JPH0785192B2 - Set value display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a set value display device for displaying exposure conditions and other set values in a light source device for an endoscope. The present invention relates to an improvement of a set value display device that stores set values and the like using a container.

[Prior Art] In recent years, a set value display device that stores a set value or the like in a semiconductor memory element has been used.
That method requires a backup power supply to save the contents of the memory after the main power is turned off, has the drawback of being relatively vulnerable to noise, and requires a CPU to write and read the memory. Therefore, a simple set value display device that stores a set value and the like by a holding type electromagnetic switch is widely used.

Conventionally, this kind of set value display device using a holding type electromagnetic switch has a holding type electromagnetic switch connected to the output end of a setting circuit composed of semiconductor elements, etc. It was simply connected to the same power source.

[Problems to be Described by the Invention] Generally, the output of a semiconductor device has a property of becoming unstable for a moment when the power is turned on and off. However, in the above-mentioned conventional set value display device, since the setting circuit and the holding type electromagnetic switch are simply connected to the same power source, the power is turned on.
-When switching OFF, when the holding type electromagnetic switch is still in operation, an unstable output signal is input from the semiconductor element of the setting circuit and the contact point of the holding type electromagnetic switch is reversed There is a defect that the value is stored and displayed.

The present invention eliminates such conventional drawbacks and turns on the power supply.
An object of the present invention is to provide a stable set value display device which is not affected by an unstable output of a semiconductor element when switching OFF.

[Means for Solving Problems] A set value display device of the present invention for solving the above problems will be described with reference to FIG. 1 corresponding to the embodiment. The input set value is output as an electric signal via the semiconductor elements 43 and 44, and the holding type electromagnetic switch 80 operates by the output signal to output a drive signal to the display means 5.

Then, the power supply 3 supplies electric power to both the setting circuit 40 and the holding type electromagnetic switch 80, and the time difference switching means 90 controls the electric power supply to the holding type electromagnetic switch 80 as follows.

(1) When the power supply 3 is turned on, the operating power is supplied to the holding type electromagnetic switch 80 after the operation of the semiconductor elements 43 and 44 is started.

(2) When the power supply 3 is turned off, the operating power supply to the holding type electromagnetic switch 80 is stopped prior to the end of the operation of the semiconductor elements 43 and 44.

[Operation] At the moment when the power supply 3 is turned on, the outputs of the semiconductor elements 43 and 44 become momentarily unstable due to malfunctions due to noise or delay of operation time, and a signal unrelated to the setting switch 41 causes a holding type electromagnetic switching. However, since the holding electromagnetic switch 80 has not been supplied with operating power and is not in the operating state, the holding electromagnetic switch 80
Does not malfunction and its contacts do not reverse.

Further, even when the power supply 3 is turned off, the outputs of the semiconductor elements 43 and 44 become unstable for a moment, but the supply of the operating power to the holding type electromagnetic switch 80 has already been stopped and is not in the operating state.
The holding type electromagnetic switch 80 does not malfunction and its contacts do not reverse.

[Embodiment] An embodiment in which the set value display device of the present invention is applied to an endoscope light source device will be described with reference to the drawings.

FIG. 1 is a circuit diagram of an embodiment, in which an AC power supply 1 is connected via a power switch 2 to a known DC stabilized power supply 3 that outputs a constant-voltage DC current, and its output voltage (a ) Is the Zener voltage of the Zener diode 97 (b)
It is set above. Then, on the anode side of the output terminal of the DC stabilized power supply 3, a setting circuit 40 that outputs the input set value as an electric signal, a display unit 5 including, for example, a light emitting diode, and an exposure condition and the like are displayed. A system control circuit 6 for controlling the system is directly connected, and the cathode side is grounded.

The base of the transistor 7 is connected to the signal output terminal of the setting circuit 40, the emitter terminal of the transistor 7 is grounded, and one coil 81 of the two-winding holding electromagnetic switch 80 is connected to the collector. . And that coil 81
The stabilized DC power supply 3 is connected to the other end of the DC power supply via the time difference switching means 90.

