JPH01114165A - Vertical deflection circuit - Google Patents

Abstract

PURPOSE:To optionally change the vertical amplitude by an external voltage adjustment by providing a circuit applying proportional control to a control voltage of a discharge constant current circuit in a sawtooth wave voltage generating circuit with respect to a frequency of a vertical synchronizing signal. CONSTITUTION:A vertical oscillation circuit 1 is oscillated synchronously with the input of a vertical synchronizing signal V-Sync and a signal is outputted. When a switch S of a sawtooth wave voltage generating circuit 2 is triggered by the signal, a sawtooth wave voltage is generated by a capacitor C and a discharge constant current circuit 3, it is amplified (5) and an output circuit 4 flows a sawtooth wave deflection current to a deflection coil L. On the other hand, when the frequency of the signal V-Sync is changed, an output voltage VF of a F-V converter 6 changes in proportion to its frequency. The voltage VF is subject to proportional control by a variable power voltage E1. Thus, the amplitude at a point (a) of the circuit 3 is proportional to the voltage E1, independently of the frequency of the signal V-Sync and the amplitude of the point (a) is changed optionally by adjusting the voltage E1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a circuit for scanning an electron beam in the vertical direction of a screen, and generates a sawtooth voltage in synchronization with a vertical synchronization signal. Regarding the vertical deflection circuit that controls the deflection of the electron beam of the picture tube by supplying voltage to the vertical deflection coil, in particular, it is not a vertical synchronization signal with a constant frequency like a television signal, but a frequency-controlled signal like an auto scan monitor. The present invention relates to a vertical deflection circuit that is applied when the circuit operates with a variable vertical synchronization signal as input.

[Conventional technology] FIG. 5 is a block diagram of a conventional vertical deflection circuit.

In the figure, (1) is a vertical oscillation circuit, and this vertical oscillation circuit (1) operates in oscillation in synchronization with the input of a vertical synchronization signal (v-sync). (2) is a sawtooth wave voltage generation circuit, which includes a switch (S) triggered by the oscillation operation of the vertical oscillation circuit (1), a charge/discharge capacitor (C), and a discharge/discharge capacitor (C). It consists of a constant current circuit (3) and a DC type ff (EO).

The constant current circuit (3) has an emitter grounded transistor (Tr) whose emitter is grounded and a bias voltage is applied to the base to take out the output from the collector, and a voltage is applied between the base and emitter of this transistor (Tr) to maintain a constant voltage. It consists of a variable bias power supply (VE) for causing a current (1) to flow, and a resistor (R).

(4) is the output circuit, which is the sawtooth voltage generation circuit (2) described above.
) is provided with an amplifier (5) for amplifying the sawtooth voltage generated in the deflection coil (L
) is applied with a sawtooth wave deflection current.

Next, the operation of the above configuration will be explained.

A vertical oscillation circuit (1) operates in oscillation in synchronization with the input of a vertical synchronization signal (V-Sync), and outputs a signal as shown in FIG. 6(a). When the switch (Si) of the sawtooth voltage generation circuit (2) is triggered by this output signal (a), the capacitor (C) is charged from the DC power source (EO).

When the switch (S) is opened after the potential of the capacitor (C) reaches the power supply voltage (E) of the DC power supply (EO), the transistor (
Since a bias voltage (VB) is applied from the bias power supply (VE) between the base and emitter of the Tr), a current (I ) is discharged from the capacitor (C).

Thereafter, by repeating the above operation, a sawtooth voltage as shown in FIG. 6(b) is generated, and this is applied to the amplifier (5).
In this case, if the gain of the amplifier (5) is constant, the vertical amplitude will be 0.
It depends on the amplitude (Vp) of the point, and this amplitude (Vp) depends on the discharge current (I).

By the way, the amplitude (Vp) at the 0 point is the vertical synchronization signal (V
-97nc), that is, when the period of the above output signal (a) is (T) and the frequency is (fma), Vp= (
1/C)-IT However, T=fmer1.

Therefore, by adjusting the voltage (VS) of the variable bias power supply (VE) and changing the discharge current (1), the amplitude (Vp) at the 0 point can be adjusted as shown by (Vpl) in FIG. 6(b). However, if the frequency (f-ma) of the vertical synchronization signal (V-Sync) changes, the amplitude unexpectedly changes as shown at (Vp2) in FIG. 6(c).

