CXLE87133AC is a four-channel constant current LED driver chip integrated with DMX512(1990) protocol decoding function. It supports transmission rate adaptation from 200Kbps to 1000Kbps, without external settings, and has a maximum addressing capacity of 4096 channels, suitable for medium and large lighting control systems. The chip has built-in E2PROM, which supports online code writing and address backup, greatly improving the reliability and maintenance convenience of the system.
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[ CXLE87133AC ]"
CXLE87133AC: high performance DMX512 LED driver chip, reshaping the new standard of intelligent lighting
In the context of the rapid development of intelligent lighting and architectural landscape lighting, the performance requirements of LED driver chips are also increasing.CXLE87133ACAs a high-performance LED driver chip designed for DMX512 differential parallel protocol, it not only has16-bit high-precision grayscale output, adaptive signal decoding, built-in E2PROMIt is also widely used in stage lighting, building facades, point light sources, wall washing lights and other diversified lighting scenes. This paper will analyze the technical characteristics, application scheme and design points of the chip in depth to help engineers better integrate it into the actual project.
1. chip overview: born for professional lighting
CXLE87133AC is a four-channel constant current LED driver chip integrated with DMX512(1990) protocol decoding function. It supports200Kbps to 1000KbpsThe transmission rate is adaptive, no external settings are required, and the maximum addressing capacity is up4096 channelSuitable for medium and large lighting control system. Chip built-inE2PROMIt supports online code writing and address backup, which greatly improves the reliability and maintenance convenience of the system.
2. core features
Compatible with DMX512 and support extended protocolExcellent signal compatibility and stability.
• 16-bit gamma correction 2.2: Output smoother grayscale changes, closer to human vision.
• 4-channel high-precision constant current output: Up to current per channel80mAThe accuracy error does not exceed 3%.
• Built-in E2PROM, support AB line online code writing: Address configuration can still be carried out after installation, and "code after installation" is supported ".
• PWM reverse polarity down function: Suitable for external triode or MOS tube expansion, refresh rate is 250Hz after frequency reduction.
• High refresh rate and low interference design: Screen Refresh Rate2kHzThe output hysteresis is only 80ns, which effectively suppresses the current surge.
3. typical application areas
CXLE87133AC is widely used in the following scenarios:
• Point light source, pixel light strip
• Architectural outline lighting, wall washer
• Stage Lighting and Performing Arts System
• Indoor and outdoor LED video wall
• City Lighting and Landscape Decoration
4. Package and Pin Description
The chip is available in two packages:SOP16withSSOP10Adapt to different onboard space and output requirements.
SOP16 (adjustable current version):
• OUTR/OUTG/OUTB/OUTW: Quad PWM outputs
• REXT: external resistor setting output current (3-80mA)
• AI/BI: differential signal input
• ADRI/ADRO: Address read and write ports
• PWM: Polarity/frequency down selection
SSOP10 (fixed 18mA output):
• Pin-down for space-constrained designs
• Fixed output current without external REXT resistor
5. electrical characteristics and operating conditions
• Operating voltage: 3.8V-6V
• Output withstand voltage: Up to 30V
• Working temperature:-40 ℃ to 85 ℃
• Inter-channel/inter-chip current difference: ≤ ± 3%
• ESD protection: Meets industrial-grade standards
5.1, limit working conditions
(1) The chip works for a long time under the above-mentioned limit parameters, which may cause the reliability of the device to be reduced or permanently damaged.
These limits are reached or exceeded by any one of the parameters in use.
(2) All voltage values are tested relative to the system ground.
5.2. Recommended working conditions
5.3. Electrical characteristics
5.4. Switching characteristics
Key Points and Precautions of 6. Design
6.1. Code Writing and Address Setting
• Support A/B line online write code, write code after the success of the chip will be a red light (first address) or white light (the rest of the address) instructions.
• After writing the code, it is recommended to use the test program to verify and avoid error code.
6.2. Wiring recommendations
• AI/BI recommendedShielded Twisted PairReduce interference.
