CN209787515U

CN209787515U - Inductive switch drive circuit of LED lamp

Info

Publication number: CN209787515U
Application number: CN201822157245.1U
Authority: CN
Inventors: 李希龙
Original assignee: Xiamen Longstar Lighting Co Ltd
Current assignee: Xiamen Longstar Lighting Co Ltd
Priority date: 2018-12-21
Filing date: 2018-12-21
Publication date: 2019-12-13
Anticipated expiration: 2028-12-21

Abstract

The utility model provides an inductive switch drive circuit of LED lamp, include: the main circuit is used for supplying power to the LED and the sub circuit is used for supplying power to the inductive switch; the two ends of the main circuit and the sub-circuit are respectively connected to the positive terminal and the negative terminal of the rectifier bridge, and the main circuit is also provided with an isolation diode D2 for isolating the main circuit and the sub-circuit; the sub-circuit comprises a first switch, a second switch and a resistor R4; when the induction switch is opened, the second switch is opened, the first switch is closed, and the resistor R4 is connected to the positive terminal and the negative terminal of the rectifier bridge through the first switch to supply power to the induction switch with small current; when the inductive switch is opened, the second switch is closed, the first switch is opened, and the resistor R4 is disconnected between the positive terminal and the negative terminal of the rectifier bridge.

Description

Inductive switch drive circuit of LED lamp

Technical Field

The utility model relates to a light emitting device especially relates to the LED lamp.

Background

due to the requirement of energy saving, a large number of inductive switches are used in public places such as corridors and staircases, wherein the inductive switches comprise touch inductive switches, voice-operated inductive switches and the like. Early inductive switches were primarily used for incandescent lamps. Since the inductive switch needs to provide leakage current to ensure its most basic operation when turned off, and the purely resistive nature of the incandescent lamp just meets this requirement, both can be well adapted. However, at present, incandescent lamps are gradually eliminated, and common LEDs cannot well meet the requirement, so that weak leakage current exists in application, the switch is not well turned off, and the switch flickers or is still bright during the turning-off period of the switch.

SUMMERY OF THE UTILITY MODEL

the utility model aims to solve the main technical problem that an inductive switch drive circuit of LED lamp is provided, provides supply current to inductive switch when the LED lamp extinguishes, cancels supply current when LED lights.

In order to solve the technical problem, the utility model provides an inductive switch drive circuit of LED lamp, include: the main circuit is used for supplying power to the LED and the sub circuit is used for supplying power to the inductive switch; the two ends of the main circuit and the sub-circuit are respectively connected to the positive terminal and the negative terminal of the rectifier bridge, and the main circuit is also provided with an isolation diode D2 for isolating the main circuit and the sub-circuit;

The sub-circuit comprises a first switch, a second switch and a resistor R4; when the induction switch is opened, the second switch is opened, the first switch is closed, and the resistor R4 is connected to the positive terminal and the negative terminal of the rectifier bridge through the first switch to supply power to the induction switch with small current; when the inductive switch is opened, the second switch is closed, the first switch is opened, and the resistor R4 is disconnected between the positive terminal and the negative terminal of the rectifier bridge.

In a preferred embodiment: the first switch is a thyristor Q1, and the second switch is a triode Q2; the anode of Q1 is connected to the positive terminal of the rectifier bridge, the control electrode is connected with the collector of Q2, and the cathode is connected to the negative terminal of the rectifier bridge through a resistor R4.

In a preferred embodiment: the collector of the Q2 is connected to the positive terminal of the rectifier bridge through a resistor R3, the emitter is connected to the negative terminal of the rectifier bridge, and the base is connected to the homonymous terminals of the resistors R5 and R6 which are connected in series.

In a preferred embodiment: the synonym terminal of the resistor R5 is connected with the cathode of the diode D1, and the anode of D1 is connected with the cathode of Q1.

In a preferred embodiment: and a resistor C2 is connected between the cathode of the Q1 and the collector of the Q2.