[Problem to be Solved by the Invention 1] In the conventional vertical deflection circuit configured as described above, the vertical amplitude can be arbitrarily changed by external voltage adjustment, and the vertical width of the screen can be adjusted according to the purpose of use, etc. Although it can be applied to auto-scan monitors that can be set arbitrarily according to the situation, it has the disadvantage that when the frequency of the input vertical synchronization signal is changed, the vertical amplitude changes unexpectedly, and the vertical width of the set screen changes.

This invention was made to eliminate the above drawbacks.
It is an object of the present invention to provide a vertical deflection circuit that can variably control vertical amplitude by external voltage adjustment without being affected by the frequency of an input vertical synchronizing signal.

[Means for solving the fif problem 1] The vertical deflection circuit according to the present invention is a frequency-voltage converter that proportionally controls the control voltage of the discharge constant current circuit in the sawtooth voltage generation circuit with respect to the frequency of the vertical synchronization signal. The present invention is characterized in that a circuit is provided, and the output voltage of the frequency-voltage conversion circuit is configured to be variably controllable.

[Function] According to the present invention, when the frequency of the vertical synchronization signal input to the vertical oscillation circuit changes, the control voltage of the discharge constant current circuit changes to the frequency of the vertical synchronization signal via the frequency-voltage conversion circuit. It is automatically controlled to a proportional value, so that the amplitude of the sawtooth voltage, which is proportional to the vertical amplitude, remains constant regardless of changes in frequency. Furthermore, the amplitude of the sawtooth voltage can be arbitrarily changed without depending on the frequency by adjusting the output voltage of the frequency-voltage conversion circuit with a variable power supply.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram of a vertical deflection circuit according to an embodiment of the present invention. In the figure, the same components as those in the conventional example shown in FIG. Omitted. “ In Figure 1, (8) is a frequency-voltage conversion circuit (hereinafter referred to as F-V converter), and this F-V:17 converter (8) is proportional to the frequency of the vertical synchronizing signal (V-S7nc). Constant current circuit (3) for discharging the voltage (VF) that changes
The output voltage (VF) is applied to the base of the transistor (Tr) as a bias voltage, and is configured to be a variable type in which the value of the output voltage (VF) can be arbitrarily controlled by controlling the variable DC voltage (El).

Next, the operation of the above configuration will be explained.

The vertical oscillation circuit (1) operates in oscillation in synchronization with the input of the vertical synchronizing signal (V-97nc), and outputs a signal as shown in FIG. 2(a). When the switch (S) of the sawtooth voltage generation circuit (2) is triggered by this output signal (a-), the capacitor (C) is charged from the DC power source (EO).

The charging potential of the capacitor (C) above is the DC power supply (EO)
When the switch (S) is opened after reaching the power supply voltage (E), the F-V converter (6
) is applied, and a current (Ix) is discharged from the capacitor (C) to the collector side indicated by ■ in FIG.

Thereafter, by repeating the above operation, a sawtooth wave voltage as shown by the solid line in FIG.
) to pass the saw deflected current. In this case, if the gain of the amplifier (5) is constant, the vertical amplitude will depend on the amplitude (Vp) at the zero point.

Next, the frequency (
fv) changes, the output voltage (VF) of the F-V converter (6) changes in proportion to its frequency (fv).

In other words, VF=KG・fv−(1)
Here, KO is a circuit constant of the FV converter.

By the way, the output voltage (V
F) is configured to be proportionally controlled by the variable power supply voltage (El), so the above circuit constant (KO) is as follows: KO=1・El...(2)
becomes.

Therefore, from equations (1) and (2) above, VF=1
- El-fv...(3) Here,
1 = constant.

Furthermore, since the current (Ix) flowing to the collector side of the transistor (Tr) is I x = VF/R...-(4), from equations (3) and (4) above, I x
= VF/R= Kl ・El ・fv/R-(5)
becomes.

Therefore, the amplitude (Vp) at the 0 point in Figure 1 is vp=(
11C) ・Eng x II = (17C) ・ (K1 fight E111rma/R) ・T
= (1/C)・(Kl・El・1/T・1/R)・T
= Kl - El/CR (8).

