CN209784719U

CN209784719U - Automatic soft start circuit of projector bulb

Info

Publication number: CN209784719U
Application number: CN201920354918.4U
Authority: CN
Inventors: 林艺鹏
Original assignee: Shenzhen Lihongwei Industrial Co Ltd
Current assignee: Shenzhen Lihongwei Industrial Co Ltd
Priority date: 2019-03-20
Filing date: 2019-03-20
Publication date: 2019-12-13
Anticipated expiration: 2029-03-20

Abstract

The utility model discloses an automatic soft start circuit of projector bulb, comprising a power circuit for voltage reduction, rectification and stabilization, a main circuit with the soft start function of bulb and a control circuit which takes the setting and resetting functions of a double D trigger as the trigger control signal; the power circuit provides working power for the main circuit and the control circuit respectively; the control circuit controls the main circuit to recover to normal work from a soft start state through a normally open contact of the relay; the utility model has the advantages that the slide bar resistor is connected in the main circuit in series, so that the voltage applied to the bulb at the moment of starting can be reduced, the surge current of the cold bulb when starting is reduced, and the service life of the bulb is prolonged; after the bulb is preheated for a certain time, the control circuit automatically controls the full voltage to be applied to the bulb through the normally open contact of the relay, so that the bulb is protected and the normal use is not influenced.

Description

Automatic soft start circuit of projector bulb

Technical Field

The utility model relates to projector bulb technical field especially involves an automatic soft start circuit of projector bulb.

Background

The projector belongs to an expensive product with relatively serious consumables, and the damage of an electronic device is often caused by improper use, so that the normal projection use is influenced, and the use cost is increased; the bulb is an important imaging device of the projector and is also the most easily damaged part, and the cold bulb is impacted by larger surge current when being started, so that the service life is greatly shortened.

Accordingly, the prior art is deficient and needs improvement.

SUMMERY OF THE UTILITY MODEL

the utility model provides an automatic soft start circuit of projector bulb solves the above-mentioned problem.

In order to solve the above problem, the utility model provides a technical scheme as follows:

an automatic soft start circuit of a projector bulb comprises a power supply circuit for voltage reduction, rectification and voltage stabilization, a main circuit with a soft start function of the bulb, and a control circuit with a setting and resetting function of a double-D trigger as a trigger control signal; the power circuit provides working power for the main circuit and the control circuit respectively; the control circuit controls the main circuit to recover to normal work from a soft start state through a normally open contact of the relay.

compared with the prior art, the utility model has the advantages that the slide bar resistor is connected in the main circuit in series, so that the voltage applied to the bulb at the moment of starting can be reduced, the surge current of the cold bulb during starting is reduced, and the service life of the bulb is prolonged; after the bulb is preheated for a certain time, the control circuit automatically controls the full voltage to be applied to the bulb through the normally open contact of the relay, so that the bulb is protected and the normal use is not influenced.

Drawings

For a clearer explanation of the embodiments or technical solutions in the prior art, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic block diagram of an automatic soft start circuit for a projector bulb according to the present invention;

Fig. 2 is a schematic circuit diagram of an automatic soft start circuit of a projector bulb according to the present invention.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The use of the terms "fixed," "integrally formed," "left," "right," and the like in this specification is for illustrative purposes only, and elements having similar structures are designated by the same reference numerals in the figures.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1-2, one embodiment of the present invention is:

the power supply circuit comprises capacitors C1-C2, a fuse FU, a single-pole double-throw switch S, a transformer T2, a rectifier bridge VC and an integrated circuit N1;

The first end of a plug for connecting a mains supply is connected with a first wire inlet end of the single-pole double-throw switch S; the second end of the plug is connected with a second wire inlet end of the single-pole double-throw switch S through a fuse FU; the outlet end of the single-pole double-throw switch S is connected with the primary coil of the transformer T2; the secondary coil of the transformer T2 is connected with the alternating current input end of the rectifier bridge VC; the positive electrode of the rectifier bridge VC is respectively connected with the first end of the capacitor C1 and the wire inlet end of the integrated circuit N1; the outlet end of the integrated circuit N1 is connected with the first end of the capacitor C2; the grounding end of the plug, the negative electrode of the rectifier bridge VC, the grounding end of the integrated circuit N1 and the second end of the capacitor C1-C2 are all grounded;

integrated circuit N1 is a 7812 type three terminal regulator.

