Abstract: A procedure and an apparatus for converting a first alternating voltage into a second alternating voltage with respect to frequency and amplitude by means of first (1) and second (2) bridges having switches (T.sub.1 . . . T.sub.12), and a resonant circuit (3) connected between the bridges. The invention also relates to the use of a frequency converter for the control of a motor. The voltages of a supplying network and the voltages of a load (M) are connected across the resonant circuit (3) in an alternating fashion by means of bridge switches (T.sub.1 . . . T.sub.6) and bridge switches (T.sub.7 . . . T.sub.12), respectively. The voltages are alternately connected across the resonant circuit for a period equal to respective half cycles of the characteristic frequency of the resulting resonant circuit formed. When power is supplied, a bridge change is effected after each period.

Abstract: A secondary flyback core reset (SFCR) scheme for single-ended forward DC-to-DC converters is disclosed. The transformer secondary magnetizing inductor and a parasitic reset capacitance of the output forward rectifier diode form a secondary flyback reset circuit. The magnetic flux built up through the primary winding when the main switch is turned on is reset through this secondary flyback reset circuit when the main switch is turned off. The secondary flyback reset circuit initiates a half resonant cycle and resets the transformer. With proper design of the reset time, the maximum duty cycle of the main switch can go beyond 50%, while still using the first and third quadrants of the core B-H loop characteristics for optimum use of the core power density, and reduced RMS switching current and rectifier blocking voltages and power switch blocking voltage.

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 controlled current source including feedback circuitry which eliminates the need for a current sensing resistor in series with the output voltage controlled current source. The feedback circuit includes circuitry for generating a reference current which is proportional to, but much smaller than, the output current produced by the current source, and current mirror circuitry for generating a sense current which is equivalent to the reference current. The sense current is provided to a current sense resistor, across which a feedback voltage is developed. The voltage controlled current source further includes an amplifier connected to receive an input control voltage and the feedback voltage for generating the output current in response to the input control voltage and the feedback voltage.

Abstract: This invention relates to a load driving circuit having a fail-safe breaking mechanism for breaking a primary power source when a failure occurs. This invention also relates to a load driving circuit capable of saving electricity in driving an inductive load and reducing a delay in stopping the load. The breaking mechanism for breaking the primary power source has no contact. The load driving circuit includes a power supply circuit involving a semiconductor switching element that turns ON and OFF the supply of power to the load. There is arranged a detector for detecting a failure in the semiconductor switching element. When detecting a failure, the detector provides an output signal to activate the breaking mechanism. To drive the inductive load, the power supply circuit may have two power supply sources. In response to a load driving instruction signal, the two power supply sources together apply a high voltage to the load.

Abstract: An inverter device is connected to output ends of a full-wave rectifier for full-wave recification of an AC input voltage from an AC power source, and includes an inductance component in a loop formed with a load circuit including an LC resonance series for charging a DC power-source capacitor through one of a pair of switching elements, whereby a high input power factor is maintained while reducing any distortion of input current, and a control of the switching elements which function to restrain any rush current can be simplified.

Abstract: A drive device for a push-pull stage includes a microcontroller in the form of a pulse-width modulator which, starting with a selected switching frequency, varies the pulse-duty ratio (modulation) of the pulse-width modulated output signal and which, with chronological delay, controls the push-pull stage. The push-pull stage has at least one upper and one lower power switch, and the microcontroller has three pulse-width modulation outputs. The actual pulse-width modulated output signal is delivered at the first output, the modulated signal plus a dead time is delivered at the second output and is supplied to the lower power switch as a drive signal, and the dead time by itself is delivered at the third output. The drive signal for the upper power switch is formed by the difference between the modulated signal and the inverted dead time is automatically decreased in the limit region of the modulation, i.e.

Abstract: A current mirror having at least one pnp-transistor and providing overvoltage protection has three collectors designed as partial collectors. Two of the partial collectors and the base are linked to a reference-current source and the other partial collector is linked to a terminal connection of the current source to be protected from overvoltage. In the event of an overvoltage across the terminal connection, an emitter is formed by the partial collector linked to this terminal connection which limits the received current in proportion, conditional upon the topology, with the mirror-reference current.

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: In an exemplary embodiment, a battery conditioning system monitors battery conditioning and includes a memory for storing data based thereon; for example, data may be stored representative of available battery capacity as measured during a deep discharge cycle. With a microprocessor monitoring battery operation of a portable unit, a measure of remaining battery capacity can be calculated and displayed. Where the microprocessor and battery conditioning system memory are permanently secured to the battery so as to receive operating power therefrom during storage and handling, the performance of a given battery in actual use can be accurately judged since the battery system can itself maintain a count of accumulated hours of use and other relevant parameters. In the case of a non-portable conditioning system, two-way communication may be established with a memory associated with the portable unit so that the portable unit can transmit to the conditioning system information concerning battery parameters (e.g.

