US2407724A

US2407724A - Voltage rectifier

Info

Publication number: US2407724A
Application number: US537917A
Authority: US
Inventors: Donald R Rasley
Original assignee: Farnsworth Television and Radio Corp
Current assignee: Farnsworth Television and Radio Corp
Priority date: 1944-05-29
Filing date: 1944-05-29
Publication date: 1946-09-17
Anticipated expiration: 1963-09-17

Description

Sept. 17, 1946. D. R. RASLEY 2,407,724

VOLTAGE RECTIFIER Filed may 29, 1944 INVENTORI DONALD R.RASLEY ATTORNEY Patented Sept. 17, 1946 VOLTAGE RECTIFIER Donald R. Rasley, Fort Wayne, Ind., assignor to Farnsworth Television and Radio Corporation, a corporation of Delaware Application May 29, 1944, Serial No. 537,917

11 Claims.

Thi invention relates to power supply apparatus and particularly to apparatus of this character wherein the supply voltage is divided among a plurality of loads.

In the operation of multistage electron multipliers it is the conventional practice to derive the accelerating voltages for the secondary electron emissive multiplier electrodes from a voltage divider which is connected across a source of direct current energy. The voltage which is developed in each divider component is dependent upon the total current fiow in that component. The total current flow consists of the circulating current through the divider component from the energy source and. the electron current flow between the associated multiplier electrodes where it is desired that the multiplier have a substantially linear response, it is necessary that the interelectrode accelerating voltages be maintained at substantially constant values. In order to efiect this result the circulating currentthrough the respective voltage divider components must be considerably greater than the associated interelectrode electron current. In this manner fluctuations of the electron current due to signal variations have little or no effect upon the voltage drop in the respective divider components. In order to achieve this end with voltage divider consisting of equal impedance components, the components must have rela tively low values of impedance.

However, as is Well known in the art, a voltage divider made up entirely of relatively low impedance components consumes considerable power from the source of energy. Inasmuch as the voltage developed in some of the divider components is not subject to appreciable variation by reason of variations of the electron current flow between the associated multiplier electrodes, it is not necessary that the impedances of these divider components be of relatively small values. Such a condition is particularly true in the initial multiplier stages where the magnitude of the electron current flow is comparatively small.

It, therefore, has become the practice to employ a voltage divider consisting partly of a group of relatively low impedance components and partly of a group of relatively high impedance components. One such arrangement is disclosed in a copending application of Donald R. Rasley, Serial No. 512,541, filed December 2, 1943. The relatively high impedance divider components are used in association with the lower multiplier stages where the electron current densities are relatively small and the relatively low impedance components are used in association with the higher multiplier stages where the electron current densities are relatively large. In this manner it is possible to provide accelerating voltages for the electron multiplier stages which are substantially constant, irrespective of fluctuations in the current densities representing intelligence signals and at the same time to minimize the consumption of power from the source of energy for the voltage divider.

Inasmuch as the energy source most conveniently used with apparatus of the character described consists of rectified alternating current energy it becomes necessary to adapt such a power supply suitably to provide energy to a load consisting of both relatively high and low impedance elements. For certain television applications the unidirectional power supply also serves as the source of scanning voltage for the deflector elements. Devices of this character used heretofore have been required to deliver energy to only one load.

It, therefore, is an object of the present invention to provide a power supply for a load circuit consisting of a plurality of impedance elements.

In accordance with this invention there is provided a source of periodic impulses from which is to be developed a substantially constant unidirectional voltage. A plurality of energy storage devices are employed. The energy storage devices are connected to different voltage points of the impulse source. There is provided impulse controlled means for storing energy in the respective storage devices. There'also is provided a plurality of circuits connected to the respective storage devices for dissipating the energy stored therein. Preferably, the dissipation circuits are connected in series.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the following drawing:

Fig. 1 is a circuit diagram of apparatus en.-

' bodying the invention in one form; and,

source of direct current energy such as a battery I3. The positive terminal of this battery is connected through the coil I 2 to the tube anode and. the negative terminal is connected to ground. A coil I 4 inductively coupled to the anode coil I2 is connected in series with a resistor I5 between the control grid and cathode of the tube II.

The relatively high voltage terminal of the coil i 2, which is connected to the anode of the tube II, is coupled by means of a condenser I6 to one terminal of a relatively high impedance element, such as a resistor IT. This resistor is connected in series with a relatively low impedance element such as a resistor I8. A relatively low voltage intermediate tap or terminal of the coil I2 is coupled by means of a condenser I9 to the junction point between the load resistors I1 and I8.

