DMX512 control circuit that meets EMC requirements

Abstract

The present invention provides a DMX512 control circuit that can meet EMC requirements, including: a protection and interference filtering circuit, a DMX512 control subcircuit, a DC-DC constant current circuit and a radiation suppression circuit, and an LED light source circuit; the input end of the protection and interference filtering circuit is connected to a DC power supply voltage, and the output end provides a DC voltage VCC to power the DMX512 control subcircuit, the DC-DC constant current circuit and the radiation suppression circuit, and the LED light source circuit; the DMX512 control subcircuit is controlled by a control signal and an address signal of a microprocessor, and generates one or more PWM control signals; the DC-DC constant current circuit and the radiation suppression circuit receive one or more PWM control signals generated by the DMX512 control subcircuit, and correspondingly generate one or more LED drive signals, which act on the corresponding one or more LED light branches in the LED light source circuit. The present invention has excellent EMC radiation suppression capability and is flexible and convenient to use.

Description

Technical Field

[0001] The invention relates to a control circuit of an LED lamp, in particular to a DMX512 control circuit that can meet EMC requirements. Background Art

[0002] At present, the high-power wall washers controlled by DMX512 in the industry basically cannot meet the EMC requirements. However, more and more projects have increasingly stringent EMC requirements, especially municipal projects. More and more LED lamps are used in landscape lighting projects. LED lamps are required to comply with EMC not only for the reliability and safety of the product itself, but also to prevent them from affecting other related products and equipment. Therefore, LED lamps with DMX512 control circuit solutions that can meet EMC requirements are needed. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a DMX512 control circuit that can meet EMC requirements and can control EMC radiation within the relevant standard range. The technical solution adopted by the present invention is:

[0004] A DMX512 control circuit that can meet EMC requirements, including: a protection and interference filtering circuit, a DMX512 control subcircuit, a DC-DC constant current circuit and a radiation suppression circuit, and an LED light source circuit;

[0005] The input end of the protection and interference filtering circuit is connected to the DC power supply voltage, and the output end provides a DC voltage VCC to power the DMX512 control subcircuit, the DC-DC constant current circuit, the radiation suppression circuit, and the LED light source circuit;

[0006] The DMX512 control subcircuit is controlled by the control signal and address signal of the microprocessor and generates one or more PWM control signals;

[0007] The DC-DC constant current circuit and the radiation suppression circuit receive one or more PWM control signals generated by the DMX512 control subcircuit, and correspondingly generate one or more LED drive signals to act on the corresponding one or more LED lamp branches in the LED light source circuit.

[0008] Further, the protection and interference filtering circuit includes a slow-blow fuse F1, an anti-reverse connection diode D1, a common-mode inductor GT1, and a transient suppression diode ZD1;

[0009] One end of the slow-blow fuse F1 is used to connect to the DC power supply voltage, and the other end of the slow-blow fuse F1 is connected to the anode of the anti-reverse polarity diode D1, and the cathode of the anti-reverse polarity diode D1 is connected to the same-name end of the first coil of the common-mode inductor GT1; the same-name end of the second coil of the common-mode inductor GT1 is grounded; at least one filter capacitor is connected in parallel between the same-name end of the first coil of the common-mode inductor GT1 and the same-name end of the second coil of GT1; the opposite-name end of the first coil of the common-mode inductor GT1 is connected to the cathode of the transient suppression diode ZD1, and the opposite-name end of the second coil of the common-mode inductor GT1 is connected to the anode of the transient suppression diode ZD1 and the ground; at least one filter capacitor is connected in parallel between the opposite-name end of the first coil of the common-mode inductor GT1 and the opposite-name end of the second coil of GT1; a DC voltage VCC is generated at the opposite-name end of the first coil of the common-mode inductor GT1.

[0010] Further, the DMX512 control subcircuit includes a DMX512 control chip U1, resettable fuses FA and FB, resistors R1, R2, R3, R4, capacitors C1 and C2;

[0011] The two signal input terminals of the DMX512 control chip U1 are connected to one end of the resistor R2 and one end of R3 respectively, the other end of the resistor R2 is connected to one end of the resettable fuse FB, the other end of the resistor R3 is connected to one end of the resettable fuse FA, and the other ends of the resettable fuses FA and FB are used to receive the control signal of the microcontroller; the address input terminal of the DMX512 control chip U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is used to receive the address signal of the microcontroller; the power supply terminal of the DMX512 control chip U1 is connected to one end of the resistor R1 and one end of the capacitor C2; the other end of the resistor R1 is connected to the DC voltage VCC and one end of the capacitor C1, and the ground terminal of the DMX512 control chip U1, the other end of the capacitor C2 and the other end of the capacitor C1 are grounded;

[0012] One or more output terminals of the DMX512 control chip U1 generate corresponding PWM control signals respectively, which are output to the DC-DC constant current circuit and the radiation suppression circuit through a corresponding resistor.

