CXLE88174 is a touch button and LED driver control integrated chip manufactured using CMOS technology, with built-in MCU digital interface, data latch, button scanning circuit, LED driver, and buzzer driver modules. The chip supports functions such as automatic calibration, resistance to voltage fluctuations, and sensitivity adjustment of external capacitors, making it suitable for stable operation in high interference environments. Its packaging form is SOP32, which is convenient for integration and soldering.
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[ CXLE88174 ]"
Introduction: Development and Application of Intelligent Touch Display Driver Chips
With the increasing demand for intelligent operation in fields such as home appliances and industrial control, chips that integrate touch buttons and LED display drivers have become key components in design. CXLE88174 is a high-performance chip that integrates 8-channel touch button scanning, LED digital tube driving, and buzzer control functions, suitable for products such as induction cookers and smart panels. This article will comprehensively analyze the technical characteristics, register configuration, communication protocol, and practical application solutions of CXLE88174, providing engineers with detailed design references.
1、 CXLE88174 chip overview
CXLE88174 is a touch button and LED driver control integrated chip manufactured using CMOS technology, with built-in MCU digital interface, data latch, button scanning circuit, LED driver, and buzzer driver modules. The chip supports functions such as automatic calibration, resistance to voltage fluctuations, and sensitivity adjustment of external capacitors, making it suitable for stable operation in high interference environments. Its packaging form is SOP32, which is convenient for integration and soldering.
2、 Core functional features
1.8-channel touch button detection
Supports up to 8 touch channels, with automatic calibration and anti-interference capabilities. Unused key ports need to be grounded.
2. Multi stage digital tube driver
Support 10 segments× 7 to 13 segments× Flexible display configuration with 4 digits, suitable for various types of digital tubes.
3. Built in buzzer driver
The duration of the active buzzer's sound can be controlled through a register, supporting 255 level time adjustment.
4. Standard I2C communication interface
The slave address is 0xA0 (write)/0xA1 (read), supporting standard mode (100kHz) communication.
5. Automatic calibration and anti-interference
The chip has an automatic benchmark calibration function, which can adapt to environmental changes and prevent false triggering.
6. Low power consumption and sleep mode
Supports entering sleep mode through I2C command or automatic timeout, and can be awakened by touch or communication.
3、 Pin definition and functional description
CXLE88174 has a total of 32 pins, mainly including:
• GRID1~GRID7: Bit driven output, built-in 2.7kΩ Pull up the resistor.
• SEG1~SEG10Segment driven output, built-in 4kΩ Pull down resistor.
• KEY1~KEY8Touch button input port.
• SDA/SCLI2C data line and clock line.
• BZBuzzer driver output.
• VDD/VCCPositive pole of power supply (recommended 5V).
ESD protection tips：
The chip is an electrostatic sensitive device, and anti-static measures should be taken during operation to avoid damage.
4、 Electrical characteristics and working conditions
It is recommended that any parameter reach or exceed these limit values during actual use.
4.1.2 All voltage values are tested relative to the system ground
4.3. Chip Parameters
4.3.2 Switch characteristics
• power supply voltageRecommended 5V, with a maximum range of -0.3V to+6.5V
• Operating Temperature：-40℃～+85℃
• drive current：
• Segment output current (Vo=VDD-3V): typical 35mA
• Position filling current (Vo=0.3V): typical 120mA
• Buzzer driving current (VDD=5V): maximum 50mA
5、 Detailed Explanation of I2C Communication Protocol
0xA0。 The main control can read the status information of touch buttons, as well as write data to drive the digital display and buzzer. I2C
The speed supports standard mode 100KHZ.
After reading the key information, wait for at least 10ms before reading the key information again.
Write display data at least 1ms apart, and write other data at least 200us apart before writing data to CXLE88174 again.
I2C timing diagram:
Busy from the machine:
After completing one byte of data (8-bit+ACK), the slave starts processing the data (the slave is busy) and cannot receive the next byte of data. At this time, the slave
The machine lowers SCL, and the host needs to wait for SCL to reach high level before continuing data transmission.
I2C data format:
The CXLE88174 chip supports single data readout. Write Slave Address as 0xA0, Read Slave Address as 0xA1, Address
DATA1 is the read data for the register address being read. Read a data format as follows:
To reduce I2C lock issues caused by receiving incorrect clock sources, CXLE88174 provides timeout functionality. If within approximately 63ms
If the I2C bus does not receive the clock source, the I2C circuit and registers will be reset.
