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CXLE88185 constant current LED driver chip: high precision dimming and multi channel output solution

In modern LED lighting and display systems, a stable and efficient driver chip is the core to ensure overall performance and reliability. As a high-performance constant current LED driver chip, CXLE88185 has become an ideal choice for all kinds of LED driver design due to its excellent current control accuracy, flexible dimming mode and wide application compatibility. This article will analyze the technical characteristics, application scenarios and design points of the CXLE88185 in depth to help engineers create better LED lighting and display products.QiQ嘉泰姆

1. chip overview and core advantages

CXLE88185 is a four-channel constant current driver chip designed for LED drivers. It can provide a constant current of 18mA to 90mA at each output port, which is suitable for high-quality LED display and lighting systems. Its excellent current consistency (inter-channel error ≤ ± 3.0%, inter-chip error ≤ ± 3.5%) ensures uniform LED brightness and effectively improves the visual experience.QiQ嘉泰姆

The chip uses ESOP8 package, compact structure, good heat dissipation performance, suitable for space-constrained applications. Its working voltage range is 4.5V ~ 5.5V, the output port withstand voltage up to 30V, with good system compatibility and reliability.QiQ嘉泰姆

Detailed description of main characteristics of 2.

2.1. Four-channel constant current output

The CXLE88185 provides four independent constant current output channels, each output current can be accurately set in the range of 18mA ~ 90mA. Users can flexibly adjust the current value through an external resistor (R-EXT) to meet different brightness and power requirements.QiQ嘉泰姆

2.2. High precision current control

A precision voltage reference (typically 1.20V) is integrated inside the chip, combined with an external resistor for precise current setting. Its output current is very little affected by the change of load voltage, and the linear adjustment rate and load adjustment rate are better than the industry standard.QiQ嘉泰姆

2.3. Wide voltage range and high withstand voltage

The output port supports a withstand voltage of up to 30V, which is suitable for multiple LEDs in series or high-voltage power supply scenarios. The chip itself works in a 5V system and can operate stably in a 12V or higher voltage system with a voltage regulator circuit.QiQ嘉泰姆

2.4. PWM Dimming Support

The PWM pin supports dimming frequencies up to 1MHz, enabling stepless brightness adjustment via a microcontroller or dimming signal for high-end lighting and display applications requiring dynamic dimming.QiQ嘉泰姆

3. Typical Application Circuit Design

3.1. 5V system application

In the 5V power supply system, the CXLE88185 can directly drive a single LED lamp bead without external current limiting resistor, and the circuit is simple and efficient. The PWM signal is provided by the MCU for flexible digital dimming.QiQ嘉泰姆

QiQ嘉泰姆
As shown in the figure above, it is a CXLE88185 5V application circuit diagram. In the case of 5V power supply, each output port is connected to a lamp bead.QiQ嘉泰姆
Both the output port and the VDD port can be connected without resistors. The PWM port can directly control the brightness of the lamp beads through the program.QiQ嘉泰姆

3.2. 12V system application

In 12V or higher voltage systems, the voltage must be reduced to 5V for chip use by the voltage regulator module. Each output port can drive multiple series LED lamp beads, such as 3 white LEDs or red LEDs (red LEDs can omit current limiting resistors).QiQ嘉泰姆
QiQ嘉泰姆
As shown in the figure above, it is a CXLE88185 12V application circuit diagram. Under the condition of 12V power supply, a voltage regulator tube is required to provide VDD portQiQ嘉泰姆
For about 5V voltage. Each output port can be connected to three series of lamp beads. If the lamp bead is red, connect the resistor R. If notQiQ嘉泰姆
The red light can save the resistance. The PWM port can directly control the brightness of the lamp beads through the program.QiQ嘉泰姆

QiQ嘉泰姆

3.3. Expanding application design.

By shorting multiple OUT ports, larger current output can be achieved, which is suitable for high-power LED driving scenarios. Attention should be paid to thermal management and power stability in the design to ensure long-term reliable operation of the system.QiQ嘉泰姆

