Abstract: A precision voltage regulator is provided for a capacitor-charging power supply. Both the power supply output and the load capacitor are shunted at the same time by a shunt control circuit. The load capacitor shunt is maintained for a period of time determined by the hysteresis of a precision comparator that compares the voltage across the capacitor with a program voltage that has been adjusted for the power supply's instantaneous current. The regulator is particularly applicable to high power applications with a high repetition rates.

Abstract: A controller for a solar electric generator that permits the generator to produce power substantially at its maximum capacity. Power is transferred from the generator to a temporary electric storage device that is periodically partially drained of power to maintain the temporary electric storage device at a voltage corresponding to the voltage needed by the generator to provide maximum generator power. The electric power drained from the temporary storage device is used to charge conventional batteries. In a preferred embodiment, the temporary storage device is a capacitor that is part of a buck regulator operating at 50 kHz with duty factor control between 0% and 100%. This buck topology switching type regulator provides the periodic draining. In the preferred embodiment control of the duty factor of the buck regulator is utilized to limit current, to prevent battery over charging, to test for the voltage corresponding to maximum power, and to operate the solar generator at is maximum power voltage.

Abstract: A load emulator provides a high current load having a specified high slew rate to replicate the load and transient currents generated by advanced high speed microprocessors. The load emulator is implemented in the form of an L-C delay line having taps between separate load stages wherein each of the load stages provides a load which forms a portion of the total load in the load emulator. The load emulator, can achieve and exceed a current slew rate of 1 ampere per nanosecond, and can achieve and exceed a load current of 50 amperes.

Abstract: A programmable controller for switch-mode power converters that operates in a digital domain without reliance on operation software and the ability to vastly reduce or eliminate analog circuitry. The digital controller is re-programmable. In one embodiment, the substantially digital portion of the controller is a Field Programmable Gate Array that controls operation of the converter by generally converting an analog reference signal(s) (e.g. the voltage output) into the digital domain. The controller then can perform distributed arithmetic to generate a square wave signal capable of controlling at least a main switch of the converter. The present invention can, if desired, essentially eliminate analog controllers in power conversion systems such as switch-mode converters.

Abstract: A single-fault tolerant DC-to-DC converter having an output voltage clamp is capable of sourcing current to and sinking current from a load while maintaining a well regulated secondary bus voltage V.sub.bus. The clamp is disabled when the DC-to-DC converter is sourcing current so that all of the current is delivered to the load and is enabled when V.sub.bus exceeds a clamp set point voltage V.sub.clamp to sink the excess current and clamp V.sub.bus at V.sub.clamp. To provide single fault tolerance, the clamp includes a fault detection clamp element that is controlled by the DC-to-DC converter so that they operate mutually exclusively and a regulator clamp element whose resistance is set in a negative feedback control loop so that, when the fault protection clamp element is activated, both clamp elements sink the excess current and control the secondary bus voltage.

Abstract: A voltage regulator for regulating a power source that supplies an input signal includes input terminals connected across the power supply, a voltage sensor, a reference generator, a variable load unit, and a control unit. The voltage sensor is connected across the input terminals and receives the input signal and generates a scaled input signal from the input signal that is a fraction of the input signal in magnitude. The reference generator receives the scaled input signal from the voltage sensor and generates a reference signal. The variable load unit is connected across the input terminals. The control unit receives and compares the scaled input signal and the reference signal and instructs the variable load unit to dissipate a first portion of the input signal if the scaled input signal exceeds the reference signal.

Abstract: Magnetic-free DC/DC converters, methods of operation thereof and a computer system employing at least one converter. In one embodiment, the converter includes: (1) an input capacitor coupled to a DC input of the converter, (2) a first switch coupled between the input capacitor and an output of the converter to transfer electrical power from the DC input to the output when the first switch is closed, (3) an output capacitor coupled in parallel with the output of the converter, (4) a second switch coupled in parallel with the input capacitor to short the input capacitor when the second switch is closed and (5) a switching controller circuit, coupled to the first and second switches, that provides complementary control signals to the first and second switches that are a function of an output voltage of the converter.