• The bus topology should be "hand in hand", avoiding star connections.
• For long-distance transmission, parallel connection is recommended at the ends120ΩMatching resistors.
6.3. Constant current setting (SOP16)
The output current is determined by the REXT resistor as follows:
common current and resistance of the corresponding relationship:
| Current (mA) | R_ext (Ω) |
|---|---|
| 18 | 2266.67 |
| 20 | 2000 |
| 36 | 933.33 |
| 60 | 400 |
(1) The current error between channels is 3℉, while the current error between chips is 3℉.
(2) When the load terminal voltage changes, the CXLE87133AC output current is not affected, as shown in the figure below.
(3) CXLE87133AC the relationship between the current I of the output port and the voltage Vds applied to the port as shown in the following figure, the smaller the current I,
The Vds required under the state is also smaller.
7. Typical Application Circuit
7.1. RGBW four-color LED driver
The chip directly drives the four-way LED, sets the current through REXT, and VCC needs to be filtered by 104 capacitor.
Note: 1. The A and B line code writing methods are adopted. When writing codes, the code writer/controller does not need to be connected to the ADRI of the first IC.
2. Pay attention to the selection of the voltage dividing resistor R1 to avoid excessive power consumption of the IC.
3. REXT port must add resistance to ground to set the output current, this port cannot be suspended.
4. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. If the channel current is set to be larger, the capacitance value should be increased,
For example, if the channel current is set to 40mA, it is recommended to use a capacitance value above 105.
2. Application Figure 2:RGB 3 color application (suspended W channel)
Note: 1. The A and B line code writing methods are adopted. When writing codes, the code writer/controller does not need to be connected to the ADRI of the first IC.
2. Pay attention to the selection of the voltage dividing resistor R1 to avoid excessive power consumption of the IC.
3. REXT port must add resistance to ground to set the output current, this port cannot be suspended.
4. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. If the channel current is set to be larger, the capacitance value should be increased,
For example, if the channel current is set to 40mA, it is recommended to use a capacitance value above 105.
7.2. External triode/MOS tube expansion
7.2.1. External triode
When PWM is connected to VDD, the chip enters the reverse polarity frequency reduction mode, and the output can be connected to NPN transistor or MOS transistor for current expansion, which is suitable for high-power LED driver.
Note: 1. When the PWM pin is connected to VDD, it is a reverse polarity reduced frequency constant voltage output, which is suitable for external NPN transistor base (B), and the output pin is applied
The pull-up resistor R1 is connected to VDD, and the pull-up resistor R1 should select the corresponding resistance value according to the amplification factor of the triode and the required current. When the output current is large,
When the pull-up resistor needs to be less than 5K (the base current is greater than 1mA), the value of the step-down resistor should be reduced accordingly and the 5V regulator tube or its
He 5V regulator.
2.REXT can be suspended when applied in reverse polarity.
3. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. If current expansion is used, it is recommended to increase the capacitance value to 106
Above, to reduce the fluctuation interference of the circuit VCC.
7.2.2. MOS tube expansion
Note: 1. When the PWM pin is connected to VDD, it is a reverse polarity reduced frequency constant voltage output, which is suitable for external MOS tube gate (G) or high-power constant current drive. Application
When the output pin is connected to the pull-up resistor R1 to VDD, the pull-up resistor takes a value of more than 10K. if you want to reduce the brightness of the first gray scale, you can increase
Pull resistor R1.
2.REXT can be suspended when applied in reverse polarity.
3. The 104 capacitance of VCC to ground is the recommended value when the channel current is set to 20mA. If current expansion is used, it is recommended to increase the capacitance value to 106
Above, to reduce the fluctuation interference of the circuit VCC.
4. When writing codes, do not connect the code line to the code writer.
5. Optional high-speed low-voltage MOS tube.
7.3. Cooperate with switch type constant current driver IC (if CXLE87184)
In high-voltage and high-current systems, the CXLE87133AC can be used as the signal front stage to output the PWM signal to the rear-stage constant current driver IC to achieve precise dimming and efficient driving.
