Circuit that can realize multiple LED lamps in series

Abstract

The present invention provides a circuit capable of connecting multiple LED lamps in series, including a DC-DC buck module and an LED light source module; the input end of the DC-DC buck module is connected to a first DC voltage VIN DC, and the output end outputs a second DC voltage VOUT DC; the first DC voltage VIN DC is higher than the second DC voltage VOUT DC, and the second DC voltage VOUT DC is supplied to the LED light source module as the working voltage of the LED light source module. Furthermore, the DC-DC buck module includes a power chip U1, diodes D1, D2, D3, an inductor T1, a voltage regulator diode Z1, resistors R1, R2, R3, R3A, R4, R4A, R5, R6, capacitors C1, C2, C3, C4, C6; the LED light source module includes a control signal transcoding circuit and one or more cascaded LED light source circuits. The present invention enables each LED lamp to achieve consistent working voltage and balanced brightness.

Description

Technical Field

[0001] The invention relates to the field of LED lamps, and in particular to a circuit capable of realizing serial connection of multiple LED lamps. Background Art

[0002] When multiple LED lamps are connected in series, the current LED lamps generally use a 24V input and 24V output solution. Because the wire itself has a certain impedance, when the line is long and the lamps are connected in series, the voltage input to the last lamps will be reduced, which may cause some of the LED lamps to be brighter and some to be dimmer. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a circuit that can realize the series connection of multiple LED lamps, so that each LED lamp can achieve consistent working voltage and balanced brightness. The technical solution adopted by the present invention is:

[0004] A circuit capable of connecting multiple LED lamps in series, comprising a DC-DC step-down module and an LED light source module;

[0005] The input end of the DC-DC buck module is connected to a first DC voltage VIN DC, and the output end outputs a second DC voltage VOUT DC; the first DC voltage VIN DC is higher than the second DC voltage VOUT DC, and the second DC voltage VOUT DC is supplied to the LED light source module as the working voltage of the LED light source module.

[0006] Further, the DC-DC buck module includes a power chip U1, diodes D1, D2, D3, an inductor T1, a voltage stabilizing diode Z1, resistors R1, R2, R3, R3A, R4, R4A, R5, R6, capacitors C1, C2, C3, C4, C6;

[0007] The anode of the diode D1 is connected to the first DC voltage VIN DC, the cathode is connected to the positive electrode of the capacitor C1 and one end of the capacitor C2, one end of the resistor R1 and the power input pin of the power chip U1, and the negative electrode of the capacitor C1 and the other end of the capacitor C2 are grounded; the chip power pin of the power chip U1 is connected to the other end of the resistor R1, one end of the capacitor C3, the cathode of the voltage zener diode Z1 and one end of the resistor R2; the other end of the resistor R2 is connected to the cathode of the diode D2; the other end of the capacitor C3 and the anode of the voltage zener diode Z1 are connected to a common node; the feedback voltage positive terminal sampling pin of the power chip U1 is connected to one end of the resistor R3 and one end of R3A, and the other end of the resistor R3A is connected to the common node, the feedback voltage negative terminal sampling pin of the power chip U1 is connected to one end of the resistor R4 and one end of R4A, and the other end of the resistor R4A is connected to the common node, and the other end of the resistor R4 is grounded;

[0008] The internal DC voltage pin of the power chip U1 is connected to one end of the capacitor C4, and the chip ground pin of U1 is connected to the other end of the capacitor C4 and a common node; the power output pin of the power chip U1 is connected to the inductor current detection pin, and is connected to one end of the resistor R5 and the cathode of the diode D3; the other end of the resistor R5 is connected to one end of the inductor T1 and a common node; the other end of the inductor T1 is connected to the other end of the resistor R3, the anode of the diode D2, one end of the resistor R6 and the positive electrode of the capacitor C6, and outputs a second DC voltage VOUT DC; the anode of the diode D3, the other end of the resistor R6 and the negative electrode of the capacitor C6 are grounded.

[0009] Furthermore, the power chip U1 adopts SL3036.

