JPS6215614A - Dimmer - Google Patents

Abstract

PURPOSE:To attain the simultaneous dimming of light emitting elements having different characteristics by an oscillation circuit, by impressing the DC voltage accordant with the voltage impressed to a transistor to an LED circuit. CONSTITUTION:The output pulse extracted out of the middle point of a time constant circuit 1819 of an astable multivibrator 3 is rectified through a diode 20 and impressed to the base of a transistor TR23 after integration. Thus the output pulse having the width varied by a variable resistor 6 is integrated and the DC voltage varied in response to the output pulse width is impressed to the TR 23. Thus the voltage is produced at both ends of a resistance 27 to drive a TR 24 and the DC voltage is produced at a point G in response to the impressed voltage. Thus the light of an LED is controlled. While the points C and D have phases opposite to each other and these phases are inverted by the TR 24 for control of light of lamps 14-16. Thus the simultaneous dimming is possible among those lamps and LED by means of a single oscillation circuit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a light control device & suitable for pulse driving of a light emitting element.

(Japanese Patent Laid-Open No. 57-197
As shown in Publication No. 621, a full-wave rectifier circuit (
A lamp (421 and a transistor (43) are connected in series through 4D. A discharging switch (4119 is connected to an integrating circuit 0 x capacitor (45), and a comparator (A
? ) and the transistor (43), an OR gate GI8 and a flip-flop Gll are connected.Furthermore, a synchronous control section ω is connected after the full-wave rectifier circuit (41).The signal of this synchronous control section - is connected to the flip-flop It consists of a synchronization signal that sets the transistor 09 and turns on the transistor 43 to start the control operation, and a synchronization signal that resets the flip 70 tube (41) and discharges the capacitor (49) of the integrating circuit 04.

When a synchronization signal is first generated by the synchronization control section (to), the transistor (43) turns on, current flows through the four lamps, and a voltage is generated across the lamp (021). It is detected, squared by the squaring circuit 6ia, and given to the integrating circuit (44) for integration. When the output voltage of this integrating circuit reaches the reference voltage so of the comparator Oη, an output is generated from the comparator (4?). The flip-flop (49) is reset. Therefore, the transistor a3 is turned on and the output to the lamp ha is stopped.

→ Problems to be Solved by the Invention In the light control device 111 (FIG. 3) as described above, multiple light control is possible when the light emitting elements, for example lamps (four lamps with the same characteristics are connected in parallel). , when attempting to dim a lamp (light-emitting elements with different characteristics, such as LEDs), a separate dimming device was required.

(Means for solving the -4 problems) The present invention has been made in view of the above problems, and includes an oscillation section (3) in which the pulse width of the oscillation signal is changed by changing the time constant; In a light control device equipped with a driver circuit unit υ which inputs an output and pulses the first light emitting element Q4) (19 (161) based on the oscillation frequency, the oscillation frequency is
111(3) and integrates the output of the first light emitting element (a).
A voltage generation circuit is installed to obtain a DC voltage that corresponds to dimming.
By using this voltage, the second light control device, LED
The solution is to control the dimming of the light.

The pulses generated by the four-action oscillator (3) (Fig. 2 [F]) are rectified by a diode and integrated by a resistor Cυ and a capacitor. Therefore, a voltage corresponding to the width of the pulse (FIG. 2 [F]) is generated at the base of the transistor (C).

Since this voltage has a negative phase relationship with the voltage applied to the base of the driver circuit αυ, it is inverted by the transistor I24J. Therefore, when the voltage applied to the base of the transistor increases, the voltage applied to the LED drive circuit decreases. Some LE16) can also be dimmed.

(F) Example An example of the present invention will be described below with reference to FIGS. 1 and 2.

The transistor (1) and the transistor (2) constitute an unstable multivibrator (3), and the collector of the transistor (2) of the astable multivibrator (3) is connected to the base of the driver circuit αD via a resistor OI. has been done. The collector of the driver circuit 0υ is connected to the base of the power transistor αy via a resistor α2, and furthermore, the collector of the driver circuit 0υ is connected to the base of the power transistor αy.
Connect the lamp Q410 between the collector and ground (GND).
51αG are connected in parallel. Further, a diode (17) is connected between the emitter of the driver circuit αυ and ground (GND). Next, the time constant circuit (8) (19 (111) of the unstable multivibrator (3)
A resistor α5 (transistor (c) e4) is connected from the midpoint of 11 to a diode (■), a resistor Cυ, and a capacitor (transistor (c) e4) through an integrating circuit composed of 2a. The emitter of the transistor (c) is connected to the transistor I24. ) and is further connected to the resistor □□□.

