JPH0326682Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a switch circuit that transmits a signal from a manual switch to an electronic switch (analog switch, etc.) via a switch drive circuit to open/close the switch. It relates to a switch circuit that has a function to set the state.

In a switch circuit that stores the operation of a switch with an automatic reset type contact and opens or closes a predetermined electronic switch, an auxiliary current source is used to maintain the switch operation in the memory circuit even when the main power is cut off. It has a circuit. However, if the main power is cut off for a long time, the capacity of the auxiliary current source circuit may become insufficient and the memory in the memory circuit may be erased. If the memory is erased, the memory may become unstable when the main power is restored. There is a drawback that is a setting condition.

The present invention is intended to eliminate the above-mentioned drawbacks, and its main purpose is to turn on a predetermined switch when the auxiliary current source circuit is insufficient in capacity when the main power is turned on (when erasing memory) to restore the initial state. The purpose of the present invention is to provide a switch circuit with a setting function.

Another object of the present invention is to provide a switch circuit that operates a switch according to a setting condition of a memory circuit when the charging voltage of a charging circuit included in the auxiliary current source circuit is at a high potential.

The switch circuit of the present invention includes a signal input stage provided with a switch connected in pairs to a plurality of indicator lights and having an automatic return type contact, a detection circuit that converts a signal from the signal input stage into a pulse, and a detection circuit that converts a signal from the signal input stage into a pulse. A memory circuit that stores signals from the circuit, a drive circuit that keeps a predetermined indicator light turned on based on the signal from the memory circuit, an electronic switch that operates based on the signal of the memory circuit, and the detection circuit. a current source circuit that supplies current to the storage circuit; an auxiliary current source circuit that is supplied with charging current from the current source circuit and includes a capacitor that supplies current to the storage circuit when the main power supply is cut off; and a predetermined portion of the signal input stage. A capacitor is connected in parallel between the contacts of the switch, and when the main power is turned on, a charging current is supplied from the current source circuit to the capacitor, thereby shorting the contacts of a predetermined switch and establishing an initial state. This is what you set.

Below, the first part of the switch circuit according to the present invention will be explained.
This will be explained based on FIGS. 4 to 4.

FIG. 1 is a block diagram of a switch circuit. The signal input stage is a switch 1 with a self-returning contact.
and an indicator light 2. The detection circuit 3, memory circuit 4, and drive circuit 9 are a switch drive circuit section. Also, connection point 1 between switch 1 and indicator light 2
A capacitor 8 is connected between the capacitor 7 and the ground, and one end of the capacitor 8 is connected to the current source circuit 6 and the auxiliary current source circuit 7 via a resistor 14. Detection circuit 3
converts the signal from switch 1 into a pulse, which is transmitted to storage circuit 4 and stored. Furthermore, the signal is transmitted to open and close the electronic switch 5 and also to the drive circuit 9.
A signal is transmitted to the indicator light 2 to cause one of the indicator lights 2 to remain lit. Also, a part of the detection circuit 3 and the storage circuit 4 are I ²
The injector current is injected into these I ² L elements from a current source circuit 6 through a resistor 11, a diode 12, and a resistor 13. When the main power is turned on, a charging current flows into the auxiliary current source circuit 7 through the resistor 15 and into the capacitor 16.

Now, when the main power supply is cut off, an injector current is injected from the auxiliary current source circuit 7 into the I ² L circuit forming the memory circuit 4 to maintain the memory. However, when the capacity of the auxiliary current source circuit 7 falls below a predetermined level,
The memory in the memory circuit 4 is erased. If the memory circuit is erased when the main power is turned on, the current source circuit 6
A charging current flows into the capacitor 8 through the resistor 14, and the contacts of a predetermined switch 1 in the signal input stage are pseudo short-circuited and turned on. In this way, switch 1 at the signal input stage is set to a predetermined state (initial state). Of course, the indicator light 2, electronic switch 5, and memory circuit 4 operate according to this initial condition. When the capacitor 8 is charged, the potential at the connection point 17 becomes a high potential, and the switch 1 at the signal input stage can be set arbitrarily. When another switch 1 in the signal input stage is turned on, the indicator light 2 corresponding to that switch lights up, and the switch 1 that was in the on state when the main power was turned on goes out. This newly set condition is then stored in the storage circuit 4. In addition, if the main power supply is cut off in this state, the auxiliary current source circuit 7
A current is injected into the memory circuit 4 from then on, and the memory is retained. When the main power is restored while the setting conditions of the switch 1 are stored, the indicator lamp 2 and the electronic switch 5 are activated based on the setting conditions.

FIG. 4 shows an embodiment of the switch circuit of the present invention. The symbol of the I ² L element is shown in FIG. 2, and its equivalent circuit is shown in FIG. I is an injector terminal. In FIG. 4, the signal input stage includes switches 1 ₁ to 1 _o having a plurality of self-resetting contacts and light emitting diodes 2 ₁ to 2 _o , which are connected in series. The detection circuit ₃₁ is formed by transistors _T1 to _T3 , an ^I2L element _A1, etc., and the detection circuit _3o has a similar configuration. The memory circuit 4 ₁ is formed from a flip-flop (hereinafter abbreviated as F/F) consisting of I ² L elements A ₂ and A ₃ , and the F/F 4 _o has a similar structure. 18 is a signal transmission circuit, one of the output terminals of the I ² L element A ₄ is connected to the electronic switch 5 ₁ , and the other output terminal is connected to the base of the transistor T ₇ of the drive circuit 9 ₁ via the I ² L element A ₅ . It is connected to the. I ² L element A ₉ is also connected in a similar manner. Electronic switch 5 ₁ ~ 5 _o
is an analog switch or the like, and a and n are signal sources.

