CN117676964A

CN117676964A - LED control system for projector

Info

Publication number: CN117676964A
Application number: CN202410129046.7A
Authority: CN
Inventors: 刘正华; 刘思旺
Original assignee: Shenzhen Chengzi Digital Technology Co ltd
Current assignee: Shenzhen Chengzi Digital Technology Co ltd
Priority date: 2024-01-31
Filing date: 2024-01-31
Publication date: 2024-03-08
Anticipated expiration: 2044-01-31

Abstract

The application relates to an LED control system for a projector, which comprises an enabling control circuit, a first LED lamp and a second LED lamp, wherein the enabling control circuit comprises a first enabling control sub-circuit and a second enabling control sub-circuit, and the first enabling control sub-circuit controls an enabling end of the first LED lamp according to a first enabling control signal; the second enabling control sub-circuit controls an enabling end of the second LED lamp; the first driving circuit is used for outputting a first driving signal and a second driving signal according to the first enabling control signal and the second enabling control signal; the enabling and driving circuit is used for outputting a third enabling signal and a third driving signal according to the second enabling control signal and the third enabling control signal to control the third LED lamp, and the LED control system realizes light mixing by using fewer driving circuits.

Description

LED control system for projector

Technical Field

The invention belongs to the technical field of projectors, and particularly relates to an LED control system for a projector.

Background

In a DLP projector, there are usually 3 lamps, such as R, G, B, and because the projector needs to use a specific chip, its control logic turns on or off for each lamp according to a certain sequence, so that each lamp needs one LED driving circuit to drive, for example, one enabling end of the main control chip controls one driving circuit, and one driving circuit controls one LED lamp; in order to increase brightness or realize light mixing, some projectors also have BP lamps, and the BP lamps are added to have more driving circuits, so that the cost of the projector is increased.

Disclosure of Invention

The application provides a control system for a projector aiming at the problem of more LED lamp driving circuits in the projector.

An LED control system for a projector, comprising

The LED lamp comprises a first LED lamp, a second LED lamp and a third LED lamp;

the enabling control circuit comprises a first enabling control sub-circuit and a second enabling control sub-circuit, the first enabling control sub-circuit comprises a third switching tube, the second end of the third switching tube is connected with the enabling end of the first LED lamp, the third end of the third switching tube is grounded, the input end of the first enabling control sub-circuit receives a first enabling control signal, and when the first enabling control signal is a high-level signal, the third switching tube is conducted; the second enabling control sub-circuit comprises an OR gate module and a sixth switching tube, the second end of the sixth switching tube is connected with the enabling end of the second LED lamp, the third end of the sixth switching tube is grounded, the first input end of the OR gate module receives a second enabling control signal, the second input end of the OR gate module receives a third enabling control signal, when the second enabling control signal and/or the third enabling control signal are high-level signals, the output end of the OR gate module outputs the high-level signals, and the sixth switching tube is conducted;

The first driving circuit is used for outputting a first driving signal and a second driving signal according to the first enabling control signal and the second enabling control signal, wherein the first driving signal is used for driving the first LED lamp, and the second driving signal is used for driving the second LED lamp;

the enabling and driving circuit is used for outputting a third enabling signal to an enabling end of the third LED lamp according to the second enabling control signal and the third enabling control signal, outputting a third driving signal according to the second enabling control signal and the third enabling control signal, and driving the third LED lamp by the third driving signal; when the second enable control signal and/or the third enable control signal is a high level signal, the third enable signal is a low level signal.

Optionally, the second current switching circuit further comprises a second analog signal switch chip, the first signal input end of the second analog signal switch chip receives a second enabling control signal, the second signal input end of the second analog signal switch chip receives a third enabling control signal, the first output reference end of the second analog signal switch chip receives a fourth PWM signal, and the second output reference end of the first analog signal switch chip receives a fifth PWM signal;

When the second enabling control signal is a high-level signal, the output end of the second analog signal switch chip is communicated with the first output reference end of the second analog signal switch chip; when the second enabling control signal is a high-level signal, the output end of the second analog signal switch chip is communicated with a second output reference end of the second analog signal switch chip;

the output end of the second analog signal switch chip is connected with the input end of the enabling and driving circuit.

Optionally, the enabling and driving circuit includes a second LED constant current buck controller, a ninth switching tube, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a second inductor, a first diode, a second diode, a fifteenth capacitor and a sixteenth capacitor;

the enabling end of the second LED constant-current voltage-reducing controller is an input end of an enabling and driving circuit and is connected with the output end of the second analog signal switch chip through a twenty-fifth resistor; the input power supply end of the second LED constant-current voltage-reducing controller is connected with the driving power supply, and the input power supply end of the second LED constant-current voltage-reducing controller is respectively connected with the driving end of the third LED lamp and the current detection end of the second LED constant-current voltage-reducing controller through a twenty-sixth resistor; the output end of a gate driver of the second LED constant-current step-down controller is connected with the first end of a ninth switching tube through a twenty-seventh resistor, the second end of the ninth switching tube is connected with the enabling end of a third LED lamp through a second inductor, and the third end of the ninth switching tube is grounded; the second end of the ninth switching tube is respectively connected with the anode of the first diode and the anode of the second diode, and the cathode of the first diode and the cathode of the second diode are respectively connected with the input power supply end of the second LED constant current step-down controller; the first end of the fifteenth capacitor and the first end of the sixteenth capacitor are connected with the power input end of the second LED constant current step-down controller, and the second end of the fifteenth capacitor and the second end of the sixteenth capacitor are connected with the first end of the second inductor.

Optionally, the second enabling control sub-circuit further includes a fourth switching tube, a fifth switching tube, a sixth switching tube, a fourth resistor, a fifth resistor, a sixth resistor, and an eighth resistor;

the output end of the OR gate module is connected with the first end of a fourth resistor, the second end of the fourth resistor is connected with the first end of a fourth switching tube, the second end of the fourth switching tube is connected with a first power supply through a fifth resistor, and the third end of the fourth switching tube is grounded; the first end of the fifth switching tube is connected with the second end of the fourth switching tube, the second end of the fifth switching tube is connected with the second power supply through a sixth resistor, the third end of the fifth switching tube is grounded, the second end of the fifth switching tube is connected with the first end of the eighth resistor, the second end of the eighth resistor is connected with the first end of the sixth switching tube, the third end of the sixth switching tube is grounded, and the second end of the sixth switching tube is connected with the enabling end of the first LED lamp.

