JPS6230356Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a repeater for relaying an input signal from a sensor or the like to a subsequent external load.

In the prior art, the input signal provided by the sensor is also used to power an internal load, such as a circuit provided in a repeater, and a capacitor is provided for power outage protection. Since this capacitor has a relatively large capacity, there is a problem in that the repeater cannot operate until the capacitor is sufficiently charged.

An object of the present invention is to provide a repeater that can operate normally within a short time after receiving an input signal.

FIG. 1 is a block diagram of a circuit including a repeater 1 according to the invention. The sensor circuit 2 detects a predetermined type of gas and outputs a high-level signal to the line 3 when the concentration of the gas becomes high. Electric power is supplied to this sensor circuit 2 via a line 4 from a commercial AC power source. this line 4
The power from the sensor circuit 2 is rectified and used within the sensor circuit 2. A signal derived from the sensor circuit 2 onto the line 3 is input to the repeater 1 . The output signal from this repeater 1 is given to a drive circuit 6 via a line 5. This drive circuit 6 drives a solenoid valve 7. The solenoid valve 7 is interposed in the middle of a pipeline that supplies the gas detected by the sensor circuit 2, and when the sensor circuit 2 detects a gas having a predetermined concentration or higher, the solenoid valve 7 closes. is closed. The solenoid valve 7 is also closed when a power outage occurs.
In order to open the solenoid valve 7, which has been once cut off, it is necessary to apply a voltage higher than the voltage normally applied to the drive circuit 6 via the line 5 for a short period of time. Only then does the solenoid valve 7 open, improving safety.

FIG. 2 is a block diagram showing a specific configuration of the repeater 1 according to the present invention. After the input signal from line 3 is stabilized by constant voltage circuit 8,
It is led out from line 9 to line 10 via diode D1. The input signal from the line 3 is also passed from the first switch 11 to the constant current circuit 12 to charge the first capacitor C1 for power failure protection. The output of the first capacitor C1 is connected to the diode D
2 to line 10. The charging voltage of the capacitor C1 is divided by voltage dividing resistors 13 and 14 and detected by a charging detection circuit 15. When the charging voltage of the first capacitor C1 reaches a predetermined value, the charging detection circuit 15 shuts off the first switch 11 to stop charging the first capacitor C1.

The power from line 9 through diode D1 is
The voltage is boosted by the DC-DC converter 16 and the second
Capacitor C2 is charged. 2nd capacitor C
The output voltage of No. 2 is divided by voltage dividing resistors 17 and 18 and detected by a boost detection circuit 19.
This boost detection circuit 19 shuts off the first switch 11 and operates the converter 16 when the output voltage of the second capacitor C2 is less than a predetermined boost value. In addition, this boost detection circuit 19
After the output voltage of the second capacitor C2 exceeds a predetermined boost value, the first switch 11 is turned on and the operation of the converter is stopped. Power on line 10 is used to power internal loads 20, such as circuits provided in repeater 1. Line 10 is also connected to line 7 on the output side via a second switch 21 and diode D3.

The output from the second capacitor C2 is led out from the third switch 23 via the diode D4 and into line 7. The signal discrimination circuit 25
Receives an input signal from and detects its voltage. This signal discrimination circuit 25 detects the occurrence of a power outage, supplies a detection signal of the power outage to the second switch 21 from a line 26, and shuts off the second switch 21 only during the period of the power outage. Also, the power failure detection signal from this line 26 is transmitted to the delay circuit 2 including a monostable circuit.
7 is given. The delay circuit 27 turns on the third switch 23 when a predetermined time W1 has elapsed after the power is restored. The capacitance of the capacitor C1 may be, for example, about 1 to 5 F, and the capacitance of the capacitor C2 may be, for example, about 1000 to 2000 μF.

During normal operation, when an input signal is input from line 3, constant voltage circuit 8 outputs to line 9,
Voltage VB is detected. This results in internal load 2
0 works normally. The voltage VB of this line 9 is
The voltage is boosted by the DC-DC converter 16, and the second capacitor C2 is boosted and charged. This step-up charging of the capacitor C2 is completed in a short time, for example, less than 1 second. When charging of the second capacitor C2 is completed, the boost detection circuit 19 switches the first switch 11
conducts. As a result, the input signal from the line 3 is applied to the first capacitor C1 via the first switch 11 and the constant current circuit 12, and the first capacitor C1 is charged. The constant current circuit 12 is
The charging current is suppressed so that the voltage applied to the first capacitor C1 does not drop, and charging of the first capacitor C1 is completed in a long period of time, for example, about 5 to 30 minutes. When the charging voltage of the first capacitor C1 reaches a predetermined value, the charging detection circuit 15
The switch 11 is shut off, thereby stopping the charging of the first capacitor C1.

