JPS5890868A - Power source circuit and power source supplying method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to power systems, particularly, but not limited to, scanning systems used in computer terminals, data display monitors, arcade games, radar, and other cathode ray tube based systems. Computer terminals, data display monitors, etc., typically consist of separate modules (e.g., keyboards, cathode ray tube (CRT) displays, etc.).

floppy disk drive, and logical unit).

Each of these electronic devices typically requires a good quality regulated power source. Thus, the display unit or terminal also typically includes a separate power supply chassis to provide power to the other modules.

Traditional computer power supplies have been relatively centralized, expensive, and completely separate units.As the price and size of computers continue to decrease, the price and size of traditional power supplies has increased with the space required by the entire system. They account for a disproportionately large proportion of the price. Therefore, there is a need to reduce cabinet size and power supply costs without sacrificing the quality, high efficiency, wide dynamic range, load sensing adjustment, and good filtering required for high-end electronic equipment.

Accordingly, it is an object of the present invention to provide a new and improved power source. One of the objectives here is to provide a spatially efficient and low-cost power source. Another purpose is to reduce power supply costs by reusing equipment intended for use elsewhere in the system. especially,
The purpose of this project is to provide a power supply that reuses the fly transformer used in the high voltage section of a CRT as the main element in a power supply regulator.

These and other objects are achieved in the present invention by using part of the high voltage circuitry in the CRT display as part of the power supply. In particular, the high-voltage flyback transformer in the CRT scanning cycle display unit switches a silicon-controlled rectifier (SCN) to perform synchronous phase control to supply the CRT with normal high voltage, which is easily rectified and filtered. It blocks high currents at high frequencies and provides a smooth and well-regulated power output. At the end of the scan cycle and during retrace, a negative pulse is generated in the winding of the flyback transformer, interrupting the SCR and interrupting the large current. Power output is well regulated, scanning cycle frequency is 10-35 kHz
z, preferably in the range 15-25 kHz. Specific frequency 15.750 kHz, 18.3) cH
;.

19.2kHz and 20.5kHz are currently often used commercially. These frequencies are easily filtered to meet the needs of electronic circuits. Space and equipment requirements are reduced because the high voltage power supply is configured as a single integrated system.

In FIG. 1, a line filter 10 (including a rectifier and a filter capacitor) has a normal A
Terminal 12 depending on commercial power supply (or equivalent)
Give a rectified input voltage to .

Flyback transformer (includes > Fi rectifier windings 14-16 and one or more secondary windings installed in a CRT display unit. Flyback transformers are used as high-speed switches to open electronic switches. Synchronization with the flyback transformer consists of a horizontal oscillator, a horizontal drive transformer, separate windings of the flyback transformer,
It can be obtained from any suitable component such as a capacitor connected in series with a yoke or the like.

The terminal 12 is connected to a rectifier @ 14 and an electronic switch (here 8
0R20) to the primary winding 16. 8
The gate of 0R is connected to a horizontal scan regulator 24 through a pulse transformer 22.

Therefore, 8CR switches in accordance with the horizontal scanning system cycle set by regulator 28. 5
cnIri opens when a negative pulse is induced in the rectifier winding 14 during the retrace period.

When 80R20 becomes conductive, the primary winding 16 of the flyback transformer is energized and induces a voltage in the secondary winding 18.

The pulses induced in the secondary winding 18 are fed back through a diode 26 to a regulator 28 which provides a reference voltage having the desired power supply characteristics.

-The voltage at the bottom of the secondary winding 16 (in FIG. 1) is the primary useful output powering the horizontal deflection drive output circuit 30 and the deflection yoke 32. Secondary winding 18 provides power to any other suitable load, computer system load 36.

A programmable unijunction transistor 5CR instead of or in addition to the horizontal scan regulator 24
It may be used for 20 periodic opening and closing.

5CR20 opens and closes at or near the zero crossing of regulator 24 to obtain a rectified DC voltage, which is a well-tuned switch for frequency.