The timeout counter received a message on the I2C bus; START” Signal and“ Address Matching” When the condition is met, the timeout counter starts counting and
Clear to zero at the falling edge of SCL. If the waiting time before the next SCL falling edge is greater than the timeout set by the I2CTOC register,
There will be a timeout phenomenon. When I2C“ STOP” When a condition occurs, the timeout counter will stop counting.
IIC timeout may cause abnormal forwarding of data, so it is necessary to avoid the occurrence of IIC timeout when using it.
CXLE88174 supports the standard I2C protocol as a slave device, with a fixed communication address of 0xA0 (write)/0xA1 (read). The following are key communication points:
• data format：
Write data format: Start→ 0xA0 → ACK → Address→ ACK → Data→ ACK → Stop
Read key format: Start→ 0xA0 → ACK → 0xF0 → ACK → Start → 0xA1 → ACK → Data→ NACK → Stop
• Timeout mechanism：
If there is no SCL signal within 63ms, the I2C module will automatically reset to prevent bus lockout.
• Communication interval：
Reading buttons requires an interval of 10ms, and writing data requires an interval of 1ms.
6、 Register Configuration and Function Analysis
Make sound, enter and wake up sleep mode. CXLE88174 Register Function Description:
6.1.1) Register 0xBD in CXLE88174 is used to set the number of segments and bits (4-7 bits, 10-13 segments). When the instruction is executed,
The display has been forcibly turned off. When the display mode remains unchanged, the data in the video memory will not be changed, and the display control command controls the display switch. When powered on,
The default display mode is 7 digits and 10 segments. If there is no need to change the bit segment mode, then this register does not need to be written.
6.1.2) Register 0xBE in CXLE88174 is used to set the read/write and address add modes for data, and bits B1 and B0 are not allowed to be set to 01 or 11.
Due to the use of address auto add mode for storing display data, it must be set to 0x40. CXLE88174 has been set to 0x40 during initialization, so there is no need to
Write again.
6.1.3) The registers 0xC0 to 0xCD in CXLE88174 are used to set the starting display address and display content data. The maximum valid address is 14
Position (C0H)
6.1.4) Register 0xBF in CXLE88174 is used to set display switches and adjust display brightness. There are 8 levels of brightness available for selection
Adjust.
6.1.5) Register 0xCE in CXLE88174 is used to set the driving time of the active buzzer. CXLE88174 has built-in active buzzer driver control
Develop programs. The external MCU can turn on the buzzer by writing data to register 0xCE. The driving time of the buzzer can be adjusted in 255 levels by modifying it
Variable DATA value to achieve level adjustment (write value range: 0x00~0xFF). The buzzing time for each level is 40ms.
The schematic diagram of IIC communication format is as follows:
6.1.6) Register 0xCF in CXLE88174 is used to set the sleep mode of the chip. The chip has two working modes, sleep mode and positive mode
Normal working mode.
There are two ways to enter sleep mode: one is to enter sleep mode without pressing the button for 8S after power on; The second is IIC communication, which writes to the register 0xCF
0x01， Approximately 1S CXLE88174 enters sleep mode.
There are two ways to wake up hibernation: one is to touch a button to wake up hibernation; The second is IIC communication, the correct IIC communication format will immediately call
Wake up and go to sleep. If the write operation to wake up sleep is forwarded by CXLE88174 to the external display chip, it will be forwarded; The correct IIC read operation
You will receive the current key touch information.
6.1.7) Register 0xF0 in CXLE88174 is used as a register for IIC to read key touch data. Bit7~Bit0 are used to indicate the corresponding
Have the touch buttons Key8 to Key1 been touched. (Note: If the read register is not 0xF0, the return value is 0xFF.)
The reading format is as follows:
Bit0: Key1 Status; (1=touched, 0=not touched)
Bit1: Key2 Status; (1=touched, 0=not touched)
Bit2: Key3 Status; (1=touched, 0=not touched)
Bit3: Key4 Status; (1=touched, 0=not touched)
Bit4: Key5 Status; (1=touched, 0=not touched)
Bit5: Key6 Status; (1=touched, 0=not touched)
Bit6: Key7 Status; (1=touched, 0=not touched)
Bit7: Key8 Status; (1=touched, 0=not touched)
CXLE88174 achieves functional control through I2C registers, with the main registers as follows:
6.2. 0xBD: Display Mode Settings
Used to configure the number of segments and digits for digital tubes, such as 7-digit 10 segment, 6-digit 11 segment, etc.