Further, a resistor (b) is connected to the emitter of the transistor Q4, and a second light emitting element, here an LED driving circuit +261, is connected from the midpoint between the collector and the resistor (c).

Also, from the midpoint of the resistor @ (c) to the zener diode (to)
Connect the transistor 01) for overvoltage protection through
The emitter of the transistor Gυ is connected to ground (GND) via a diode a.

Here, the waveforms at points A...G shown in FIG. 1 correspond to the waveforms (A)...(G) shown in FIG. 2, respectively.

The operation of this circuit will be explained below. The variable resistor (
6) makes the pulse width of the pulse generated by the integrator circuit (8) α-α-α- and the pulse generated by the integrator circuit (41 (5)) variable, and the point B outputs the pulse width according to this time constant. A pulse is generated.When this pulse is applied to the driver circuit συ, the power transistor (
13&house pulse driven. Therefore, the lamp (141Q!
19c16) enables dimming according to this output pulse width. Here, if overvoltage is applied to the driver circuit Uυ, the Zener diode (to) and transistor 01
) to bypass this overvoltage and protect the driver circuit αυ. Also, a diode αη provides reverse bias protection.

The following are the features of the present invention: the output pulse taken out from point C is rectified through a diode wire, then integrated by an integrating circuit and applied to the base of the transistor (24). The output pulse with the pulse width varied by is integrated by the integrating circuit 01)@, and a DC voltage that changes according to the output pulse width is applied to the transistor (c).

This DC voltage drives the transistor device and generates a voltage across the resistor (5). This voltage is transistor C!
It is applied to the base of (A) and drives the transistor Q4. Therefore, a DC voltage corresponding to the voltage applied to the transistor is generated at point G and dims the LED through the LED drive circuit. Also, since the point and point C are in opposite phase, the transistor @
Since the light is inverted at , the LED as the second light emitting element can be dimmed in the same phase as the lamp α4 Jastte, which is the first light emitting element driven by pulses.

(G) Effects of the Invention As is clear from the above description, the present invention is based on the time constant circuit in the unstable multivibrator (3) K [(11) in which the output pulse taken from the midpoint is rectified through a diode wire. and this output pulse is connected to resistor Qυ and capacitor @
It is rectified and integrated through an integrating circuit consisting of Therefore, a DC voltage that changes depending on the output pulse width is applied to the pace of the transistor (c). This DC voltage drives transistor (c) Q4. Therefore, since a DC voltage corresponding to the voltage applied to the transistor Q4 is applied to the LED circuit, the second light emitting element having different characteristics from the first light emitting element can be simultaneously dimmed using one oscillation circuit (3). Become.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a light control device that is an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the circuit of FIG. 1, and FIG. 3 is a circuit diagram of a conventional light control device. . (1) +21 is a transistor, (3) is an unstable multivibrator, (4) (7) is a resistor, (51 (8) is a capacitor, (6) is a variable resistor, 011 resistor,
where υ is the driver circuit, where is the resistor, α3 is the power transistor, α4J (19αQ is the lamp, aη is the diode, α8)H is the resistor, (1) is the diode,
Qυ is a resistor, (company) is a capacitor, (c) @ is a transistor, (c) is a resistor, (c) is an LED drive circuit, @@ is a resistor, (to) is a zener diode,
Gυ is a transistor for overvoltage protection, ? 3 (to) are diodes, and 04) (to) are resistors. Applicant Sanyo Electric Co., Ltd. and one other representative Patent attorney Shizuka Sano

Claims (1)

[Claims] (1) Dimming comprising an oscillation unit whose pulse width of an oscillation signal is changed by changing the time constant, and a driver circuit unit which inputs the output of the oscillation unit and pulse-drives the first light emitting element based on the oscillation frequency. A light control device, characterized in that the device is provided with a voltage generation circuit that integrates the output of the oscillation section and obtains a DC voltage corresponding to light control of the first light emitting element.