Compared with the prior art, the technical scheme of the utility model possess following beneficial effect:

The utility model provides an inductive switch drive circuit of LED lamp, when inductive switch's touch piece unmanned touch, the LED lamp does not light, second switch Q2's base voltage is low, Q2 ends, Q2's collecting electrode voltage approximately equals the voltage that rectifier bridge positive terminal reached the negative pole end, be greater than first switch Q1's opening voltage far away, Q1 is in the on-state this moment, current I's flow direction is positive terminal → Q1 → R4 → negative pole end, because R4's reason, current I is less in order to satisfy the electric current demand when inductive switch standby. When a human body touches the touch sheet of the inductive switch, the LED is lightened, the voltage from the positive electrode end to the negative electrode end of the rectifier bridge is increased, meanwhile, the base voltage of the Q2 is increased, the Q2 is conducted, the collector voltage of the Q2 is reduced to 0.3V and is lower than the starting voltage of the Q1, the Q1 is cut off, and the current I disappears.

Drawings

FIG. 1 is a schematic diagram of an inductive switch;

Fig. 2 is a circuit diagram of the preferred embodiment of the present invention.

Detailed Description

The technical solution of the present invention will be further explained with reference to the accompanying drawings and the detailed description.

The inductive switch mainly comprises a unidirectional silicon controlled rectifier MCR100-6 and a control circuit which are connected in series in the LED lamp string; the control circuit is composed of a metal touch sheet, BG1, BG2, a time-delay capacitor C and the like as shown in figure 1, so as to complete the control of the timed conduction of the unidirectional silicon controlled rectifier MCR 100-6.

When the metal touch sheet D is not touched by a person, the BG1 tube is turned off by no signal at the base, and the BG2 tube is turned on by the high level at the collector. At the same time, the power supply charges the capacitor C from point E to about 0.7V through R3 (BG2 tube base clamp action). At the moment, the collector potential of the BG2 tube is close to zero level, and as a result, the one-way thyristor MCR100-6 is cut off, no current passes through the main loop, and the LED lamp is not on.

when the metal touch sheet D is touched by a person, the voltage induced by the person causes the BG1 tube to be conducted through the voltage dividing circuits of R1 and R2, the voltage charged when the capacitor C is static is discharged through the BG1 tube, the BG2 tube is cut off as long as the voltage on the C is reduced to be less than 0.7V, at this time, the collector of the BG2 tube is at a high level, the one-way thyristor MCR100-6 is conducted, and as a result, alternating current completes a circuit from point A → L → D1(D4) → MCR100-6 → D3(D2) → C, and the LED is lightened. As long as the LED lamp is on, the potential of the point E drops to a very low potential.

When the touch sheet is not touched by people, the BG1 tube is cut off, the voltage at the point E charges the capacitor through the R3, when the voltage on the C rises to be more than 0.7V, the BG2 tube is conducted again, the zero-crossing of the unidirectional silicon controlled rectifier is cut off, and the LED is extinguished.

From the above physical process, the charging time of the E-point power supply to the capacitor C through R3 after the touch sheet is touched once is the delay time for the lamp to turn on. It can be seen that, when R3 is constant, the larger the value of C is obtained, the longer the lamp lighting delay time is. As shown in the parameters of FIG. 2, when the touch time is more than or equal to 1 second, the LED lamp can be turned on for 45-85 seconds. Enough pedestrians walk on the corridor to illuminate.

According to the working principle of the touch switch, the touch sheet, the BG1, the C, R1, the R2 and the R3 are still in a standby state when the silicon controlled rectifier MCR100-6 is turned off to ensure that the BG1 can be turned on when a human body contacts the touch sheet, so that a path needs to be formed to provide weak leakage current for the touch switch, but the leakage current does not pass through the light source of the LED lamp to avoid the light source of the LED lamp from flickering or slightly lighting, and meanwhile, when the LED lamp is lighted, the circuit needs to be turned off to reduce unnecessary loss of the LED lamp.