A rectifier tube 2|, having its anode connected to the coupling condenser I6, is connected in parallel with the high impedance load resistor I'I. Another rectifier tube 22, having itsanode connected to the coupling condenser I9, is connected in parallel with the relatively low impedance load resistor I8.

Referring now to the operation of the apparatus shown in Fig. 1, a brief consideration will be given to the impulse generator including the relaxation oscillator. The coupling between coils I2 and I4 is regenerative so that, during periods of current increase in the coil I2, the control grid of the tube I I is biased so as to maintain the tube conducting. Also, during periods of cur rent increase in the coil I2, the anode voltage of the tube is maintained at a substantially constant value. At a critical interelectrode voltage the current through the tube II and the coil I2 ceases to increase and, as a consequence, the control grid of the tube becomes negatively biased and current conduction through the tube and the coil I2 is interrupted. As a result of the rapid decay of current in the coil I2 there is developed at the anode of the tube II an impulse of positive polarity and of considerable voltage. At the same time similar impulses are developed in all parts of the coil I2, the voltage thereof being of increasingly lesser magnitude the farther removed from the anode is the coil portion in which they are developed.

During periods of current increase in the coil I2, when the anode voltage of the tube I I is being maintained at a substantially constant value, the energy stored in the condenser I6 is dissipated through the load resistors I1 and I8. The rate at which this energy is dissipated depends upon the time constant of the discharge circuit which is a function of the size of the condenser I6 and also of the value of the load resistors I1 and I8. Inasmuch as the value of the former is considerably greater than that of the latter, the effect of the latter upon the dissipation rate is negligible. Similarly, the energy stored in the condenser I9 is dissipated through the relatively low impedance resistor I8 during periods of cur-- rent increase in the coil I2. This dissipation rate is a function of the value of the condenser I i! and also of the resistor l8. By properly choosing the time constant determining elements of these two circuits the respective rates at which the energy stored in the condensers i6 and I9 may be made substantially equal.

During periods of current decay in the winding I2 the relatively high voltage impulses developed at the anode terminal and at the intermediate terminal of the coil render the rectifiers 2| and 22 conducting. In this manner the energy which ance resistor Il may be associated with the lower multiplier stages and the relatively low impedance I8 may be coupled to the higher multiplier stages. In this manner the circulating current through the load resistor I! may be maintained at a relatively low value and the circulating current through the resistor I8 may be maintained at a sufficiently higher value so that the voltages developed in this resistor are not afiected materially by the interelectrode electron currents of substantial magnitudes.

Referring now to Fig. 2 of the drawing, the apparatus embodying the instant invention is essentially the same as that shown in Fig. 1. Corresponding characters of reference are used in the two figures to designate similar apparatus. In this modication of the invention the only essential difierence between that described in connection with Fig. 1 is that the rectifier 2| is connected in parallel with both of the load resistors I1 and IB.

There also is no material difference in the mode of operation of the apparatus of Fig. 2 from that of Fig. 1. The dissipation circuits for the respective condensers I6 and I9 ar the same as those shown in Fig. 1. Instead of utilizing only the higher voltage p rtion of the impulses developed in the coil I2 to restore the energy content of the condenser I6, in this case the full voltage is utilized. It is believed unnecessary to describe in any greater detail the operation of this modifi-cation of the invention.

Values of the circuit components of apparatus in accordance with thi invention necessarily will depend upon the particular requirements of apparatus of this character. Without intending to limit the invention in any manner, the following table of values of the more important circuit elements is given by way of example for the development from a source of approximately 14,000 impulses per second of a power supply to furnish 1,500 volts at a current drain of 1 milliampere in a relatively high impedance load such as the resistor I1 and also 1,000 volts at a current drain of 10 milliamperes in a relatively low impedance load uch as the resistor I8.

Condenser l6 .001 microfarad Resistor I'I 2 megohms Resistor l8 0.1 megohm Condenser I9 0.02 microfarad Rectifier tube 2I 8016 Rectifier 22 6H6 While there has been described What, at presout, are considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the invention, and therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. A unidirectional power supply comprising, a source of impulses, a plurality of energy storage devices, one of said storage devices being connected to a relatively high voltage point of said impulse source and another of said storage devices being connected to a relatively low voltage point of said impulse source, means controlled by said impulses for storing energy in said storage devices, and a plurality of dissipation circuits connected respectively to said energy storage devices.

2. A unidirectional power supply comprising, a source of impulses, a plurality of energy storage devices, one of said storage device being connected to a relatively high voltage point of said impulse source and another one of said storage devices being connected to a relatively low voltage point of said impulse source, means controlled by said impulses for storing energy in said storage devices, and a plurality of dissipation circuits connected respectively to said energy storage devices, one of said dissipation circuits being of relatively high impedance and another of said dissipation circuits being of relatively low impedance.

