JP5630204B2 - 2-wire wiring device - Google Patents

Description

  One embodiment of the present invention relates to a two-wire wiring device provided with connection terminals for two electric wire lines for supplying electric power.

  The conventional two-wire wiring device has only two power supply line connection terminals for supplying power, and incorporates a power supply unit, an operation unit, and a load switching unit in a load switching device having a human detection function. The load opening / closing control is performed based on the detection result of the human detection function. (For example, Patent Document 1)

JP 2000-133473 A

  In the technique of Patent Document 1 described above, the short-circuit current generated when the load is short-circuited flows to the load and the 2-wire wiring device for a long time, and the 2-wire wiring device may be damaged. There was a problem.

  An object of the present invention is to provide a two-wire wiring apparatus capable of preventing the self-damage by instantaneously suppressing the influence of the short-circuit current when a load short-circuit current occurs.

One embodiment of this invention, the control electrode to the supply power from a power source to the load by opening and closing in response to signals supplied, the switching element of the non-self holding type of unpowered, the load current flows to the switching elements compared signal based on the mean value and a first set value, compares the first control means for controlling the switching elements in the result, signal and the first based on the instantaneous value of the load current flowing to the switching element set height has to compare the second set value than value, characterized by comprising second control means for controlling said switching element in comparison result.

  According to one embodiment of the present invention, when there is a short circuit current, it is possible to instantaneously suppress the influence of the short circuit current and prevent the load from being damaged.

It is a circuit block diagram for demonstrating one Embodiment regarding the two-wire type wiring instrument of this invention. It is explanatory drawing for demonstrating the effect | action of one Embodiment. It is a circuit block diagram for demonstrating other embodiment regarding the 2-wire type wiring instrument of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 and FIG. 2 are for explaining an embodiment relating to the two-wire wiring device of the present invention, FIG. 1 is a circuit configuration diagram, and FIG. 2 is an explanatory diagram for explaining the operation.

  100 shown in FIG. 1 is a load switching device with a human detection function corresponding to a two-wire wiring device. The load switching device with human detection function 100 includes connection terminals T1 and T2 for connecting two power supply lines, and a commercial power supply 11 and a load 12 are connected in series between the connection terminals T1 and T2. To do.

  A rectifier circuit unit 13 configured by a diode bridge is connected from the connection terminals T <b> 1 and T <b> 2 to the inside of the load switching device 100 with a human detection function, and converts the AC voltage of the commercial power supply 11 into a DC voltage. The output of the rectifier circuit unit 13 is supplied to a power supply unit 14 that generates a secondary voltage. The power supply unit 14 has output terminals T3 and T4, and supplies power used in the load switching device 100 with a human detection function. That is, for example, a DC voltage VDD of 5 V is output from the output terminal T3, and a predetermined DC voltage of 7 to 12 V, for example, is output from the output terminal T4, and a three-terminal regulator or the like is provided therein as necessary.

  The DC voltage VDD output from the output terminal T3 of the power supply unit 14 is supplied as the power supply for the infrared sensor 15. The infrared sensor 15 detects infrared rays radiated from the human body passing through the sensing area and outputs the infrared rays from the output OS as a human detection signal.

  Between the output of the rectifier circuit section 13 and the input of the power supply section 14, the drain electrode of the transistor Q1, which is a switching element using a MOS FET for opening and closing the load 12, is connected. The source electrode of the transistor Q and the reference potential point A bias resistor R1 is connected between the two. The connection point between the source electrode of the transistor Q1 and the resistor R1 is connected to the non-inverting input of the comparator CA via the resistor R2 and to the non-inverting input of the comparator CB.

  The non-inverting input of the comparator CA is connected to the reference potential point via the capacitor C1. The resistor R2 and the capacitor C1 constitute an averaging circuit 16. The output of the averaging circuit 16 averages the input load current and supplies it to the non-inverting input.

  Furthermore, the DC voltage VDD generated by the power supply unit 14 is connected to a reference potential point via a series circuit of resistors R3 to R5. The connection point between the resistors R4 and R5 is connected to the inverting input of the comparator CA, and the connection point between the resistors R3 and R4 is connected to the inverting input of the comparator CB. With this connection, for example, 0.2V is set as the first setting value based on the resistors R3 to R5 for the non-inverting input of the comparator CA, and the second setting based on the resistors R3 to R5 is set for the non-inverting input of the comparator CB. For example, 0.5 V higher than the first set value is supplied as a value. The comparator CA outputs the H level from the comparison output when the non-inverting input exceeds 0.2V, and the comparator CB outputs the H level from the comparison output when the non-inverting input exceeds 0.5V.

  The comparison output of the comparator CA is connected to the anode of the diode D1, and the comparison output of the comparator CB is connected to the anode of the diode D2. The cathodes of the diodes D1 and D2 are connected in common to the input of the inverter INV whose output is connected to the gate of the transistor Q1 and one end of the resistor R6. The diodes D1 and D2 constitute a diode OR circuit. The other end of the resistor R6 is connected to the collector electrode of the NPN transistor Q2 whose emitter electrode is connected to the reference potential point, and the collector and one end of the NPN transistor Q3 whose emitter is connected to the reference potential point are connected to the DC voltage VDD. Connected to the other end of the resistor R7 connected to.