6.3. 0xBE: Data read-write mode
It needs to be set to 0x40 (automatic address increment mode), which is already configured by default and does not need to be modified.
6.4. 0xC0~0xCD: Display Data Register
Corresponding to 14 display addresses, used to write display data for each segment of the digital tube.
6.5. 0xBF: Display switch and brightness adjustment
Support 8-level duty cycle adjustment, control display brightness and switch status.
6.6. 0xCE: Buzzer Time Setting
Writing 0x00~0xFF can control the duration of the beep, with each level lasting approximately 40ms.
6.7. 0xCF: Sleep mode control
Write 0x01 to enter sleep mode, which can be awakened by communication or touch.
6.8. 0xF0: Key status reading
Reading this register can obtain the touch status (Bit0~Bit7) of KEY1~KEY8.
7、 Touch function optimization and display driver
7.1. Sensitivity adjustment
Touch response can be optimized by external capacitors (0-25pF) or adjusting the size of PCB electrodes.
Sensitivity adjustment: Adjusting the sensitivity of touch buttons according to user needs is a very important consideration in most applications.
Sensitivity can be adjusted by changing the size and floor area of the PCB electrodes (directly below the electrodes), or by changing the thickness of the insulation material. Simultaneously CXLE88174
Provides a way to adjust different sensitivity requirements by adding capacitors to the touch input pins.
7.2. Maximum button time protection
After pressing the button for more than 64 seconds, it will automatically reset to prevent accidental locking.
To minimize unintentional key detection such as accidentally touching the sensing electrode, the chip has set a maximum key duration function internally
Can. When a touch button is pressed, the internal timer starts counting. Once the button is pressed for too long, exceeding approximately 64 seconds, the touch
The chip will ignore the state of the touched key and recalibrate to obtain a new reference value, while resetting the output state to the initial state.
7.3. Automatic Calibration Function Description
After power on, the chip will initialize and obtain the first reference value. No buttons will be pressed, and the touch chip will arrive at a fixed time period
Afterwards, the benchmark value will be automatically calibrated so that it can dynamically change according to the external environment.
7.4. Digital tube driving mode
7.4.1) Common cathode connection methodSEG is connected to the anode, and GRID is connected to the cathode.
Figure 7 shows a schematic diagram of the connection of a common cathode digital tube. If the digital tube displays“ 0” Just need to go from low to C0H (GRID1) address
Just start writing 0x3F data, and the data for each SEG1 to SEG8 corresponding to 00H is shown in the table below.
7.4.2) Common anode connection methodSEG is connected to the cathode, and GRID is connected to the anode.
The display data needs to be configured in reverse according to the connection method.
Figure 8 shows the schematic diagram of the connection of the common anode digital tube. If the digital tube displays“ 0” To address unit C0H (GRID1)
Write data 01H in C2H (GRID2), C4H (GRID3), C6H (GRID4), C8H (GRID5), and CAH (GRID6) respectively, and write the rest of the addresses
All CCH (GRID7) units are written with data 00H. The data corresponding to each SEG1 to SEG8 is shown in the table below.
▲ Note: Whether driving a common cathode digital tube or a common anode digital tube, the SEG pin can only be connected to the anode of the LED, and the GRID pin can only be connected to the anode of the LED
The cathode cannot be reversed.
8、 Example of Application Circuit Design
8.1. Common cathode digital tube connection example：
8.1.1) CXLE88174 driver common cathode digital screen hardware circuit diagram,SEG1~SEG8 connected to digital tube segment pole (a~dp)
8.1.2) CXLE88174 Driver Common Yang Digital Screen Hardware Circuit Diagram,GRID1~GRID7 connecting poles (com)
• The buzzer is driven by the BZ pin and connected in series with 1kΩ resistance
8.2. Touch button design：
Each KEY pin can be connected to an external capacitor to adjust sensitivity, and unused pins need to be grounded.
9、 Programming flowchart
• Initialize I2C interface
• Configure display mode (0xBD)
• Write display data (0xC0~0xCD)
• Set display switch and brightness (0xBF)
• Loop reading of key status (0xF0)
• Perform corresponding operations according to the buttons (such as beeping, display updates)
10、 Packaging and Dimensional Information
CXLE88174 is packaged in SOP32 and has a size of 20.23mm× 7.44mm， Pin spacing of 1.27mm, suitable for standard PCB layout.