Abstract: A power factor correction device of a rectifier bridge supplied by an a.c. voltage for providing, by means of at least two capacitors, a rectified d.c. supply, comprises between two rectified supply lines a charge path of each capacitor; a switchable discharge path of each respective capacitor; a first control block for closing a first discharge path associated to a first capacitor only after the a.c. supply voltage crosses a maximum value; and a second control block for closing a second discharge path associated to a second capacitor at the expiry of a predetermined delay following the closing of the previous discharge path.

Abstract: A synchronization device for a redundant power supply system synchronizes resetting of tripping type current limiter devices which are reset automatically, to prevent the current limiters tripping out in cascade when the system is started up or automatically reset after the disappearance of a short-term current surge. It includes a synchronization link interconnecting all the current limiters of all the power supply units. Each current limiter includes a generator sending a synchronization signal on the synchronization link periodically and independently for each current limiter. The generator which sends a synchronization signal first resets all the current limiters simultaneously. The device has applications in electronic equipment comprising a plurality of power supply units connected in parallel.

Abstract: A circuit that involves the application of boost mode regulator techniques is used to regulate the output of an a.c. source. The source inductance becomes part of the boost mode circuit, thus avoiding the losses associated with the addition of external inductors. When a three-phase alternator is the power source, the circuit comprises a six diode, three-phase rectifier bridge, three FET transistors and a decoupling capacitor. The invention involves shorting the output of the power source to allow storage of energy within the source inductance. During this time, the decoupling capacitor supports the load. When the short is removed, the energy stored in the inductances is delivered to the load. Because the circuit uses the integral magnetics of the source to provide the step-up function, the efficiency of the design can be quite high.

Abstract: The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a preferred embodiment is also disclosed herein. The preferred circuitry of this aspect of the invention uses four solid state switches, such as IGBT's, four diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input.

Abstract: Instabilities in the output voltage provided from an AC power supply system such as an uninterruptible power supply connected to a power factor correcting load are suppressed by a dynamic voltage regulation stabilizer system which is connected across the output lines from the power supply system to the load. The DVR stabilizer system includes a rectifier connected to the power supply system output lines. A capacitor is connected across the output nodes of the rectifier. Switching devices form a bridge that connects the capacitor to the output lines. Selected switching devices in the bridge are turned on for a selected duration encompassing the time of the peak of each half-cycle of the AC voltage waveform provided by the power supply system. During normal operation, where the peak AC voltage from the power supply system is substantially constant, the capacitor charges up through the rectifier to a voltage level near the peak value of the AC voltage waveform.

Abstract: A battery load leveling arrangement for an electrically powered system in which battery loading is subject to intermittent high current loading utilizes a passive energy storage device and a diode connected in series with the storage device to conduct current from the storage device to the load when current demand forces a drop in battery voltage. A current limiting circuit is connected in parallel with the diode for recharging the passive energy storage device. The current limiting circuit functions to limit the average magnitude of recharge current supplied to the storage device. Various forms of current limiting circuits are disclosed, including a PTC resistor coupled in parallel with a fixed resistor. The current limit circuit may also include an SCR for switching regenerative braking current to the device when the system is connected to power an electric motor.

Abstract: A shunting regulator which is configured to act as a switch. The regulator includes an enabling input which can be used to turn it on and off when the switch is desired to be closed and opened. Preferably, the regulator includes a switching transistor connected to the enabling input which activates a drive transistor circuit. A current mirror is connected to the regulator output and provides current to both the drive circuit and a differential amplifier used for error correction. The two transistors of the differential amplifier are connected to first and second resistor divider circuits to provide the appropriate reference voltages. The invention thus provides what is essentially an adaptive current drive with a high dynamic range.