After that, during the rectifier 26#-j horizontal scanning period, the secondary winding 18
returns the pulse induced in the This feedback is to regulator 28 which controls regulator 24 which gates the SCR. The smoothing capacitor 34 maintains a steady DC reference voltage corresponding to the voltage induced in the secondary winding 18 and the obtained rectified voltage. Alternatively, capacitor 34 may be replaced by a rechargeable battery (such as an nickel-cadmium battery) that maintains a constant voltage. For the opening of 80R, the circuit relies on the rectifying effect of the large negative pulse in winding 14 of the flyback transformer. This negative pulse occurs during retrace.

The cycle of diode 26 controlled by the flyback transformer is closed during approximately 85 horizontal scans and open during approximately 15 retrace lines, leading to a useful output that can be easily filtered. The design and capacity of the flyback transformer are normal CR
It is regulated to supply both high voltage for the T and rectified DC power. This will reduce the number of equipment and the overall amount required.

The embodiment of FIG. 2 has a pulse transformer 38 that opens and closes an 80R40 type electronic switch. The output of the 80R40 is filtered at 42 and fed back to the horizontal deflection circuit 44 as a B+ supply. The output of the horizontal deflection circuit 44 is sent to the timer circuit 46.
is applied to This timer includes a trigger circuit 48 and a rectifier circuit 5 which control the voltage pulses induced in the transformer 38.
0 periodically to open and close the 5CR40 at the desired duty cycle.

The embodiment of FIG. 3 has a choke coil 52 in series with the collector-emitter circuit of an electronic switch, transistor 54. The output of this transistor is applied to a horizontal deflection circuit 56. Capacitor 58 filters and smoothes the output voltage. The output voltage of the feedback circuit 60 is applied to a pulse polarization modulator 62 which provides periodically occurring pulses of a desired pulse width to determine the duty cycle of the transistor.

In each of these systems, the periodic opening and closing was assumed to be synchronized with the horizontal scan period. However, any conventional independent time axis power switching operation is also possible with the present invention. In each of the embodiments, feedback control is performed from the secondary winding of the transformer, but feedback control from the -order winding is also possible.

The use of high frequency switchgear such as 80R, PUT', and flyback transformers with unique design characteristics provides a wide dynamic operating range of voltage and current. This use of high frequency equipment allows the system to respond quickly and accurately to finite variations in feedback control.

A schematic circuit diagram (FIG. 4) shows a practical embodiment of the invention. A commercial AC power line is connected to input terminal 64, and fuse 65. It reaches the rectifier diode 72 through the choke coil 68 and current limiting resistor 79. Electrolytic capacitor 74 smoothes and filters the rectified voltage.

The rectified voltage from the diode 72 is passed through the voltage divider 76°78, which is connected to the filter 80 and Zener diode 82 in parallel.
Grounded via. This combination maintains a stable, well-regulated reference voltage at the center of the voltage divider (point PI), and the differential voltage it supplies through resistors 112, 114, 118, and 116 eliminates fluctuations in AC power 64. Simple matrix of feedback voltage) is corrected during IJ socks.

Most of the current from the rectifier diode 72 flows through the rectifier winding 14.
to the anode of a silicon controlled rectifier (80R) 84. Rectifier winding 14 is part of a flyback transformer having a primary winding 4116 and a secondary winding 18.

Therefore, when the 80R84 closes and conducts a strong current, a voltage is induced in the primary and secondary windings. As those skilled in the art will know, during the retrace period a negative voltage is induced in the rectifier winding 14 and the voltage induced in the primary winding 16 is a normal part of the horizontal deflection drive circuit of a CRT display unit. Drive 30.

This horizontal deflection circuit 30 includes driver transistors 86 .
It has an output transistor 88 and a damper diode 90. The construction and operation of such force horizontal deflection circuits are well known and will not be further described. It is an aspect of the invention that the circuit 30 receives power from the primary winding 16 of the flyback transformer. .

80R84 (or - order winding 1)
The rate of variation of the current through 6) is controlled by the pulse applied to the SCR gate and depends on the cycle whose initiation is controlled by the trigger device 92. Device 92 is a programmable unijunction transistor, also referred to as a "PUT." The rectifier winding 1 ends the conduction period of the cycle.
At 4, a negative pulse is induced to switch the SCR to the open state.

