Abstract: A disk drive system includes a fixed output voltage regulator including an output terminal that provides a substantially fixed output voltage. A plurality of loads, each includes a voltage supply terminal. A programmable resistor bank which is adapted to selectively provide a plurality of different resistances, is connected in series between the output terminal of the voltage regulator and the voltage supply terminals of the plurality of loads. One of the plurality of different resistances can be selected to adjust a voltage provided to the voltage supply terminals of the plurality of loads.

Abstract: Methods and apparatus are disclosed for suppressing circuit noise due to parasitic elements in switch mode power supplies. The presented embodiments use actively controlled damping devices such as controllable resistors, current sources, and tri-state power devices to achieve required damping and to minimize power loss.

Abstract: A synchronous DC-DC regulator, adapted to receive a high side pulsed signal and a low side pulsed signal that is substantially the inverse of the high side pulsed signal. The regulator includes an inductor, and a capacitor having one port connected to ground, and having a second port providing an output voltage of the DC-DC regulator. A driver is provided for driving pulses of current to the inductor when the high side pulsed signal is asserted. An undercurrent sense circuit is adapted to sense a driving current flowing through the driver and to assert a disable signal when the driving current is less than a predetermined amount. An enable/disable circuit is adapted to allow the low side pulsed signal to turn the switch on when the disable signal is not asserted, and to not allow the low side pulsed signals from turning the switch on when the disable signal is asserted.

Abstract: A PWM circuit is provided that is capable of PWM control with duties in a range of 0-100%, and that is also capable of high-speed responses.

Abstract: A power supply apparatus includes an output voltage generator, a reference voltage generator, a voltage divider, and a voltage control circuit. An input voltage is supplied from a direct current power source. The output voltage generator generates a constant output voltage based on the input voltage. The reference voltage generator generates a reference voltage. The voltage divider divides the constant output voltage into a divided voltage in accordance with a voltage dividing ratio variable in response to an externally-input control signal. The voltage control circuit controls the output voltage generator to regulate the constant output voltage such that the divided voltage from the voltage divider is equalized to the reference voltage.

Abstract: A regulator provides a load voltage. The regulator includes a power driver having a feedback input and a power driver voltage. The regulator includes a comparator having a comparator output related to a combination of the load voltage and a power driver current. The regulator includes a pulse generator controlled by the comparator output and having output pulses with fixed pulse widths. The regulator includes a time limit circuit controlled by the output pulses. The time limit circuit provides the output pulses to the feedback input subject to a time limit between the output pulses.

Abstract: A DC-DC converter of low ripple voltages which has a bi-directional power conversion means between an input power source and a smoothing capacitor and can quickly change the output voltage independently of the load. Said DC-DC converter comprises a main circuit of a non-insulated step-down DC-DC converter comprising at least two semiconductor elements, a DC reactor, and a smoothing capacitor, means for generating a variable reference voltage, means for comparing a reference voltage generated by said reference voltage generating means by the output voltage and outputting differential voltage information, means for generating a signal to be applied to the control terminals of said semiconductor element according to said differential voltage information, and means for discriminating the direction of a current flowing through said DC reactor.

Abstract: This invention synchronizes the control signals generated by the out-of-range detection circuits with a predefined event. In one aspect, the invention relates to a method of controlling a switching regulator to regulate an output voltage. The method includes receiving a first enable signal and a second enable signal, comparing a feedback voltage representative of the output voltage to a first reference voltage and generating a first limit signal in response thereto and generating, in response to the first enable signal, a close switch command if the first limit signal indicates that the feedback voltage is less than the first reference voltage. The method further includes comparing the feedback voltage to a second reference voltage and generating a second limit signal in response thereto and generating, in response to the second enable signal, an open switch command if the second limit signal indicates that the feedback voltage is greater than the second reference voltage.

Abstract: A circuit and method for providing a regulated output voltage. In one embodiment, the circuit includes a feedback comparator, a latch module, a switch, a current limit module and a pulse module. The pulse module generates an off-time signal that is substantially proportional to the reciprocal of the difference of the output voltage and a supply voltage. In another aspect, the method includes the step of comparing the output voltage and a reference voltage, and comparing an inductor current and a reference current. Additionally, the method includes the step of charging the inductor in response to the comparisons, and discharging the inductor for a minimum period of time if the inductor current increase to substantially equal the reference current.

