JPS5816159Y2 - lamp display circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lamp display circuit device for preventing rush current.

FIG. 1 and FIG. 4 show a conventionally used L-lamp display circuit.

In the circuit of Fig. 1, when the transistor Tr is turned on, the lamp L is turned on.
In the circuit where the lamp is lit, a lamp such as L must be used in which the rush current of the lamp L does not exceed the maximum rated output current of the transistor Tr.

When the rush current of the lamp exceeds the maximum rated output current of the transistor Tr, the circuit configuration shown in FIGS. 2 and 3 is used.

The circuit shown in FIG. 2 connects a rush current prevention resistor Rs in series with the lamp L to prevent the rush current of the lamp L from exceeding the maximum rated output current of the transistor Tr.

Also, in the circuit shown in Figure 3, a resistor Rp is connected in parallel with the transistor Tr, and when the transistor Tr is turned off, the resistor Rp is connected in parallel with the transistor Tr.
The lamp L does not light up, and a dark current of about L is passed through the transistor T to warm the filament of the lamp L.
Rush current does not flow even when r b' is turned on.

In addition, in the circuit shown in Fig. 2, a resistor Rs is inserted in series with the lamp L, so that when the transistor Tr is turned on, the voltage applied to the lamp decreases slightly, resulting in a dark lighting. When the number of lamps in both FIG. 3 and FIG. 3 is n, n resistors Rsp and Rp are required.

However, in the lit state, the one in Figure 3 is better than the one in Figure 2 because it lights up brighter.

FIG. 4 shows a circuit in which the number of lamps in FIG. 3 is increased to n, and a lamp inspection circuit is added thereto.

In Figure 4, L1 to Ln are lamps, Rp1 to Rpn are resistors for flowing dark current to the lamps, Tr] to Trn are transistors for lighting the lamps, D1 to Dn are diodes to prevent interference, and 30T is the lamp. This is an inspection switch.

Generally, this figure 4 is used, and because it is necessary to install a resistor to flow dark current to the lamps in proportion to the number of lamps, there is a disadvantage that the number of assembly and wiring increases. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a lamp display circuit device that effectively suppresses rush current and requires only one resistor for flowing dark current regardless of the number of lamps.

The present invention will be described below with reference to an embodiment shown in FIG.

In Fig. 5, L1 to Ln are indicator lamps, DI-Dn
Trl to Trn are transistors, 30゛T is a lamp inspection switch, ZD is a constant voltage diode, and R is a resistor for flowing dark current.

In this circuit, transistor T r ] −T rn is OF
The dark current at 'l' is the lamp L1゜(orDn), diode Dl (orDn), diode D, resistor 11-
flows through.

In general, if the circuit voltage for lighting a lamp is Va, the voltage applied to the lamp when dark current flows to the lamp is approximately! 4
That's about it.

When dark current flows, the diode DI (orDn), D
If the forward voltage at each is set as IV, and a constant voltage diode with an energy voltage a (-+2)V is used, the voltage applied to the resistor R becomes Va-(''-+2)V, and its resistance value is the constant current Let RL be the lamp resistance at
When , almost no current flows through the constant voltage diode ZD.

When the transistor Tri turns on, the dark current that had been flowing through the diode DJ to the lamp L stops flowing, and a corresponding amount flows through the constant voltage diode ZD, so the voltage applied to the resistor R does not change. .

In other words, transistors Trl to Trn are turned on and off.”
is constant regardless of

In addition, the diode D is L so that the voltage Va is not applied to the constant voltage diode when the lamp inspection switch is 30TON.
- Set it up as a stomper like L.

As explained above, only one resistor is required for flowing dark current to the lamps, regardless of the number of lamps.

6 to 8 show other embodiments.

In Fig. 5, even when the lamp inspection 3 inch 30T is turned on, a constant voltage is applied to the resistor R.
It is the same as if the power supply used is losing that much power.

An improved version 9 is shown in Fig. 6.

Figure 6 shows the operational close contact of a 3-inch 30T lamp inspection.
When the voltage is set to N, the current flowing through the constant voltage diode ZD is turned off by the operating contact of the 3-inch 30T lamp.

FIG. 7 shows an L circuit with a lamp inspection circuit.

In this circuit, since the diode D in the circuit of the resistor R in Figure 5 is L, the constant voltage diode ZD has an energy voltage ('
It is sufficient to use a resistor of M+Bv, and the voltage applied to the resistor R is Va+(s+)Vo
Let R be the resistance value of .

Figure 8 shows a diode D instead of a constant voltage diode ZD.
i1 to Din'r were used.

For example, if the energy voltage of the voltage regulator diode ZD in FIG.
Assuming that +1 is 5V, five diodes are required.

Also, there is no problem if you replace the transistor with a contact.

As mentioned above, the present invention is to set up as many diodes as there are display lamps, and connect several diodes in series to control the voltage applied to the lamps when the current is flowing in the dark. The dark current resistance is 1 to ensure that
Only one piece is enough.

Therefore, when the number of lamps increases to 100 or 200, the number of assembly and wiring steps is greatly reduced.

[Brief explanation of drawings]

Figures 1 and 4 are circuit diagrams showing conventional lamp display circuits, Figure 5 is a connection diagram showing an embodiment of the lamp display circuit of the present invention, and Figures 6, 7, and Figure 8 is a connection diagram showing other different embodiments of the present invention. L1 to Ln... Lamps, Tr1 to Trn...
・・・Transistor, Ds D1 to Dns Di
1~Din=Diode, ZD... Constant voltage diode, R... Resistor, 30T... Lamp inspection switch.

Claims (1)

[Scope of utility model registration request] A lamp display circuit device in which a lamp is connected to a resistor for flowing a dark current through a diode, and the voltage dropped between the lamp and the diode is guaranteed by the forward voltage of a constant voltage diode.