Therefore, the amplitude (Vp) at the 0 point in FIG.
It is proportional to the power supply voltage (El) of the -V converter (6), independent of the frequency (fv) of the vertical synchronization signal (V-Sync), and as shown in Fig. 2 (b), the F-V converter ( 8
) by adjusting the power supply voltage (El) of
) can be changed as desired.

Furthermore, as shown in FIG. 2(C), the set amplitude (Vp) can be maintained regardless of changes in frequency (fv).

FIG. 3 is a diagram showing an example of the configuration of the variable F-V converter (6).

In the same figure, (11) is a one-shot multi-circuit,
This one-shot multi-circuit (11) has a time constant circuit consisting of a fixed capacity capacitor (C1) and a resistor (R1), and has a variable frequency input pulse, that is, a vertical periodic signal (
V-Sync), and outputs a negative pulse signal (bl) having a pulse width (T) and a peak value (Vp2).

(12) is an integrating circuit, and this integrating circuit (12) is a resistor (
R2) and a capacitor (C2), the output pulse signal (bl) from the one-shot multi-circuit (11)
Integrate and output. (14) is an inverter, and this inverter (14) is a one-shot multi-circuit (tt)
A grounded emitter switching transistor (
Tr) and J on the collector side of this transistor (Tr).
It is composed of a DC power source (Elf) with a variable voltage connected to it, and is inserted between the one-shot multi-circuit (11) and the integrating circuit (12).

Next, the operation of the variable F-V converter (8) having the configuration shown in FIG. 3 will be explained.

When a variable frequency vertical synchronization signal (V-5ync) is applied to the one-shot multi-circuit (11), the one-shot multi-circuit (11) is triggered in synchronization with it,
A negative polarity pulse signal (bl) is output.

This negative pulse signal (bl) is connected to a transistor (Tr).
This transistor (
Tr) is cut off, and the voltage (El) of the DC power supply (Ell) is output in a state opposite in phase to the input pulse signal (bl). At this time, the power supply voltage (E
By variably controlling l), the value of the output voltage (VF) can be arbitrarily controlled.

That is, when the voltage (El) of the DC power supply (Ell) is changed, the output voltage (VF) from the integrating circuit (12)
The relationship between and the human power frequency (fma) is vF=fma・1・RIICllEl (7).

At this time, since Kl・R・G=T is constant, the F −V # characteristic can be arbitrarily controlled as shown in Fig. 4 by changing the power supply voltage (El), and the output voltage (VF )
is added to the base of the transistor (Tr) shown in FIG.

C. Effects of the Invention] As described below, according to the present invention, by controlling the DC voltage from the outside, the vertical amplitude can be set and changed as desired. Moreover, the vertical amplitude once set will not change unexpectedly due to a change in frequency.

Therefore, in an auto-scan monitor or the like that uses a variable frequency vertical synchronization signal, it is possible to change the setting of the vertical width of the screen and maintain the set width.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a vertical deflection circuit according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram of each part for explaining the operation, and FIG.
The figure is a configuration diagram showing an example of a variable F-V converter.
This figure is an F-V characteristic diagram of FIG. 3, FIG. 5 is a block diagram of a conventional vertical deflection circuit, and FIG. 6 is a signal waveform diagram of each part for explaining the operation of FIG. (1)... Vertical oscillation circuit, (2)... Sawtooth voltage generation circuit, (3)... Constant current circuit for discharge, (0...
・Output circuit, (5)...Amplifier, (6)...Variable F-V converter, (T")...Transistor, CC
)...Capacitor, (S)...Switch, (L)
...Deflection coil. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A vertical oscillation circuit that operates in synchronization with the input of a variable frequency vertical synchronization signal, and a discharge constant current circuit that has a switch, a charge/discharge capacitor, and a control pole that is triggered by the oscillation operation of this vertical oscillation circuit. In a vertical deflection circuit that includes a sawtooth voltage generation circuit and an output circuit that amplifies the sawtooth voltage generated by this sawtooth voltage generation circuit and drives a deflection coil, the control voltage of the discharge constant current circuit is controlled. A vertical deflection circuit comprising: a frequency-voltage conversion circuit that performs proportional control to the frequency of the vertical synchronization signal; and an output voltage of the frequency-voltage conversion circuit that can be variably controlled by a variable power source.