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Showing papers on "Forward converter published in 1975"


Patent
Herko Joseph M1, James Maurice Joyce1
20 Oct 1975
TL;DR: In this paper, an improved pulse width modulated (PWM) voltage regulator-converter system is presented, which can function alone as a switched voltage regulator system or in combination with a switched power converter.
Abstract: Disclosed herein is an improved pulse width modulated (PWM) voltage regulator-converter system which can function, alone, as a switched voltage regulator system or in combination with a switched power converter, synchronized therewith to form an improved voltage regulator-converter/power converter system. In the pulse width modulated voltage regulator-converter embodiment of the invention, secondary windings of a "current mode" regulator-converter interstage transformer are coupled to regulator-converter power transistors in a push-push circuit configuration. Signals generated by a system clock means and an error signal, derived from the output of an averaging filter, drive a pulse width modulated control means connected to the primary windings of the regulator-converter interstage transformer to thereby increase the maximum regulated output voltage of the voltage regulator-converter system after conditioning in the averaging filter. In the pulse width modulated voltage regulator-converter/power converter embodiment of the invention, the aforementioned output voltage of the voltage regulator-converter system is coupled directly to a switched power converter connected in a push-pull circuit configuration. In turn, additional signals generated by the system clock means switch the power converter in synchronizm with the voltage regulator-converter system.

54 citations


Patent
09 Jun 1975
TL;DR: In this paper, a multiple output DC-to-DC converter is described, where the DC input power is filtered and passed through a chopper preregulator, and the output is then passed through the current source inverter controlled by a squarewave generator.
Abstract: Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

39 citations


Patent
29 May 1975
TL;DR: In this article, a regulated voltage converter utilizing an improved method of pulse width modulation is disclosed, where acceptable current balance and limiting in the converter switching elements are speedily achieved within one half cycle of converter operation.
Abstract: A regulated voltage converter utilizing an improved method of pulse width modulation is disclosed wherein acceptable current balance and limiting in the converter switching elements are speedily achieved within one half cycle of converter operation. Converter output current is monitored, shaped according to a non-linear transfer function, and integrated to form a voltage signal for comparison with a predetermined reference level. When the integrated signal exceeds the reference level, a control signal is generated to terminate the current pulse in the inverter section of the converter. The inherent balancing and limiting characteristics of this arrangement are easily extended to applications wherein multiple converter stages are paralleled to supply higher power to a common load.

35 citations


Proceedings ArticleDOI
09 Jun 1975
TL;DR: In this article, a nonlinear, discrete-time system is derived that models the converter exactly, and the system is linearized about its steady state solution, and converter stability, transient response and audio susceptibility are studied.
Abstract: Using state variable representation a nonlinear, discrete-time system is derived that models the converter exactly. This system is linearized about its steady state solution, and converter stability, transient response and audio susceptibility are studied. The steady state solution of the converter is stable if and only if all the roots of the linearized system are absolutely less than unity. Excellent agreement with laboratory test data has been observed.

31 citations


Patent
17 Nov 1975
TL;DR: In this article, a DC to DC converter with voltage regulator for converting a low level voltage source to a higher level DC, comprising an oscillator circuit with a low resistance starting current path, a rectifier circuit for rectifying the oscillator output, and a regulator for providing a regulated DC output voltage of predetermined level.
Abstract: A DC to DC converter with voltage regulator for converting a low level voltage source to a higher level DC, comprising an oscillator circuit with a low resistance starting current path, a rectifier circuit for rectifying the oscillator output, and a regulator for providing a regulated DC output voltage of predetermined level. The oscillator embodies one or more FET devices connected to provide an extremely low DC startup resistance as well as a low cutoff voltage characteristic. With this configuration, the low startup current from the voltage source can initiate switching so that oscillation can occur.

20 citations


Patent
11 Feb 1975
TL;DR: In this paper, a power converter for operation with a d.c. power supply to provide an output voltage having a level controlled in response to an external control signal is presented. And the converter uses a dual chopper configuraton with the out of phase outputs from the respective chopper halves being combined in an interphase transformer.
Abstract: A power converter for operation with a d.c. power supply to provide an output voltage having a level controlled in response to an external control signal. The converter uses a dual chopper configuraton with the out of phase outputs from the respective chopper halves being combined in an interphase transformer. To prevent the interphase transformer from saturating, the chopper control includes an oscillator, counter, D/A converter and phase delay comparator arrangement for maintaining substantially identical duty cycles in the respective legs while, of course, allowing the duty cycles to be varied in unison. The interphase transformer is wound in a configuration which presents a magnetic shunt between the halves of the transformer, said shunt serving to limit transients which might be coupled to the chopper load.

16 citations


Patent
Kurt Franke1
20 Oct 1975
TL;DR: In this paper, a transportable X-ray diagnostic generator is described, in which the primary windings of the high-voltage transformer and the filament transformer are connected to a DC/AC converter or inverted converter.
Abstract: A transportable X-ray diagnostic generator, in effect an X-ray diagnostic generator which can be transported without an interfering cable after charging of the condenser and in which the weight is maintained as low as possible. For the charging of the high-voltage condenser and for the supply of the filament transformer, a DC/AC converter or inverted converter is connected to the primary windings of the high-voltage transformer and to the filament transformer, and which has a storage cell connected ahead or at the input thereof.

