CXLE87133AB is a four-channel LED constant current driver chip based on DMX512 single-line parallel protocol. It is not only compatible with DMX512(1990) standard protocols, but also supports adaptive decoding with transmission rates ranging from 200Kbps to 1000Kbps without external settings. The chip has built-in E2PROM, supports up to 4096-Channel addressing, and has the function of online code writing. It can write addresses to 1024 chips at a time within a distance of 100 beige dotted, truly realizing the installation first, write code later ".
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[ CXLE87133AB ]"
CXLE87133AB: high-performance adjustable current four-channel DMX512 LED driver chip deep analysis
In the field of LED lighting control, DMX512 protocol has become the mainstream communication standard for stage lighting, building facade lighting, city lighting and other projects due to its stable, flexible and easy to expand characteristics. In order to meet the market demand for high power, multi-channel, flexible and adjustable LED driving solutions,JTM-ICLaunchedCXLE87133AB-- An advanced driver chip that integrates four-channel high-precision stable output current, supports external resistance to adjust current, and has strong anti-interference and online code writing capabilities. This article will systematically introduce the core features, typical applications and design points of the chip, helping lighting system developers and engineers to achieve more efficient and reliable lighting control schemes.
I. Product overview and technical highlights
CXLE87133AB is based onDMX512 single-wire parallel protocolFour-channel LED constant current driver chip. It is not only compatible with the DMX512(1990) standard protocol, but also supports transmission rates200Kbps ~ 1000KbpsAdaptive decoding within the range without external settings. The chip has built-in E2PROM, which supports the maximum4096 ChannelAddressing,Online code writingFunction, you can write addresses to 1024 chips at a time within a distance of beige dotted, and truly realize "install first, then write code".
Its most prominent feature isFour-channel independent output, up to 60mA per channel current, and can be flexibly set through external resistor, cooperatePWM reverse polarity frequency reduction outputFunction, suitable for high-order applications with external triode, MOS tube or high-power constant current drive IC.
II. Features of core functions
2.1. Four-channel high-precision adjustable constant current
• Output channels: R, G, B, and W four independent PWM stable output current
• Default current: 18mA, support external resistance adjustment, the highest per channel60mA
• Accuracy performance: Inter-channel error <± 3%, inter-chip error <± 5%
2.2. Smart protocol compatibility and adaptive decoding
•Support for DMX512(1990) and extended protocols
•The transmission rate is 200Kbps to 1000Kbps fully adaptive without setting
•Screen refresh rate3.6kHzTo ensure smooth dynamic effect
2.3. Flexible selection of fields and output modes
•PORT pinSupport 1-field/4-field mode selection, suitable for monochrome, RGB, RGBW and other applications
•PWM pinWhen the suspension is normal output, the reverse polarity frequency reduction output (refresh rate reduced to 450Hz) is enabled for grounding, which is convenient for external switching devices.
2.4. Built-in E2PROM and anti-interference code writing
•Built-in E2PROM supports cascading code writing and real-time implementation.
•HaveXUEZ address code backup mechanism, single storage damage does not affect system operation
•8 anti-interference designs to effectively prevent miswriting codes
2.5. Industrial reliability design
•Operating temperature:-40℃ ~ 85℃
•Encapsulation:SOP16, excellent heat dissipation
•Built-in 5V voltage regulator tube, output port withstand voltage> 26V
3. Typical application scenarios
CXLE87133AB is widely used in the following scenarios due to its high integration, flexibility and high drive capability:
•RGBW full color point light source and pixel screen
•Building contour lamp, wall washer, Line light
•Stage lighting and Performance Control system
•Indoor and outdoor decorative lighting and media facade
•High-power plug-in MOS tube/triode drive system
IV. Key Design Guidelines
4.1. Output current setting
The chip output is 18mA by default, and the current can be adjusted through the external resistor of the REXT pin. The calculation formula is as follows:
Examples of common current corresponding to Rext resistance:
| Target current (mA) | Rext resistance (Ω) |
|---|---|
| 20 | 37.1k |
| 30 | 5.85k |
| 40 | 3K |
| 60 | 1.38k |
Constant current curve:
CXLE87133AB the constant current characteristic is excellent, and the current difference between channels and even chips is extremely small.