[0010] Further, the LED light source module includes a control signal transcoding circuit, one or more cascaded LED light source circuits;

[0011] The control signal transcoding circuit includes a control signal conversion chip U2, resistors R7, R8, R9, capacitors C7, C8, resistors R10, R11, R12;

[0012] An LED light source circuit includes an LED driver chip U3, resistors R13, R14, capacitors C9, C10, and a four-color LED light string LED4;

[0013] The ground pin of the control signal conversion chip U2 is grounded, the address output pin is used to connect to the address input pin of the control signal conversion chip in the next-level LED lamp, and the transcoded data output pin of the control signal conversion chip U2 is connected to the data input pin of the LED driver chip U3;

[0014] The address input pin of the control signal conversion chip U2 is connected to the resistor R10, which is used to receive the address signal sent by the main controller or the upper-level LED lamp; the differential signal input pins A and B of U2 are respectively connected to the resistors R11 and R12, which are used to receive the input control signal; the power pin of U2 is connected to one end of the resistor R7 and one end of the capacitor C8; the other end of the resistor R7 and one end of the capacitor C7 are connected to the second DC voltage VOUT DC; the other ends of the capacitors C7 and C8 are grounded;

[0015] The four color LED signal output terminals OUTR, OUTG, OUTB, and OUTW of the LED driver chip U3 are respectively connected to the four cathodes R-, G-, B-, and W- of the LED light string LED4; the common anode of the LED light string LED4 is connected to the second DC voltage VOUT DC; the data output pin of the LED driver chip U3 is used to connect to the data input pin of the LED driver chip in the next-level LED light source circuit through the resistor R13; the ground pin of the LED driver chip U3 is grounded, and the power pin of the LED driver chip U3 is connected to one end of the resistor R14 and one end of the capacitor C10; the other end of the resistor R14 and one end of the capacitor C9 are connected to the second DC voltage VOUT DC; the other ends of the capacitors C9 and C10 are grounded.

[0016] Furthermore, the control signal conversion chip U2 adopts SM17500, and the LED driver chip U3 adopts SM16704PB.

[0017] The advantages of the present invention are:

[0018] 1) When multiple LED lamps are connected in series, the operating voltage of each lamp is guaranteed to be +24V, so that each LED lamp can emit light normally and the brightness will not be dim due to the voltage drop caused by the long line.

[0019] 2) Using DMX512 solution four-color LED light source, it can realize colorful gradient, flowing water and other effect change functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a general schematic diagram of the present invention.

[0021] Figure 2 This is a schematic diagram of the DC-DC buck module of the present invention.

[0022] Figure 3 This is a schematic diagram of the LED light source module of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0024] An embodiment of the present invention provides a circuit capable of connecting multiple LED lamps in series, comprising a DC-DC buck module and an LED light source module;

[0025] The input end of the DC-DC buck module is connected to a first DC voltage VIN DC, and the output end outputs a second DC voltage VOUT DC; the first DC voltage VIN DC is higher than the second DC voltage VOUT DC, and the second DC voltage VOUT DC is supplied to the LED light source module as a working voltage of the LED light source module;

[0026] DC-DC step-down module such as Figure 2 As shown, Figure 2 Where VIN DC is the first DC voltage, which is +36V in this example, and VOUT DC is the second DC voltage, which is +24V in this example;

[0027] The DC-DC step-down module includes a power chip U1, diodes D1, D2, D3, an inductor T1, a voltage-stabilizing diode Z1, resistors R1, R2, R3, R3A, R4, R4A, R5, R6, and capacitors C1, C2, C3, C4, and C6;

[0028] Among them, the power chip U1 adopts SL3036;

[0029] The anode of the diode D1 is connected to the first DC voltage VIN DC, the cathode is connected to the positive electrode of the capacitor C1 and one end of the capacitor C2, one end of the resistor R1 and the power input pin (pin 1) of the power chip U1, and the negative electrode of the capacitor C1 and the other end of the capacitor C2 are grounded; the chip power pin (pin 2) of the power chip U1 is connected to the other end of the resistor R1, one end of the capacitor C3, the cathode of the voltage regulator diode Z1 and one end of the resistor R2; the other end of the resistor R2 is connected to the cathode of the diode D2; the other end of the capacitor C3 and the anode of the voltage regulator diode Z1 are connected to the common node ( Figure 2 The positive sampling pin (pin 3) of the feedback voltage of the power chip U1 is connected to one end of the resistor R3 and one end of R3A, and the other end of the resistor R3A is connected to the common node. The negative sampling pin (pin 4) of the feedback voltage of the power chip U1 is connected to one end of the resistor R4 and one end of R4A, and the other end of the resistor R4A is connected to the common node, and the other end of the resistor R4 is grounded.