The periodic opening and closing of PUT 92 is controlled by the current in primary winding 16. More specifically, at the beginning of each CRT scan cycle, a rectified current flows from rectifier diode 72 and flows through winding 14.
．． Suppression capacitor 94. A voltage is induced in the negative winding 16 through a resistor 96 and a decoupling filter capacitor 98 to ground. In response, current flows from the primary winding 16 to the resistor 100° capacitor 102. Flows through resistor 104 and isolation diode 106 to the gate of PUT 92. In this circuit, a pair of parallel capacitors 108, 11
0 is connected between both sides of isolation diode 1060 and ground. The charging and discharging times of these two capacitors control timing switching of the PUT 92.

This operation i;j depends on the DC level applied to the anode of the PUT 92. This DC level is set by a regulated voltage at point P1 and resistor 112. It is connected to ground through a voltage divider consisting of a potentiometer 114 and a resistor 118. The midpoint of this voltage divider is connected through resistor 116 to PUT9.
2 anodes.

Switching of the timing of PU'r92 is adjusted by potentiometer 114. A pair of decoupling capacitors 120
, 122, the voltage at the anode is maintained constant.

- resistor 100 and capacitor 102 for synchronization and coordination;
I/'i obtains a positive pulse from the flyback winding 16. The amplitude of the pulse is adjusted by a Zener diode 124, and the pulse is sent to the PU through a resistor 104 and a diode 106.
Added to the gate voltage of T92 to perfectly synchronize the trigger point with the horizontal output stage.

The PUT 92 becomes conductive for a predetermined time after current flows through the rectifier winding 14 of the flyback transformer. This time is Boten,
It is adjusted by a thometer 114.

When PU'r92 opens, capacitors 108 and 110
The charge stored in PU'r92. It is discharged through the choke coil 132 and the capacitor 134 to the gate of the 5CR84. This discharge is a control pulse that closes 80R84. Circuit 1364i Chi Yoke Coil 132
and a parallel resistor and diode that serve as a one-way discharge path for the capacitor 134.

5CR84Fi, remains on during the required period of the CRT scan period when there is a positive voltage on winding 14 of the flyback transformer. However, when the horizontal deflection circuit 30 finishes scanning and the retrace cycle begins, a large negative pulse is generated in the rectifier winding 14 connected to the anode of the 8CR84. When the anode becomes negative with respect to the cand, 80R turns off. During the next scan cycle, the same process repeats and PUT 92 closes 80R84 until the retrace cycle begins.

Therefore, the output of 5CR84 is a unipolar repetitive pulse train.

Resistance 140. Diode 26. The load 36 and capacitor 34 load the secondary winding 18 of the flyback transformer. A diode 26 rectifies the voltage induced in the secondary winding 18, and a capacitor 34 smoothes it. The load 36 is the fourth
Any suitable auxiliary circuit that may be powered by the circuit shown.

The voltage on line 27 is connected to resistor 1 as a control signal to maintain load regulation through any fluctuations that occur in the load during normal operation.
Sensed through 40. The signal sensed through resistor '140 affects the anode voltage of PU'r92;
The operating time of the PUT during the scan period is adjusted to provide a correction factor for variations in load demand. When there is a fluctuation in the AC input to the terminal 64, the fluctuation is reflected at both the point P1 and the line 27, and the anode voltage of the PUT 92 is controlled together to provide a correction coefficient.

In operation, commercial AC power from line 64 is rectified at 72;
The voltage is applied to the rectifier winding 14 as a B battery. Winding wire 14
．． Capacitor 94. There is an initial current flowing through resistor 96 and capacitor 98 to ground. The rectified output of diode 72 energizes voltage divider 76.78 to apply the voltage regulated by Zener diodes 82, 124 to the gate and anode of PUT 92.

The voltage induced in the primary winding 16 is connected to the resistor 100. Capacitor 102. P through resistor 104 and diode 106
Applied to the gate of UT92. PUT92u is closed,
Applying a pulse to the gate of 5CR84 then 8C
R84' closes with a strong current to power the horizontal deflection circuit 30 during the CR'I' scan.

At the end of the scan period, transistor 88 is opened and a positive pulse is applied to primary winding 1 in accordance with normal and well-known transformer operation.
Occurs on 6th. A negative voltage is induced in the rectifier winding 14, and CR
Open 80R84 during the T retrace period.

