Showing papers on "Charge pump published in 1971"

High dc to low dc voltage converter

Abstract: Transformerless high DC to low DC voltage conversion is achieved by alternately charging a plurality of capacitors in series from the input voltage source, and discharging them in parallel into the load. The charging and discharging are effected by transistor switches, which are in turn controlled by the voltage across one of the plurality of capacitors. Charging stops, and discharging begins, when this voltage rises above a first predetermined value; discharging stops, and charging begins, when this voltage falls below a second, lower, predetermined value. During charging, voltage across the load is maintained by a permanently connected reservoir capacitor. The difference between the predetermined voltage values, and hence the ripple on the output voltage, is preselected by certain circuit constants, whereas the mean of the two values is controlled by comparing the DC component of the output voltage with a reference value, so as to maintain the DC load voltage constant despite variations in load current.

Pulse-width modulated dc to dc converter with zero percent duty cycle capability

Abstract: A pulse-width modulated DC to DC converter is enabled to operate into short circuits and limit the current output by having the capability of operating at zero percent duty cycle. The regulation feedback loop utilizes a light-emitting diode and phototransistor optical arrangement to permit isolation between the input and output sides of the converter. The light emitting diode is responsive to voltage monitoring and current monitoring circuitry on the output side of the converter. The converter operates in a crossover mode in which the regulation switches from voltage regulation to current regulation or vice versa as load conditions change.

Dc to dc converter with voltage regulation feedback loop achieving isolation between input and output by time domain techniques

Abstract: A DC to DC converter includes a digital type voltage regulation control circuit which permits complete isolation between the input and output circuits. The regulation signals comprise timing pulses coupled by a pulse transformer from voltage monitoring circuitry on the output side of the converter to switching control circuitry on the input side of the converter. The rectifier of the converter utilizes synchronous rectifying transistors driven by a proportional base drive arrangement which utilizes the regenerative action of a current transformer to transform the collector current of the transistor into a base drive current. This proportional base drive arrangement includes a third stored charge sweep-out winding and a diode to permit high frequency operation of the converter rectifier with low voltage high current saturation transistors.

Dual voltage system

Abstract: Two 12-volt batteries are connected in series across the output of a 24-volt charging system, and a DC to DC converter is connected between the output of the charging system and a junction between the batteries. To maintain equal voltages across both batteries, the voltage at the junction is compared with a reference voltage by a voltage regulator that is operatively connected with a DC to DC converter to maintain a regulated output therefrom to the junction.

Dual voltage charging system

Abstract: First and second batteries are connected in series between the terminals of a vehicle starting motor. The DC output terminals of a DC generator are connected across the first battery and also across a voltage sensitive switch and the oscillator transformer input stage of a DC to DC converter. The rectifier output stage of the DC to DC converter is combined with a voltage regulator that is connected across a second battery. The voltage sensitive switch renders the input stage of the converter operative when the output of the the generator is greater than a first predetermined voltage and inoperative below. The voltage regulator maintains a second predetermined voltage across the second battery by rendering the output stage of the converter operative to charge the second battery when the voltage thereon is below the second voltage and inoperative above.

True rms to dc converters

Abstract: An apparatus for converting a complex AC voltage wave to an equivalent DC value which is a measure of its true RMS value and which may then be read on an accurate indicating device such as a digital voltmeter, incorporating thermal converters and operational amplifiers in a temperature-compensated configuration The apparatus maintains a portion of an unknown AC voltage wave, which is thermally converted into a DC voltage, substantially equal to a DC reference voltage A portion of a DC output voltage is also maintained substantially equal to the DC reference voltage Since the proportioning means for the complex AC voltage wave and the DC output voltage is the same, the true RMS value of the complex AC voltage wave is equal to the DC output voltage

Stored charge detection by charge transfer

Abstract: The amount of charge stored in a charge storage system can be transferred with negligible loss from the storage system to a charge detector without regard to the size of any distributed capacitance present on the line transferring the charge. This is achieved by charging a detector capacitor and the capacitance of the transfer line, to a reference voltage, allowing the stored charge system and the transfer line capacitance to equalize at a voltage level below the reference voltage, and transferring charge from the detector capacitor to the line capacitance and the charge storage system to return the line and the charge storage system to the reference voltage of charge. The voltage remaining on the detector capacitor is then equal to the original state of charge in the storage system. A particular circuit for performing this method in conjunction with semiconductor memory arrays is also disclosed.

Variable displacement pump control system

Abstract: A radial piston variable displacement hydraulic pump has a discharge line and an inlet line, which is connected to a fixed displacement charge pump. The pistons are returned by the fluid pressure in the inlet line, and the displacement of the pump is controlled by varying the pressure in the drive chamber of the pump, increasing pressure in the drive chamber resisting the return of the pistons to decrease the piston strokes. The pressure in the chamber is supplied by the charge pump through a pilot-operated stroke control valve, which is biased toward a dump position, wherein it exhausts the pressurized fluid from the chamber, and is shiftable to an alternate position wherein it connects the charge pump to the chamber in response to pressure in a pilot line connected to the pump discharge.

Dc voltage multiplier

Abstract: A DC voltage multiplier having a plurality of voltage multiplying stages using transistors that are capacitively coupled to an inverter to conduct current in only one direction. A variable impedance is responsive to a signal to vary the factor of multiplication of the DC voltage multiplier between a maximum value and a lower value that is determined by the number of voltage multiplying stages affected by the variable impedance and bypassed within the multiplier by a unidirectional current conducting device.

D.c. converter having control transistor in blocking oscillator feedback

Abstract: An apparatus for increasing an applied DC voltage level to a higher DC voltage level by utilizing a current feedback network to provide fast switching and control in the power transistors.