Abstract: This invention relates to a push-pull inverter used, for example, as a driver for cold-cathode discharge tube, hot-cathode discharge tube, etc. and comprises a boosting transformer including an input coil, an output coil and a feedback coil, and first and second switching elements for input coil current of this transformer, wherein the output of the boosting transformer is divided into a pair of output coil sections connected in series with each other and a conductor section lying between these output coil sections is circuit-arranged so that this conductor section be at the negative potential of the DC source.

Abstract: An electrical power energy savings circuit for use with 220 volt ac power delivery systems for reducing the power drain of the power delivery system during the "off phase" for each of the 110 volt legs of the ac power supply circuit, as measured across the load.

Abstract: A voltage regulator circuit having one input to receive a voltage to be limited, this input being connected to a ground by means of a limiting transistor. To control this transistor, a comparator and a dissymetrical differential stage are used. The differential stage receives the voltage to be limited and a reference voltage produced by means of a Zener diode, and supplies the comparator with voltages lower than those that it receives. The output of the comparator is connected to the control gate of the limiting transistor. This regulator circuit can advantageously be used to regulate a voltage produced by a voltage multiplier within an electrically programmable memory.

Abstract: A device for supplying a power supply voltage to an electronic circuit, in particular to an electronic circuit associated with a current sensor for measuring the electrical current in a high-tension line, comprises a current transformer having a primary circuit and a secondary circuit, a rectifier bridge shunting the secondary circuit and output terminals of the rectifier bridge, a first capacitor in parallel with a first resistor across which said power supply voltage is obtained, and a first switch disposed between the output terminals of the rectifier bridge. It includes between the output terminals of the rectifier bridge a branch comprising in series a second capacitor, a second switch and a second resistor. The first switch is controlled by a first threshold detector shunting the second capacitor. The second switch is controlled by a second threshold detector shunting the first capacitor.

Abstract: A downhole power supply system having a variable voltage surface power supply and a downhole shunt voltage regulator between which is disposed in series an energy transducing device. The shunt voltage regulator comprises a current control device which controls the amount of current shunted to the power return line between the series connected energy transducing device and the input to the voltage regulator to maintain a selected voltage at the voltage regulator. The shunt regulator senses the voltage on the power line, compares the sensed voltage to the selected voltage, and controls the shunt current control device to conduct more or less current in the event that the two voltages are not equal. As a result, changing the voltage at the remote power source will change the voltage across the transducing device and the amount of current conducted through it thus changing its output.

Abstract: A first current mirror circuit for driving a first output stage transistor to flow out current to a coil in a motor is disposed between a power source voltage line and a reference voltage line, and a second current mirror circuit for driving a second output stage transistor to receive a current flowing out from the coil of the motor is disposed between a reference voltage line and a ground line.

Abstract: A voltage regulator (11) having an input (12) for receiving an input current and an output (13) for providing a regulated voltage. The voltage regulator (11) comprising a diode (14), a capacitor (16), a first comparator (17), a second comparator (18), a logic circuit (19), and a switch circuit (21). The capacitor (16) is charged by the input current coupled through the diode (14). The first comparator (17) senses when the voltage on the capacitor (16) exceeds a first reference voltage and provides a signal to the logic circuit (19). The logic circuit (19) enables the switch circuit (21) for shunting the input current from charging the capacitor (19). The second comparator (18) senses when the voltage on the capacitor (16) falls below a second reference voltage and provides a signal to the logic circuit (19). The logic circuit (19) disables the switch circuit (21) from shunting the input current thereby charging the capacitor (19).

Abstract: A voltage regulator (200) includes a controller (204) which selectively activates a plurality of switching means (208, 210, 214, and 212) in order to select between a first current loop in which an energy storage device is charged by an input supply and a second loop in which the energy storage device is coupled to the output terminal (242) of the regulator (200). The switching from the second current loop to the first is governed by the controller (204) determining that the loop current in the second loop has reached a predetermined level. A first switching audio amplifier (300) is disclosed which uses the voltage regulator (200) to provide a continuously variable output voltage (318) in order to provide for high quality amplification which is independent of the volume setting. A second audio amplifier (400) includes a converter (436) which provides discrete voltage levels to a full wave bridge in order to provide improved audio output.