Abstract: A method and power supply device for generating a regulated direct voltage from an alternating voltage using a step-down transformer, a step-up transformer, an inductance coil and a control device that controls the transformer in a step-down or step-up transformation mode is disclosed herein. An inductance coil voltage measuring signal is compared with three limiting values (A, B, C), wherein A corresponds to zero, B lies between A and C and B and C correspond to the direct voltage. Switching from the step-down to the step-up transformation mode is effected when the increasing voltage measuring signal drops after reaching B and A is not reached again and increases to C instead. Switching from step-down to step-up transformation mode is effected when the decreasing voltage measuring signal increases after reaching A and B is not reached and drops to A instead.

Abstract: An inductor current measurement circuit (25) accurately measures current supplied to an inductor (17) by a first transistor (2) and/or a second transistor (3). The first transistor (2) has a drain coupled to an input voltage conductor (8), a gate coupled to a switching signal (4), and a source coupled to a the first terminal of an inductor 17. A first sense transistor (7) has a gate and a drain connected to the gate and train, respectively, of the first transistor (2), and a source coupled to a first input of a first amplifier (13) and a drain of a third transistor (12) having a source coupled to a second supply voltage conductor (9), and a gate connected to the gate of a fourth transistor (15). The source of the fourth transistor (15) is connected to the second supply voltage conductive (9) and its drain is connected to an output terminal (18) and a second terminal coupled to the second supply voltage conductor (9). The first transistor (2) and second transistor (3) are included in a DC-DC converter.

Abstract: A DC-DC converter includes a main switching device and a synchronous switching connected in series between a power supply and a ground, and a drive control circuit for supplying a first drive signal to the main switching device and a second drive signal to the synchronous switching device to alternately activate and deactivate the main switching device and the synchronous switching device. A detection circuit is connected to the synchronous switching device for detecting a malfunction of the synchronous switching device, such as a short-circuit, and generates a detection signal when a malfunction is detected. A protection circuit is connected to the detection circuit and the drive control circuit and inhibits the first and second drive signals in response to the detection signal. The drive control circuit, the detection circuit and the protection circuit are all formed on a single semiconductor substrate.

Abstract: A comparator monitors an output voltage V.sub.out. When an output voltage V.sub.out decreases to a predetermined output voltage or less, the comparator sends a signal that represents this state to a controlling circuit. When the controlling circuit receives the signal, it causes a switching device to be turned on. Thus, a coil current I.sub.L is increased. A hysteresis (window) comparator monitors the coil current I.sub.L. When the coil current I.sub.L reaches a comparison current I.sub.LP, the controlling circuit causes the switching device to be turned off. When the coil current I.sub.L decreases to the comparison current I.sub.LB (where I.sub.LP >I.sub.LB), the controlling circuit references an output signal of the comparator. When the output voltage V.sub.out is lower than the predetermined output voltage, the controlling circuit causes the switching device to be turned on.

Abstract: A non-isolated voltage converter, of switch-mode type, includes a capacitor between terminals that provide an output voltage regulated by a circuit that controls a switch that provides current to an inductive element. A local supply for the control circuit receives energy from the inductive element. In one embodiment, the inductive element has a tab between two windings, and the output voltage of the converter is smaller than the local supply voltage of the control circuit. In another embodiment, a diode is interposed between a positive terminal of the output capacitor and a positive terminal of a capacitor of the local supply of the control circuit. The negative terminal of the local supply capacitor is connected to the mid-point of a series association of the switch with the inductive element. A zener diode is interposed, in series with the local supply capacitor and the local supply diode, between the mid-point and the positive 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 controller circuit for controlling and continuously varying the average value of discontinuous current pulses in a step down switching regulator operating in discontinuous conduction mode effects improvements in efficiency and output ripple of the switching regulator.