Optionally, the first enabling control sub-circuit includes a first switching tube, a second switching tube, a third switching tube, a first resistor, a second resistor, a third resistor and a seventh resistor;

the first end of the first resistor receives a first enabling control signal, the second end of the first resistor is connected with the first end of the first switch tube, the second end of the first switch tube is connected with a first power supply through the second resistor, the third end of the first switch tube is grounded, the first end of the second switch tube is connected with the second end of the first switch tube, the second end of the second switch tube is connected with a second power supply through the third resistor, and the third end of the second switch tube is grounded; the first end of the seventh resistor is connected with the second end of the second switching tube, the second end of the seventh resistor is connected with the first end of the third switching tube, the third end of the third switching tube is grounded, and the second end of the third switching tube is connected with the enabling end of the first LED lamp.

Optionally, the first current switching circuit further comprises a first analog signal switch chip, a first signal input end of the first analog signal switch chip receives a first enabling control signal, a second signal input end of the first analog signal switch chip receives a second enabling control signal, a first output reference end of the first analog signal switch chip is used for receiving a first PWM signal, and a second output reference end of the first analog signal switch chip is used for receiving a second PWM signal;

when the first enabling control signal is a high-level signal, the output end of the first analog signal switch chip is communicated with a first output reference end of the first analog signal switch chip; when the second enabling control signal is a high-level signal, the output end of the first analog signal switch chip is communicated with the second output reference end of the first analog signal switch chip;

the output end of the first analog signal switch chip is connected with the input end of the first driving circuit.

Optionally, the first driving circuit includes a first LED constant current buck controller, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventh switching tube, an eighth switching tube, a seventh capacitor, and a third capacitor;

The first IO port of the first LED constant-current voltage-reducing controller is an input end of a first driving circuit and is connected with an output end of a first analog signal switch chip through a ninth resistor; the second IO port of the first LED constant current step-down controller is connected with the second end of the fourth capacitor, the third end of the seventh switching tube and the first end of the first inductor, the first end of the fourth capacitor is connected with the first end of the seventh switching tube and the second end of the fourteenth resistor, the first end of the fourteenth resistor is connected with the seventh IO port of the first LED constant current step-down controller, and the second end of the seventh switching tube is connected with the driving power supply;

the third IO port of the first LED constant current step-down controller is connected with the first end of the thirteenth resistor, the second end of the thirteenth resistor is connected with the first end of the eighth switching tube, the third end of the eighth switching tube is grounded, and the second end of the eighth switching tube is connected with the first end of the first inductor;

the second end of the first inductor is connected with the first end of the fifteenth resistor and the first end of the sixteenth resistor, and the second end of the fifteenth resistor, the second end of the sixteenth resistor, the driving end of the first LED lamp and the driving end of the second LED lamp are connected with each other;

the first end of the fifteenth resistor is connected with the fifth end of the first LED constant-current voltage-reducing controller through the tenth resistor, the second end of the fifteenth resistor is connected with the fourth end of the first LED constant-current voltage-reducing controller through the twelfth resistor, and the second end of the fifteenth resistor is connected with the sixth end of the first LED constant-current voltage-reducing controller through the eleventh resistor; the third capacitor is connected in parallel with the two ends of the eleventh resistor, the first end of the seventh capacitor is connected with the fourth end of the first LED constant current step-down controller, and the second end of the seventh capacitor is connected with the fifth end of the first LED constant current step-down controller.

Optionally, the seventh switching tube and the eighth switching tube are both MOS tubes;

the first end of the seventh switching tube is a grid electrode of the MOS tube, the second end of the seventh switching tube is a drain electrode of the MOS tube, and the third end of the seventh switching tube is a source electrode of the MOS tube;

the first end of the eighth switching tube is a grid electrode of the MOS tube, the second end of the eighth switching tube is a drain electrode of the MOS tube, and the third end of the eighth switching tube is a source electrode of the MOS tube.

Optionally, the first switching tube, the second switching tube, the third switching tube, the fourth switching tube, the fifth switching tube and the sixth switching tube are all MOS tubes;

the first end of the first switching tube is a grid electrode of the MOS tube, the second end of the first switching tube is a drain electrode of the MOS tube, and the third end of the first switching tube is a source electrode of the MOS tube;

the first end of the second switching tube is a grid electrode of the MOS tube, the second end of the second switching tube is a drain electrode of the MOS tube, and the third end of the second switching tube is a source electrode of the MOS tube; the first end of the third switching tube is a grid electrode of the MOS tube, the second end of the third switching tube is a drain electrode of the MOS tube, and the third end of the third switching tube is a source electrode of the MOS tube;

the first end of the fourth switching tube is a grid electrode of the MOS tube, the second end of the fourth switching tube is a drain electrode of the MOS tube, and the third end of the fourth switching tube is a source electrode of the MOS tube;

The first end of the fifth switching tube is a grid electrode of the MOS tube, the second end of the fifth switching tube is a drain electrode of the MOS tube, and the third end of the fifth switching tube is a source electrode of the MOS tube;

the first end of the sixth switching tube is a grid electrode of the MOS tube, the second end of the sixth switching tube is a drain electrode of the MOS tube, and the third end of the sixth switching tube is a source electrode of the MOS tube.

Optionally, the device also comprises a main control chip,

the first IO port of the main control chip is used for outputting a first enabling control signal, the second IO port of the main control chip is used for outputting a second enabling control signal, the third IO port of the main control chip is used for outputting a third enabling control signal,

the fourth IO port of the main control chip is used for outputting the first PWM signal, the fifth IO port of the main control chip is used for outputting the second PWM signal, the sixth IO port of the main control chip is used for outputting the third PWM signal, the seventh IO port of the main control chip is used for outputting the fourth PWM signal, and the eighth IO port of the main control chip is used for outputting the fifth PWM signal.

The beneficial effects are that: according to the LED control system for the projector, when the second enabling control signal or the third enabling control signal is high, the second LED lamp and the third LED lamp are simultaneously on, and the light mixing effect can be achieved without adding a BP lamp; the brightness of the first LED lamp, the second LED lamp and the third LED lamp can be adjusted through the first current switching circuit and the second current switching circuit; the first LED lamp and the second LED lamp share the first driving circuit, so that the cost can be effectively saved, the two driving circuits are used for driving 3 LED lamps, and the light mixing effect is realized.

Drawings

The invention will now be described in further detail with reference to the drawings and to specific embodiments.

Fig. 1 is a schematic diagram of the overall structure of an LED control system for a projector according to the present embodiment.