3. A unidirectional power supply comprising, a source of impulses, a first energy storage device connected to a relatively high voltage point of said impulse source, a second energy storage device connected to a relatively low voltage point of said impulse source, means controlled by said impulses for charging said energy storage devices, means including a relatively high impedance circult for dissipating energy stored in said first storage device, and means including a relatively low impedance circuit in series with said relatively high impedance circuit for dissipating energy stored in said second storage device.

4. A unidirectional power supply comprising, a relaxation oscillator having an output circuit impedance device for the development of a series of voltage impulses, a first condenser connected to a relatively high voltage point of said output circuit impedance device, a second condenser connected to a relatively low voltage point of said output circuit impedance device, a pair of rectifiers each connected to one of said condensers and controlled by said impu ses for charging said condensers, a relatively high impedance energy issipation circuit connected to said first condenser, and a relatively low impedance energy dissipation circuit connected in series with said relatively high impedance dissipation circuit and also connected to said second condenser.

5. A unidirectional power supply comprising, a relaxation oscillator having connected in the output circuit thereof an inductive Winding for the development of a series of voltage impulses under the control of relatively rapid current changes therein, a first condenser connected to a relatively high voltage point of said inductive winding, a second condenser connected to a relatively low voltage point of said inductive winding, a pair of rectifier tubes, each connected to one of said condensers and controlled by said impulses for charging said condensers, an energy dissipation circuit including a relatively high impedance element connected to said first condenser, and an energy dissipation circuit including a relatively low impedance element connected in series with said relatively high impedance element and also connected to said second condenser.

6. A unidirectional power supply comprising, a relaxation oscillator having an output circuit for the development of a series of voltage impulses, a load circuit including a relatively high impedance element and a relatively low impedance element, a first condenser connected between one terminal of said relatively high impedance element and a high voltage portion of said output circuit, a second condenser connected between one terminal of said relatively low impedance element and a low voltage portion of said output circuit, means connected in parallel with said relatively high impedance element and controlled by said impulses ior charging said first condenser, and means connected in parallel with said relatively low impedance element and controlled by said impulses for charging said second condenser.

7. A unidirectional power supply comprising, a relaxation oscillator having an output circuit impedance device for the development of a series of voltage impulses, a load circuit including a relatively high impedance element and a relatively low impedance element, a first rectifier connected in parallel with said relatively high impedance element and capacitatively coupled across a high voltage portion of said output circuit impedance device, and a second rectifier connected in parallel with said relatively low impedance element and capacitatively coupled across a low voltage ortion of said output circuit impedance device.

8. A unidirectional power supply comprising, a relaxation oscillator having connected in the output circuit thereof an inductive winding for the development of a series of voltage impulses under the control of relatively rapid current changes therein, a load circuit including the series connection of a relatively high impedance element and a relatively low impedance element, a first rectifier tube connected in parallel with said relatively high impedance element and capacitatively coupled across a high voltage portion of said inductive winding, and a second rectifier tube connected in parallel with said relatively low impedance element and capacitatively coupled across a load voltage portion of said inductive winding.

9. A unidirectional power supply comprising, a relaxation oscillator having an output circuit for the development of a series of voltage impulses, a load circuit including a relatively high impedance element and a relatively low impedance element, at first condenser connected between one terminal of said relatively high impedance element and a high voltage portion of said output circuit, a second condenser connected between one terminal of said relatively low impedance element and a low voltage portion of said output circuit, means connected in parallel with both of said impedance elements and controlled by said impulses for charging said first condenser, and means connected in parallel with said relatively low impedance element and controlled by said impulses for charging said second condenser.

10. A unidirectional power supply comprising, a relaxation oscillator having an output circuit impedance device for the development of a series of voltage impulses, a load circuit including a relatively high impedance element and a relatively low impedance element, a first rectifier connected in parallel with both of said impedance elements and capacitatively coupled across the terminals of said output circuit impedance device, and a second rectifier connected in parallel with said relatively low impedance element and capacitatively coupled across a low voltage portion of said output circuit impedance device.

11, A unidirectional power supply comprising,

a relaxation oscillator having connected in the output circuit thereof an inductive winding for the development of a series of voltage impulses under the control of relatively rapid current changes therein, a load circuit including the series connection of a relatively high impedance element and a relatively low impedance element,

a first rectifier tube connected in parallel with said load circuit and capacitatively coupled across the terminals of said inductive winding, and a second rectifier tube connected in parallel with said relatively low impedance element and capacitatively coupled across a low voltage portion of said inductive winding.

DONALD R. RASLEY.