The main circuit comprises a slide bar resistor RU, a fan F, a transformer T1 and a bulb DP for the projector;

the outlet end of the single-pole double-throw switch S is connected with the fan F in parallel;

A first end of the fan F is connected to a first end of the primary winding of the transformer T1; the second end of the fan F is respectively connected with the first end of the sliding rod resistor RU and the first end of the normally open contact of the relay K1; the second end of the primary coil of the transformer T1 is respectively connected with the second end of the sliding rod resistor RU and the second end of the normally open contact of the relay K1; the secondary coil of the transformer T1 is connected in parallel with the bulb DP;

The sliding rod resistor RU is used for reducing the voltage applied to the bulb at the moment of starting up, and soft starting is realized.

The control circuit comprises resistors R1-R3, capacitors C3-C4, diodes VD1-VD2, a triode VT, a relay K1 and an integrated circuit N2;

A first end of the capacitor C2 is connected with a first end of the resistor R1;

a first end of the resistor R1 is respectively connected with a first end of the capacitor C4, cathodes of the diodes VD1-VD2, a first end of the relay K1 and a 14 th pin of the integrated circuit N2; a second end of the resistor R1 is respectively connected with a first end of the capacitor C3, the anode of the diode VD1 and the 4 th pin of the integrated circuit N2; the second end of the capacitor C4 is respectively connected with the first end of the resistor R3 and the 6 th pin of the integrated circuit N2; the second end of the resistor R3, the second end of the capacitor C3, the emitter of the triode VT and pins 3, 5 and 7-11 of the integrated circuit N2 are all grounded; the 2 nd pin of the integrated circuit N2 is connected with the base electrode of the triode VT through a resistor R2; the collector of the triode VT is respectively connected with the anode of the diode VD2 and the second end of the relay K1;

The triode VT is a 9013 type NPN transistor; the model of the integrated circuit N2 is CD 4013.

The utility model discloses a theory of operation:

At the moment of starting up, a primary loop of the projection lamp power supply transformer T1 is connected in series with a 50 omega sliding rod resistor to reduce the voltage applied to the lamp at the moment of starting up, and after the lamp is preheated for a few seconds, the full voltage is applied to the lamp, so that the large surge current of the cold-state lamp during starting up can be greatly reduced, and the safety of the lamp is protected.

when the projector lamp bulb soft start circuit is used, the switch S is turned on, the cooling fan starts to rotate, the primary winding of the transformer T1 for supplying power to the projector lamp bulb obtains a power supply, but a sliding rod resistor is connected in series in the circuit, the voltage at two ends of the projector lamp bulb is obviously reduced, and the projector lamp bulb soft start circuit enters a soft start state. And since the power is proportional to the voltage squared, the magnitude of the power reduction experienced by the lamp during soft start is large. After the switch S is closed, the transformer T2 also obtains power supply, and the voltage on the secondary side of the transformer T2 forms a 12V direct current power supply after being rectified by a bridge type and stabilized by a three-terminal regulator 7812, and supplies power to the integrated circuit CD 4013. CD4013 is a dual D flip-flop, here using set and reset functions. When the set S end is applied with high level, the Q end is high, and the reverse Q end is low; when a high level is applied to the reset R terminal, the Q terminal is low and the inverted Q terminal is high. Obviously, the R and S terminals cannot apply a high level simultaneously. After the CD4013 is powered on, under the action of a capacitor C4 and a resistor R3, a set high level is applied to the S1 end of the CD4013, at the moment, the reset R end of the CD4013 is at a low level due to the action of a resistor R1 and a capacitor C3, so that the Q1 end of the CD4013 is at a high level, the reverse Q1 end is at a low level, the triode VT is cut off, and the relay K1 does not act. That is, the electrical appliance K1 does not act immediately after the switch S is closed. Thereafter, the capacitor C3 is charged through the resistor R1. When the voltage on the C3 is charged to the reset threshold value of the R1 end of the CD4013 (at the moment, the time constant of the C4 and the R3 is small and is changed into low level in advance), the state of the output end is turned over, the potential of the end of the inverse phase Q1 is changed to be high, the triode VT is conducted in saturation, the coil of the relay K1 is electrified, the dynamic contact is closed, the sliding rod resistor is short-circuited, the projection lamp bulb obtains full voltage and enters a normal working state, and the soft start process is finished.

it should be noted that the above technical features are continuously combined with each other to form various embodiments which are not listed above, and all the embodiments are regarded as the scope of the present invention described in the specification; moreover, modifications and variations will occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention as defined by the appended claims.