Abstract: A digitally controlled switchmode power supply by the use of a pulse width modulated (PWM) controlled field effect transistor, switches an inductor between input and output sides to provide a controllable DC output voltage. The digital processor receives and digitizes the input and output voltages and also the current through the associated inductor and derives a PWM control loop signal driving the associated field effect switching device to switch the inductor. The foregoing compensates for nonlinear changes in the value of the inductance due to changes in inductor currents and also avoids resonance at pole points of the LC circuit in the power supply. In addition a change in buck to boost modes may be accomplished automatically depending on input voltage operating conditions.

Abstract: Power saving circuitry is provided for use with fluorescent lights, inductive loads and resistive loads. The circuitry comprises a power circuit connectable to an alternating circuit power supply and a control circuit. The power circuit includes a bilateral switch, and the control circuit includes means for timing the operation of the bilateral switch so that the switch conducts current for a predetermined time during each half-cycle of the power supply which terminates at a predetermined interval before the end of each half cycle. A preferred embodiment of the power saving circuitry, adapted for use with fluorescent lights or inductive loads such as electrical motors, also comprises a Back-EMF suppressor circuit. The bilateral switches are preferably made up of one or more unilateral switch devices such as field effect transistors. The subject circuitry reduces power consumption while at the same time providing for a power factor correction.

Abstract: A rectifier-capacitor power supply has source terminals across which is connected the series combination of a voltage dropping resistor and a transistor circuit comprising (a) an NPN resistor connected in a common emitter configuration and having its collector connected by a load resistor to the voltage dropping resistor, and (b) a PNP transistor connected in a common collector configuration across the series combination of the NPN transistor and its load transistor. A pair of output terminals for a load are connected to opposite ends of that last named series combination. Also connected between those opposite ends is a voltage divider circuit consisting of two resistors in series and having a junction directly connected to the base of the NPN transistor.

Abstract: A switching power supply contains a transformer. Connected on the secondary side of the transformer is a dummy load circuit. The dummy load circuit rectifies, voltage divides and low-pass filters the signal on the secondary side of the transformer. If the output of the low-pass filter is below a predetermined value, it is recognized that an insufficient load (which might be no load at all) is connected to the output of the switching power supply. In that case, the dummy load circuit activates a transistor which switches a dummy load resistor across the output of the power supply to assure at least a predetermined minimum electrical load on the output. If the electrical loads on the output of the switching power supply include a voltage source such as a battery, a relay is connected in series with the dummy load resistor within the switching power supply.

Abstract: A boosting circuit generates an internal high voltage of a level higher than that of an internal voltage which is used in a semiconductor memory device. The boosting circuit has an output end connected to a capacitor having a large capacitance, and this capacitor is charged to an internal high voltage. The output end of the boosting circuit is connected to a drain of an N-channel transistor. This transistor has a gate which is supplied with a voltage V.sub.G higher than the internal voltage by a difference equivalent to a threshold voltage of the transistor. The internal voltage is outputted from a source of the transistor. When a skew occurs and the internal voltage is lowered while an address signal is changed, the internal high voltage charged in the capacitor is discharged through the transistor and the internal voltage is thus stabilized.

Abstract: A dimmer control system includes two discrete silicon controlled rectifiers which respectively energize a lamp load during alternate half cycles of the input AC voltage. The separate placement of the SCRs ensures that much lower temperatures are reached than would occur if a single triac were used to energize a lamp during both half cycles. The system also includes a pair of diacs which energize the respective SCRs when a respective capacitor directly connected to each diac discharges through one of them. The system further includes a respective capacitor charging circuit for each capacitor, each of the two charge circuits including a series connections of the gate to cathode junction of the SCR other than the one which the capacitor being charged discharges through, a diode, a common fixed resistor, and a common variable resistor.