Fig. 2 is a schematic circuit diagram of an enable control circuit of an LED control system for a projector according to the present embodiment.

Fig. 3 is a schematic circuit diagram of a first current switching circuit of an LED control system for a projector according to the present embodiment.

Fig. 4 is a schematic circuit diagram of a first driving circuit of an LED control system for a projector according to the present embodiment.

Fig. 5 is a schematic circuit diagram of a second current switching circuit of an LED control system for a projector according to the present embodiment.

Fig. 6 is a schematic circuit diagram of an enabling and driving circuit of an LED control system for a projector according to the present embodiment.

Fig. 7 is a schematic diagram of a main control chip interface of an LED control system for a projector according to the present embodiment.

Reference numerals:

u1, a first LED constant current step-down controller; u2, a second LED constant current step-down controller; u3, a first analog signal switch chip; u4, a second analog signal switch chip; u5, OR gate module;

J1, a first LED lamp interface; j2, a second LED lamp interface; j3, a third LED lamp interface; j4, a main control chip interface;

r1, a first resistor; r2, a second resistor; r3, a third resistor; r4, a fourth resistor; r5, a fifth resistor; r6, a sixth resistor; r7, a seventh resistor; r8, eighth resistor; r9, ninth resistor; r10, tenth resistor; r11, eleventh resistor; r12, twelfth resistor; r13, thirteenth resistance; r14, fourteenth resistor; r15, fifteenth resistor; r16, sixteenth resistance; r17, seventeenth resistance; r18, eighteenth resistor; r19, nineteenth resistor; r20, twentieth resistance; r21, twenty-first resistance; r22, a twenty-second resistor; r23, twenty-third resistor; r24, twenty-fourth resistor; r25, twenty-fifth resistance; r26, twenty-sixth resistance; r27, twenty-seventh resistor;

d1, a first diode; d2, a second diode;

l1, a first inductor; l2, a second inductor;

c1, a first capacitor; c2, a second capacitor; c3, a third capacitor; c4, a fourth capacitor; c5, a fifth capacitor; c6, a sixth capacitor; c7, a seventh capacitor; c8, an eighth capacitor; c9, a ninth capacitor; c10, tenth capacitance; c11, eleventh capacitance; c12, twelfth capacitance; c13, thirteenth capacitance; c14, fourteenth capacitor; c15, fifteenth capacitor;

Q1, a first switching tube; q2, a second switching tube; q3, a third switching tube; q4, a fourth switching tube; q5, a fifth switching tube; q6, a sixth switching tube; q7, a seventh switching tube; q8, an eighth switching tube; q9, ninth switching tube.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Examples

As shown in fig. 1, the present embodiment provides an LED control system for a projector, including a main control chip, a first LED lamp, a second LED lamp, a third LED lamp, an enable control circuit, a first driving circuit, an enable and driving circuit, a first current switching circuit, and a second current switching circuit. In the drawing of this embodiment, a first LED lamp is represented by a first LED lamp interface J1, a second LED lamp is represented by a second LED lamp interface J2, a third LED lamp is represented by a third LED lamp interface J3, and a main control chip is represented by a main control chip interface J4.

As shown in fig. 7, the main control chip is represented by a main control chip interface J4, in fig. 7, led_en_red represents a first enable control signal, led_en_grn represents a second enable control signal, led_en_blu represents a third enable control signal, pwm_led represents a first PWM signal, pwm_rled represents a second PWM signal, pwm_gpled represents a third PWM control signal, pwm_bpled represents a fourth PWM control signal, and pwm_ble represents a fifth PWM control signal. The main control chip comprises a plurality of IO ports, and the first IO port, the second IO port and the third IO port of the main control chip sequentially send out a first enabling control signal for controlling the first LED lamp, a second enabling control signal for controlling the second LED lamp and a third enabling control signal for controlling the third LED lamp; the fourth IO port of the main control chip sends out a first PWM signal, the fifth IO port of the main control chip sends out a second PWM signal, the sixth IO port of the main control chip sends out a third PWM signal, the seventh IO port of the main control chip sends out a fourth PWM signal, the eighth IO port of the main control chip sends out a fifth PWM signal, and the first PWM signal, the second PWM signal, the third PWM signal, the fourth PWM signal and the fifth PWM signal are used for controlling the brightness of the three LED lamps. In this embodiment, the first LED lamp is a red lamp, the second LED lamp is a green lamp, and the third LED lamp is a blue lamp; the model of the main control chip can be DLPC3439, DLPC6540, etc.

The enabling control circuit comprises a first enabling control sub-circuit and a second sub-enabling control sub-circuit; the first enabling control sub-circuit outputs a first enabling signal to an enabling end of the first LED lamp according to the first enabling control signal; the second enabling control sub-circuit outputs a second enabling signal to an enabling end of the second LED lamp according to the second enabling control signal and the third enabling control signal; the control logic is used for outputting a first enabling signal to be a low-level signal when the first enabling control signal is outputted as a high-level signal, namely the enabling end of the first LED lamp is grounded; when the second enabling control signal or the third enabling control signal is output as a high-level signal, the output end of the second enabling control sub-circuit is a low-level signal, namely the enabling end of the second LED lamp is grounded; when the driving end of the first LED lamp or the driving end of the second LED lamp is connected with a corresponding driving power supply, the enabling end of the first LED lamp or the enabling end of the second LED lamp is grounded, and therefore current passes through the first LED lamp or the second LED lamp. In this embodiment, the first LED lamp is controlled to be turned on when the first enable control signal is high, and the second LED lamp is controlled to be turned on when the second enable control signal or the third enable control signal is high.

As shown in fig. 2, specifically, the first enable control sub-circuit includes a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, a first resistor R1, a second resistor R2, a third resistor R3, and a seventh resistor R7; the first end of the first resistor R1 receives a first enabling control signal, the second end of the first resistor R1 is connected with the first end of the first switching tube Q1, the second end of the first switching tube Q1 is connected with a first power supply through the second resistor R2, the third end of the first switching tube Q1 is grounded, the first end of the second switching tube Q2 is connected with the second end of the first switching tube Q1, the second end of the second switching tube Q2 is connected with a second power supply through the third resistor R3, and the third end of the second switching tube Q2 is grounded; the first end of the seventh resistor R7 is connected with the second end of the second switching tube Q2, the second end of the seventh resistor R7 is connected with the first end of the third switching tube Q3, the third end of the third switching tube Q3 is grounded, and the second end of the third switching tube Q3 is connected with the enabling end of the first LED lamp.