Abstract: An adapter designed to connect a dc to dc power converter between a dc power supply and an electronic sensor that provides inputs to an electronic controller. The dc to dc power converter transforms the voltages from the power supply so that the voltage signal to the sensor on the negative lead is biased at a level that prevents noise from triggering an unintended response from the electronic controller.

Abstract: A control system using pulse width modulation, current-mode control to regulate a flyback converter for small input currents. The control system generates a ramp voltage indicative of an input current of the converter with an added bias to overcome the effects of switching noise attributable to parasitic elements in the converter. The ramp voltage is compared with an error voltage is order to obtain the pulse width modulated on-time of a primary switch. Thus, the control system maintains control for small duty cycles of the primary switch by having a control region immune to switching noise.

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 system and method for measuring the load current in a power supply driven by switched transformer or the like. Rectified rectangular waveform input voltage pulses are interrupted to exhibit a less than 100 percent duty cycle with an off state value approaching zero volts. A filtering inductor is situated in normal manner between the input voltage pulses and the load. Preferably, a capacitor is connected across the load. A freewheeling diode and sensing resistor are connected across the less than 100 percent duty cycle rectangular input voltage. The peak values of the current pulses through the sensing resistor have been determined to be related to the load current of the power supply. The voltage drop across the resistor is amplified, detected and used to regulate the magnitude of the limited duty cycle input voltage. The voltage drop across the resistor may be used to limit the power supply output current or to balance current in parallel configurations of multiple power supplies.

Abstract: A converter employs a comparator sensing the current through an output diode, for generating a confirmation signal of an OFF state of the switch until the discharge current of the inductor toward the user circuit and the external filter capacitance has become null, thus ensuring the operation in a discontinuous mode under any condition. A turn-off signal of the switch is provided by another comparator which, instead of the voltage on a sensing resistance connected in series with the switch, may sense the voltage across the switch itself. This latter embodiment is particularly suited in case of an output MOS transistor and the circuit comprises means for masking for a preset period of time the turn-off signal produced by said comparator, in order to allow a predefined turn-on phase of the switch. Enabling of the turn-on of the switch is conventionally provided by a dedicated (third) comparator of the output voltage.

Abstract: A dc-to-dc converter circuit for generating an output voltage from a source voltage includes a plurality of first metal oxide semiconductor field effect transistors (MOSFETs) connected in parallel and collectively defining a gate, a source and a drain. A driver circuit preferably includes a bipolar transistor connected to the gate for turning on the first MOSFETs. A second MOSFET is preferably connected to the gate for turning off the plurality of first MOSFETs. The dc-to-dc converter also preferably includes a clamp circuit connected to the plurality of first MOSFETs across the drain and source thereof. Protection, soft-start and status features are also preferably incorporated into the dc-to-dc converter. A voltage divider is connected to a reference voltage for dividing a first reference voltage to thereby generate a second reference voltage less than a desired output voltage.

Abstract: A synchronous regulator circuit including a transformer having a secondary inductor magnetically coupled to a primary inductor, where the secondary inductor is coupled to control a synchronous power switch. The secondary inductor operates to drive the synchronous power switch using self-regeneration during a flux reversal phase of each cycle. A timing circuit or simple pulse width modulation circuit (PWM) turns on the primary switch and turns off the synchronous switch during a power phase of each cycle, and then turns off the primary switch during the flux reversal phase of each cycle. The flux reversal of the secondary inductor drives the synchronous switch on, thereby achieving synchronous operation without an expensive dual output PWM. The present invention is illustrated using both a buck and a boost topology. A third switch is preferably used to clamp the synchronous switch off during the power phase.

Abstract: A switching voltage regulator achieves high efficiency by automatically switching between a pulse frequency modulation (PFM) mode and a pulse-width modulation (PWM) mode. Switching between the modes of voltage regulation is accomplished by monitoring the output voltage and the output current, wherein the regulator operates in PFM mode at small output currents and in PWM mode at moderate to large output currents. PFM mode maintains a constant output voltage by forcing the switching device to skip cycles when the output voltage exceeds its nominal value. In PWM mode, a PWM signal having a variable duty cycle controls the switching device. A constant output voltage is maintained by feedback circuitry which alters the duty cycle of the PWM signal according to fluctuations in the output voltage.