Here, the primary winding 16 of the flyback transformer is 80R.
84 and is self-regulated, so a completely separate power supply is not required. The induced voltage in the secondary winding 18 provides auxiliary power for any suitable load or load 36 during the horizontal scan period, which is approximately 85% of the conduction period of the rectifier 26. Horizontal scan frequencies are easily filtered and smoothed above 15 kHz. Thus, the flyback transformer already present in virtually all CRT control circuits can be easily reused as a power source and control device to generate a well-regulated voltage.

FIG. 5 shows another embodiment somewhat similar to the embodiment of FIG. 1, with like parts having like reference numerals. The principle of FIG. 5 is that the secondary winding 18 and its cooperating parts and loads are electrically isolated from the alternating current line 13. Here, an optical coupler 200 (usually an LED and a phototransistor, etc.) is connected into the circuit, and an AC line 1
2 and the load 36. Thus, the load 36 may be a remotely powered device that can be plugged into the coupler at contacts CI, C2 without the user risking contact with points energized directly from the line 13. A plurality of such secondary windings 18 may be provided with a plurality of separate power supplies. The optical coupler effectively isolates the secondary windings, so that if separate loads are connected to each secondary winding, the loads are not affected by other loads.

For example, FIG. 6 shows windings 18A and 18B. These windings are completely independent and separate from each other. Each may be controlled by its own feedback circuit, or alternatively, a variety of winding techniques may be used to simply Several independent secondary windings may be formed in a single transformer.In this multi-turn transformer, one winding senses the current in all windings and outputs the resulting signal. Supply for feedback adjustment.

FIG. 7 is a diagram showing a circuit similar to the circuits of FIGS. 1 and 4. Parts already described are given the same reference numbers,
The explanation is omitted.

Load 36 is powered by the system of the present invention, and its power output voltage is placed between conductors 300 and 302. This output voltage has analog fluctuations in response to fluctuations in the power input to terminal 64 or load 36. The purpose of this circuit is to provide a corrective control signal to immediately cancel analog fluctuations and restore voltage stability.

Analog-to-digital converter 304 is a voltage controlled oscillator (VCO) that generates a continuous train of pulses with a frequency that is a function of the input voltage level. Lines 300, 302
If the analog voltage between them increases, the frequency decreases, and if the analog voltage decreases, the frequency increases. These pulses are counted by a countdown counter 306 that is preprogrammed to provide an output after counting the number of pulses. The frequency of the vCO and the program count depend on the solution sought.

Simultaneously with the countdown in counter 306, resettable main oscillator 308 operates to detect the start and end of each horizontal scan cycle. Main oscillator 3 at the end of each cycle
08 generates a pulse that restores the entire circuit to its normal state.

310 is essentially an AND gate that generates a pulse when countdown counter 306 reaches a preprogrammed count.

The operation of the circuit shown in FIG. 7 will be explained using the voltage diagram shown in FIG. Three horizontal scan pulses 312, 314, 316 define two horizontal synchronization cycles. The output voltage curve shows the voltage between conductors 300 and 302. (2) The level for one period can be arbitrarily assumed, for example, 90 volts. ■2
During this period, the load draws a large current and the voltage drops, reaching, for example, 89 volts. ■ During period 3, the voltage becomes 90 volts again. ■ During period 4, the load stops passing the large current and the voltage increases to, say, 91 volts.

■During one period, the vCO output of converter 304 has a stable frequency f1. (2) If the voltage across the conductors 300° 302 drops during period 2, the frequency of vCO increases to f2. Thus, the counter 306 quickly reaches the programmed count @N'' and triggers the trigger pulse 318 to gate 310.
8CR84 and close it. At the end of the horizontal period, the main oscillator 308 issues a wake-up pulse 320 to
Open CR84.

Thus, 8CR conducts for a relatively long time between pulses 318, 320 that return the output voltage to its original 90 volt level.

In the next cycle, VCO 304Fi again operates at frequency f1. However, this time the voltage across conductors 300, 302 increases and the frequency of vCO decreases to f3.

This means that counter 306 has a programmed count of
Trigger pulse 32 reaches ``N# and closes 8CR84
This means that it takes a longer time to produce 2.