On the other hand, the contact 82 of the holding type electromagnetic switch 30 is connected with the signal lines 83 and 84 to the display means 5 and the system control circuit 6,
By switching the contact 82, it is connected so as to be intermittently connected to the ground. A plurality of the holding type electromagnetic switch 80 and the display means 5 are provided in parallel, and the contact 82
When the display is switched, the display means 5 provides a predetermined display appealing to the human eye, and the system control circuit 6 operates in accordance with the predetermined display.

Reference numeral 41 is a setting switch for inputting a set value, one end of which is grounded and the other end of which is connected to the DC stabilized power supply 3 through a resistor 42 and which functions as a buffer, for example, TTL (transistor transistor transistor It is connected to the input terminals of semiconductor elements 43 and 44 forming a logic). The semiconductor element 44 is the final stage of a logic circuit (not shown).
These semiconductor elements 43 and 44 are connected to the DC stabilized power supply 3 and supplied with power, and the signal output terminal is connected to the base of the transistor 7 via the resistor 45.

The lowest voltage (c) for ensuring the operation of these semiconductor elements 43, 44 is selected to be lower than the Zener voltage (b) of the Zener diode 97.

The time difference switching means 90, via the resistors 95, 96,
It has first and second transistors 91, 92 whose collectors are connected to the DC stabilized power supply 3 and a third transistor 93 whose collector is directly connected to the DC stabilized power supply 3. The base of the first transistor 91 is the resistor 94.
Is connected to the stabilized DC power supply 3 via a zener diode 97, and the collector of the second transistor 92 is connected to the base of the second transistor 92 via a diode 98.
The base of the third transistor 93 is connected to the collector of 92.

The emitters of the first and second transistors 91 and 92 are both grounded, and the emitter of the third transistor 93 is connected to the coil 81 of the holding type electromagnetic switch 80 as the output terminal of the time difference switching means 90. There is.

Next, the operation of the above embodiment will be described.

First, the operation of the time difference switching means 90 will be described. When the input voltage to the time difference switching means 90 is equal to or higher than the Zener voltage (b) of the Zener diode 97, a reverse current flows in the Zener diode 97. 1
The transistor 91 has a base current and is turned on, and the collector voltage becomes zero. Therefore, the second transistor 92
Is off because the base current does not flow, the base current flows to the third transistor 93, and the third transistor 93
It is turned on, and the coil 81 of the holding type electromagnetic switch 80 is connected to the stabilized DC power supply 3.

When the input voltage to the time difference switching means 90 is lower than the Zener voltage (b), the reverse current does not flow in the Zener diode 97, which is the reverse of the above.
In 91, the base current does not flow and is turned off. Therefore, the base current flows through the second transistor 92 and is turned on, and the collector voltage thereof becomes zero. Therefore, the third transistor 93 is turned off because the base current does not flow, and the coil 81 is not supplied with power.

Thus, when the input voltage is equal to or higher than the Zener voltage (b) of the Zener diode 97, the time difference switching means 90
When ON and the input voltage is lower than the Zener voltage (b)
It turns off.

Next, when the power switch 2 is ON and when it is OFF
Will be described.

When the power switch 2 is ON, the setting circuit 4
0, the display means 5 and the system control circuit 6 are supplied with power from the stabilized DC power supply 3. DC stabilized power supply 3
Since the input voltage (a) to the time difference switching means 90 is equal to or higher than the Zener voltage, the time difference switching means 90 is turned on, and the holding type electromagnetic switch 80 is also supplied with the power of the stabilized DC power supply 3.

Therefore, by operating the setting switch 41 of the setting circuit 40, the holding type electromagnetic switch 80 becomes a predetermined setting state corresponding to the state of the setting switch 41, and the signal is displayed on the display means 5 and the system control circuit 6. sending.

Further, when the power switch 2 is off, the circuit does not operate at all, and the holding type electromagnetic switch 80 stores and retains the setting state.

Next, regarding the operation at the moment when the power switch 2 is turned on,
To explain with reference to the time chart of FIG. 2, the setting circuit 40, the display means 5 and the control circuit 6 are supplied with power from the stabilized DC power supply 3 at the same time when the power switch 2 is turned on. Then, each of the semiconductor elements 43 and 44 starts its operation when the input voltage becomes higher than the minimum voltage (c) for ensuring the operation.