Claims

1. An automatic soft start circuit of a projector bulb is characterized by comprising a power supply circuit for voltage reduction, rectification and stabilization, a main circuit with a soft start function of the bulb, and a control circuit with a setting and resetting function of a double-D trigger as a trigger control signal; the power circuit provides working power for the main circuit and the control circuit respectively; the control circuit controls the main circuit to recover to normal work from a soft start state through a normally open contact of the relay.

2. An automatic soft start circuit for a projector bulb as claimed in claim 1, wherein the power supply circuit comprises capacitors C1-C2, fuse FU, single pole double throw switch S, transformer T2, rectifier bridge VC and integrated circuit N1.

3. The projector bulb automatic soft start circuit as claimed in claim 2, wherein a first end of a plug for connecting to a mains supply is connected to a first line inlet end of a single-pole double-throw switch S; the second end of the plug is connected with a second wire inlet end of the single-pole double-throw switch S through a fuse FU; the outlet end of the single-pole double-throw switch S is connected with the primary coil of the transformer T2; the secondary coil of the transformer T2 is connected with the alternating current input end of the rectifier bridge VC; the positive electrode of the rectifier bridge VC is respectively connected with the first end of the capacitor C1 and the wire inlet end of the integrated circuit N1; the outlet end of the integrated circuit N1 is connected with the first end of the capacitor C2; the grounding end of the plug, the negative electrode of the rectifier bridge VC, the grounding end of the integrated circuit N1 and the second end of the capacitor C1-C2 are all grounded.

4. A projector lamp bulb automatic soft start circuit as claimed in claim 2 or 3, wherein the integrated circuit N1 is a 7812 type three terminal regulator.

5. The projector bulb automatic soft start circuit as claimed in claim 1, wherein the main circuit comprises a sliding resistor RU, a fan F, a transformer T1 and a projector bulb DP.

6. A projector bulb automatic soft start circuit as claimed in claim 5 wherein a first terminal of fan F is connected to a first terminal of a primary winding of transformer T1; the second end of the fan F is respectively connected with the first end of the sliding rod resistor RU and the first end of the normally open contact of the relay K1; the second end of the primary coil of the transformer T1 is respectively connected with the second end of the sliding rod resistor RU and the second end of the normally open contact of the relay K1; the secondary coil of the transformer T1 is connected in parallel with the bulb DP.

7. a projector lamp bulb automatic soft start circuit as claimed in claim 5 or 6, wherein the sliding rod resistor RU is used to reduce the voltage applied to the lamp bulb at the moment of starting up, so as to realize soft start.

8. A projector lamp bulb automatic soft start circuit as claimed in claim 1, wherein the control circuit comprises resistors R1-R3, capacitors C3-C4, diodes VD1-VD2, transistor VT, relay K1 and integrated circuit N2.

9. The automatic soft start circuit for projector bulbs as claimed in claim 8, wherein the first terminal of the resistor R1 is connected to the first terminal of the capacitor C4, the cathodes of the diodes VD1-VD2, the first terminal of the relay K1, and the 14 th pin of the integrated circuit N2, respectively; a second end of the resistor R1 is respectively connected with a first end of the capacitor C3, the anode of the diode VD1 and the 4 th pin of the integrated circuit N2; the second end of the capacitor C4 is respectively connected with the first end of the resistor R3 and the 6 th pin of the integrated circuit N2; the second end of the resistor R3, the second end of the capacitor C3, the emitter of the triode VT and pins 3, 5 and 7-11 of the integrated circuit N2 are all grounded; the 2 nd pin of the integrated circuit N2 is connected with the base electrode of the triode VT through a resistor R2; the collector of the triode VT is connected with the anode of the diode VD2 and the second end of the relay K1, respectively.

10. An automatic soft start circuit for a projector lamp bulb as claimed in claim 8 or 9, wherein the transistor VT is a 9013 NPN transistor; the model of the integrated circuit N2 is CD 4013.