Abstract: A shunt regulator for isolating a power supply and load is described which automatically adjusts the quiescent current though the shunt, and therefore its available dynamic range, in proportion to the load current fluctuations. A signal proportional to the load current fluctuations is differentiated, detected, integrated and fed back to control the bias on the shunt. When large load current fluctuations occur, the operating point of the shunt is shifted to higher current values so as to provide a large dynamic regulation range. When load current fluctuations are small or zero, the operating point of the shunt is moved toward cut-off, thereby reducing the dynamic range of the shunt and conserving power. This substantially reduces the power dissipation in the regulator because the shunt need not be constantly biased to handle the largest anticipated load current fluctuation.

Abstract: Disclosed is an integrated circuit which comprises: a constant voltage circuit including a reference voltage generator, a feedback amplifier, a differential amplifier having an input for receiving an output signal of the reference voltage generator as a reference signal and another input for receiving an output of the feedback amplifier as a negative feedback signal, and a monochannel output driver driven in accordance with an output of the differential amplifier; a circuit load connected to an output of the constant voltage circuit; and an MOS transistor connected in parallel to the circuit load and arranged so as to be driven when a heavy load is periodically driven.

Abstract: An integrable shunt regulator includes two connection terminals to be connected between poles of a supply voltage source. A controllable semiconductor component has a control input and a load path connected to the two connection terminals. A differential amplifier has first and second inputs and an output connected to the control input of the controllable semiconductor component. First and second transistors have emitter terminals and interconnected base and collector terminals connected to one of the connection terminals. A first resistor is provided. The emitter terminal of the first transistor is connected to the first input of the differential amplifier and is connected through the first resistor to the other of the connection terminals. A series circuit of second and third resistors has a connection node connected to the second input of the differential amplifier.

Abstract: An arrangement is provided for accurately sensing the source voltage of a high-impedance source while supplying a variable burden. A current-sensing element is connected in series with a load circuit across a high-impedance source. The load circuit includes a variable burden load. A shunt regulator is connected with the variable burden load and is arranged to operate so that the combination of the shunt regulator and the variable burden present a controlled, nearly constant burden to the high-impedance source. The source voltage of the high-impedance source is sensed via the voltage across the series current-sensing element. While the output voltage is directly proportional to the burden, the output current is essentially unaffected by small variations in the burden.

Abstract: A superconductive voltage stabilizer employs an improved current switch. The improved current switch controls the release of current stored in an energy storage device or superconducting inductive energy storage coil for selective delivery of the current to a load or an electric utility system. A transformer employed in the current switch provides isolation of the energy storage components from the load, thereby making a local ground possible. The amount of energy which can be recovered from the energy storage device is also increased.

Abstract: A variable-frequency pulse-width-modulated D-C to D-C converter allows operation at very high frequencies with minimal power transistor switch transient turn-on losses. A frequency control scheme is utilized wherein the controller of the converter causes switching to occur when the voltage across the power transistor switch is near zero volts. In addition to reducing transient turn-on losses, zero-voltage switching reduces noise generation in the circuit and simplifies the power transistor drive requirements.Other characteristics of opimal power transistor switch utilization are met in addition to turning the switch on under a zero potential. Maximum peak voltage across the switch is limited to approximately the ouput or input voltage level depending on the configuration used. In addition, peak and average currents through the switch are proportional to output power requirements and turn off transient dissipation is held to a minimum.

Abstract: A series of Zener diodes (25) and an electronic power switch, such as an IGBT (18), are connected across a power supply. A circuit including a resistor (20) in series on the electronic switch, a threshold device (36, 38) connected to the resistor and a ramp generator with multiplier (40, 42, 44, 46, FIG. 2) or a thermal sensor (50, 44, 46 FIG. 3) detect the energy level dissipated in the electronic power switch when a transient occurs when the level exceeds a present value, the circuit supplies an output signal to a monostable circuit (26, 28, 48) to drive the electronic power switch with low resistance conditions for a preset time starting from the occurrence of the output signal. Another threshold device, connected to a resistor (30, 32), preferably senses the instantaneous power dissipated in the electronic switch to control the monostable circuit when the instantaneous power is higher than a preset threshold.