(1) the current error between channels is less than ± 3, while the current error between chips is less than ± 5.
(2) when the load terminal voltage changes, the output current of CXLE87133AB will not be affected, as shown in the following figure.
(3) as shown in the following figure CXLE87133AB the relationship between the current I of the output port and the voltage Vds curve applied to the port shows that the smaller the current I, the constant current
The smaller the Vds is required. The minimum value of Vds is a key parameter representing the constant current range. Under the same conditions, the smaller the minimum value of Vds, the larger the constant current range.
Wide.
4.2. Calculation of divider resistance
Take 24V power supply and 6 LEDs in series as an example:
•Red Light (VF = 2V):R = (24V-6 × 2V-3V)/18mA & asymp; 500Ω
•Green/blue light (VF = 3V):R = (24V-6 × 3V-3V)/18mA & asymp; 150Ω
CXLE87133AB is a SOP16 package. When working for a long time, the power consumption on the IC should generally not exceed 300mW. Each channel is output with 3 channels.
Constant current 18mA is taken as an example. If the voltage drop (Vds) of each output pin of the IC is 3V, the power consumption (when all lights are on) on the IC is:
3 channels P = PRGB PVDD = 3*3V * 18mA 5V * 10mA = 0.16 0.05=210MW
4-channel P = 210MW 210MW/3=280MW
The maximum power consumption is not exceeded.
Divider resistance calculation formula:
Red Light current limiting resistance: R =(VCC-N * VR-Vds)/I
Green Light current limiting resistance: R =(VCC-N * VG-Vds)/I
Blue lamp current limiting resistance: R =(VCC-N * VB-Vds)/I
White lamp current limiting resistance: R =(VCC-N * VW-Vds)/I
Note: VCC refers to the power supply voltage, N refers to the number of lamp beads connected in series. VR,VG,VB, and VW represent the opening voltage of RGBW lamp beads, and Vds is
IC port voltage, I is the constant current setting value
Example 1: 24V power supply, RGB output, 6 strings each, no parallel connection, constant current default setting 18mA,Vds take 3v
Red light R =(24V-6 * VR-3V)/18mA =(24V-6 * 2V-3V)/18mA = 500
Green, Blue Light R =(24V-6 * VG,B-3V)/18mA =(24V-6 * 3V-3V)/18mA = 150
Recommended value table for Vds:(3-color application)
4.3. Suggestions on power consumption control
The maximum package power consumption of the chip is 800MW, and the Vds voltage drop should be reasonably controlled during design. It is recommended that Vds take 3.5V at 18mA output and 1.2V at 60mA output to ensure stable operation of the system.
4.4. System grounding and anti-interference
•Ground voltage difference is the key to affect system stability
•It is recommended that the "-" pole of all switching power supplies be directly connected through the shortest path.
•Double-headed power supply and bold ground wire are adopted to reduce the pressure difference.
V. Typical application Circuit description
5.1. RGBW four-color application
Four-channel Drive R, G, B, and W four-color LED respectively, support full color mixing, suitable for scenarios with high color restoration requirements.
Note: 1. Output high-precision constant current. The default value is 18mA. When larger current is applied, GND can be set by adding corresponding resistance through REXT terminal.
The constant current value of each channel can reach up to 60mA.
When no route amplifier is added, the standard speed of 250k should be adopted. It is not recommended to expand to 500K. At the standard speed of 250K,
To reach nearly 25 frames (3-color applications), the number of single-port connections of the controller cannot exceed 280 points. If less than 25 frames are allowed, they can be connected under certain conditions.
To 512 points. (For more information about the connection length under different transmission frequencies, see our sales engineer)
The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. For example, if the channel current is set to larger, the capacitance value should be plus-sized, for example
Set the channel current to 40mA. We recommend that you use a capacitor value above 105.