13 citations


Patent
02 Oct 1975
TL;DR: In this paper, a single-ended transformer circuit with a single switch transistor at the input and a rectifier at the output is used to convert a DC-to-DC power converter.
Abstract: A pulse width modulated DC-to-DC power converter wherein a single ended transformer circuit includes a single switch transistor at the input and a rectifier at the output. A control circuit to the switch transistor base is powered by a drive winding on the transformer which is shunted by the primary winding of a saturable reactor. A regenerative winding opposing, and in series with, the drive winding provides the regenerative drive necessary to support oscillation of the circuit at a frequency determined by the saturation period of the saturable reactor. A resistor between the drive winding and the saturable reactor establishes both the magnitude of the drive current and the magnetizing current of the transformer. Pulse width modulation of the DC output is attained by a single, isolated DC voltage at the secondary of the saturable reactor. Supplemental circuitry provides for regulation of the isolated DC voltage to produce a constant output voltage and for protection of the switch transistor against overloads.

13 citations


Proceedings ArticleDOI
J. La Duca1, R. P. Massey1
09 Jun 1975
TL;DR: In this article, three basic single-ended converter configurations are compared analytically and experimentally, and the ringing-coil converter is recommended for low power, high voltage, single output applications where low cost is essential.
Abstract: Three basic single-ended converter configurations are compared analytically and experimentally. The ringing-coil converter is recommended for low-power, high voltage, single output applications where low cost is essential. The single-ended half-wave transformer-coupled converter is recommended where the maximum output power is being squeezed for a given switching transistor power handling capability. The single-ended full-wave converter is recommended for applications with tight regulation, size, ripple and trouble voltage requirements.

10 citations


Patent
19 Feb 1975
TL;DR: In this article, the output of the secondary winding is rectified and filtered to provide the converter output, and voltage regulation is accomplished by controlling the one-shot multivibrator.
Abstract: Various types of static DC to DC converters are known. Some of these have output rectifiers including phase controlled SCRs. The present invention eliminates the need for controlled output SCRs by pulse width modulation of switching elements in a control circuit controlling the converter circuitry itself. This results in the elimination of some switching devices, higher reliability and higher-efficiency, A unijunction oscillator drives a one-shot multivibrator and a flip flop. The unijunction oscillator, one-shot multivibrator and flip flop feed two AND gates which are alternately enabled to allow pulses of current to flow from a DC source through opposite halves of a primary winding of a transformer. The output of the secondary winding is rectified and filtered to provide the converter output. Voltage regulation is accomplished by controlling the one-shot multivibrator. In one embodiment, paralleling of a number of converters is enabled by providing for frequency and pulse width synchronization.

10 citations


Patent
02 May 1975
TL;DR: In this article, a liquid crystal display cell driving circuit adapted to apply a stabilized DC drive voltage having a temperature characteristic corresponding to the temperature characteristic of the display cell is provided, and a power source includes a DC converter coupled to the display cells for applying a DC-drive voltage.
Abstract: A liquid crystal display cell driving circuit adapted to apply a stabilized DC drive voltage having a temperature characteristic corresponding to the temperature characteristic of the display cell is provided. A power source includes a DC converter coupled to the display cell for applying a DC drive voltage thereto. A feedback control circuit is coupled to the DC converter for stabilizing the DC drive voltage. The feedback control circuit further includes a temperature dependent reference voltage means, for effecting a temperature adjustment of the DC drive voltage corresponding to the temperature characteristic of the liquid crystal display cell.


Patent
29 Dec 1975
TL;DR: A DC to DC power supply, which includes simplified semiconductor circuitry and has features enabling the semiconductors to become nonconducting when the output is unloaded or causing battery connected to the input to charge when a higher than normal output voltage is applied to the circuit output, is described in this paper.
Abstract: A DC to DC power supply, which includes simplified semiconductor circuitry and has features enabling the semiconductors to become non-conducting when the output is unloaded or causing battery connected to the input to charge when a higher than normal output voltage is applied to the circuit output

Patent
10 Feb 1975
TL;DR: In this article, the instantaneous switching element current is used to develop a cutoff signal at some predetermined current level which enables a cutoff circuit to quickly switch off the conducting switching element at that time.
Abstract: Switching current spikes are limited in a self-saturating DC/DC converter by sensing the instantaneous switching element current to develop a cutoff signal at some predetermined current level which enables a cutoff circuit to quickly switch off the conducting switching element at that time.

Journal ArticleDOI
TL;DR: The technique for improving the linearity between the input voltage and the frequency of oscillation is described, accomplished by adding a control circuit to Concentional voltage-to-frequency converters.
Abstract: The technique for improving the linearity between the input voltage and the frequency of oscillation is described. This improvement is accomplished by adding a control circuit to Concentional voltage-to-frequency converters. From the experimental results, the linearity of this converter was about 0.15 percent at the frequency of 1 MHz.