Abstract: A synchronous rectifying circuit for a switching power supply is disclosed which is arranged such that the necessity to provide a diode element in parallel with a rectifying transistor is eliminated so that a highly efficient and stable operation can be achieved. "On" drive signal of a switching transistor (Q1) is detected by a first limiter circuit (6), and a flip-flop circuit (5) causes a rectifying transistor (Q2) to be turned off in response to output of the first limiter circuit (6); turning-off operation of the switching transistor (Q1) is detected by a second limiter circuit (7), and the flip-flop circuit (5) causes the rectifying transistor (Q2) to be turned on in response to output of the second limiter circuit (7). The necessity to provide a diode element in parallel with the rectifying transistor is eliminated. Stable operation can be performed even if the switching element has an indefinite operation delay time. An enhanced efficiency can be achieved.

Abstract: A power supply in which control of the switch-on instant of a power device of a boost-circuit (operating in a discontinuous mode) is implemented by monitoring the current which actually flows through the "fly-back" inductance. The current is monitored on a sensing resistance, and, by the use of a comparator, a signal is produced for enabling/disabling the transfer to an input of a PWM driving circuit of a switch-on signal produced by a null detector. This configuration provide good noise immunity, which is particularly useful in power-factor-correction applications, and reduced power dissipation.

Abstract: A boost converter having a plurality of boost converter units in parallel operation. Within each boost converter unit, current transformers 22,23 are connected in series respectively to switching element 7 and diode 8. The current transformers 22,23 permit detected current therefrom to output current detection signals from current detection circuits. Then, the current detection signals within one converter unit 3 will be compared with those within the other converter unit 3A in parallel operation by comparing circuit 33. On the basis of a result of such comparison, D.C. output voltage Vout can be controlled to be equal to each other in each converter unit 3,3A.

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: Adaptive control of converters is provided to achieve, in one case, a constant current characteristic by controlling input power as a function of the ratio of output voltage to output current. In another class of circuits, input current to the converter is controlled under an adaptive control arrangement in response to output voltage/output current ratios which may also be modified by input current or input voltage. The adaptive control may be augmented with low frequency negative feedback control loops.

Abstract: A circuit capable of driving inductive loads below a chip substrate voltage level while minimizing on-chip power dissipation and eliminating parasitic effects. Two negative voltage drive modes are included in the circuit design. The first drive circuit forces a low negative voltage referenced to the circuit output voltage across an inductive load referenced to ground to provide a slow recirculation of the current in the inductive load. The second drive circuit forces a large negative voltage referenced to the circuit output voltage across the inductive load to provide a fast collapse of the inductive load. The switching regulator switches off when the current to the inductive load reaches a first value and switches on when the recirculating current from back e.m.f. reaches a second value. The switching regulator initially provides a higher level of power when first tuned on.

Abstract: A driver circuit for an inductive load, such as a solenoid winding, includes flyback and energization current sensors which respectively sense the current through the coil during flyback and energization. The flyback current sensor includes a flyback current resistor disposed in the flyback current path of the winding for producing a flyback signal proportional to the flyback current. The energization current sensor includes an energization current resistor disposed within the energization current path of the winding. The energization current resistor is adapted to produce an energization signal in response to the energization current flowing through the winding. Control of the solenoid winding is effected by a switch which connects and disconnects the winding from a power source in response to the duty factor of a control signal. A first summing amplifier receives the flyback and energization signals and produces an actual current signal in response to the received signals.

Abstract: A current regulator for an inductive load especially for a coil of an electromagnetic solenoid valve. The current flow through the coil is regulated and compared by means of an operational amplifying nominal current value. The inductive load comparator is initially controlled by a first conductive diode. A second diode having a higher voltage rating than that of the first diode is rendered conductive whenever the nominal current value in an inductive coil decreases rapidly. The current regulator ensures that the magnetic energy in the inductive load remains unchanged when the nominal current value remains constant or changes in small amounts. When a rapid decrease of the coil current occurs, the second diode is rendered conductive.