2. Application Figure 2:RGB 3-color application
Note: 1. Output high-precision constant current. The default value is 18mA. When larger current is applied, GND can be set by adding corresponding resistance through REXT terminal.
The constant current value of each channel can reach up to 60mA.
2. When no route amplifier is added, the standard speed of 250k should be adopted. It is not recommended to expand to 500K. At the standard speed of 250K,
To reach nearly 25 frames (3-color applications), the number of single-port connections of the controller cannot exceed 280 points. If less than 25 frames are allowed, it can be connected under certain conditions.
Connect to 512 points. (For more information about the connection length under different transmission frequencies, see our sales engineer)
5.2. Monochromatic high current application
Four channels are used in parallel, and the maximum output current can reach240mA, suitable for high-power monochrome lighting system.
Note: 1. Output high-precision constant current, the default value is 18mA/channel. When larger current is applied, GND can be set by adding corresponding resistance through REXT terminal. Every
The channel constant current value can reach up to 60mA, and the 4-channel parallel output can reach 240mA. Pay attention to the resistance value of divider resistance R to avoid excessive IC power consumption,
At the same time, pay attention to the specification of divider resistance R to prevent excessive power consumption. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA, such as setting
If the channel current is larger, the capacitance value should be plus-sized. For example, if the channel current is set to 40mA, we recommend that you use a capacitance value above 105.
Application Figure 4: Amplifier application (4 colors)
Note: When there is a long connection between points, or when the number of single-port connection points of the controller is large, the frame rate also needs to be high, you can use route amplifier
Use mode. In route amplifier applications, 485 differential transmission is between the controller and the amplifier, and the amplifier converts the differential signal into a single line signal,
The distance between amplifier and lamp should be as short as possible. (For more information about the connection length under different transmission frequencies, see our sales engineer)
5.3. External triode/MOS tube application
By setting the PWM pin to ground and enabling reverse polarity frequency reduction output, NPN triode, MOS tube or high-power constant current drive IC with DIM dimming function can be connected to further expand the driving capability.
Note: 1. When the PWM pin is connected to GND, it is reverse polarity frequency reduction constant voltage output, suitable for external NPN triode base (B),MOS tube or any with DIM
(Dimming terminal) high-power constant current drive IC. When using, the output pin is pulled up to VDD through the pull-up resistor R, and the pull-up resistor R is connected to the external MOS tube.
Or when driving IC with constant current, the value is generally 10K. When external triode is connected, the corresponding resistance value should be selected according to the amplification factor of triode and the current required. It is recommended that
The value is 2k, and the value of the step-down resistance is correspondingly reduced, and 5V voltage regulator tube or other 5V regulator is connected to VDD. For more information, see component selection value table.
(Triode application).
2. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. If a larger channel current is set, the capacitance value should be plus-sized,
For example, if the channel current is set to 100mA, we recommend that you use a capacitor value above 106.
5.4. Component selection value table
The following table lists the values that do not add an amplifier.
VI. Code writing and system debugging
•Supports online cascading code writing, and supports up to 1024 chips to write codes at a time.
•After the code is written, the blue light is automatically turned on. The new address code takes effect immediately.
•Keep PI and DI high during code writing to avoid signal interference
6.1. Instructions for power-on lighting:
Power-on: After the self-test is normal, the RGBW channel is turned on at 12.5% duty cycle.
6.2 Communication Data Protocol:
CXLE87133AB data receiving is compatible with standard DMX512(1990) protocol and extended DMX512 protocol, with data transmission rate of 200Kbps ~
1000Kbps adaptive decoding. The protocol waveform is as follows:
Note1: The field consists of 11 bits, including 0 start bits, 8 data bits, and 2 stop bits. Where 0 start bit is low and stop bit is high
Level: if the data in the data bit is 0, the corresponding time period is low; If the data is 1, the corresponding time period is high. 0 start bit
The length of the stop bit and data bit must be the same.
6.3 IC receiving instructions:
6.3.1.When a reset signal appears on the DI line, the IC enters the reception preparation state. The address counter is cleared to 0.