Patent
27 Mar 1975
TL;DR: In this article, an analog-to-pulse integrating converter uses dual slope integration to achieve DC voltage to pulse rate conversion, where an input signal is integrated, the integrator output is level detected and reset, at the same time there is issued an output pulse.
Abstract: An analog-to-pulse integrating converter uses dual slope integration to achieve DC voltage to pulse rate conversion. An input signal is integrated, the integrator output is level detected and the integrator reset, at the same time there is issued an output pulse. The output pulse rate is proportional to the level of the DC input signal.

Patent
Kenzo Masuda1
24 Jul 1975
TL;DR: In this paper, a frequency-voltage converter using a charge-pump element and a pulse generating circuit stabilized in frequency of the output pulse signal by using the frequency voltage converter for detecting the deviation or variation of the frequency.
Abstract: A frequency-voltage converter using a charge-pump element and a pulse generating circuit stabilized in frequency of the output pulse signal by using the frequency-voltage converter for detecting the deviation or variation of the frequency of the output pulse signal.

Patent
29 Aug 1975
TL;DR: In this paper, a highly linear AC to DC conversion system comprises a variable gain amplifier via which an AC signal to be converted is applied to an AC/DC converter, and the output of the converter is compared with a reference level and a control signal dependent on the difference there between adjusts the gain of the variable gain amplifiers so as to reduce the difference.
Abstract: A highly linear AC to DC conversion system comprises a variable gain amplifier via which an AC signal to be converted is applied to an AC/DC converter. The output of the AC/DC converter is compared with a reference level and a control signal dependent on the difference therebetween adjusts the gain of the variable gain amplifier so as to reduce the difference. The output of the AC/DC converter is also applied to one input of a comparator, whose DC output is applied via the variable gain amplifier to the other input of the comparator. The variable gain amplifier has exactly the same gain for both AC and DC signals. It can then be shown that the DC output signal produced by the comparator is very accurately linearly related to the magnitude of the AC input signal.

Patent
27 Jan 1975
TL;DR: In this article, a gate is interposed between the voltage converter and the impulse preparation device, which is connected to the converter which compares its output to an adjustable reference voltage, and the gate is closed.
Abstract: Logic circuit device and frequency voltage converter connected to the impulse preparation device. A gate being interposed between voltage converter and the impulse preparation device. Comparator connected to the converter which compares its output to an adjustable reference voltage.

Patent
Siepmann Bernd Josef1, Thilo P1
11 Aug 1975
TL;DR: In this paper, a voltage comparison device is provided for comparing the collector-emitted voltage of the switching transistor with a predetermined reference value, and upon overshoot of the reference voltage the voltage is analyzed for disconnection of the base current of the transistor.
Abstract: A circuit arrangement for a DC to DC converter has at least one switching transistor and one transformer. The transformer includes a primary winding which is connected in the collector circuit of the transistor and a secondary winding from which at least one stabilized DC voltage may be tapped by way of rectifiers. The switching transistor is actuated and blocked by way of a control component in dependence upon load. A voltage comparison device is provided for comparing the collector-emitted voltage of the switching transistor with a predetermined reference value, and upon overshoot of the reference voltage the collector-emitter voltage is analyzed for disconnection of the base current of the switching transistor.

Patent
26 Feb 1975
TL;DR: In this article, a dc. motor was adapted to drive an alternator which produces an ac. output for powering a remote load device, which was connected to the converter by a three-wire extension cord having a ground wire for grounding the load device.
Abstract: The converter includes a dc. motor energizable from a battery and adapted to drive an alternator which produces an ac. output for powering a remote load device. The latter is adapted to be connected to the converter by a three-wire extension cord having a ground wire for grounding the load device. A manually operable switch is located near the output end of the extension cord and is connected across the ground wire and one of the conducting wires of the cord. The motor of the converter may be started by momentarily closing the switch and may be stopped when the switch is next closed momentarily.


Patent
15 May 1975
TL;DR: In this article, a two-term process controller is proposed based upon an analogue channel and a digital integrating channel. But the output frequency is processed in a frequency dividing circuit with a number of pick-off output lines and the output of the frequency divider is used to change the state of a bi-directional counter coupled to a digital to analogue converter.
Abstract: A two term process controller is based upon an analogue channel and a digital integrating channel. An input voltage is fed to an analogue-to-digital converter in the form of a voltage to frequency signal converter. The output frequency is processed in a frequency dividing circuit with a number of pick-off output lines. The output of the frequency divider is used to change the state of a bi-directional counter coupled to a digital to analogue converter. Directional control of the bidirectional counter is exercised directly from the voltage to frequency converter. In the fully automatic mode of the output of the digital to analogue converter is compared with the input voltage and the difference stored in an analogue memory. For smooth change-over to the manual mode a standard frequency signal is substituted upon direction of a control circuit.