[0013] Furthermore, the four output terminals of the DMX512 control chip U1 generate four PWM control signals PWM-R, PWM-G, PWM-B, and PWM-W respectively, and output them through resistors RR, RG, RB, and RW respectively.

[0014] Furthermore, the DMX512 control chip U1 also has an address output terminal, which is connected to one end of the resistor R5, and the other end of the resistor R5 is used for cascading.

[0015] Furthermore, the DC-DC constant current circuit and the radiation suppression circuit include one or more identical circuits, one of which includes:

[0016] LED driver chip U2, diode D2, magnetic bead inductor B1, energy storage inductor T1, resistors R6, R7, R8, R9, R10, R11, capacitors C3, C4, C5, C6, C7;

[0017] The dimming signal input terminal of the LED driver chip U2 is connected to the PWM control signal; the LX terminal of U2 is connected to one end of the magnetic bead inductor B1, one end of the energy storage inductor T1 and one end of the capacitor C7; the other end of the magnetic bead inductor B1 is used to output the LED drive signal; the other end of the capacitor C7 is connected to one end of the resistor R6, and the other end of the magnetic bead inductor B1 is connected to the anode of the diode D2; the other end of the resistor R6 is connected to the cathode of the diode D2, one end of the resistors R8 and R9, and the CSN terminal of U2, the power supply terminal of U2 is connected to the DC voltage VCC and the other end of the resistors R8 and R9, the positive electrode of the capacitor C3 and one end of the capacitor C4; the VCC terminal of U3 is connected to one end of the capacitor C5; the negative electrode of the capacitor C3, the other end of C4 and C5 are grounded;

[0018] The CSP terminal of U2 is grounded through resistors R10 and R11; the COMP terminal of U2 is grounded through capacitor C6; and the FS terminal of U2 is grounded through resistor R7.

[0019] Furthermore, the LED driver chip U2 adopts MBI6662.

[0020] Furthermore, the LED light source circuit includes one or more LED lamp branches; one end of each LED lamp branch is connected to the DC voltage VCC through a magnetic bead inductor, and the other end is connected to the DC-DC constant current circuit and the corresponding LED driving signal output by the radiation suppression circuit through another magnetic bead inductor.

[0021] The advantages of the present invention are:

[0022] 1) It has excellent EMC radiation suppression capability and can meet the requirements of relevant EMC standards.

[0023] 2) Flexible use, can be applied to a variety of lamps such as single color, dual color, RGB three color, and RGBW four color.

[0024] 3) Complete protection functions and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of a protection and interference filtering circuit in an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the DMX512 control subcircuit in an embodiment of the present invention.

[0027] Figure 3 The figure is a schematic diagram of a DC-DC constant current circuit and a radiation suppression circuit in an embodiment of the present invention.

[0028] Figure 4 4 is a schematic diagram of a LED light source circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The present invention proposes a DMX512 control circuit that can meet the EMC requirements. In a specific embodiment, it includes: a protection and interference filtering circuit, a DMX512 control subcircuit, a DC-DC constant current circuit and a radiation suppression circuit, and an LED light source circuit;

[0031] The input end of the protection and interference filtering circuit is connected to the DC power supply voltage, and the output end provides a DC voltage VCC to power the DMX512 control subcircuit, the DC-DC constant current circuit, the radiation suppression circuit, and the LED light source circuit;

[0032] The DMX512 control subcircuit is controlled by the control signal and address signal of the microprocessor and generates one or more PWM control signals;

[0033] The DC-DC constant current circuit and the radiation suppression circuit receive one or more PWM control signals generated by the DMX512 control subcircuit, and correspondingly generate one or more LED drive signals to act on the corresponding one or more LED light branches in the LED light source circuit;