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: The synchronous switching power supply can be employed in power supply system requiring multiple outputs and extremely high efficiency. The input signal may be AC or pulsating DC. A switching power supply with flyback converter includes an inductor coupled to ground for attaining a current. A switch is coupled between the AC input signal and inductor for selectively applying the AC input signal of one polarity to the inductor. A rectifier is coupled to the inductor for conducting the current and providing a first DC signal. Another converter converts the AC input signal of the opposite polarity into a second DC signal having the same polarity as the first DC signal. The first and second DC signals are applied to a capacitor which provides a DC output signal.

Abstract: A control circuit for controlling a known active harmonic filter operating as a step-up converter in a power supply with sinusoidal network current input and a power factor of almost unity. The step-up converter comprises: a main rectifier, a storage inductance (L.sub.S), a cross-connected high-speed transistor (T.sub.Q), a diode (D1) and a power storage capacitor (C.sub.L). The high-speed transistor (T.sub.Q) is controlled by a first threshold switch (STc) whose input is controlled by a control capacitor (C12) coupled to receive a signal representative of instantaneous rectified d.c. output voltage (U.sub.E), instantaneous power output voltage (U.sub.o) and a signal representative of the charge state of the inductance.

Abstract: A DC voltage converter comprising: a switching transistor for establishing a load current circuit which connects a DC power source to a load to supply a load current to the load; a differentiating circuit connected in series to the load current circuit for producing a voltage drop corresponding to a differentiated value of the load current; an integrating capacitor connected in parallel with the load via an output terminal for outputting as an output voltage to be supplied to the load a voltage corresponding to an integrated value of a current flowing through the capacitor; a control width setting circuit for setting a width defined by upper and lower limits for controlling the output voltage in accordance with the voltage drop derived from the differentiating circuit; a ripple detection circuit receiving the output voltage from the capacitor and for detecting a ripple caused by an "ON-OFF" operation of the switching transistor; an output-reference-level setting circuit for setting a reference voltage of the

Abstract: In the preferred and illustrated embodiment of a DC to DC power converter in a sonde and exposed to high temperatures, a transformer with primary and secondary provides AC to a full wave rectifier bridge. The bridge output is DC with ripple on it. The bridge output is connected serially to the primary winding and also to a shunt capacitor. The circuit provides high temperature performance including slower switching speeds, reduced power dissipation and wider current range.

Abstract: A pulse generator for spark-erosive metal working contains a charge regulator circuit for charging a storage capacitor. A storage capacitor is sinusoidally discharged across a switching device to a spark gap. Charging always occurs in a defined manner independently of the preceding pulses, so that uniform pulses can be generated. The storage capacitor is charged with an energy excess of required for discharge and the energy still remaining after spark discharge is recovered in a d.c. voltage source. The switching device (3) is non-conductive only when the discharge current has substantially decayed.

Abstract: A solid state switching regulator is disclosed whereby rectified line voltage, and current is converted by the switching action of On and Off switching elements to produce a regulated voltage output with short circuit protection. The switching element or elements are switched in a manner such that they are turned off and on when no current is passing through them, thus eliminating the switching losses and the energy consuming snubbing networks normally associated with switching regulator devices.

Abstract: A DC to DC power converter having reduced switching loss for operation at high frequencies. As disclosed, a buck, or forward, converter includes a first FET as the switching device in series with an inductor and a second FET as the flywheel device. At the common node to which the two FET's and the inductor are connected, there is sufficient capacitance that the FET's may be turned off without appreciable voltage change across the FET's. The value of the inductor is chosen, with respect to the input and output voltages and frequencies of operation involved, to insure that the inductor current polarity reverses each cycle, raising the node voltage to the level of the input voltage, substantially eliminating turn-on losses of the first FET. Control circuitry is provided for regulation of the power converter to control the peak-to-peak current in the inductor and to insure that at least a selected minimum value of the inductor current is present for each cycle of operation of the converter.