The I ² L element forming the switch circuit is supplied with an injector current from the current source circuit 6. Its configuration is a voltage source circuit 10 and an injector resistor 11.
, a diode 12 and an injector resistor 13. The other end of the injector resistor 11 is connected to I ² L elements A ₂ , A ₃ ...A ₇ , which form the memory circuit 4.
A ₈ is connected to the injector terminal and also to the auxiliary current source circuit 7. The connection point 19 is connected to the capacitor 8 via the resistor 14. Both ends of the capacitor 8 are connected to the terminals of the switch ₁₁ , respectively. Further, the auxiliary current source circuit 7 is formed from a resistor 15 and a voltage source 16. Voltage source 16 is formed by a capacitor.

Now, turn on the main power to this switch circuit.
Since the auxiliary current source circuit 7 is in a discharged state, the potential of the input/output terminal 19 of the auxiliary current source circuit 7 is approximately zero potential. Therefore, the memory circuit 4 is in a state where the memory has been erased, and a charging current flows from the current source circuit 6 to the capacitor 8. Further, the auxiliary current source circuit 7 is usually formed from a capacitor and a resistor, and charging is started at the same time as the capacitor 8 is charged. The capacitor 8 needs to be charged faster. As described above, since a charging current flows through the capacitor 8 at the same time as the main power is turned on, the switch ₁₁ becomes short-circuited, a switch-on signal is transmitted, and the transistors _T1 to _T3 of the detection circuit ₃₁ are turned off. Then, since the potential of the input terminal of the I ² L element A ₁ becomes a high potential (H level), the output terminal becomes L level and at the same time resets the F/F 4 _o .
Furthermore, the I ² L elements A ₄ and A ₅ are activated in sequence, the transistor T ₇ is turned on, the drive circuit 9 ₁ is activated, and the light emitting diode 2 ₁ is maintained in a lighting state. Also,
Based on the operation of the drive circuit 9 ₁ , the output terminal of the I ² L element A ₁ of the detection circuit 3 ₁ is inverted from L level to H level. In this way, the input stage switch is set to a predetermined setting state.

Next, with this setting, other switches 1 _o
When is pressed, the switch drive circuit is activated and the light emitting diode _2o is kept lit. At the same time, a reset signal is transmitted from ^I2L circuit _A6 to F/ _{F41 .}
Cancel the memory of. When the switch 1 of the signal input stage is set in this way, it is stored in the memory circuit 4. Further, if the main power supply is cut off in such a state, the injector current is supplied from the auxiliary current source circuit 7 to the I ² L elements of F/Fs _{4 1} to 4 _o , and the memory is retained. However, if the main power supply is cut off for a long time, the capacity of the auxiliary current source circuit 7 becomes insufficient and the memory of the storage circuit 4 is erased. and,
When the main power is restored, a charging current flows through the capacitor 8 in the same way as when the main power is turned on, the contacts of switch ₁₁ are pseudo-on, and the signal input stage switch is initialized based on predetermined conditions. The state is set.

Of course, the present invention is not limited to the embodiment shown in FIG. 4, and if it is desired to obtain a predetermined current amplification degree, I ² L elements may be connected in several stages, or various known methods may be used. Further, the switch 1 may be a transistor switch.

As mentioned above, the switch circuit of the present invention adds a capacitor to a predetermined switch, and when the main power is turned on, a charging current flows into the capacitor to short-circuit the terminals of the switch, thereby creating a pseudo-predetermined signal. This is to set the initial state by turning on the switch. If the memory circuit is in an operating state, the switch circuit is restored under the memorized setting conditions. Therefore, there is no possibility of unstable operation when the main power is turned on or restored, and there is an advantage that a stable and highly reliable switch circuit can be provided by a simple circuit.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a switch circuit according to the present invention, Fig. 2 is a diagram showing the symbol of an I ² L element, Fig. 3 is an equivalent circuit diagram thereof, and Fig. 4 is a diagram of a switch circuit according to the present invention. FIG. 2 is a circuit diagram showing an example. 1... Switch, 2... Indicator light, 3... Detection circuit, 4... Memory circuit, 5... Electronic switch, 6...
...Current source circuit, 7...Auxiliary current source circuit, 8...Capacitor, 9...Drive circuit, 10...Voltage source, 1
1, 13...Injector resistance, _A1 ~ _A10 ... ^I2
L element.

Claims (1)

[Scope of utility model registration request] A signal input stage connected in pairs to a plurality of indicator lights 2 and provided with a switch 1 having an automatic return type contact; a detection circuit 3 for converting a signal from the signal input stage into a pulse; a memory circuit 4 that stores signals from the memory circuit; a drive circuit 9 that keeps a predetermined indicator light lit based on the signal from the memory circuit; and an electronic switch 5 that operates based on the signal from the memory circuit.
, a current source circuit 6 that supplies current to the detection circuit and the memory circuit, and an auxiliary current source circuit 7 that includes a capacitor that is supplied with charging current from the current source circuit and supplies current to the memory circuit when the main power supply is cut off. and a capacitor 8 connected in parallel between the contacts of a predetermined switch of the signal input stage. A switch circuit characterized in that an initial state is set by short-circuiting the contacts of a predetermined switch.