The second enabling control sub-circuit further comprises an OR gate module, a fourth switching tube Q4, a fifth switching tube Q5, a sixth switching tube Q6, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and an eighth resistor R8. The first input end of the OR gate module receives a second enabling control signal, the second input end of the OR gate module receives a third enabling control signal, the output end of the OR gate module is used for controlling the enabling end of the second LED lamp, and when the second enabling control signal and/or the third enabling control signal are high-level signals, the output end of the OR gate module outputs the high-level signals. The output end of the OR gate module is connected with the first end of a fourth resistor R4, the second end of the fourth resistor R4 is connected with the first end of a fourth switching tube Q4, the second end of the fourth switching tube Q4 is connected with a first power supply through a fifth resistor R5, and the third end of the fourth switching tube Q4 is grounded; the first end of the fifth switching tube Q5 is connected with the second end of the fourth switching tube Q4, the second end of the fifth switching tube Q5 is connected with a second power supply through a sixth resistor R6, the third end of the fifth switching tube Q5 is grounded, the second end of the fifth switching tube Q5 is connected with the first end of an eighth resistor R8, the second end of the eighth resistor R8 is connected with the first end of a sixth switching tube Q6, the third end of the sixth switching tube Q6 is grounded, and the second end of the sixth switching tube Q6 is connected with the enabling end of the first LED lamp.

In this embodiment, the type of the or gate module is SN74LVC1G332DBV, and the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, the fourth switching tube Q4, the fifth switching tube Q5, and the sixth switching tube Q6 are all MOS tubes; the first end of the first switching tube Q1 is a grid electrode of the MOS tube, the second end of the first switching tube Q1 is a drain electrode of the MOS tube, and the third end of the first switching tube Q1 is a source electrode of the MOS tube; the first end of the second switching tube Q2 is a grid electrode of the MOS tube, the second end of the second switching tube Q2 is a drain electrode of the MOS tube, and the third end of the second switching tube Q2 is a source electrode of the MOS tube; the first end of the third switching tube Q3 is a grid electrode of the MOS tube, the second end of the third switching tube Q3 is a drain electrode of the MOS tube, and the third end of the third switching tube Q3 is a source electrode of the MOS tube; the first end of the fourth switching tube Q4 is a grid electrode of the MOS tube, the second end of the fourth switching tube Q4 is a drain electrode of the MOS tube, and the third end of the fourth switching tube Q4 is a source electrode of the MOS tube; the first end of the fifth switching tube Q5 is a grid electrode of the MOS tube, the second end of the fifth switching tube Q5 is a drain electrode of the MOS tube, and the third end of the fifth switching tube Q5 is a source electrode of the MOS tube; the first end of the sixth switching tube Q6 is a grid electrode of the MOS tube, the second end of the sixth switching tube Q6 is a drain electrode of the MOS tube, and the third end of the sixth switching tube Q6 is a source electrode of the MOS tube. The first power supply is a 3.3V power supply, and the second power supply is a 5V power supply.

As shown in fig. 3, the first current switching circuit is configured to output a PWM signal to control the brightness of the first LED lamp and the second LED lamp, and includes a first analog signal switch chip U3, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, and an eleventh capacitor C11. The first signal input end of the first analog signal switch chip U3 receives a first enabling control signal, the second signal input end of the first analog signal switch chip U3 receives a second enabling control signal, the first output reference end of the first analog signal switch chip U3 is connected with the second end of the nineteenth resistor R19, and the first end of the nineteenth resistor R19 is connected with the fourth IO port of the main control chip, namely the first output reference end of the first analog signal switch chip U3 is used for receiving a first PWM signal; the second output reference end of the first analog signal switch chip U3 is connected with the second end of the eighteenth resistor R18, and the first end of the eighteenth resistor R18 is connected with the fifth IO port of the main control chip, namely the second output reference end of the first analog signal switch chip U3 is used for receiving a second PWM signal; the third output reference end of the first analog signal switch chip U3 is connected with the second end of the seventeenth resistor R17, and the first end of the seventeenth resistor R17 is connected with the sixth IO port of the main control chip, namely the third output reference end of the first analog signal switch chip U3 is used for receiving a third PWM signal; meanwhile, the first output reference end of the first analog signal switch chip U3 is grounded through an eleventh capacitor C11, the second output reference end of the first analog signal switch chip U3 is grounded through a ninth capacitor C9, and the third output reference end of the first analog signal switch chip U3 is grounded through a tenth capacitor C10.

In this embodiment, the model of the first analog signal switch chip U3 is SGM48780, and pin 1, pin 2, pin 3, and pin 5 of the first analog signal switch chip U3 are respectively a third output reference end, a second output reference end, an output end, and a first output reference end of the first analog signal switch chip U3; the pin 7 and the pin 8 of the first analog signal switch chip U3 are respectively a second signal input end and a first signal input end of the first analog signal switch chip U3; the No. 4 pin of the first analog signal switch chip U3 is grounded through a twenty-first resistor R20, the No. 10 pin of the first analog signal switch chip U3 is connected with a first power supply, the No. 10 pin of the first analog signal switch chip U3 is grounded through an eighth capacitor C8, and the No. 9 pin of the first analog signal switch chip U3 is grounded; the No. 6 pin and the No. 11 pin of the first analog signal switch chip U3 are respectively grounded.

The control logic of the first analog signal switch chip U3 is shown in table 1, and when the first enable control signal is high, the output end of the first analog signal switch chip U3 is connected to the first output reference end of the first analog signal switch chip U3; when the second enabling control signal is high, the output end of the first analog signal switch chip U3 is communicated with the second output reference end of the first analog signal switch chip U3; when the first enable control signal and the second enable control signal are both low, the output terminal of the first analog signal switch chip U3 is connected to the third output reference terminal of the first analog signal switch chip U3, and in this embodiment, there is no case where the first enable control signal and the second enable control signal are both high, i.e., y=y3, so the fourth output reference terminal of the first analog signal switch chip U3 is grounded.

Table 1: control logic table of first analog signal switch chip U3

First signal input terminal (B)	Second signal inputEnd (A)	Output terminal (Y)
			L	L	Y=Y0
L	H	Y=Y1
			H	L	Y=Y2
H	H	Y=Y3

The output end of the first analog signal switch chip U3 is connected with the input end of the first driving circuit, and the first driving circuit outputs different driving voltages according to PWM signals output by the first analog signal switch chip U3 so as to change the currents of the first LED lamp and the second LED lamp, thereby changing the brightness of the first LED lamp and the second LED lamp.