Note: 1. When the PWM pin is connected to VDD, it is a reverse polarity frequency reduction constant voltage output, which is suitable for external high-power constant current driver IC.
2. REXT can be suspended when applied in reverse polarity.
3. Please refer to the CXLE87184 specification for constant current drive IC components or operation.
4. When using switch-type constant current drive IC, the interference may be very large (and power wiring and other factors are related), the system will produce
Noise and surge, in order to avoid problems such as code writing or abnormal picture changes, the following measures are recommended:
A. the VDD pin of the CXLE87184 is directly connected to the CXLE87133AC step-down resistor RZ and connected to the same anti-reverse connection diode to reduce waves
Surge effects cannot occur with CXLE87184 VDD and buck resistor RZ connected behind different anti-reverse diode.
B. The trace from the CXLE87184 VDD pin on the circuit board to the CXLE87133AC buck resistor RZ is as thick and short as possible (as close to equipotential as possible),
The trace between the GND pin of the CXLE87184 and the GND pin of the CXLE87133AC is as thick and short as possible (as close to the equal potential as possible).
C, a 47uF electrolytic capacitor and a 105 capacitor are added to each CXLE87184 near the VDD and GND pins, and the voltage is reduced near the CXLE87133AC
The resistance RZ and GND pins are combined with a 47uF electrolytic capacitor and a 105 capacitor.
D and AB lines are always wired in parallel on the board. Do not insert other elements between AB lines under special circumstances that cannot be crossed.
pieces or traces (even in special cases to be limited to the shortest local). Otherwise, the anti-interference function of AB line balanced transmission will be weakened.
E, under special circumstances, because the PWM pin is interfered, resulting in abnormal control, at this time need to be in the CXLE87184 PWM pin to GND
Add a capacitor CDIM, the size of the capacitor depends on the actual situation, generally in the tens to 100PF.
F, when the interference is too large and the code cannot be written, a filter capacitor can be added between the ADRI pin of the CXLE87133AC and GND.
(CPI), in order to filter out certain interference, the capacitance size is generally recommended to be within 103.
7.4. Component Selection Table 1 (Non-triode Application)
7.5. Component Selection Table 2 (triode application, single current not exceeding 120mA)
(1) Value selection of lamp string resistance R
Since the long-term power consumption of the package is recommended not to be greater than 650mW, the IC power consumption should be set to be less than 650mW. As the drive current increases,
The output voltage Vout of the chip channel should be reduced, I .e. 650mW>5.2V * 10mA Vout * Iout * N(N is the number of channels and Vout is the channel end
Port voltage, Iout is the channel setting current), when N = 4,Iout = 30mA, Vout<4.98V, and because Vout = VCC-M * VL-R1 * Iout
(m is the number of lamps connected in series on a single channel, VL is the voltage drop of the lamps). when VCC = 24V,VL = 2,M = 8, R1>100 Ω is obtained. in addition, it is
In order to make the output constant current, Vout should also be made> 0.8V, so R1<240 Ω, in order to make the chip have better performance under the condition that the power consumption meets the requirements.
Output characteristics, it is recommended that R1 choose the appropriate intermediate value.
Why did 8. choose CXLE87133AC?
• High degree of integration: Built-in E2PROM, 485 module, gamma correction, reduce peripheral components.
• strong anti-interference ability: Differential input, hysteresis design, adapt to complex electromagnetic environment.
• Flexible system scalabilitySupports up to 4096 channels of addressing, suitable for large projects.
• Industrial grade reliability: Wide temperature work, ESD protection, to ensure long-term stable operation.
9. epilogue
With its excellent performance, flexible configuration and stable performance, CXLE87133AC has become an ideal drive solution for architectural decoration and professional stage lighting systems. Whether it is a new project or an existing system upgrade, the chip can provide excellent grayscale performance and system reliability.
For more technical information, sample application or design support, please visitJTMIC official website (jtm-ic.com）We will provide you with professional product selection and technical support services.
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