[0030] The internal DC voltage pin (pin 5) of the power chip U1 is connected to one end of the capacitor C4, and the chip ground pin (pin 6) of U1 is connected to the other end of the capacitor C4 and a common node; the power output pin (pin 8) of the power chip U1 is connected to the inductor current detection pin (pin 7), and is connected to one end of the resistor R5 and the cathode of the diode D3; the other end of the resistor R5 is connected to one end of the inductor T1 and a common node; the other end of the inductor T1 is connected to the other end of the resistor R3, the anode of the diode D2, one end of the resistor R6 and the positive electrode of the capacitor C6, and outputs a second DC voltage VOUTDC; the anode of the diode D3, the other end of the resistor R6 and the negative electrode of the capacitor C6 are grounded;

[0031] The role of diode D1 is to prevent the reverse connection of positive and negative poles from burning out chip U1 and exploding electrolytic capacitor C1. Electrolytic capacitor C1 is connected in parallel with ceramic capacitor C2 to filter out high-frequency and low-frequency noise of DC input. R1 is the starting resistor, R3, R3A, R4, and R4A are sampling resistors to set the output voltage, R5 is the setting resistor to limit the maximum current and peak current, C4 and C3 are filter capacitors from VCC pin (pin 5) and VDD pin (pin 2) to ground respectively to make the circuit more stable; T1 is the energy storage inductor, C6 is the output filter capacitor, R6 is the output protection resistor, D3 is the freewheeling diode, D2 is the power supply diode, and R2 is the voltage divider protection resistor to prevent the voltage regulator diode Z1 from burning out;

[0032] The LED light source module can adopt a constant voltage LED light source or a constant current LED light source. In this embodiment, a DMX512 four-color LED light source is preferably adopted; DMX512 is a standard for digital signal control of lighting equipment;

[0033] like Figure 3 As shown, the LED light source module includes a control signal transcoding circuit and one or more cascaded LED light source circuits;

[0034] The control signal transcoding circuit includes a control signal conversion chip U2, resistors R7, R8, R9, capacitors C7, C8, resistors R10, R11, R12;

[0035] An LED light source circuit includes an LED driver chip U3, resistors R13, R14, capacitors C9, C10, and a four-color LED light string LED4;

[0036] The control signal conversion chip U2 uses SM17500, and the LED driver chip U3 uses SM16704PB;

[0037] The ground pin (pin 1) of the control signal conversion chip U2 is grounded, the address output pin (pin 2) is used to connect to the address input pin of the control signal conversion chip in the next-level LED lamp, and the transcoded data output pin (pin 3) of the control signal conversion chip U2 is connected to the data input pin (pin 7) of the LED driver chip U3;

[0038] The address input pin (pin 5) of the control signal conversion chip U2 is connected to the resistor R10, which is used to receive the address signal sent by the main controller or the upper-level LED lamp; the differential signal input pins A and B (pins 6 and 7) of U2 are respectively connected to the resistors R11 and R12, which are used to receive the input control signal; the power supply pin (pin 8) of U2 is connected to one end of the resistor R7 and one end of the capacitor C8; the other end of the resistor R7 and one end of the capacitor C7 are connected to the second DC voltage VOUT DC; the other ends of the capacitors C7 and C8 are grounded;

[0039] The four color LED signal output terminals OUTR, OUTG, OUTB, and OUTW of the LED driver chip U3 are respectively connected to the four cathodes R-, G-, B-, and W- of the LED light string LED4; the common anode of the LED light string LED4 is connected to the second DC voltage VOUT DC; the data output pin (pin 5) of the LED driver chip U3 is used to connect to the data input pin of the LED driver chip in the next-level LED light source circuit through the resistor R13; the ground pin of the LED driver chip U3 is grounded, and the power pin (pin 8) of the LED driver chip U3 is connected to one end of the resistor R14 and one end of the capacitor C10; the other end of the resistor R14 and one end of the capacitor C9 are connected to the second DC voltage VOUT DC; the other ends of the capacitors C9 and C10 are grounded.

[0040] The DMX512 four-color LED light source can achieve colorful gradient, flowing water and other effect change functions.