As shown in fig. 4, specifically, the first driving circuit includes a first LED constant current step-down controller U1, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventh switching tube Q7, an eighth switching tube Q8, a seventh capacitor C7, a first capacitor C1, a second capacitor C2, and a third capacitor C3.

The first IO port of the first LED constant-current voltage-reducing controller U1 is an input end of a first driving circuit, and the first IO port of the first LED constant-current voltage-reducing controller U1 is connected with an output end of the first analog signal switch chip U3 through a ninth resistor R9; the second IO port of the first LED constant current step-down controller U1 is connected with the second end of the fourth capacitor C4, the third end of the seventh switching tube Q7 and the first end of the first inductor L1, the first end of the fourth capacitor C4 is connected with the first end of the seventh switching tube Q7 and the second end of the fourteenth resistor R14, the first end of the fourteenth resistor R14 is connected with the seventh IO port of the first LED constant current step-down controller U1, the second end of the seventh switching tube Q7 is connected with a driving power supply, and the second end of the seventh switching tube Q7 is grounded through the fifth capacitor C5. The third IO port of the first LED constant current step-down controller U1 is connected with the first end of a thirteenth resistor R13, the second end of the thirteenth resistor R13 is connected with the first end of an eighth switching tube Q8, the third end of the eighth switching tube Q8 is grounded, and the second end of the eighth switching tube Q8 is connected with the first end of the first inductor L1. The second end of the first inductor L1 is connected with the first end of the fifteenth resistor R15 and the first end of the sixteenth resistor R16, the second end of the first inductor L1 is grounded through a sixth capacitor C6, and the second end of the fifteenth resistor R15, the second end of the sixteenth resistor R16, the driving end of the first LED lamp and the driving end of the second LED lamp are connected with each other. The first end of the fifteenth resistor R15 is connected with the fifth end of the first LED constant-current step-down controller U1 through a tenth resistor R10, the second end of the fifteenth resistor R15 is connected with the fourth end of the first LED constant-current step-down controller U1 through a twelfth resistor R12, and the second end of the fifteenth resistor R15 is connected with the sixth end of the first LED constant-current step-down controller U1 through an eleventh resistor R11; the third capacitor C3 is connected in parallel with two ends of the eleventh resistor R11, a first end of the seventh capacitor C7 is connected with a fourth end of the first LED constant current step-down controller U1, and a second end of the seventh capacitor C7 is connected with a fifth end of the first LED constant current step-down controller U1.

In this embodiment, the model number of the first LED constant current buck controller U1 is PL56002, the first IO port of the first LED constant current buck controller U1 is pin No. 8 of the first LED constant current buck controller U1, the second IO port of the first LED constant current buck controller U1 is pin No. 19 of the first LED constant current buck controller U1, the third IO port of the first LED constant current buck controller U1 is pin No. 78 of the first LED constant current buck controller U1, the fourth IO port of the first LED constant current buck controller U1 is pin No. 15 of the first LED constant current buck controller U1, the fifth IO port of the first LED constant current buck controller U1 is pin No. 14 of the first LED constant current buck controller U1, the sixth IO port of the first LED constant current buck controller U1 is pin No. 13 of the first LED constant current buck controller U1, and the seventh port of the first LED constant current buck controller U1 is pin No. 1 of the first LED constant current buck controller U1. The No. 6 pin of the first LED constant-current voltage-reducing controller U1 is grounded through the second capacitor C2, the No. 2 pin of the first LED constant-current voltage-reducing controller U1 is grounded through the first capacitor C1, and the No. 1 pin of the first LED constant-current voltage-reducing controller U1 outputs 5V voltage. The seventh switching tube Q7 and the eighth switching tube Q8 are MOS tubes, the first end of the seventh switching tube Q7 is a grid electrode of the MOS tube, the second end of the seventh switching tube Q7 is a drain electrode of the MOS tube, the third end of the seventh switching tube Q7 is a source electrode of the MOS tube, the first end of the eighth switching tube Q8 is a grid electrode of the MOS tube, the second end of the eighth switching tube Q8 is a drain electrode of the MOS tube, and the third end of the eighth switching tube Q8 is a source electrode of the MOS tube.

The second end of the fifteenth resistor R15 is an output end of the first driving circuit, and the second end of the fifteenth resistor R15 is connected with the driving end of the first LED lamp and used for outputting a first driving signal; the second end of the fifteenth resistor R15 is connected with the driving end of the second LED lamp and used for outputting a second driving signal. In the same time period, the first driving signal is the same as the second driving signal, but the signals received by the enabling end of the first LED lamp and the enabling end of the second LED lamp are different, and in this embodiment, the first LED lamp and the second LED lamp cannot be simultaneously turned on. When the first LED constant-current voltage reducing controller U1 receives the first PWM signal, the second PWM signal or the third PWM signal, the duty ratio of the seventh switching tube Q7 and the eighth switching tube Q8 is changed through the No. 3 pin and the No. 1 pin of the first LED constant-current voltage reducing controller U1, so that the current of the first LED lamp and the second LED lamp can be adjusted.

When the first enabling control signal is at a high level, the first current switching circuit outputs a second PWM signal, and the output end of the first enabling control sub-circuit outputs a low-level signal, namely the third switching tube Q3 is conducted to enable the enabling end of the first LED lamp to be grounded; the first driving circuit controls the duty ratio of a seventh switching tube Q7 and an eighth switching tube Q8 according to the second PWM signal, when the seventh switching tube Q7 is opened, a driving power supply charges and stores energy to the first inductor L1 through the seventh switching tube Q7, then the driving power supply passes through a sampling resistor, namely a fifteenth resistor R15 and a sixteenth resistor R16, and then the driving end of the first LED lamp, at the moment, a current path is formed between the driving end of the first LED lamp and an enabling end of the first LED lamp, and the first LED lamp is lightened; the first LED constant current step-down controller U1 detects the current of a fifteenth resistor R15 and a sixteenth resistor R16 through a 14 th pin of the first LED constant current step-down controller, when the current of the fifteenth resistor R15 and the sixteenth resistor R16 exceeds a preset current, the first LED constant current step-down controller U1 controls a seventh switching tube Q7 to be closed, an eighth switching tube Q8 is opened, the first inductor L1 continuously charges the fifteenth resistor R15 and the sixteenth resistor R16 because the current at two ends of the inductor cannot be suddenly changed, the first LED lamp discharges, and when the first LED constant current step-down controller U1 detects that the current of the fifteenth resistor R15 and the sixteenth resistor R16 is smaller than the preset current, the seventh switching tube Q7 is opened again, and the circulation is performed in this way, so that the purpose of constant current of the first LED lamp is achieved; the same applies to the first LED lamp when controlling the second LED lamp.

