JPS6111776Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention attempts to propose a load driving device that is lightweight, compact, and inexpensive.

The conventional load driving device shown in FIG. 1 uses a diode 3 and a capacitor 4 to generate a DC power source from the output of a transformer 2 connected to an AC power source 1, and a processing circuit 5 such as a timer circuit to drive a load 6. It controls the operation. Further, the conventional example shown in FIG. 2 obtains a DC power source using a resistor 7, a diode 8, and a capacitor 9, and achieves the same purpose as that shown in FIG.

In such conventional examples, a direct current path from the AC power source is required to obtain DC power for the processing circuit, and the device shown in Figure 1 uses a transformer as an element to create the DC power, thereby reducing the size of the device. In addition, the one shown in FIG. 2 has problems such as the power consumption of the resistor 7 being large and requiring appropriate countermeasures.

The present invention was devised to eliminate such conventional drawbacks, and one embodiment thereof will be described below with reference to FIG. 3.

First, in Fig. 3, resistor 11 and diode 1
3 series circuit, diode 14 and thyristor 1
5 series circuits are connected in parallel. Also,
A series circuit of a capacitor 16 and a resistor 12 has a capacitor 16 connected to both ends of the diode 14 on the anode side.
A series circuit of an AC power source 17 and a load 18 is connected between the connection point of the resistor 12 and the capacitor 16 and the cathode of the thyristor 15, and the voltage across the capacitor 16 is connected to the timer circuit. It is used as a power source for processing circuits 19 such as the following. The output of the processing circuit 19 controls the gate of the thyristor 15.

Now, when the condition of the processing circuit 19 is that the load 18 is not driven, the thyristor 15 becomes non-conductive, as shown in the equivalent circuit of FIG.
8, a resistor 11, and a diode 13. This charging voltage serves as a power supply voltage for the processing circuit 19. In this case, the resistance value of resistor 11 is load 1
It is necessary to select a value sufficiently large compared to the impedance of 8. At this time, the diode 14 is reverse biased and therefore does not become conductive. Further, it is desirable that the current consumption of the processing circuit 19 be small at this time. In fact, since the processing circuit 19 does not require power to drive the load 18 at this time, it can be designed to operate with low current consumption.

Next, when the condition of the processing circuit 19 becomes such that the load 18 is driven, the current consumption of the processing circuit 19 increases rapidly, causing the thyristor 15 to conduct.
At this time, the conduction impedance between the diode 14 and the thyristor 15 is smaller than the conduction impedance between the resistor 11 and the diode 13, so that the equivalent circuit shown in FIG. 5 is approximated. At this time, a load current flows through the resistor 12 and the thyristor 15. For this reason, the resistance value of the resistor 12 is selected to be sufficiently low to allow the necessary current to flow through the load 18. Further, the load current at this time also flows through the capacitor 16 and the diode 14, charging the capacitor 16. The circuit constants of this charging current can be selected so that the increased current consumption of the processing circuit 19 can be covered.

In another embodiment of the present invention shown in FIG. 6, a resistor 20 is connected in series to the capacitor 16, both ends of which are connected to the gate and cathode of a thyristor 21, and the output terminals c and d of the processing circuit 19 are closed. When this happens, the charge that had been stored in the capacitor 16 until this point is transferred to the resistor 2.
0, the gate and cathode of thyristor 21, and discharge through the resistor 22, and at the same time the thyristor 2
1 is in a unidirectional conduction state. After the half cycle of conduction of thyristor 21 is completed, capacitor 23 has been charged and begins to discharge. This discharge current flows through the resistors 24 and 25, but also serves as an effective trigger current for the thyristor 15, and the thyristor 15 is conductive for the following half cycle. A portion of the current flowing through the thyristor 15 during this half cycle charges the capacitor 16. Furthermore, if the circuit between CD and C of the processing circuit 19 is closed in the next half cycle, the charge in the capacitor 16 is discharged through the resistor 22, and the thyristor 21 is made conductive. vice versa
If the gap between CD and C is open, the thyristor 21 is not conductive. In this way, the thyristor 21 and the thyristor 15 are controlled simultaneously according to the conditions of the processing circuit 19, and the AC drive of the load 18 is controlled. In FIG. 6, a and b are power supply terminals of the processing circuit 19.

Further, in this embodiment, when the power supply voltage of the AC power supply 17 is lower than the rated value, the condition of the processing circuit 19 is CD closed, and the charge in the capacitor 16 is discharged through the resistors 22 and 20. Even if the current is applied, it may not become an effective trigger current for the thyristor 21. If the power supply voltage is slightly higher than this voltage V _S , an effective trigger current for the thyristor 21 can be obtained, and the charging voltage of the capacitor 16 when the thyristors 21 and 15 are conducting becomes higher than the charging voltage when they are not conducting. When the values of the resistors 11 and 12 are selected as follows: (1) If the AC voltage is below a certain value V _S [V], the load 18 will not be driven regardless of the conditions of the processing circuit 9.

(2) When the AC voltage is above the above V _S [V], the load 18 is driven according to the conditions of the processing circuit 19.

(3) Once the load 18 is driven, A: The condition of the processing circuit 19 is to open between CDs.

B V _T where the AC voltage is lower than V _S [V]
[V] becomes lower.

Drive of the load 18 is canceled under conditions A or B.

The above operation is effective as a reduced voltage safety operation when the load 18 is driven at a low AC voltage and malfunctions such as humming occur.

As can be understood from the above description, the present invention allows a power source for driving a processing circuit to be configured without using large circuit components as in the conventional case, and thus a small and lightweight load driving device can be realized. Furthermore, since the processing circuit is used with a low-voltage DC power supply, even a complex processing circuit can be designed compactly. Furthermore, since the current consumption during load driving can be increased, the internal configuration can be simplified. Furthermore, it is convenient because the DC voltage of the processing circuit can be selected fairly freely when the load is being driven and when the load is not being driven. For example, as explained in the second half of the embodiment of FIG. 6, a reduced voltage safety operation can be performed. In addition, as shown in the example in FIG.
The load driving device of the present invention is configured to be connected in series with the load and connected to the AC power source.

It can be installed with the same construction details as a normal 2-terminal switch that is inserted into the power supply line.
Furthermore, since the current consumption when the thyristor is OFF can be reduced to a very small current of 1 mA or less, the power consumption when the load is OFF can be extremely reduced.

[Brief explanation of the drawing]

1 and 2 are electrical circuit diagrams of a conventional load driving device, FIG. 3 is an electrical circuit diagram showing an embodiment of the load driving device according to the present invention, and FIG. 4 is an electrical circuit diagram of a load driving device according to the present invention.
FIG. 5 is an approximate equivalent circuit diagram when the load is on, and FIG. 6 is an electrical circuit diagram showing another embodiment of the device of the present invention. 11...First resistance, 12...Second resistance, 1
3...First diode, 14...Second diode, 15...Thyristor, 16...Capacitor, 17...AC power supply, 18...Load, 19...
processing circuit.

Claims (1)

[Scope of utility model registration request] A series circuit of the first resistor and the anode/cathode of the first diode is connected in parallel with a series circuit of the anode/cathode of the second diode and the anode/cathode of the thyristor, and the capacitor and the second diode are connected in parallel.
A series circuit of resistors is connected to both ends of the second diode so that one end of the capacitor is on the anode side, and an AC power source is connected between the connection point of the second resistor and the capacitor and the cathode of the thyristor. A load characterized in that the load is driven by connecting a series circuit with the load, using the charge in the capacitor as a power source for a processing circuit, and controlling conduction of the thyristor by the output of the processing circuit. Drive device.