses from the reactors. An output circuit receives the rippled current comprised of the overlapped output current pulses for reducing the ripple therein. The output circuit includes a choke in series with the output which induces phase shift between the rippled current and the output current. A sensing winding associated with the choke eliminates the phase shift voltage for forming a feedback signal as an input to a control circuit. The control circuit utilizes the feedback signal to control the rate at which the rectifiers are gated sequentially.

Abstract: A switching voltage regulator for regulating line voltage which produces an output proximating that of a linear voltage regulator. The switching voltage regulator includes a linear amplifier which receives a reference signal as well as an output feedback signal and produces an overall feedback signal for utilization. A discrete processor receives the overall feedback signal as well as a feedback from its own switching output signal in order to produce its output switching signal as a pulse strength modulation signal. The pulse strength modulation signal is then used to switch on and off the line voltage in order to produce an intermediate output signal which is then filtered in order to produce the voltage regulated output signal. A feedback processor can be included between the voltage regulated output signal and the linear amplifier and can provide either regular voltage feedback or can also include damping factor feedback.