As shown in fig. 5, the second current switching circuit is configured to output a PWM signal to control the third LED lamp, and includes a second analog signal switch chip U4, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, an eleventh capacitor C11, a twelfth capacitor C12, and a thirteenth capacitor C13. The first signal input end of the second analog signal switch chip U4 receives a second enabling control signal, the second signal input end of the second analog signal switch chip U4 receives a third enabling control signal, the first output reference end of the second analog signal switch chip U4 is connected with a seventh IO port of the main control chip through a twenty-second resistor R22, namely a fourth PWM signal is received, and the second output reference end of the first analog signal switch chip U3 is connected with an eighth IO port of the main control chip, namely a fifth PWM signal is received; meanwhile, the first output reference end of the second analog signal switch chip U4 is grounded through a twelfth capacitor C12, and the first output reference end of the second analog signal switch chip U4 is grounded through a thirteenth capacitor C13.

In this embodiment, the model of the second analog signal switch chip U4 is SGM48780, and the pin No. 2, pin No. 3, pin No. 5 of the second analog signal switch chip U4 are the second output reference terminal, the output terminal, and the first output reference terminal of the second analog signal switch chip U4, respectively; the pin 7 and the pin 8 of the second analog signal switch chip U4 are respectively a first signal input end and a second signal input end of the first analog signal switch chip U3. The pin 1 of the second analog signal switch chip U4 is grounded through a twenty-fourth resistor R24, the pin 4 of the second analog signal switch chip U4 is grounded through a twenty-third resistor R23, the pin 10 of the second analog signal switch chip U4 is connected with a first power supply, the pin 10 of the second analog signal switch chip U4 is grounded through an eleventh capacitor C11, and the pin 9 of the second analog signal switch chip U4 is grounded; and the No. 6 pin and the No. 11 pin of the second analog signal switch chip U4 are respectively grounded.

The control logic of the second analog signal switch chip U4 is shown in table 2, and when the second enable control signal is high, the output end of the second analog signal switch chip U4 is connected to the first output reference end of the second analog signal switch chip U4; when the third enabling control signal is high, the output end of the second analog signal switch chip U4 is communicated with the second output reference end of the second analog signal switch chip; when the second enabling control signal and the third enabling control signal are simultaneously low, the third LED lamp does not need to be lighted, and the output end of the second analog signal switch chip U4 is communicated with the No. 1 pin of the second analog signal switch chip U4.

Table 2: control logic table of second analog signal switch chip U4

Second signal input terminal (B)	First signal input terminal (A)	Output terminal (Y)
			L	L	Y=Y0
L	H	Y=Y1
			H	L	Y=Y2
H	H	Y=Y3

As shown in fig. 6, specifically, the enabling and driving circuit includes a second LED constant current buck controller U2, a ninth switching tube Q9, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a second inductor L2, a first diode D1, a second diode D2, a fourteenth capacitor C14, a fifteenth capacitor C15, and a sixteenth capacitor C16;

the enabling end of the second LED constant-current voltage-reducing controller U2 is an input end of an enabling and driving circuit, and the enabling end of the second LED constant-current voltage-reducing controller U2 is connected with the output end of the second analog signal switch chip U4 through a twenty-fifth resistor R25; the input power end of the second LED constant-current voltage-reducing controller U2 is connected with a driving power supply, and the input power end of the second LED constant-current voltage-reducing controller U2 is respectively connected with the driving end of the third LED lamp and the current detection end of the second LED constant-current voltage-reducing controller U2 through a twenty-sixth resistor R26; the output end of a gate driver of the second LED constant-current step-down controller U2 is connected with the first end of a ninth switching tube Q9 through a twenty-seventh resistor R27, the second end of the ninth switching tube Q9 is connected with the enabling end of a third LED lamp through a second inductor L2, and the third end of the ninth switching tube Q9 is grounded; the second end of the ninth switching tube Q9 is respectively connected with the anode of the first diode D1 and the anode of the second diode D2, and the cathode of the first diode D1 and the cathode of the second diode D2 are respectively connected with the input power supply end of the second LED constant current step-down controller U2; the first end of the fifteenth capacitor C15 and the first end of the sixteenth capacitor C16 are connected with the power input end of the second LED constant current step-down controller U2, and the second end of the fifteenth capacitor C15 and the second end of the sixteenth capacitor C16 are connected with the first end of the second inductor L2.

The model of the second LED constant current voltage reducing controller U2 is MP24894, the No. 1 pin of the second LED constant current voltage reducing controller U2 is an input power end of the second LED constant current voltage reducing controller U2, the No. 2 pin of the second LED constant current voltage reducing controller U2 is a current detection end of the second LED constant current voltage reducing controller U2, the No. 3 pin of the second LED constant current voltage reducing controller U2 is an enabling end of the second LED constant current voltage reducing controller U2, the No. 4 pin of the second LED constant current voltage reducing controller U2 is grounded, the No. 5 pin of the second LED constant current voltage reducing controller U2 is a gate driver output end of the second LED constant current voltage reducing controller U2, and the No. 6 pin of the second LED constant current voltage reducing controller U2 is grounded through a fourteenth capacitor C14; and the No. 1 pin of the second LED constant current step-down controller U2 is grounded through a plurality of capacitors.

The ninth switching tube Q9 is a MOS tube, the first end of the ninth switching tube Q9 is a grid electrode of the MOS tube, the second end of the ninth switching tube Q9 is a drain electrode of the MOS tube, and the third end of the ninth switching tube Q9 is a source electrode of the MOS tube.

When the second LED constant-current voltage-reducing controller U2 receives the fourth PWM signal or the fifth PWM signal, the No. 2 pin of the second LED constant-current voltage-reducing controller U2 changes the duty ratio of the ninth switching tube Q9, so that the current of the third LED lamp can be adjusted.