11、 Summary and Market Application
CXLE88174 is an ideal choice for touch display solutions due to its high integration, strong anti-interference ability, and flexible display configuration. Especially suitable for scenarios such as induction cookers, smart home appliances, industrial control panels, etc. With the increasing demand for human-computer interaction, the market prospects for such multifunctional driver chips are broad.
TwelveSelection Guide for Related Chips; More similar products ....
| model | Number of interfaces | Drive dot matrix number | Segment/Position | common cathode drive | Gongyang Drive | button | package form | remark |
| CXLE88134N | three | twenty-eight | 7*4 | 7-segment 4-digit | - | - | SOP16/DIP16 | LED panel display driver chip |
| CXLE88135N | three | twenty-one | 8*2/7*3 | 8 segments 2 digits/7 segments 3 digits | - | 6*1 | SOP16 | LED panel display driver chip |
| CXLE88136N | three | thirty-five | 5*7/8*4 | 7-segment 5-digit/8-segment 4-digit | 7-segment 5-digit | 5*1 | SOP18/DIP18 | LED panel display driver chip |
| CXLE88137BN | three | forty-eight | 6*7/9*4 | 7-segment 6-digit/9-segment 4-digit | 7-segment 6-digit | 6*1 | SOP20 | LED panel display driver chip |
| CXLE88137N | three | forty-eight | 8*6/10*4 | 8 segments with 6 digits/10 segments with 4 digits | - | - | SOP20 | LED panel display driver chip |
| CXLE88138C | four | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*3 | SOP32 | LED panel display driver chip |
| CXLE88138N | four | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*3 | SOP32 | LED panel display driver chip |
| CXLE88139N | three | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | - | SOP24/QSOP24 | LED panel display driver chip |
| CXLE88141N | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88142A | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88142E | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88143AN | three | one hundred and twenty-eight | 16*8 | 16 segments with 8 digits | 8 segments with 16 digits | - | SOP32 | LED panel display driver chip |
| CXLE88143BN | three | one hundred and twelve | 14*8 | 14 segments with 8 digits | 8 sections with 14 digits | 8*2 | SOP32 | LED panel display driver chip |
| CXLE88143CN | three | one hundred and twenty | 15*8 | 15 segments with 8 digits | 8 segments with 15 digits | 8*1 | SOP32 | LED panel display driver chip |
| CXLE88143DN | three | ninety-six | 12*8 | 12 segments with 8 digits | 8 segments with 12 digits | 8*4 | SOP32 | LED panel display driver chip |
| CXLE88143N | four | one hundred and twenty-eight | 16*8 | 16 segments with 8 digits | 8 segments with 16 digits | 8*4 | QFP44 | LED panel display driver chip |
| CXLE88147N | three | eighty | 10*8 | 10 segments with 8 digits | 8 sections with 10 digits | 8*3 | SOP28 | LED panel display driver chip |
| CXLE88148N | three | sixty-four | 8*8 | 8 segments and 8 digits | 8 sections with 6 digits | 4*2 | SOP24/QSOP24 | LED panel display driver chip |
| CXLE88149B | two | one hundred and twenty-eight | 8*16 | 8 segments with 16 digits | 16 segments with 8 digits | - | SOP28、SSOP28 | LED panel display driver chip |
| CXLE88155N | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP24/SSOP24/SDIP24 | LED panel display driver chip |
| CXLE88171 | four | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*3 | SOP32 | LED panel display driver chip |
| CXLE88172 | two | one hundred and twenty-eight | 8*16 | 8 segments with 16 digits | 16 segments with 8 digits | - | SOP24 | LED panel display driver chip |
| CXLE88173 | two | one hundred and forty-four | 8*9*2 | Forward and backward push digital tube | Forward and backward push digital tube | - | QSOP24 | LED panel display driver chip |
| CXLE88174 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 8 touch buttons | SOP32 | LED panel display driver chip |
| CXLE88175 | five | one hundred and twenty | 15*8 | 15 segments with 8 digits | 8 segments with 15 digits | 8*1/8 | QFN48 | LED panel display driver chip |
| CXLE88176 | three | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*1 | SOP24 | LED panel display driver chip |
| CXLE88156 | three | one hundred and twenty-eight | 8*16 | 8 segments with 16 digits | 16 segments with 8 digits | - | SOP32 | LED panel display driver chip |