[0034] like Figure 1 As shown, in one embodiment, the protection and interference filtering circuit includes a slow-blow fuse F1, an anti-reverse connection diode D1, a common-mode inductor GT1, and a transient suppression diode ZD1;

[0035] One end of the slow-blow fuse F1 is used to connect to a DC power supply voltage. In this example, the DC power supply voltage is DC24v. The other end of the slow-blow fuse F1 is connected to the anode of the anti-reverse connection diode D1. The cathode of the anti-reverse connection diode D1 is connected to the same-name end of the first coil of the common-mode inductor GT1. The same-name end of the second coil of the common-mode inductor GT1 is grounded. At least one filter capacitor is connected in parallel between the same-name end of the first coil of the common-mode inductor GT1 and the same-name end of the second coil of GT1. For example, Figure 1 The chip electrolytic capacitors CL1, CL2 and the chip ceramic capacitors CX1, CX2 in the common mode inductor GT1 are connected to the cathode of the transient suppression diode ZD1 at the opposite end of the first coil of the common mode inductor GT1, and the anode and ground of the transient suppression diode ZD1 at the opposite end of the second coil of the common mode inductor GT1; at least one filter capacitor is connected in parallel between the opposite end of the first coil of the common mode inductor GT1 and the opposite end of the second coil of GT1, for example Figure 1The chip electrolytic capacitors CL3, CL4 and the chip ceramic capacitors CX3, CX4 in the common mode inductor generate a DC voltage VCC at the opposite end of the first coil of the common mode inductor GT1;

[0036] The anti-reverse connection diode D1 specifically adopts a Schottky diode, which is used to prevent damage to the lamp and electrolytic capacitor from being broken down when the positive and negative poles of DC24V are connected in reverse; the slow-break fuse F1 is used to withstand the impact current and provide protection against overload; the chip electrolytic capacitors CL1, CL2, CL3, CL4, the chip ceramic capacitors CX1, CX2, CX3, CX4 and the common mode inductor GT1 together constitute the CLC filter circuit, which is used to filter out the interference of conduction to the circuit; the main function of the transient suppression diode ZD1 is to prevent static electricity;

[0037] like Figure 2 As shown, in one embodiment, the DMX512 control subcircuit includes a DMX512 control chip U1, self-recovery fuses FA and FB, resistors R1, R2, R3, R4, capacitors C1 and C2; wherein U1 may adopt SM16512;

[0038] The two signal input terminals (pin 1 and pin 2) of the DMX512 control chip U1 are connected to one end of the resistor R2 and one end of the resistor R3 respectively, the other end of the resistor R2 is connected to one end of the self-recovery fuse FB, the other end of the resistor R3 is connected to one end of the self-recovery fuse FA, and the other ends of the self-recovery fuses FA and FB are used to receive the control signal of the microcontroller; the address input terminal of the DMX512 control chip U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is used to receive the address signal of the microcontroller; the DMX512 control chip U1 also has an address output terminal, which is connected to one end of the resistor R5 through the address output terminal, and the other end of the resistor R5 is used for cascading; the power supply terminal (pin 7) of the DMX512 control chip U1 is connected to one end of the resistor R1 and one end of the capacitor C2; the other end of the resistor R1 is connected to the DC voltage VCC and one end of the capacitor C1, and the ground terminal (pin 8) of the DMX512 control chip U1, the other end of the capacitor C2 and the other end of the capacitor C1 are grounded;

[0039] One or more output terminals of the DMX512 control chip U1 generate corresponding PWM control signals respectively, and output them to the DC-DC constant current circuit and the radiation suppression circuit through a corresponding resistor; in this embodiment, the LED light source circuit includes four LED light branches of R, G, B, and W, so the four output terminals of the DMX512 control chip U1 generate four PWM control signals of PWM-R, PWM-G, PWM-B, and PWM-W respectively, and output them through resistors RR, RG, RB, and RW respectively;

[0040] The chip electrolytic capacitor C1 and the ceramic capacitor C2 are the system power supply to ground capacitors, which are used to filter out high-frequency and low-frequency noise and reduce power supply fluctuations; R1 is a current limiting resistor, which is used to limit the working current of the internal voltage stabilization module when the voltage stabilization function of the chip U1 is turned on; the resistors R2, R3, and R4 act as port protection resistors to prevent damage to the signal port caused by hot plugging, power supply positive and negative poles, and signal reverse connection; the resettable fuses FA and FB are used to protect the pins of the chip U1 from burning out when the signal is short-circuited;

