SU1637027A1 - Line sweep generator - Google Patents

Abstract

The invention relates to television. The purpose of the invention is to increase speed by reducing the time of the transient process and reducing power consumption. Hr television line scan contains a master Hr 1, control block 2, transistors 3 and 5, capacitive voltage divider 4, voltage limiter 6, diodes 7, 8 and 11, inductive load 9, transformer 10, resistors 12 and 13 and sources 14 and 15 voltages. Increased speed, i.e. a twofold decrease in the horizontal sweep time is achieved by increasing the voltage twice on the inductive load 9 during the current decay. The reduction in power consumption is achieved by eliminating the delay in the onset of the decay of the collector current of transistor 3 (5), due to the resorption of minority carriers when it is closed. 1 silt I (/

Description

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The invention relates to television technology and can be used in information display devices based on electron beam devices.

The purpose of the invention is to increase speed by reducing the time of the transient process and reducing power consumption.

The essence of the invention is to increase the speed, i.e. halving the reverse horizontal sweep time by doubling the voltage on an inductive load during a current decay, as well as reducing power consumption by eliminating the delay of the beginning of the fall of the collector current of the transistor due to resorption of minority carriers when it is closing

The drawing shows a circuit diagram of the device.

The device contains a master oscillator 1, a control unit 2, a first transistor 3, a capacitive voltage divider 4, a second transistor 5, a voltage limiter 6, the first and second diodes 7 and 8, an inductive load 9, a transformer 10, a third diode 11, the first and the second resistors 12 and 13, the first and second sources 14 and 15 of the voltage E1 and E2.

The device works as follows.

The master oscillator 1 generates square-shaped pulses whose frequency is equal to the frequency of the sync pulses arriving at the input bus of the master oscillator 1. From the output of the master oscillator 1, the pulses go to control unit 2, which generates a control signal for the TV horizontal line output stage. This signal closes the first transistor 3 during the horizontal flyback and opens it during the second half of the horizontal horizontal stroke.

The load of the first transistor 3 is the emitter-to-base transition of the second transistor 5. The supply voltage of the base of the first transistor .3 is selected from the condition of ensuring its operation in active mode using the first resistor 12 and the second resistor 13. Resistor 13 does not provide

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possibility of operation of the first transistor of torus 3 in the saturation mode. Since the first transistor 3 operates in the active mode, the collector current decreases during a time of 0.2-0.5 μs. The first transistor 3 opens the emitter circuit of the second transistor 5, and in the inductive load 9, the current decreases, leading to the appearance of a horizontal reversing pulse voltage. At the same time, the base-emitter transition of the second transistor 5 from the secondary winding of the transformer 10 through the voltage limiter 6 is supplied with a voltage that reliably closes the second transistor 5 during the horizontal flyback time. Diodes 7 and 11 when the voltage across the capacitive divider 4 of the voltage of the second source 15 of the E2 voltage is disconnected, the bus of the second source 15 is disconnected from the base circuit of the second transistor 5. Therefore, at equal capacitance values of the capacitor divider 4, the voltage is applied to the base of the second transistor 5 voltage equal to half the maximum amplitude of the pulse voltage generated on the inductive load 9.

When the magnetic energy stored in the inductive load 9 is fully transferred to the electrical voltage in the capacitive divider 4, the pulse voltage amplitude reaches a maximum. From this moment on, the electrical energy decreases and the electromagnetic voltage increases, and when the amplitude of the pulsed voltage on inductive load 9 reaches the voltage of the second source 15 of the E2 voltage 15, the beam on the CRT screen will move to the initial point of the beginning of the horizontal scanning. During the formation of the second half of the forward sweep from the master oscillator 1, a pulse voltage is applied to the control unit 2, which opens the first and second transistors 3 and 5 and the whole process repeats.

Thus, the introduction of the second transistor 5, the first, second and third diodes 7, 8 and 11 into the base circuit allows the work of the first and second transistors 3 and 5 connected in series to form the pulse voltage of the reverse

line scan in such a way that the collector junction — the base of each transistor — accounts for only half of the pulse amplitude on the reverse sweep yarn, which makes it possible to double the amplitude of the pulse voltage on an inductive load, and consequently, to shorten the horizontal stroke reverse duration compared to the known device.

Claims (1)

Invention Formula Television line scan generator, containing a series-connected master oscillator and a control unit, the first transistor, the emitter of which is connected to the output of the control unit, the second transistor, the emitter of which is connected to the collector of the first transistor, the transformer, the first output of the primary winding , and the second output - to the collector of the second transistor and to the first output of the inductive load, the second output of which is connected to the common bus, capacitive divi- 50 five The first and second terminals of which are connected respectively to the emitter and collector of the second transistor, the second voltage source, the output of which through the first resistor is connected to the base of the first transistor, the voltage limiter, the first and second inputs of which are connected to the corresponding terminals of the secondary winding of the transformer, and the first output to the base of the second transistor, which is due to the fact that, in order to increase speed by reducing the transient time and reducing power consumption, the first The second diode whose cathode is connected to the base of the second transistor, the second diode whose cathode is connected to the collector of the second transistor, the third diode whose cathode is connected to the anodes of the first and second diodes, and the anode to the output of the second voltage source, the second resistor, the first output which is connected to the base of the first transistor, and the second pin to the common bus, and the second pin of the voltage limiter is connected to the emitter of the second transistor.