Abstract: A shunt regulator for the programming voltage of programmable circuit devices employs components formed of the same layers that make up the regulated devices, including the same tunnel structure (52) of floating gate devices that are being regulated. A transistor (66) connected as a load on the programming voltage line (10) is itself controlled by tunneling structure (52) and capacitors (18, 20) formed by layers corresponding to layers of the regulated devices so that variations in the regulator components will track variations of the regulated components to automatically compensate for manufacturing process variations.

Abstract: After an AC voltage was rectified and smoothed, it is stepped up by a chopper circuit. Another winding is magnetically coupled to a choke coil of the chopper circuit so as to have the same polarity. An inductance for adjusting a current is connected serially with another winding. A current of a phase opposite to a phase of a current flowing in the choke coil is generated in another winding, thereby setting off a ripple current flowing in an input smoothing capacitor.

Abstract: A regulator is provided for receiving electrical power from an external alternating magnetic field and developing a regulated output voltage. The regulator is operatively coupled to a resonant inductive circuit for obtaining input power. It includes a circuit for regulating output power by shunting input power and providing separate current paths for shunt current and output current. The circuit includes a rectifier in the output current path. The regulator is integrated on a single VLSI chip.

Abstract: A DC-DC converter regulates the maximum current through an inductor. The DC-DC converter operates within a paging receiver and boosts a voltage from a single cell battery to substantially 3.1 VDC in order to operate circuits which require more voltage than that produced by the single cell battery. Such circuits include CMOS microcomputers and code plug. The DC-DC converter is current regulated thus providing for improved power conversion efficiency. The DC-DC converter is active when the voltage is below a minimum voltage and inactive when above a maximum voltage. The DC-DC converter provides for a wide range of load currents from the converted voltage without being controlled by a microcomputer and while delivering the power to the loads with an improved efficiency.

Abstract: A telephone device, typically a terminal, that receives a.c. communication signals and that sinks d.c. current to provide the off-hook signal is powered from (i) the telephone lines and, if line voltage is less than 7.4 v.d.c., from (ii) a 6 v.d.c. battery. Connection to telephone lines of voltage greater than 7.4 v.d.c. recharges the battery. The terminal further contains a CMOS microprocessor that may be declocked and placed in standby mode to conserve power. When so placed, the microprocessor maintains some of its signal lines at a logic High, 6 v.d.c., condition. In order to both unpower circuits such as a display, a memory, a DTMF dialer, and a modem to which the microprocessor signal lines connect, and to (ii) disrupt current leakage paths from the signal lines to ground through the unpowered circuits, the ground is removed from the circuits. This removal, controlled by a signal from the standby microprocessor, is performed by a transistor switch.

Abstract: Voltage drop developed across a transformer primary winding coupled in series with a primary a.c. power circuit including an a.c. power source and an a.c. load is utilized to provide a secondary source of a.c. power having secondary voltage level stability which is substantially independent from otherwise influential changes in primary power circuit levels. Secondary power stabilization is mainly established by constant voltage limiting of the primary winding excitation by the forward voltage drop developed across an arrangement of semiconductor junctions coupled in parallel with the primary winding. The transformer may be used to change the source level of the secondary a.c. power which is produced, and to obtain electrical isolation between the primary power circuit and any ancillary circuits coupled with the secondary a.c. power source.

Abstract: A power controller is provided for controlling the average power provided from an AC voltage source power supply to an AC electrical load. Three shunt connected elements, comprising two electronic switches and a capacitor with rectifying diodes, are connected betwen the AC source and the load. A control circuit controls switching of the switches in timed relationship to the state of the voltage on the shunt capacitors so as to control the average power supply to the load. The control circuit switches one of the electrical switches to the conductive state thereof near the zero crossover of the AC wave of the source voltage and subsequently switches the second switch to the conducting state thereof at a variable time during each half wave in a manner that causes the first switch to return to the non-conducting state thereof.