  The base electrode of the transistor Q2 is connected to the reference potential point via the capacitor C2, and is connected to the connection point between the source electrode of the transistor Q1 and the resistor R1 via the resistor R8. The base electrode of the transistor Q3 is connected to an output terminal T4 that generates a predetermined constant voltage via a resistor R9, and is connected to the output OS of the infrared sensor 15 via a diode D3 having the polarity shown. .

  The system that controls the transistor Q1 with the output of the comparator CA determined based on the voltages applied to the inverting input and the non-inverting input of the comparator CA constitutes a first control means. The system that controls the transistor Q1 with the output of the comparator CB determined based on the voltages applied to the inverting input and the non-inverting input of the comparator CB constitutes a second control means.

  Here, consider a case where the voltage applied to the gate electrode of the transistor Q1 is at the L (low) level. The transistor Q1 in this case is in an OFF state, and the AC voltage of the commercial power supply 11 is converted into a DC voltage by the rectifier circuit unit 13, and this DC voltage is supplied to the power supply unit 14 via the backflow prevention diode D4. The power supply unit 14 outputs, for example, a DC voltage VDD of 5 V, which is a secondary power supply, from the output terminal T3, and a DC voltage that varies between 7 and 12 V, for example, from the output terminal T4. At this time, the direct-current voltage VDD is applied to the infrared sensor 15, and the human sensor can be detected.

  When the infrared sensor 15 detects a person, it outputs an H (high) level that is a human detection signal from the output OS. Since the cathode of the diode D3 is at the H level, the anode is at the H level, the base electrode of the transistor Q3 is also at the H level, and the transistor Q3 is turned on. When the transistor Q3 is turned on, the voltage between the resistor R7 and the collector electrode of the transistor Q3 becomes H level. As a result, the input of the inverter INV becomes L level, the output of the inverter INV becomes H level, the transistor Q1 is turned on, and power is supplied to the load 12. When the transistor Q1 is turned on, the transistor Q2 is turned on to hold the on state of the transistor Q1 for a preset period.

  At this time, a divided voltage based on the resistors R3 to R5 based on the DC voltage VDD is applied to the comparator CA as the first setting voltage, and a divided voltage based on the resistors R3 to R5 based on the DC voltage VDD is applied to the comparator CB as the second setting voltage. Applied as a voltage. When the detection voltage obtained by dropping the load current flowing through the resistor R1 applied to the non-inverting inputs of the comparators CA and CB is lower than the voltage applied to the inverting input, each output is L level. It becomes a state.

  When the human detection signal from the infrared sensor 15 is at the L level where no person is detected, the cathode of the diode D3 is at the L level, the anode is at the L level, and the base electrode of the transistor Q3 is also at the L level. The transistor Q3 is turned off. As the transistor Q3 is turned off, the level is between the resistor R7 and the collector electrode of the transistor Q3. As a result, the input of the inverter INV becomes H level, the output of the inverter INV becomes L level, and the transistor Q1 is turned off.

  When the transistor Q1 is on, it is supplied to the non-inverting inputs of the comparators CA and CB based on the voltage generated by the current flowing through the resistor R1 and the voltage generated between the source electrode of the transistor Q1 and the resistor R1. If the load current flowing through the transistor Q1 is in a normal state, the voltages applied to the non-inverting input of the comparators CA and CB are lower than the voltage applied to the inverting input. Therefore, the comparators CA and CB are in a non-operating state, and the inverter INV performs an operation based on the output information of the infrared sensor 15 or the holding circuit (transistor Q2).

  Conversely, when the load current flowing through the transistor Q1 is higher than usual, the voltage applied to the non-inverting inputs of the comparators CA and CB is higher than the voltage applied to the inverting input. Comparators CA and CB output an H level from the comparison output. Since the output of the inverter INV is at the L level, the transistor Q1 is turned off, and an overcurrent can be prevented from flowing through the load 12. For example, when a load having a different rated capacity is mistakenly attached and an overcurrent flows and the average value exceeds the first reference value, the output of the comparator CA becomes H level.

  By the way, as shown in FIG. 2, with the transistor Q1 turned on, the voltage 100V of the commercial power supply 11 shown in (a) and the current shown in (b) accompanying this voltage are applied to the load switching device 100 with human detection function. It is assumed that the short-circuit current shown in (c) occurs at the stage where the voltage is about to be applied, for example, due to a short circuit of the load 12 or the like.