| CXLE88134 | three | twenty-eight | 7*4 | 7-segment 4-digit | - | - | SOP16/DIP16 | LED panel display driver chip |
| CXLE88135 | three | twenty-one | 8*2/7*3 | 8 segments 2 digits/7 segments 3 digits | - | 6*1 | SOP16 | LED panel display driver chip |
| CXLE88136 | three | thirty-five | 5*7/8*4 | 7-segment 5-digit/8-segment 4-digit | 7-segment 5-digit | 5*1 | SOP18/DIP18 | LED panel display driver chip |
| CXLE88137 | three | forty-eight | 8*6/10*4 | 8 segments with 6 digits/10 segments with 4 digits | - | - | SOP20 | LED panel display driver chip |
| CXLE88137A | three | forty-eight | 6*7/9*4 | 7-segment 6-digit/9-segment 4-digit | 7-segment 6-digit | 6*1 | SOP20 | LED panel display driver chip |
| CXLE88138 | four | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*3 | SOP32 | LED panel display driver chip |
| CXLE88139 | three | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | - | SOP24/QSOP24 | LED panel display driver chip |
| CXLE88140A | four | seventy-seven | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*1 | SOP32 | LED panel display driver chip |
| CXLE88140B | three | seventy-seven | 11*7/14*4 | 11 segments with 7 digits/14 segments with 4 digits | 7 sections with 11 digits | 10*3 | QFP44 | LED panel display driver chip |
| CXLE88141 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88142 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88143 | four | one hundred and twenty-eight | 16*8 | 16 segments with 8 digits | 8 segments with 16 digits | 8*4 | QFP44 | LED panel display driver chip |
| CXLE88143A | three | one hundred and twenty-eight | 16*8 | 16 segments with 8 digits | 8 segments with 16 digits | - | SOP32 | LED panel display driver chip |
| CXLE88143B | three | one hundred and twelve | 14*8 | 14 segments with 8 digits | 8 sections with 14 digits | 8*2 | SOP32 | LED panel display driver chip |
| CXLE88143C | three | one hundred and twenty | 15*8 | 15 segments with 8 digits | 8 segments with 15 digits | 8*1 | SOP32 | LED panel display driver chip |
| CXLE88143D | three | ninety-six | 12*8 | 12 segments with 8 digits | 8 segments with 12 digits | 8*4 | SOP32 | LED panel display driver chip |
| CXLE88144 | three | thirty-five | 7*5/8*4 | 7-segment 5-digit/8-segment 4-digit | - | 7*1 | DIP18 | LED panel display driver chip |
| CXLE88145 | two | thirty-two | 8*4 | - | 8 sections with 4 digits | 8*2 | DIP18 | LED panel display driver chip |
| CXLE88146 | two | forty-eight | 8*6 | - | 8 sections with 6 digits | 8*2 | SOP20/DIP20 | LED panel display driver chip |
| CXLE88147 | three | eighty | 10*8 | 10 segments with 8 digits | 8 sections with 10 digits | 8*3 | SOP28 | LED panel display driver chip |
| CXLE88148 | three | sixty-four | 8*8 | 8 segments and 8 digits | 8 sections with 6 digits | 4*2 | SOP24/QSOP24 | LED panel display driver chip |
| CXLE88149 | two | one hundred and twenty-eight | 8*16 | 8 segments with 16 digits | 16 segments with 8 digits | - | SOP28/SSOP28 | LED panel display driver chip |
| CXLE88150 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88151 | two | thirty-two | 8*4 | 8-segment 4-digit/7-segment 4-digit | - | 7*4 | SOP16/DIP16 | LED panel display driver chip |
| CXLE88152 | two | twenty-eight | 7*4 | - | 7-segment 4-digit | 7*1 | SOP16/DIP16 | LED panel display driver chip |
| CXLE88153 | one | forty | 7*6/8*5 | 7-segment 6-digit/8-segment 5-digit | 6 segments with 7 digits/5 segments with 8 digits | - | SOP16 | LED panel display driver chip |
| CXLE88154 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP28 | LED panel display driver chip |
| CXLE88155 | three | seventy | 10*7/13*4 | 10 segments with 7 digits/13 segments with 4 digits | 7 sections with 10 digits | 10*2 | SOP24/SSOP24/SDIP24 | LED panel display driver chip |
| CXLE88133 | two | two hundred and fifty-six | 32*8/24*16 | 32 segment 8-bit/24 segment 16 bit | 8 segments 32-bit/16 segments 24 bit | - | LQFP48/LQFP52 | LED panel display driver chip |
| CXLE88132 | four | two hundred and fifty-six | 32*8/24*16 | 32 segment 8-bit/24 segment 16 bit | 8 segments 32-bit/16 segments 24 bit | - | LQFP48/LQFP52 | LED panel display driver chip |