Abstract: A regulator circuit for use with a connectorless power supply system in which power is inductively supplied to a plurality of remote loads. A sinusoidal current, at a frequency of 38 kHz, is provided by a power distribution system (10), and circulates through a supply loop (68), which is disposed under the floor of an aircraft cabin. Three parallel connected capacitors (78, 80, and 82) and a multi-turn coil (70) that is inductively coupled to the supply loop comprise a resonant tank circuit in which current circulates. The voltage developed across the tank circuit is half wave rectified, filtered, and supplied to a load connected circuit. An op-amp (134) compares the potential across the load to a regulated voltage. The output of the op-amp is used to control the period of time during which an N channel FET (96) shunts current to regulate the output voltage.

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 highly accurate current-limiting circuit prevents an output current (I.sub.OUT) flowing through an output line (L.sub.OUT) from exceeding a specified value (I.sub.LIM) of an input current (I.sub.IN) flowing through an input line (L.sub.IN). The circuit contains a first channel device (10) controlled by a first reference voltage (V.sub.REF1), a current source (12) that supplies a reference current (I.sub.REF), a second channel device (14) controlled by a second reference voltage (V.sub.REF2), a current bypass device (16), and a bypass control system (18). The current gain below the specified value of the input current is close to one. By suitably choosing certain of the circuit parameters, the circuit operates in a substantially temperature-independent manner.

Abstract: A control device for energization of a load employs a bidirection triggerable solid state switching device connected in series with an alternating current power source and the load. In order to prevent the passage of excessive, potentially destructive currents through the switch if the load is shorted out, the microprocessor which controls the energization of the switch senses the time required for the voltage across the switch to attain a predetermined value. If the load is shorted the potential difference across the switch increases and attains the predetermined value a shorter time after zero-crossing of the alternating current. When this occurs more than a predetermined number of consecutive times, the generation of triggering pulses for the solid state switch is inhibited for a predetermined time. In the preferred embodiment the control device is a thermostat for controlling a temperature modifying load such as a furnace or air conditioner.

Abstract: A voltage regulator for an anode voltage supply in a CRT powered by a deflection flyback pulse generator includes a voltage sensing network for providing a feedback signal to a summing amplifier. A pulse sensing network which may be a capacitive divider is connected between the output of the flyback pulse generator and the input to the summing amplifier. The resultant output of the summing amplifier is the flyback pulse level shifted with respect to a DC level which is applied to a MOSFET switch to turn it on whenever the flyback pulse goes above the MOSFET's threshold. The output of the MOSFET switches current through a shunt capacitor coupled to the output of the deflection flyback pulse generator for altering its capacitance thereby regulating the height of the flyback pulses, and thus regulating the anode voltage supply.

Abstract: An electronic endoscope apparatus comprises an endoscope and a video processor unit. The video processor unit includes a drive pulse generator for generating vertical drive pulses, a power supply for generating a +16 V power supply voltage, and a video processor for sampling and holding an input image signal. The endoscope includes an insertion portion which incorporates a solid-state image sensing element using a CCD at its distal end portion, a manipulator portion, and a universal cord for connecting an electronic endoscope body to the video processor unit. An integrated circuit unit is incorporated near the solid-state image sensing element at the distal end portion of insertion portion.

Abstract: A device for driving an electro-luminescence in which an electrical power source, a coil and a switching means are connected in series to each other. The switching means is time-serially opened and closed by a control unit, and is connected in parallel to the electro-luminescence.

Abstract: An integrated circuit includes an interface circuit for coupling with a relative high-level VOICE circuit and a relatively low-level DIALER circuit to a subscriber line. A first shunt transistor is coupled across the telephone line and has its collector current forced by a current sink driven from the VOICE circuit. A second shunt transistor is coupled in a current mirror configuration to the first shunt transistor and supplies current to the DIALER circuitry. The interface circuit includes a saturation prevention circuit coupled to the current sink and to the second shunt transistor for sensing a tendency of the second shunt transistor toward saturation and for increasing the collector current load on that transistor in response. The saturation prevention circuit includes a voltage offset element and a sensing transistor arranged to form a loop with the collector-to-base junction of the second shunt transistor.