When the third LED lamp is to be lighted, the second LED constant-current voltage-reducing controller U2 turns on a ninth switching tube Q9, a driving power supply charges and stores energy to the second inductor L2 through a twenty-sixth resistor R26, the third LED lamp, the second inductor L2 and the ninth switching tube Q9 to form a current path, and the third LED lamp is lighted; when the second LED constant current voltage reduction controller U2 detects that the current of the twenty-sixth resistor R26 exceeds the preset current, the ninth switching tube Q9 is closed, the second inductor L2 continuously discharges the twenty-sixth resistor R26 through the first diode D1 and the second diode D2, the current slowly drops, and when the second LED constant current voltage reduction controller U2 detects that the current of the twenty-sixth resistor R26 is smaller than the preset current, the ninth switching tube Q9 is opened again to charge the second inductor L2, and the circulation is performed, so that the purpose of constant current of the third LED lamp is achieved.

According to the LED control system for the projector, when the second enabling control signal or the third enabling control signal is high, the second LED lamp and the third LED lamp are simultaneously on through the OR gate module and the second current switching circuit, and the light mixing effect can be achieved without adding the BP lamp; the brightness of the first LED lamp, the second LED lamp and the third LED lamp can be adjusted through the first current switching circuit and the second current switching circuit; the first LED lamp and the second LED lamp share the first driving circuit, so that the cost can be effectively saved.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments, and are intended to be included within the scope of the claims and description.

Claims

1. An LED control system for a projector, comprising

the enabling control circuit comprises a first enabling control sub-circuit and a second enabling control sub-circuit, the first enabling control sub-circuit comprises a third switch tube (Q3), the second end of the third switch tube (Q3) is connected with the enabling end of the first LED lamp, the third end of the third switch tube (Q3) is grounded, the input end of the first enabling control sub-circuit receives a first enabling control signal, and when the first enabling control signal is a high-level signal, the third switch tube (Q3) is conducted; the second enabling control sub-circuit comprises an OR gate module and a sixth switching tube (Q6), the second end of the sixth switching tube (Q6) is connected with the enabling end of the second LED lamp, the third end of the sixth switching tube (Q6) is grounded, the first input end of the OR gate module receives a second enabling control signal, the second input end of the OR gate module receives a third enabling control signal, when the second enabling control signal and/or the third enabling control signal are high-level signals, the output end of the OR gate module outputs high-level signals, and the sixth switching tube (Q6) is conducted;

2. An LED control system for a projector according to claim 1, further comprising a second current switching circuit comprising a second analog signal switching chip (U4), a first signal input of the second analog signal switching chip (U4) receiving a second enable control signal, a second signal input of the second analog signal switching chip (U4) receiving a third enable control signal, a first output reference of the second analog signal switching chip (U4) receiving a fourth PWM signal, a second output reference of the first analog signal switching chip (U3) receiving a fifth PWM signal;

When the second enabling control signal is a high-level signal, the output end of the second analog signal switch chip (U4) is communicated with the first output reference end of the second analog signal switch chip (U4); when the second enabling control signal is a high-level signal, the output end of the second analog signal switch chip (U4) is communicated with a second output reference end of the second analog signal switch chip (U4);

the output end of the second analog signal switch chip (U4) is connected with the input end of the enabling and driving circuit.

3. An LED control system for a projector according to claim 2, wherein the enable and drive circuit comprises a second LED constant current buck controller (U2), a ninth switching transistor (Q9), a twenty-fifth resistor (R25), a twenty-sixth resistor (R26), a twenty-seventh resistor (R27), a second inductor (L2), a first diode (D1), a second diode (D2), a fifteenth capacitor (C15), and a sixteenth capacitor (C16);

the enabling end of the second LED constant-current voltage-reducing controller (U2) is an input end of an enabling and driving circuit, and the enabling end of the second LED constant-current voltage-reducing controller (U2) is connected with the output end of the second analog signal switch chip (U4) through a twenty-fifth resistor (R25); the input power end of the second LED constant-current voltage-reducing controller (U2) is connected with a driving power supply, and the input power end of the second LED constant-current voltage-reducing controller (U2) is respectively connected with the driving end of the third LED lamp and the current detection end of the second LED constant-current voltage-reducing controller (U2) through a twenty-sixth resistor (R26); the output end of a gate driver of the second LED constant-current step-down controller (U2) is connected with the first end of a ninth switching tube (Q9) through a twenty-seventh resistor (R27), the second end of the ninth switching tube (Q9) is connected with the enabling end of a third LED lamp through a second inductor (L2), and the third end of the ninth switching tube (Q9) is grounded; the second end of the ninth switching tube (Q9) is respectively connected with the anode of the first diode (D1) and the anode of the second diode (D2), and the cathode of the first diode (D1) and the cathode of the second diode (D2) are respectively connected with the input power supply end of the second LED constant current step-down controller (U2); the first end of the fifteenth capacitor (C15) and the first end of the sixteenth capacitor (C16) are connected with the power input end of the second LED constant current step-down controller (U2), and the second end of the fifteenth capacitor (C15) and the second end of the sixteenth capacitor (C16) are connected with the first end of the second inductor (L2).

4. An LED control system for a projector according to claim 1, wherein the second enable control sub-circuit further comprises a fourth switching tube (Q4), a fifth switching tube (Q5), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6) and an eighth resistor (R8);

the output end of the OR gate module is connected with the first end of a fourth resistor (R4), the second end of the fourth resistor (R4) is connected with the first end of a fourth switching tube (Q4), the second end of the fourth switching tube (Q4) is connected with a first power supply through a fifth resistor (R5), and the third end of the fourth switching tube (Q4) is grounded; the first end of the fifth switching tube (Q5) is connected with the second end of the fourth switching tube (Q4), the second end of the fifth switching tube (Q5) is connected with the second power supply through a sixth resistor (R6), the third end of the fifth switching tube (Q5) is grounded, the second end of the fifth switching tube (Q5) is connected with the first end of an eighth resistor (R8), and the second end of the eighth resistor (R8) is connected with the first end of the sixth switching tube (Q6).

5. The LED control system for a projector according to claim 4, wherein the first enable control sub-circuit comprises a first switching tube (Q1), a second switching tube (Q2), a first resistor (R1), a second resistor (R2), a third resistor (R3) and a seventh resistor (R7);

The first end of the first resistor (R1) receives a first enabling control signal, the second end of the first resistor (R1) is connected with the first end of the first switch tube (Q1), the second end of the first switch tube (Q1) is connected with a first power supply through the second resistor (R2), the third end of the first switch tube (Q1) is grounded, the first end of the second switch tube (Q2) is connected with the second end of the first switch tube (Q1), the second end of the second switch tube (Q2) is connected with a second power supply through the third resistor (R3), and the third end of the second switch tube (Q2) is grounded; a first end of a seventh resistor (R7) is connected with a second end of the second switching tube (Q2), and a second end of the seventh resistor (R7) is connected with a first end of the third switching tube (Q3).