Abstract: According to the present invention a bus voltage limiter is connected between a photovoltaic solar panel array and a load to limit the output voltage to a fixed dc reference voltage. The limiter includes a pulse width modulator which controls the duty cycle of a power switch from 0% to 100% to maintain a substantially constant output voltage V.sub.ref. A coupled inductor type boost DC to DC converter includes a pair of main windings which cooperate with the duty cycle modulated power switch to provide the output voltage. An auxiliary winding provides input ripple current cancellation in conjunction with a second inductor and a dc blocking capacitor.

Abstract: A switching method and apparatus for increasing the efficiency of an inductive motor. A switching device connects, according to a PWM process, a D.C. voltage (E) to an inductive motor creating a low-frequency contribution UmLF rising from 0V to the peak voltage at the beginning of each half period T/2. The peak voltage is maintained for at least one sixth of a period T/6 creating a plateau and, then, the switching device connects, according to the PWM process, the D.C. voltage (E) to the inductive motor for the remainder of the half period T/2 creating a low frequency contribution UmLF declining from the peak voltage to 0V. With this arrangement, motor vibration is reduced and efficiency is increased.

Abstract: A method and apparatus for reducing the effects of ground float upon electrical signal measurements in an electronic control system. The signals are measured with respect to a virtual ground rather than signal or chassis ground, where the virtual ground provides a regular and reliable signal level regardless of circuit electrical variances.

Abstract: The present invention is a concentric servo method and apparatus using two servo loops to control and stabilize the output of an electronic voltage regulator. An inner and outer servo loop are employed. The inner servo loop resembles the control loop of a conventional voltage regulator while the outer servo loop controls the sense threshold of the inner servo loop. The outer servo loop senses the voltage delivered to an external load resistance and controls the sense threshold of the inner servo loop to compensate for the voltage loss which may occur between the regulator output and the actual load resistance. The inner loop retains its high speed to regulate out any input voltage irregularities such as ripple and noise. The present invention gives better stability than conventional remote sensing voltage regulator circuits.

Abstract: The PSRR (power supply rejection ratio) of a current mirror circuit is increased by cascoding the output transistor of the current mirror, and the precision of the circuit is enhanced by employing a frequency compensated gain stage utilizing a field effect transistor to drive a bipolar current output transistor.

Abstract: A pulse width modulated system for driving an inductive load. In the system, a switched current is supplied to the load. A duty cycle of the switched current is derived from a pulse width modulation controller and the amplitude of the switched current is determined. A multiplier device is provided to process the amplitude of the current supplied to a driver stage and to derive, in conjunction with the duty cycle, the load current.

Abstract: A regulated DC voltage power supply including a plurality of power circuits connected in parallel, and a control circuit. Each of the power circuits includes a switching device that chops the input DC voltage, and the control circuit includes a detecting circuit, a control IC, and a timing adjusting circuit. The ripple components of the output voltage produced as the output of the parallely connected power circuits is less than the ripple components of individual power circuits. This makes it possible to realize a small, high efficiency regulated DC voltage power supply with low rated current semiconductor switching devices.

Abstract: In order to improve the operation of a dc transmission unit (GU) between a rectifier (R) and an inverter (I), an extinction angle signal (LS) of the inverter (I) is fed as reference variable to the rectifier regulator (RR). A current signal (ID) of the dc transmission unit (GU) is preferably fed to an inverter regulator (IR) of the inverter (I) as input variable. In addition, the current signal (ID) can be fed as input variable to the rectifier regulator (RR) for the start-up and/or in the event of a malfunction. Another solution consists of a circuit arrangement (S1, S2, S3) for the carrying out of the method.

Abstract: A correction circuit (12) for providing an error correction voltage for a voltage reference (11). The voltage reference (11) provides a reference voltage within a predetermined temperature range. The voltage reference prior to correction has a peak magnitude at a temperature T.sub.0 within the predetermined temperature range. A first circuit (13) generates a correction current. Zero current is provided by the first circuit (13) at T.sub.0. A second circuit (14) receives the correction current and provides an output current that is uni-directional or of the same sense above and below T.sub.0. [Means responsive to t] The output current of the second circuit (14) generates a voltage across a resistor (28) that is [combined] added to the reference voltage above and below T.sub.0.

Abstract: A filter short circuit is detected when the primary voltage of the high-voltage transformer drops below a specified minimum value and does not rise above the specified minimum value during a specified delay period and a filter current is greater than a specified minimum current. No current is drawn from the external current supply for a variable time delay when a filter short circuit is detected. A filter short circuit count is incremented when a filter short circuit is detected. When the count exceeds a specified, variable limit within a specified, variable time span, the indirect converter is disconnected.