Master oscillator 308 generates a pulse 324 that opens the SCR at the end of the horizontal scan cycle.

This time, the 5CR81t pulses are on for a relatively short time between 322 and 324. After this, the output voltage returns to 90 volts in period 4.

The power supply system of the present invention has the advantage that it operates with much greater efficiency than is normally expected from power supplies currently in use. This efficiency can be achieved by reusing equipment you already have. Therefore, any loss, heat loss or power consuming functions are folded into the system and
It will not be repeated by the power supply. Rigid systems also typically cover the entire power needs of the CRT and cooperating systems, including slave monitors, logic systems, and other peripheral systems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first preferred embodiment of a power supply according to the invention using a flyback track and an 80R as a switching device; FIG.
FIG. 3 is a block system diagram of the second embodiment of the present invention using a transformer and transistor switch, and FIG. 4 is a flyback transformer that controls 8CR. FIG. 5 is a schematic diagram of an example of a power supply circuit using an optical coupler; FIG. 6 is a schematic diagram of another embodiment of the invention using an optical coupler; FIG. FIG. 7 is a diagram showing another embodiment of the present invention in which an electronic switch is logically controlled; FIG. 8 is a time scale for explaining the operation of the circuit in FIG. 7. It is a figure showing the voltage curve above. 10...Line filter, 12...Terminal, 13...
Input terminal, 14... rectifier winding, 16... - next winding,
18゜18A・, 18B...Secondary winding chopsticks, 20...Silicon control rectifier, 22...Pulse transformer, 24...
・Horizontal scanning regulator, 26 ・Diode, 27 ・・
- Line, 28...Adjuster, 30...Horizontal deflection drive output circuit, 32...Deflection yoke 34...Smoothing capacitor, 36...Load, 38=...Female transformer, 40...
・Silicon controlled rectifier, 42...filter, 44...
- Horizontal deflection circuit, 46... Timer circuit, 48... Trigger circuit, 50... Rectifier circuit, 52... Choke coil, 54... Transistor, 56... Horizontal deflection circuit, 58...・Capacitor, 60... Feedback circuit, 62
...Pulse width modulator, 64...Input terminal, 65...
・Fuse, 68... Choke coil, 72... Rectifier diode, 74... Electrolytic capacitor, 76.78
...Voltage divider, 79... Current limiting resistor, 80... Filter, 82... Zener diode, 84... Silicon/controlled rectifier, 86... Driver transistor,
88... Output transistor, 90... Damper diode, 92... Programmable unijunction transistor, 94... Suppression capacitor, 96... Resistor, 98... Decoupling filter capacitor, 100...
・Resistance, 102... Capacitor, 104... Resistor,
106... Separation diode, 108, 110...
Capacitor, 112, 116, 118...resistance,
114...Potentiometer, 120, 122...
・Decoupling capacitor, 124... Zener diode, 132... Choke coil, 134... Capacitor, 136... Circuit, 140... Resistor, 200...
・Optical coupler, 300, 302...Conductor, 304
...Analog/digital converter, 306...Countdown count, 398...Main oscillator, 310...
- Gate, 312, 314, 31.6...Horizontal scanning pulse, 318...Pulse, 320...Return pulse, 322...Trikahalus, 324...Pulse.

Claims (1)