[0041] like Figure 3 As shown, in one embodiment, the DC-DC constant current circuit and the radiation suppression circuit include one or more identical circuits, wherein one circuit includes:

[0042] LED driver chip U2, diode D2, magnetic bead inductor B1, energy storage inductor T1, resistors R6, R7, R8, R9, R10, R11, capacitors C3, C4, C5, C6, C7; LED driver chip U2 adopts MBI6662;

[0043] The dimming signal input terminal (pin 4) of the LED driver chip U2 is connected to the PWM control signal; the LX terminal (pin 1) of U2 is connected to one end of the magnetic bead inductor B1, one end of the energy storage inductor T1 and one end of the capacitor C7; the other end of the magnetic bead inductor B1 is used to output the LED drive signal ( Figure 3 LED- in the middle); the other end of capacitor C7 is connected to one end of resistor R6, and the other end of magnetic bead inductor B1 is connected to the anode of diode D2; the other end of resistor R6 is connected to the cathode of diode D2, one end of resistors R8 and R9, and CSN end (pin 2) of U2, the power end (pin 3) of U2 is connected to DC voltage VCC and the other end of resistors R8 and R9, the positive electrode of capacitor C3 and one end of capacitor C4; VCC end of U3 is connected to one end of capacitor C5; the negative electrode of capacitor C3, the other end of C4 and C5 are grounded; CSP end (pin 10) of U2 is grounded through resistors R10 and R11; COMP end (pin 7) of U2 is grounded through capacitor C6; FS end (pin 6) of U2 is grounded through resistor R7;

[0044] Figure 3 In the circuit, Schottky diode D2 plays a freewheeling role, R7 is a switching frequency resistor, ceramic capacitor C5 is used to provide instantaneous temporary energy current to chip U2, ceramic capacitor C6 is used to control the feedback compensation bandwidth, magnetic bead inductor B1 is connected in series to the freewheeling diode D2, and the RC filter circuit is connected in parallel to the freewheeling diode D2. The RC filter circuit is composed of chip resistor R6 and chip ceramic capacitor C7; the role of B1, R6, and C7 is to suppress EMC radiation so that the radiation is within the standard frequency range;

[0045] Figure 3 LED in - for connection Figure 4 R- or G- or B- or W- in;

[0046] like Figure 4 As shown, in one embodiment, the LED light source circuit includes one or more LED lamp branches; one end of each LED lamp branch is connected to the DC voltage VCC through a magnetic bead inductor, and the other end is connected to the DC-DC constant current circuit and the corresponding LED driving signal output by the radiation suppression circuit through another magnetic bead inductor;

[0047] exist Figure 4 In the example shown, a total of 6 four-in-one LED light-emitting units are used, each of which includes four-color LEDs of R, G, B, and W; LEDs of the same color are connected in series to form an LED lamp branch; an LED lamp branch includes at least one LED of a certain color; the magnetic bead inductors B2-B9 are designed to make the frequency corresponding to the maximum attenuation point fall within the bandwidth of EMI radiation, so that its radiation is within the standard range.