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As shown in the figure above, it is a CXLE88185 circuit diagram for expanding current applications. In the case of power supply greater than 5V, it is necessary to connect the voltage regulator to the VDD terminal.QiQ嘉泰姆
The port provides a voltage of about 5V. The PWM port can directly control the brightness of the lamp beads through the program.QiQ嘉泰姆

3.4. Output and input equivalent circuitQiQ嘉泰姆

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4. current setting and adjustment method

The output current is determined by the external resistor Riref, and the calculation formula is as follows:QiQ嘉泰姆

IoT = 1.20v/riref × 45QiQ嘉泰姆

For example:QiQ嘉泰姆

•  Riref = 600Ω时，Iout ≈ 90mAQiQ嘉泰姆

•  Riref = 1KΩ时，Iout ≈ 54mAQiQ嘉泰姆

In the design, it should be noted that the constant current turning point voltage changes with the current, and the turning point voltage is lower under low current. It is necessary to reasonably plan the voltage drop at the OUT terminal to avoid the current substandard or the chip overheating.QiQ嘉泰姆
Riref in the formula refers to the resistance of the R-EXT terminal. When the resistance value is 600 Ω, the output current value is 90mA calculated by the formula. When the resistance value is 1KΩ, the outputQiQ嘉泰姆
The current is 54mA.QiQ嘉泰姆
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The R-EXT pin is connected to GND with different resistance values to obtain different constant currents at the output of the OUT pin, but different constant currents enter the constant current.QiQ嘉泰姆
The voltage at the flow turning point is different. As can be seen in the figure, the constant current voltage point & asymp at 90mA; 0.8V, while the constant current voltage point drops to & asymp at 15mA;QiQ嘉泰姆
0.5V, when designing the circuit, the voltage drop at the OUTx end should be fully considered to avoid the driving current not reaching the set pre-value.QiQ嘉泰姆
In addition, the OUTx terminal is not suitable to work at a high voltage drop for a long time when it is turned on, which will increase the power loss of the chip and thus lead.QiQ嘉泰姆
Causing serious chip heating, affecting the stability of the system performanceQiQ嘉泰姆

5. packaging and layout recommendations

The CXLE88185 is packaged in ESOP8, which has good heat dissipation and soldering reliability. When designing a PCB, it is recommended that:QiQ嘉泰姆

•   Fully connect the GND pin with the bottom pad to improve heat dissipation and anti-interference ability;QiQ嘉泰姆

•   The R-EXT resistor should be arranged close to the chip to reduce noise interference;QiQ嘉泰姆

•   The output path is as short and wide as possible to reduce the line voltage drop.QiQ嘉泰姆

6. electrical performance characteristics

6.1. Absolute maximum rating range

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(1) These grades in the above table cannot allow the chip to work at the limit value for a long time. If the chip works at the limit value for a long time, it is easy to reduce the reliability of the device and mayQiQ嘉泰姆
Permanent damage can occur. It is not recommended to operate the chip beyond these limit parameters under any other conditions.QiQ嘉泰姆
(2) All voltage values are tested relative to the network groundQiQ嘉泰姆
6.2. Recommended Scope of Working ConditionsQiQ嘉泰姆
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6.3. Electrical characteristicsQiQ嘉泰姆
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7. epilogue

With its high precision, high integration and flexible application mode, CXLE88185 has become the preferred scheme in LED driver design. Whether in indoor lighting, advertising display or intelligent dimming system, it can provide stable and reliable performance support. Asjtm-ic.comOne of the recommended core driver chips, CXLE88185 will continue to help customers create more competitive LED products.QiQ嘉泰姆

For more technical details, sample application or purchasing information, please visit JTM-IC website or contact our technical support team.QiQ嘉泰姆

8.Related Chip Selection GuideMore similar products.....QiQ嘉泰姆

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