During normal operation when the sensor circuit 2 is not detecting an abnormality in the gas concentration, a signal having a voltage V1 shown in FIG. , diode D
1, line 10, second switch 21 and diode D3 to line 5, the signal shown in FIG. When the gas concentration increases at time t1, the signal from the sensor circuit 2 led out to line 3 increases to V2. Therefore, the signal discrimination circuit 25 outputs a low level signal to the line 26, thereby blocking the second switch 21. Therefore, as shown in FIG. 3, a low level signal is sent to line 5 after time t1.

When the normal state returns at time t2, the signal discrimination circuit 25 outputs a high-level signal to the line 26, thereby making the second switch 21 conductive.
The delay circuit 27 waits for a predetermined time W1 from time t2.
After a period of time, the third switch 23 is turned on. This leads to a high voltage from the second capacitor C2 on line 7 as shown in FIG. The drive circuit 6 opens the electromagnetic valve 7 in response to the pulse p1 delivered to the line 7 by the conduction of the third switch 23. In this way, gas is supplied again and normal operation is performed.

Referring to FIG. 4, assume that the input signal shown in FIG. 4 is applied to repeater 1 from line 3. From time t3 to time W2, the second capacitor C2 is boosted and charged as described above. The output voltage of the second capacitor C2 is shown in FIG. At time t4, the first capacitor C1 is charged and its charging voltage increases as shown in FIG. 42. At time t5, the first switch 11 is cut off and charging of the first capacitor C1 is stopped.
The voltage of the second capacitor C2 is as shown in FIG. 4, and step-up charging is performed for a time W2 from time t3 to t4.

When a power outage occurs at time t4, the voltage drawn from constant voltage circuit 8 to line 9 becomes zero. At this time, the output voltage of the first capacitor C1 is
The signal is applied to the internal load 20 from the diode D2, and the internal load 20 is protected from power failure.

Diode D2 is activated when the first capacitor C1 is not fully charged, i.e. when the voltage on line 9
When VB exceeds the voltage VC1 of the first capacitor C1, current is prevented from flowing into the first capacitor C1 from the line 9, thereby preventing the voltage of the line 9 from dropping. Further, current is prevented from flowing backward from the internal load 20 and line 10 side to the first capacitor C1.

As described above, according to the present invention, the internal load provided in the repeater can operate normally at the same time as the input signal is input. Furthermore, since the second capacitor is boosted and charged only for a short period of time when the input signal is applied, power consumption can be reduced. Therefore, it becomes possible to connect and use a plurality of repeaters 1 to a single sensor circuit 2, and the range of use of the repeater of the present invention can be expanded.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram including a repeater 1 according to an embodiment of the present invention, FIG. 2 is a block diagram showing a specific configuration of a repeater 1 according to an embodiment of the present invention, and FIGS. FIG. 4 is a waveform diagram for explaining the operation of the repeater 1. DESCRIPTION OF SYMBOLS 1...Repeater, 2...Sensor circuit, 6...Drive circuit, 7...Solenoid valve, 8...Constant voltage circuit, 11...
...First switch, 12... Constant current circuit, 15...
Charging detection circuit, 16...DC-DC converter, 1
9... Boost detection circuit, 20... Internal load, 21...
...Second switch, 23...Third switch, C1...
...First capacitor, C2...Second capacitor, D
1, D2, D3, D4...Diode.

Claims (1)

[Scope of Claim for Utility Model Registration] A first switch; a first capacitor for power failure protection that charges an input signal via the first switch to energize an internal load such as a circuit provided in the repeater; A converter that boosts the input signal, a second capacitor that is charged by the output of the converter, and a first switch that detects the output voltage of the second capacitor and switches the first switch until the output voltage reaches a predetermined boost value. a boost detection circuit that shuts off the voltage and operates the converter, and after reaching a predetermined boost value, turns on the first switch and stops the operation of the converter; and a boost detection circuit that connects the input signal to an external load following the repeater. a second switch that outputs the output from the second capacitor to the external load following the repeater, and a third switch that detects the occurrence of a power outage and outputs the second
A repeater comprising: a circuit that cuts off the switch; and a circuit that turns on the third switch when a predetermined period of time has elapsed after the power is restored in response to a detection output of the occurrence of a power outage.