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[FAQ] Design an Automotive Animation Lighting with TPS929120-Q1 within 5min

Part Number: TPS929120-Q1
Other Parts Discussed in Thread: MSP430F5529

What can user realize using TPS929120-Q1

Nowadays animation rear lighting such as sequential turn and welcome/goodbye lighting is becoming more and more popular. Different OEMs have various requirements, such as off-board communication, off-board LED drive, fail-safe mode, etc. TPS929120-Q1 is dedicated for automotive animation lighting with intelligent Bus control and Pixel control. By using TPS929120-Q1, users can realize platform animation lighting design which can meet all kinds of OEMs requirements easily.

Below is several TPS929120-Q1 key features benefit platform design.

  1. Flexwire Bus
    1. UART by CAN structure for robust long distance off-board communication
    2. Integrated CRC check function for good communication integrity

  2. Pixel Control
    1. 12 independent controlled channels supporting hundreds of LED control
    2. 12-bit PWM and 6-bit Analog dimming fitting all kind of animation
    3. Parallel channels for higher current
  3. Safety
    1. Programmable fail-safe state in EEPROM
    2. LED Open, Short, Single LED Short fault detection
    3. UART communication monitoring with internal watchdog timer
    4. 8-bit ADC for pin voltage monitoring

How to design hardware


To reduce design effort, it is better to design the system from platform approach.

The most efficient way is to standardize the control module board and TPS929120-Q1 LED boards.

For different projects, users can reuse the same control module, and sharp the TPS929120-Q1 LED boards according to different car models.

Schematic and PCB Design

To design the system from platform approach, users need to implement a robust off-board communication through CAN transceiver physical layer.

Below are Altium project files for LCM and LED board. LCM contains DC/DC, MCU, CAN which can provide stable voltage rail to LED board to optimize thermal performance and send control UART commands through CAN transceiver. LED board contains TPS929120-Q1 and CAN, which can receive the UART command from LCM through long cables.

If users don't need off-board communication, users can drive TPS929120-Q1 through MCU UART port direclty without CAN transceiver. CAN transceiver is only used to convert UART signal to CANH/L differential mode signal for long distance communication.


Design Check list

Tips for schematic and layout which can benefit BCI and RI test.

    • Cap as close to SUPPLY & VCC as possible for better noise filter
    • GND as short as possible for better noise filter
    • Thermal pad as large as possible for better thermal dissipation
    • RX trace as direct as possible without via

 How to develop software

Communication port of TPS929120-Q1 is based on standard half-duplex UART port. Any standard UART program can be used to send command frame to control the TPS929120-Q1 according to the protocol of TPS929120-Q1. 

Every command frame will be ended with one CRC byte, CRC calculation function needs to be implemented in the software to check the communication integrity. A brief introduction of the CRC programming guide and CRC calculation tool are showed below.

Keep in mind that send register unlock commands before controlling specific channels, otherwise the channel configuration command will not be recognized.

TPS929120-Q1 Programming Guide v3.0.pdf

CRC Calculation Programming Guide.pdf


Sample codes

NXP S9KEAZ128AMLH demo codes ( demo video effect is showed at the bottom)

S9KEAZ128 Demo

TI MSP430F5529 demo codes (this code can be used to control a single LED board with 2 pcs TPS929120-Q1 configuration)

MSP430F5529 Demo

Demo Video

Below are two demo video using 10 pcs TPS929120-Q1, all TPS929120-Q1 devices are controlled through one MCU, the baurdrate is 375kbps. Sample codes are in the above.