Therefore, the present embodiment provides an inductive switch driving circuit of an LED lamp, including: the main circuit is used for supplying power to the LED and the sub circuit is used for supplying power to the inductive switch; the two ends of the main circuit and the sub-circuit are respectively connected to the positive terminal and the negative terminal of the rectifier bridge, and the main circuit is also provided with an isolation diode D2 for isolating the main circuit and the sub-circuit;

specifically, the first switch is a thyristor Q1, and the second switch is a triode Q2; the anode of Q1 is connected to the positive terminal of the rectifier bridge, the control electrode is connected with the collector of Q2, and the cathode is connected to the negative terminal of the rectifier bridge through a resistor R4.

The collector of the Q2 is connected to the positive terminal of the rectifier bridge through a resistor R3, the emitter is connected to the negative terminal of the rectifier bridge, and the base is connected to the homonymous terminals of the resistors R5 and R6 which are connected in series.

The synonym terminal of the resistor R5 is connected with the cathode of the diode D1, and the anode of D1 is connected with the cathode of Q1.

And a resistor C2 is connected between the cathode of the Q1 and the collector of the Q2.

When the touch sheet is not touched by people, the MCR100-6 in fig. 1 is in an off state, the LED lamp in fig. 2 is not on, and as known from the principle of voltage division, the base voltage of Q2 is low (< 0.7V), Q2 is off, the collector voltage of Q2 is approximately equal to the voltage from "V +" to "V-" of the rectifier bridge and is much greater than the turn-on voltage of Q1, at this time, Q1 is in an on state, and the current I passes through V + → Q1 → R4 → V-, and due to the resistor R4, the current I is small, and simultaneously the operating current requirement of BG1 in fig. 1 is met, namely the leakage current requirement when the touch switch is in standby is met. When a human body touches the switch, the MCR100-6 in fig. 1 is turned on, the LED in fig. 2 is turned on, the voltage of the rectifier bridge from "V +" to "V-" is increased, meanwhile, the base voltage of Q2 reaches 0.7V, Q2 is turned on, the collector voltage of Q2 is reduced to 0.3V, which is lower than the turn-on voltage (0.6V) of Q1, Q1 is turned off, and the current I disappears, thereby reducing the power loss in the circuit in fig. 2.

The application principle of the circuit is explained by the power supply structure with resistance-capacitance voltage reduction, and in fact, the circuit is also applicable to power supplies with other topological structures, including buck, boost, buck-boost, flyback and the like, and can be well adapted to an inductive switch. In view of the great application of corridor lamps, staircase lamps and inductive switches in the market, the circuit has wide prospect, is very simple, can be independently made into a module, and can be installed on the original circuit board as a connector on the lamp needing to be applied to the inductive switch to realize the function.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and variations or technical scope of the present invention disclosed may be easily conceived by those skilled in the art. Alternatives are intended to be within the scope of the invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. An inductive switch driving circuit of an LED lamp, characterized by comprising: the main circuit is used for supplying power to the LED and the sub circuit is used for supplying power to the inductive switch; the two ends of the main circuit and the sub-circuit are respectively connected to the positive terminal and the negative terminal of the rectifier bridge, and the main circuit is also provided with an isolation diode D2 for isolating the main circuit and the sub-circuit;

2. The inductive switch driving circuit of the LED lamp according to claim 1, wherein: the first switch is a thyristor Q1, and the second switch is a triode Q2; the anode of Q1 is connected to the positive terminal of the rectifier bridge, the control electrode is connected with the collector of Q2, and the cathode is connected to the negative terminal of the rectifier bridge through a resistor R4.

3. The inductive switch driving circuit of the LED lamp according to claim 2, wherein: the collector of the Q2 is connected to the positive terminal of the rectifier bridge through a resistor R3, the emitter is connected to the negative terminal of the rectifier bridge, and the base is connected to the homonymous terminals of the resistors R5 and R6 which are connected in series.

4. The inductive switch driving circuit of the LED lamp according to claim 3, wherein: the synonym terminal of the resistor R5 is connected with the cathode of the diode D1, and the anode of D1 is connected with the cathode of Q1.

5. the inductive switch driving circuit of the LED lamp according to claim 4, wherein: and a resistor C2 is connected between the cathode of the Q1 and the collector of the Q2.