6. An LED control system for a projector according to claim 1, further comprising a first current switching circuit comprising a first analog signal switching chip (U3), a first signal input of the first analog signal switching chip (U3) receiving a first enable control signal, a second signal input of the first analog signal switching chip (U3) receiving a second enable control signal, a first output reference of the first analog signal switching chip (U3) receiving a first PWM signal, a second output reference of the first analog signal switching chip (U3) receiving a second PWM signal;

When the first enabling control signal is a high-level signal, the output end of the first analog signal switch chip (U3) is communicated with a first output reference end of the first analog signal switch chip (U3); when the second enabling control signal is a high-level signal, the output end of the first analog signal switch chip (U3) is communicated with the second output reference end of the first analog signal switch chip (U3);

the output end of the first analog signal switch chip (U3) is connected with the input end of the first driving circuit.

7. The LED control system for a projector according to claim 6, wherein the first driving circuit includes a first LED constant current step-down controller (U1), a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11), a twelfth resistor (R12), a thirteenth resistor (R13), a fourteenth resistor (R14), a fifteenth resistor (R15), a sixteenth resistor (R16), a seventh switching tube (Q7), an eighth switching tube (Q8), a seventh capacitor (C7), and a third capacitor (C3);

the first IO port of the first LED constant-current voltage-reducing controller (U1) is an input end of a first driving circuit, and the first IO port of the first LED constant-current voltage-reducing controller (U1) is connected with an output end of a first analog signal switch chip (U3) through a ninth resistor (R9); the second IO port of the first LED constant current step-down controller (U1) is connected with the second end of a fourth capacitor (C4), the third end of a seventh switching tube (Q7) and the first end of a first inductor (L1), the first end of the fourth capacitor (C4) is connected with the first end of the seventh switching tube (Q7) and the second end of a fourteenth resistor (R14), and the first end of the fourteenth resistor (R14) is connected with the seventh IO port of the first LED constant current step-down controller (U1), and the second end of the seventh switching tube (Q7) is connected with a driving power supply;

The third IO port of the first LED constant current step-down controller (U1) is connected with the first end of a thirteenth resistor (R13), the second end of the thirteenth resistor (R13) is connected with the first end of an eighth switching tube (Q8), the third end of the eighth switching tube (Q8) is grounded, and the second end of the eighth switching tube (Q8) is connected with the first end of the first inductor (L1);

the second end of the first inductor (L1) is connected with the first end of a fifteenth resistor (R15) and the first end of a sixteenth resistor (R16), and the second end of the fifteenth resistor (R15), the second end of the sixteenth resistor (R16), the driving end of the first LED lamp and the driving end of the second LED lamp are connected with each other;

a first end of a fifteenth resistor (R15) is connected with a fifth end of the first LED constant current voltage reduction controller (U1) through a tenth resistor (R10), a second end of the fifteenth resistor (R15) is connected with a fourth end of the first LED constant current voltage reduction controller (U1) through a twelfth resistor (R12), and a second end of the fifteenth resistor (R15) is connected with a sixth end of the first LED constant current voltage reduction controller (U1) through an eleventh resistor (R11); the third capacitor (C3) is connected in parallel with two ends of the eleventh resistor (R11), the first end of the seventh capacitor (C7) is connected with the fourth end of the first LED constant current step-down controller (U1), and the second end of the seventh capacitor (C7) is connected with the fifth end of the first LED constant current step-down controller (U1).

8. The LED control system for a projector according to claim 7, wherein the seventh switching tube (Q7) and the eighth switching tube (Q8) are both MOS tubes;

the first end of the seventh switching tube (Q7) is a grid electrode of the MOS tube, the second end of the seventh switching tube (Q7) is a drain electrode of the MOS tube, and the third end of the seventh switching tube (Q7) is a source electrode of the MOS tube;

the first end of the eighth switching tube (Q8) is a grid electrode of the MOS tube, the second end of the eighth switching tube (Q8) is a drain electrode of the MOS tube, and the third end of the eighth switching tube (Q8) is a source electrode of the MOS tube.

9. The LED control system for a projector according to claim 5, wherein the first switching tube (Q1), the second switching tube (Q2), the third switching tube (Q3), the fourth switching tube (Q4), the fifth switching tube (Q5) and the sixth switching tube (Q6) are MOS tubes;

the first end of the first switching tube (Q1) is a grid electrode of the MOS tube, the second end of the first switching tube (Q1) is a drain electrode of the MOS tube, and the third end of the first switching tube (Q1) is a source electrode of the MOS tube;

the first end of the second switching tube (Q2) is a grid electrode of the MOS tube, the second end of the second switching tube (Q2) is a drain electrode of the MOS tube, and the third end of the second switching tube (Q2) is a source electrode of the MOS tube; the first end of the third switching tube (Q3) is a grid electrode of the MOS tube, the second end of the third switching tube (Q3) is a drain electrode of the MOS tube, and the third end of the third switching tube (Q3) is a source electrode of the MOS tube;

The first end of the fourth switching tube (Q4) is a grid electrode of the MOS tube, the second end of the fourth switching tube (Q4) is a drain electrode of the MOS tube, and the third end of the fourth switching tube (Q4) is a source electrode of the MOS tube;

the first end of the fifth switching tube (Q5) is a grid electrode of the MOS tube, the second end of the fifth switching tube (Q5) is a drain electrode of the MOS tube, and the third end of the fifth switching tube (Q5) is a source electrode of the MOS tube;

the first end of the sixth switching tube (Q6) is a grid electrode of the MOS tube, the second end of the sixth switching tube (Q6) is a drain electrode of the MOS tube, and the third end of the sixth switching tube (Q6) is a source electrode of the MOS tube.

10. An LED control system for a projector according to any of the claims 1-9, further comprising a main control chip,

the first IO port of the main control chip is used for outputting a first enabling control signal, the second IO port of the main control chip is used for outputting a second enabling control signal, the third IO port of the main control chip is used for outputting a third enabling control signal, the fourth IO port of the main control chip is used for outputting a first PWM signal, the fifth IO port of the main control chip is used for outputting a second PWM signal, the sixth IO port of the main control chip is used for outputting a third PWM signal, the seventh IO port of the main control chip is used for outputting a fourth PWM signal, and the eighth IO port of the main control chip is used for outputting a fifth PWM signal.