[Claims] 1. An electronic switch means for supplying a rectified DC voltage pulse train, and a steady and well-regulated DC voltage by filtering and smoothing the rectified voltage according to the output of the electronic switch means. means for energizing an operating device having its own closing and opening cycles in response to the smoothed voltage; and controlling the frequency of the DC pulse train by opening and closing the electronic switch means in response to the cycles. A power supply circuit comprising: control means for reusing the cycle as a voltage regulator for controlling the electronic switch; and means for supplying power to the device in accordance with the output of the electronic switch means. 2. The power supply circuit according to claim 1, wherein the DC voltage pulse is a horizontal deflection pulse. 3. The power supply circuit according to claim 1, wherein the control means comprises a flyback transformer. 4. The power supply circuit according to claim 1, wherein the control means is a pulse transformer driven by a timer. 5. The power supply circuit according to claim 1, wherein the control means is a pulse width modulator. 6. The power supply circuit according to claim 1, wherein the control means includes logic circuit means for counting the output and pulses of a voltage sensing oscillator that generates pulses with a frequency corresponding to the power supply output. 7. The electronic switch means includes a thyristor device, means for applying a closing signal to the thyristor device at a controlled point of each closing period of the cycle in response to the control means, and 7. A power supply circuit according to claim 1, further comprising means for applying an opening signal to the thyristor device at the beginning of each opening period of a cycle. 8. The power supply circuit of claim 7, wherein the thyristor device is a silicon controlled rectifier. 9. The power supply circuit of claim 8, wherein said operating device is a CRT display device, and said close and open cycles are CRT horizontal deflection scan and retrace cycles. 10. 10. The power supply circuit of claim 9, further comprising a programmable unijunction transistor which is driven in response to the start of each shell closing period to close said electronic switch for a predetermined time at the start of said closing period. 11. The electronic switch has approximately 85 points closed and approximately 15 points closed.
2. The power supply circuit according to claim 1, which supplies a transformed output in a cycle in which the voltage is open. 12. Claim 7, wherein separation means is provided to combine the outputs of a plurality of power supply circuits so that each of the power supply circuits operates completely independently of each other and supplies power to a common device.
Section power supply circuit. 13. The power supply circuit according to claim 7, further comprising a multiple winding element 1 for supplying power to a plurality of separate circuits according to each winding. 14. (a) driving an electronic switch in closing and opening cycles as periodically occurring in one module; Φ) filtering and smoothing the output of the switching means to provide a smooth and well-regulated DC voltage; and (C) the cycle that naturally occurs in the one module of the pl(a) stage from each stage of applying a skeleton DC voltage to power other such modules. A method of powering a module of an electronic system, characterized in that it generates, filters, and smoothes a constant frequency DC voltage pulse signal that is reused to maintain control. 15. The method of claim 14, wherein one module of step (a) includes an OR,T horizontal deflection circuit, and the occurring events are scan and retrace cycles in the deflection circuit. 16. The method of claim 15, wherein the deflection circuit includes a flyback transformer connected to control the closing and opening cycles of the electronic switch. 17. The method of claim 14, wherein said (a) one module per stage includes a timer driven pulse transformer having a voltage sensitive close/open cycle. 18. The method of claim 14, wherein one module of step (a) includes a pulse width modulator having a synchronous close-V open cycle. 19. The method of any one of claims 14 to 18, wherein the electronic switch #'1SCR. 20, #Each cycle start scrap period of occurrence event corresponding SCR
Claim 1 further comprising PUT means for closing the
Method of Section 6. 21. The method of claim 14, wherein the electronic switch provides a transformer output in cycles of approximately 85 Q6 closed and approximately 15 Q6 open. 22. - line filter means comprising a flyback transformer having a secondary winding, a secondary winding and a rectifier winding, and a rectifier connecting an alternating current power supply to the rectifier winding; means consisting of a programmable unijunction transistor for generating pulses in response to the rectified voltage and the voltages in the primary and secondary windings; a silicon-controlled rectifier having an anode receiving the rectified voltage via a nuclear rectifier winding; means for applying the pulse from the junction transistor to the gate of the silicon-controlled rectifier; and the line filter, the rectifier winding connected to the cathode of the silicon-controlled rectifier while the silicon-controlled rectifier is conducting. and circuit means for energizing current from the alternating current source through the silicon controlled rectifier;
A power supply circuit comprising means for generating an open cycle to open and close the silicon controlled rectifier at a predetermined rate of about 15 to 25 kHz and at a predetermined output cycle of about 85% closed and about 15% open. 23. The power supply circuit according to claim 22, comprising circuit means for driving a cathode ray tube horizontal deflection circuit, in which the 85% is a scanning period and the 15% is a retrace period. 24. The power supply circuit according to claim 23, wherein the load means is connected to the shell secondary winding. 25. The power supply according to claim 22, which is provided with separation means for combining the outputs of a plurality of power supply circuits, so that each of the power circuits operates completely independently of each other and supplies power to a common device. circuit. 26. The power supply circuit according to claim 22, further comprising multiple winding means for supplying power to a plurality of separate circuits according to each winding.