  Then, when the inrush current becomes, for example, 5 A, the voltage applied to the non-inverting input of the comparator CB becomes higher than 0.5 V that is the voltage applied to the inverting input. For this reason, the output of the comparator CB becomes H level, the output of the inverter INV becomes L level, and the transistor Q1 is turned off. As a result, the inrush current flowing through the load 12 becomes 0 level as shown in FIG. 2C, and damage to the load switching device 100 with human detection function can be prevented. This is because the transistor Q1 as a switching element is not a self-holding type such as a thyristor or a triac, but a non-self-holding type such as a MOS FET whose opening and closing is controlled according to a signal supplied to the control electrode. It is possible to achieve an instantaneous off. The time when the voltage exceeding 0.5 V, which is the reference voltage applied to the inverting input of the comparator CB, is applied to the non-inverting input is as short as several μs, and the load on the load 12 is suppressed. be able to.

  Thus, even when a short-circuit current flows in the load current, the comparator CB that detects the instantaneous value operates before the peak value of the short-circuit current is reached, and the load 12 is closed immediately by the transistor Q1. For this reason, as in the conventional case where a triac is used as a switching element, a short-circuit current of several hundreds A flows through the load 12 for a long time of 10 ms, for example, as shown in FIG. A relatively low short-circuit current value was allowed to flow only for a short time. The current interruption in FIG. 2 (d) assumes that the fuse is blown. Control based on the instantaneous value and average value of load ionization makes it possible to keep the current withstand capability of the transistor Q1 within the rating, and it is possible to prevent damage to the two-wire wiring device.

  In this embodiment, it is possible to suppress a high current from flowing through the two-wire wiring device by instantaneously reducing the short-circuit current, and also to shorten the time for the short-circuit current to flow, thereby reducing the burden on the two-wire wiring device. Reduction can be achieved, and damage to the two-wire wiring device can be prevented.

  FIG. 3 is a circuit configuration diagram for explaining another embodiment relating to the two-wire wiring device of the present invention. In addition, the same code | symbol is attached | subjected to the component same as the said embodiment, and it demonstrates centering on a different part here.

  In this embodiment, a resistor R10 is connected between the non-inverting input of the comparator CB and the connection point of the source electrode of the transistor Q1 and the resistor R1, and a positive feedback is provided between the output of the comparator CB and the non-inverting input. The resistor R11 is connected. The comparator CB constitutes a hysteresis comparator 17 by connecting the resistors R10 and R11. The hysteresis comparator 17 is configured so that the comparison threshold when the comparison output changes from negative to positive and the comparison threshold when the comparison output changes from positive to negative are slightly different.

In this case, when the non-inverting input of the comparator CB rises above the inverting input, the comparison output of the comparator CB becomes H level. Since this H level is positively fed back to the non-inverting input of the comparator CB via the resistor R11, the comparator CB is in a latched state. This state continues until, for example, the load 12 is removed and the commercial power supply 11 is not supplied with power to the load switching device 100 with human detection function.

  Further, since the comparator CB has a hysteresis function, even if there is a short-circuit current, if the current value is a noise value that does not turn off the transistor Q1, the transistor Q1 is kept on as it is. Can be. Thereby, it is possible to prevent the transistor Q1 from continuing the protection operation against a noisy load abnormality, and it is possible to prevent the transistor Q1 from generating heat when the load 12 is not abnormal.

  In this embodiment, the non-inverting input side of the comparator CB that detects the instantaneous value of the load current is provided with hysteresis and has a latch function, thereby preventing a protective operation against a noisy load abnormality and reducing the load. When is closed, power can be prevented from being supplied until the load is removed.

  The present invention is not limited to the above-described embodiment. For example, the comparison input value supplied to the non-inverting inputs of the comparators CA and CB is based on the voltage drop voltage due to the load current generated at both ends of the resistor R1, but a current transformer or the like may be used, or the load current You may make it use the electric current corresponding to load current instead of itself. Although a MOS type FET is used as a switching transistor for opening and closing a load, an insulated gate bipolar transistor, a power transistor, or the like may be used as long as the output can be controlled by a control signal applied to a control terminal.

  In addition, as an example of the human sensor, an infrared sensor is used as an example, but an ultrasonic sensor, a visible light sensor, or the like may be used. Further, it may be a human sensor that combines an infrared sensor and a visible light sensor. However, the present invention is not limited to the one provided with the sensor.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 100 Load switching apparatus 11 with human detection function Commercial power supply 12 Load 13 Rectifier circuit part 14 Power supply part 15 Infrared sensor 16 Averaging circuit 17 Hysteresis comparator T1, T2 Connection terminal T3, T4 Output terminal Q1-Q3 Transistor R1-R11 Resistance CA , CB Comparator C1, C2 Capacitor INV Inverter D1-D4 Diode

Claims (2)

A non-self-holding type switching element that feeds power from a power source to a load by power switching by a switching according to a signal supplied to the control electrode, and
A first control means for comparing a signal based on an average value of a load current flowing through the switching element and a first set value, and controlling the switching element by a comparison result;
Comparing the second set value has higher than the signal based on the instantaneous value of the load current flowing through the switching element and the first set value, and second control means for controlling said switching element in comparison, A two-wire wiring device comprising:   The second control means is provided with a latch function for latching until the power supply is cut off or the load is removed once the second control means has operated to de-energize the switching element. The two-wire wiring device according to claim 1.

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