JPS58131692A - Load control circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load control circuit, and more particularly to a load control circuit that energizes a load such as a lighting lamp for a predetermined period of time, and then de-energizes it in a rest period.

In order to turn the light of honor as negative #I into II+a, if the light is turned on for a predetermined period of time and then suddenly turned off,
At night, the surrounding area becomes pitch-black and blinding, and if these lights are installed in staircases, entrances, bedrooms, etc., it may become dangerous to walk.

An object of the present invention is to provide a load control circuit that gradually reduces the energizing power of the load over time and eventually deenergizes the load.

FIG. 1 is an electrical circuit diagram of an embodiment of the present invention. Electric power from the commercial AC power supply 1 is applied to a lighting lamp 5 as a load via a load control circuit 4 according to the invention interposed between lines 2 and 3. The illumination lamp 5 may be an incandescent bulb or a discharge lamp. In the load control circuit 4, a series circuit consisting of a manually operated switch 8 such as a push button and a primary coil 10 of a current transformer 9 is configured to Connected between lines 2.3.

The output from the secondary coil 11 of the current transformer 9 is connected to the diode 1
It is rectified by 5vc and charges the capacitor 16. Capacitor 16 and Ruda J'KFI on that capacitor 16
The gauze variable resistor 17 constitutes a first time constant circuit 18. The output of capacitor 16 is applied to the gate of field effect transistor 19.

The source of field effect transistor 19 is connected to line 2ovc
MH is done. A resistor 23 connected to the drain of the field effect transistor 19 is connected to the secondary side of a full-wave rectifier circuit 29 made up of diodes 25-28.

A capacitor 52 is connected in connection with the aftermath rectifier circuit 29 . A capacitor 51 is connected in parallel to the direct circuit between the capacitor 52 and the full-wave rectifier circuit 29. h is done. A resistor 50 is interposed between the connection point 53 of the capacitor 51, 52 and the line 3.

In this way, the aftereffect rectifier circuit 29, the capacitor 51.5
2 and the resistor 5o constitute a second time constant circuit 54. In this time constant circuit 54, as the impedance of the field effect transistor 19 changes, the composite valleys of the capacitors 51 and 52 change, and thereby the time constant of the time constant circuit 54 changes. One terminal of the diac 31 is connected to the connection point 53. The other terminal of this diac 31 is connected to the gate of the diac 30. The triac 30 is connected in parallel with the switch 8 between lines 2.3.

State I with switch 8 shut off! In step 2, the gate-source voltage of the field effect transistor 9 is in an unbiased state, and therefore the field effect transistor 19 is conductive. Therefore capacitor 51.52
The combined capacitance of is 051 for each capacitance of capacitors 51 and 52.
, 052, it becomes (051+052), and the time constant of the time constant circuit 54 is sufficiently large. Therefore, in each half-cycle of the power supply I, the voltage at the node 53 does not rise sufficiently, so that the diac 31 and thus the triac 30 remain switched off. In this way, Qingming Lantern 5 is turned off.

When the switch 8 is turned on at time t, as shown in FIG. In this way, the illuminating lamp 5 is turned on. The voltage applied to the illumination lamp 5 is shown in FIG. 2(2).

Further, this generates an induced electromotive force in the secondary coil 11, so that the capacitor 16 is charged.

Field effect transistor 19 is therefore cut off.

At time t2, when the switch 8 is turned off, the capacitor 16 is discharged depending on the time constant of the first time constant 18 due to the action of the resistor 17. Therefore, the gate-source 1141 voltage of the field effect transistor 19 approaches zero as time passes.

After a predetermined time from time t2, the impedance of the field effect transistor 19 decreases over time. The resistance value of resistor 50 is R50,
If the capacitance of the capacitor 51.52 is 051,052, the wattage at the second time constant of 540 times is at least 1iR50.05
1 to the maximum field R5().
Electricity LF: , rises more slowly. Therefore, the conduction angle of the diac 31 and the triac 30 becomes smaller over time, and the period during which they are cut off in each half cycle becomes longer. In this way, the brightness of the warehouse lamp 5 gradually decreases over time. Therefore, when the illumination light 5 is installed in an entrance, a staircase, a bedroom, etc., it does not suddenly become pitch black, and the user is safe when walking without being blinded.

Instead of the diac 31, another semiconductor switching element may be used that has a characteristic of becoming conductive when the voltage across both ends reaches a certain point. The present invention can also be implemented in connection with loads other than lanterns.

As described above, according to the present invention, the field effect transistor is inhibited according to the time constant of the first time constant circuit.

- changing the impedance of the field effect transistor to change the time constant of the second time constant circuit;
Therefore, the conduction angle of the triac changes small over time and is finally cut off, making it possible to change the energizing power of the load small over time.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the embodiment shown in FIG. l...Commercial AC power supply, 4...Load control circuit, 5...
・Lighting light, 9...Current transformer, 15...Diode, 1
6... Capacitor, 17... Variable resistor, 18...
First time constant circuit, 19... field effect transistor, 2
9... Full wave rectifier circuit, 30... Triac, 31
...Diac, 50...i anti, 51.52...
Capacitor, 54...Second time constant circuit agent Patent attorney Kei Nishi Partial Proceeding Amendment June 7, 1980 Commissioner of the Patent Office Tono 11 Case Indication Special - 1982-14217 2. Name of the invention Load control Circuit 3, Relationship with the amended person case Applicant address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (58
B) Matsushita Electric Aji Shiki Kaisha - Representative Iku Kobayashi 4, Agent Address 1-13-38 Nishihonmachi, Nishi-ku, Osaka Shinkosan Building Voluntary Amendment 6, Claims column of the specification subject to amendment and Invention Detailed Explanation Column 7, Contents of Amendment (1) The scope of claims is as shown in the attached sheet. (2) In the specification, page 2, line 18 to page 2, line 14, the phrase ``incandescent light bulb...'' is replaced with ``d usual,''
It's an incandescent light bulb.A,''K corrects. (3) In the specification tIg page 4, line 4, “Switch 8
The phrase "in parallel with the switch 8 and the ffIt device 9" should be corrected to "in parallel with the series circuit of the switch 8 and the ffIt device 9." (4) On page 4, line 7 of the specification, ``field effect transistor 9'' is corrected to r[field effect transistor 19''. (5) On page 4, line 12 of the specification, r(C61+0
52) Correct the word "J" to "Habo (C51+Cf12)". (6) On page 6, line 19 of the specification, the word "small" is corrected to "in an analog manner." The capacitor connected to the gate of the transistor is connected to the resistor to form the first time constant circuit, and the impedance of the VIL field effect transistor is changed by charging the capacitor. (a second whose time constant changes in response to the impedance of the field effect transistor)
The output of the time constant circuit. It is characterized in that it is applied to the gate of a doubly-ac connected in parallel to the series circuit struck from the switch and the primary coil of the current transformer, thereby changing the conduction angle of the trybook in an analog manner as the capacitor discharges. Load control circuit.

Claims (1)

[Claims] '4 The capacitor connected to the four-field effect transistor is
A resistor is connected to this capacitor to form a first time constant circuit, which changes the impedance of the field effect transistor depending on the charging voltage of the capacitor, and changes the time constant in response to the impedance of the cooperative field effect transistor. 2. A load control circuit characterized in that the output of a two-time constant circuit is applied to the gate of a triac which is inherited in tandem with a switch, thereby causing the conduction angle of the triac to change small as the capacitor discharges.