[0048] 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 DMX512 control circuit that can meet EMC requirements, characterized in that: include: Protection and interference filtering circuit, DMX512 control sub-circuit, DC-DC constant current circuit and radiation suppression circuit, LED light source circuit; The input end of the protection and interference filtering circuit is connected to the DC power supply voltage, and the output end provides a DC voltage VCC to power the DMX512 control subcircuit, the DC-DC constant current circuit, the radiation suppression circuit, and the LED light source circuit; The DMX512 control subcircuit is controlled by the control signal and address signal of the microprocessor and generates one or more PWM control signals; The DC-DC constant current circuit and the radiation suppression circuit receive one or more PWM control signals generated by the DMX512 control subcircuit, and correspondingly generate one or more LED drive signals to act on the corresponding one or more LED light branches in the LED light source circuit; The protection and interference filtering circuit includes a slow-blow fuse F1, an anti-reverse connection diode D1, a common-mode inductor GT1, and a transient suppression diode ZD1; One end of the slow-blow fuse F1 is used to connect to the DC power supply voltage, and the other end of the slow-blow fuse F1 is connected to the anode of the anti-reverse connection diode D1, and the cathode of the anti-reverse connection diode D1 is connected to the same-name end of the first coil of the common-mode inductor GT1; the same-name end of the second coil of the common-mode inductor GT1 is grounded; at least one filter capacitor is connected in parallel between the same-name end of the first coil of the common-mode inductor GT1 and the same-name end of the second coil of GT1; the opposite-name end of the first coil of the common-mode inductor GT1 is connected to the cathode of the transient suppression diode ZD1, and the opposite-name end of the second coil of the common-mode inductor GT1 is connected to the anode of the transient suppression diode ZD1 and the ground; at least one filter capacitor is connected in parallel between the opposite-name end of the first coil of the common-mode inductor GT1 and the opposite-name end of the second coil of GT1; a DC voltage VCC is generated at the opposite-name end of the first coil of the common-mode inductor GT1; The DMX512 control subcircuit includes a DMX512 control chip U1, self-recovery fuses FA and FB, resistors R1, R2, R3, R4, capacitors C1 and C2; The two signal input terminals of the DMX512 control chip U1 are connected to one end of the resistor R2 and one end of R3 respectively, the other end of the resistor R2 is connected to one end of the resettable fuse FB, the other end of the resistor R3 is connected to one end of the resettable fuse FA, and the other ends of the resettable fuses FA and FB are used to receive the control signal of the microcontroller; the address input terminal of the DMX512 control chip U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is used to receive the address signal of the microcontroller; the power supply terminal of the DMX512 control chip U1 is connected to one end of the resistor R1 and one end of the capacitor C2; the other end of the resistor R1 is connected to the DC voltage VCC and one end of the capacitor C1, and the ground terminal of the DMX512 control chip U1, the other end of the capacitor C2 and the other end of the capacitor C1 are grounded; One or more output terminals of the DMX512 control chip U1 generate corresponding PWM control signals respectively, and output them to the DC-DC constant current circuit and the radiation suppression circuit through a corresponding resistor; The DC-DC constant current circuit and the radiation suppression circuit include one or more identical circuits, one of which includes: LED driver chip U2, diode D2, magnetic bead inductor B1, energy storage inductor T1, resistors R6, R7, R8, R9, R10, R11, capacitors C3, C4, C5, C6, C7; The dimming signal input terminal of the LED driver chip U2 is connected to the PWM control signal; the LX terminal of U2 is connected to one end of the magnetic bead inductor B1, one end of the energy storage inductor T1 and one end of the capacitor C7; the other end of the magnetic bead inductor B1 is used to output the LED drive signal; the other end of the capacitor C7 is connected to one end of the resistor R6, and the other end of the magnetic bead inductor B1 is connected to the anode of the diode D2; the other end of the resistor R6 is connected to the cathode of the diode D2, one end of the resistors R8 and R9, and the CSN terminal of U2, the power supply terminal of U2 is connected to the DC voltage VCC and the other end of the resistors R8 and R9, the positive electrode of the capacitor C3 and one end of the capacitor C4; the VCC terminal of U3 is connected to one end of the capacitor C5; the negative electrode of the capacitor C3, the other end of C4 and C5 are grounded; The CSP terminal of U2 is grounded through resistors R10 and R11; the COMP terminal of U2 is grounded through capacitor C6; and the FS terminal of U2 is grounded through resistor R7.

2. The DMX512 control circuit that can meet EMC requirements as claimed in claim 1, characterized in that: The four output terminals of the DMX512 control chip U1 generate four PWM control signals, PWM-R, PWM-G, PWM-B, and PWM-W, and output them through resistors RR, RG, RB, and RW, respectively.

3. The DMX512 control circuit that can meet EMC requirements as claimed in claim 1, characterized in that: The DMX512 control chip U1 also has an address output terminal, which is connected to one end of the resistor R5, and the other end of the resistor R5 is used for cascading.

4. The DMX512 control circuit that can meet EMC requirements as claimed in claim 1, characterized in that: LED driver chip U2 uses MBI6662.

5. The DMX512 control circuit that can meet EMC requirements as claimed in claim 1, characterized in that: The LED light source circuit includes one or more LED lamp branches; one end of each LED lamp branch is connected to the DC voltage VCC through a magnetic bead inductor, and the other end is connected to the DC-DC constant current circuit and the corresponding LED driving signal output by the radiation suppression circuit through another magnetic bead inductor.

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