6.3.2.The first field in the packet is the start field, and its 8-bit data must be "0000_0000", which is not used as the display data.
The valid field used for display starts from the second field, and the second field of the DMX512 packet is the first field of valid data. IC adaptive
The data transmission rate is 200Kbps to 1000Kbps. The duration of fields corresponding to different rates varies, regardless of whether the transmission frequency is 200Kbps ~
1000Kbps. Make sure that the duration of all valid fields is the same as that of the start field.
6.3.3.The IC determines to intercept the corresponding field in the DMX512 packet based on its E2 address. If the chip address is 0000_0000_0000, the number is
The first valid field of the packet starts to be truncated, and the address 0000_0000_0001 starts from the second valid field. The number of fields used by the chip.
PORT settings.
6.3.4 precautions for sending data by the controller:
1.) the adaptive data transmission frequency of IC is 200Kbps to 1000Kbps, and the bit duration varies according to different frequencies. Regardless of transmission frequency
The rate is 200Kbps to 1000Kbps. Make sure that the bit duration of all fields is the same as that of the start field.
2.) when entering the code writing function, after the address code data is sent, the PI (write address port) and DI port are maintained before the picture data starts to be sent.
High level, do not pull low, to keep the blue light indication of IC driver can be maintained after code writing is completed.
6.3.5. Notes on code writing:
1.) there is A/D coder except for the write address terminal (PO) on terminal. When writing the code, the DI line must be connected to the coder A/D Terminal. Write the code.
The A terminal of the device should be kept at A high level when writing codes, and the IC must be in the DI high level state before writing codes normally.
2.) read the code from E2 after writing the code inside the IC. After reading the code, the blue light will be on normally, and the new address code will take effect without re-power on.
6.3.6 power supply:
1.) in the power supply link of parallel system, the ground voltage difference between different lamps and controllers is a more serious unstable factor than insufficient power supply.
2.) as a key factor of system stability, ground voltage difference should be reduced as much as possible. In addition to the main line thickness of the power supply, it is mainly affected by the single
The number of lamps connected to each Power Tap, the overcurrent capability of ground wire on the lamps, the length of lines between lamps, the diameter of lines between lamps and the influence of wires,
There is also a large impact on single-head power supply or double-head power supply. The following is the maximum reference suggestion for a single-head power supply connection (the voltage of the main power cord is not considered
Difference): piercing light, 0.32mm2 copper wire, 50 light strings, single head power supply.
In the above example, if the wire diameter changes to 0.25 mm2 copper wire, only 40 lamps can be used in a single-head power supply (RGB 3-color lamps are used as an example).
Note: If route amplifier is added and resistance voltage division is adopted on the lamps, the above conditions can exceed 50% at most.
3.) for the parallel system, the ground voltage difference caused by the accumulation of ground voltage difference will have a fatal impact on the general meeting, and the actual project should ensure the same
The "-" pole of the switching power supply used by all lamps controlled by the controller port must be directly connected by the shortest line to eliminate the "-" power supply.
The differential pressure between poles should not be connected by the circuitous connection of lamps alone.
VII,Pins and functions
8. Working conditions and parameters
8.1. Extreme working conditions
(1) when the chip works for a long time under the above limit parameter conditions, the reliability of the device may be reduced or permanently damaged.
It is suggested that any parameter reaches or exceeds these limit values in actual use.
(2) all voltage values are tested systematically.
IX. Conclusion
CXLE87133AB as a four-channel DMX512 driver chip integrating high-precision output, flexible current regulation and powerful scalability, it is not only suitable for conventional RGBW lighting systems, but also can meet the requirements of high-order and high-power applications through external power devices, it is an ideal choice for architectural lighting, stage lighting, intelligent decoration and other fields.
For more information about the technical information, selection suggestions or sample applications of CXLE87133AB and other DMX512 series chips, please visit 【JTM-IC.com] on the official website, we provide you with professional and complete product solutions and technical support.
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