On the other hand, when the input voltage to the time difference switching means 90 becomes equal to or higher than the Zener voltage (b) of the Zener diode 97, the time difference switching means 90 is turned on and the holding type electromagnetic switch 80 is supplied with the operating power to hold it. The type electromagnetic switch 80 starts to operate.

In this embodiment, since b> c is set, when the semiconductor elements 43 and 44 start operating, the holding type electromagnetic switch 8
At 0, the operating power has not been supplied yet, and the holding type electromagnetic switch 80 has not started operating.

Therefore, immediately after the semiconductor elements 43 and 44 are in the operating state, the output is momentarily unstable due to malfunction due to noise or delay in the operating time, and a signal unrelated to the state of the setting switch 41 causes a holding type electromagnetic switching. However, in the above embodiment, the holding electromagnetic switch 80 is not yet supplied with operating power, and the holding electromagnetic switch 80 is not in the operating state. The contact 82 does not reverse due to the holding type electromagnetic switch 80 malfunctioning.
Therefore, an erroneous signal is not output to the display means 5 or the system control circuit 6, and the device always performs the correct display and the correct operation as the input of the setting switch 41.

Contrary to the above, the operation at the moment when the power switch 2 is turned off is first the input voltage of the time difference switching means 90 becomes the Zener voltage (b) or less, and the operating power to the holding type electromagnetic switch 80 is changed. The supply is stopped, and the holding type electromagnetic switch 80 stores the setting state at that time. And then the semiconductor element
The operation voltage of the semiconductor elements 43 and 44 is stopped when the input voltage to 43 and 44 becomes the minimum voltage (c) for ensuring the operation or less.

Even at this time, the outputs of the semiconductor elements 43, 44 become unstable, but since the holding type electromagnetic switch 80 has already stopped the supply of operating power, the holding type electromagnetic switch 80 does not reverse and the holding type electromagnetic switch 80 does not reverse. The switch 80 continues to memorize the correct setting state.

The operation time deviations Δt and Δt ′ between the semiconductor elements 43 and 44 and the holding type electromagnetic switch 80 are the minimum voltage (c) for ensuring the operation of the semiconductor elements 43 and 44 and the Zener voltage (b) of the Zener diode 97. ) And can be freely selected by appropriately setting.

Although the two-winding type holding electromagnetic switch 80 is used in the above embodiment, the present invention can be applied to the one-winding type.

EFFECTS OF THE INVENTION According to the set value display device of the present invention, since the holding type electromagnetic switch is in the non-operating state at the moment when the operation of the semiconductor element of the setting circuit is turned on and off, The unstable output of the holding type electromagnetic switch does not malfunction and its contacts do not reverse, and always maintains the correct setting state corresponding to the state of the setting switch.

Therefore, the device has an excellent effect of always performing a correct display and a correct operation without storing an erroneous set value or a display state.

Also, because it does not require a CPU or backup power supply,
It is simple, inexpensive, and resistant to noise.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is a time chart showing its operation. 3 ... DC stabilized power supply, 5 ... display means, 40 ... setting circuit, 41 ... setting switch, 43, 44 ... semiconductor element, 80 ...
… Holding type electromagnetic switch, 90 …… Time difference switching means, 9
1,92,93 …… Transistor, 97 …… Zener diode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H03K 17/28 Z 9184-5J

Claims (2)

[Claims] 1. A setting circuit for outputting a set value input from a setting switch as an electric signal via a semiconductor element,
A holding type electromagnetic switch that operates according to the output signal from the setting circuit and outputs a drive signal to the display means, a power supply that supplies power to both the setting circuit and the holding type electromagnetic switch, and the power supply is turned on. If this happens, the operating power will be supplied to the holding type electromagnetic switch after the start of the operation of the setting circuit, and the power will be turned off.
And a time difference switching means for stopping the supply of operating power to the holding type electromagnetic switch before the operation of the semiconductor element is finished. 2. The holding type electromagnetic switch is connected to a power source through a time difference switching means, and when an input voltage to the time difference switching means is a predetermined voltage value higher than an operating voltage of the semiconductor element. The set value display device according to claim 1, wherein the time difference switching means is turned on.