Abstract: A pulse generator for spark erosive machining of a conductive workpiece, including a d.c. voltage source, a switching element such as a switching transistor connected in circuit with an inductive coil and the work gap across the voltage source, and a high frequency transformer, where one winding of the transformer is connected in parallel with the voltage source and the other winding is connected in parallel to the series circuit consisting of the inductance coil and the work gap. When the switching element is turned on, a machining pulse is applied to the gap; when the switching is turned off, stored energy in the inductance coil is dissipated across the gap and, owing to the transformer connection, generates a recuperation current flowing into the voltage source. The switching element is preferably controlled on the basis of the magnitude of the current flow through the circuit.

Abstract: An electric discharge machining power source for a capacitor discharge circuit for use in an electric discharge machine having charging and discharging switching elements (Q1, Q2). A charging current limiting resistor is omitted to decrease energy loss and to prevent the charging switching element (Q1) from being damaged by a surge voltage. A diode (D) is arranged in parallel with a charging/discharging capacitor (C1). The diode (D), the charging switching element (Q1) and a power source smoothing capacitor (C2) are arranged on a printed circuit board to decrease the stray inductances and hence prevent generation of the surge voltage.

Abstract: A wire-cut, electric discharge machining power supply unit charges a capacitor (4) by a DC power source (2) via a switching element (1), and discharges the stored charges of the capacitor (4) between a workpiece (6) and a wire electrode (7) via another switching element (5). A single-polarity discharge current of a small pulse width is supplied between the wire electrode (7) and the workpiece (6). A series circuit of an impedance element (50, 80) other than a capacitance and a diode (51), is connected in a backward direction with respect to a capacitor charging voltage to effect recharging of the capacitor (4) with high efficiency.

Abstract: A circuit arragement for monitoring current in a switching converter, wherein an inductance is charged pulse-wise with a current via a power switch. In accordance with the invention, the mean value of the voltage drop across the inductance is formed via an RC-component and the power switch is blocked via a threshold value switch when a predetermined maximum voltage drop is exceeded across the inductance.

Abstract: A hybridized solenoid driver circuit includes a first and second current sensing resistor. The first current sensing resistor is disposed within the flyback current path of the windings of an electrically actuated solenoid and provides a signal proportional to the flyback current only. Control of the solenoid current is effected by operation of a power transistor to controllably connect and disconnect the solenoid from the power supply at a preselected duty cycle. Operation of the driver circuit in the energization mode has no effect on the first current sensing resistor. Conversely, the second current sensing resistor is disposed within the energization current path and provides a signal proportional to the energization current only. Operation of the driver circuit in the flyback mode has no effect on the second current sensing resistor.

Abstract: The invention relates to a changeover discharge circuit for an electronic switching circuit of the type having a semiconductor switching element in series with a DC source and an inductive load. Initiation of the discharge current of a discharge capacitor is delayed upon the switching on of the switching element until the substantial termination of the load current by a commutation choke coil and a recovery diode in shunt with the load.

Abstract: A voltage regulator for flyback-type high voltage supplies having a supplementary energy storage transformer with its secondary interconnected in series with the primary of the conventional flyback transformer, a control circuit for sensing (a) the generation of the conventional flyback pulse, (b) a reference voltage, and (c) a feedback voltage signal appearing at the output of the conventional flyback transformer and a switch for selectively applying energy to the primary of the supplemental energy storage transformer. The aforesaid switch being activated whenever the feedback voltage is less than the reference voltage and said switch being activated earlier in time as the aforesaid difference becomes greater.

Abstract: A switching voltage regulator achieves high efficiency by automatically switching between a pulse frequency modulation (PFM) mode and a pulse-width modulation (PWM) mode. Switching between the modes of voltage regulation is accomplished by monitoring the output voltage and the output current, wherein the regulator operates in PFM mode at small output currents and in PWM mode at moderate to large output currents. PFM mode maintains a constant output voltage by forcing the switching device to skip cycles when the output voltage exceeds its nominal value. In PWM mode, a PWM signal having a variable duty cycle controls the switching device. A constant output voltage is maintained by feedback circuitry which alters the duty cycle of the PWM signal according to fluctuations in the output voltage.