[0041] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A circuit capable of connecting multiple LED lamps in series, characterized in that: Including DC-DC step-down module and LED light source module; The input end of the DC-DC buck module is connected to a first DC voltage VIN DC, and the output end outputs a second DC voltage VOUTDC; the first DC voltage VIN DC is higher than the second DC voltage VOUT DC, and the second DC voltage VOUT DC is supplied to the LED light source module as the working voltage of the LED light source module; The DC-DC step-down module includes a power chip U1, diodes D1, D2, D3, an inductor T1, a voltage-stabilizing diode Z1, resistors R1, R2, R3, R3A, R4, R4A, R5, R6, and capacitors C1, C2, C3, C4, and C6; The anode of the diode D1 is connected to the first DC voltage VIN DC, the cathode is connected to the positive electrode of the capacitor C1 and one end of the capacitor C2, one end of the resistor R1 and the power input pin of the power chip U1, and the negative electrode of the capacitor C1 and the other end of the capacitor C2 are grounded; the chip power pin of the power chip U1 is connected to the other end of the resistor R1, one end of the capacitor C3, the cathode of the voltage zener diode Z1 and one end of the resistor R2; the other end of the resistor R2 is connected to the cathode of the diode D2; the other end of the capacitor C3 and the anode of the voltage zener diode Z1 are connected to a common node; the feedback voltage positive terminal sampling pin of the power chip U1 is connected to one end of the resistor R3 and one end of R3A, and the other end of the resistor R3A is connected to the common node, the feedback voltage negative terminal sampling pin of the power chip U1 is connected to one end of the resistor R4 and one end of R4A, and the other end of the resistor R4A is connected to the common node, and the other end of the resistor R4 is grounded; The internal DC voltage pin of the power chip U1 is connected to one end of the capacitor C4, and the chip ground pin of U1 is connected to the other end of the capacitor C4 and a common node; the power output pin of the power chip U1 is connected to the inductor current detection pin, and is connected to one end of the resistor R5 and the cathode of the diode D3; the other end of the resistor R5 is connected to one end of the inductor T1 and a common node; the other end of the inductor T1 is connected to the other end of the resistor R3, the anode of the diode D2, one end of the resistor R6 and the positive electrode of the capacitor C6, and outputs a second DC voltage VOUT DC; the anode of the diode D3, the other end of the resistor R6 and the negative electrode of the capacitor C6 are grounded; The LED light source module includes a control signal transcoding circuit and one or more cascaded LED light source circuits; The control signal transcoding circuit includes a control signal conversion chip U2, resistors R7, R8, R9, capacitors C7, C8, resistors R10, R11, R12; An LED light source circuit includes an LED driver chip U3, resistors R13, R14, capacitors C9, C10, and a four-color LED light string LED4; The ground pin of the control signal conversion chip U2 is grounded, the address output pin is used to connect to the address input pin of the control signal conversion chip in the next-level LED lamp, and the transcoded data output pin of the control signal conversion chip U2 is connected to the data input pin of the LED driver chip U3; The address input pin of the control signal conversion chip U2 is connected to the resistor R10, which is used to receive the address signal sent by the main controller or the upper-level LED lamp; the differential signal input pins A and B of U2 are respectively connected to the resistors R11 and R12, which are used to receive the input control signal; the power pin of U2 is connected to one end of the resistor R7 and one end of the capacitor C8; the other end of the resistor R7 and one end of the capacitor C7 are connected to the second DC voltage VOUTDC; the other ends of the capacitors C7 and C8 are grounded; The four color LED signal output terminals OUTR, OUTG, OUTB, and OUTW of the LED driver chip U3 are respectively connected to the four cathodes R-, G-, B-, and W- of the LED light string LED4; the common anode of the LED light string LED4 is connected to the second DC voltage VOUT DC; the data output pin of the LED driver chip U3 is used to connect to the data input pin of the LED driver chip in the next-level LED light source circuit through the resistor R13; the ground pin of the LED driver chip U3 is grounded, and the power pin of the LED driver chip U3 is connected to one end of the resistor R14 and one end of the capacitor C10; the other end of the resistor R14 and one end of the capacitor C9 are connected to the second DC voltage VOUT DC; the other ends of the capacitors C9 and C10 are grounded.

2. The circuit for connecting multiple LED lamps in series as claimed in claim 1, characterized in that: The power chip U1 adopts SL3036.

3. The circuit capable of connecting multiple LED lamps in series as claimed in claim 1, characterized in that: The control signal conversion chip U2 adopts SM17500, and the LED driver chip U3 adopts SM16704PB.

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