SN75DP130: ESD BLACK SCREEN PROBLEM

Hello,

Could you provide more details on when you experienced this black screen problem?

Could you provide more details on the register configuration of your device and schematic?

Thanks,

Zach

Hi，

Our exprienced:

During the ESD test of the entire machine, when the 2/4/6/8k contact discharge is applied at a interval of 1s or a single time, the screen will go black. After stopping the electrostatic discharge, the screen will recover for about 2 seconds.

During the test process, all registers of DP130 are read at intervals of 1s. When the black screen is found, register 0X19 changes from 18 to 10 and then recovers to 18. This register is not described in the specification. What does this register represent, or does it mean that the DP130 anomaly causes a black screen when static electricity is applied? How to solve this problem？

Here are our schematic and configuration.Please help to check.

Thanks.

Our schematic:

Our register configuration：

  Dp130Write(0x03, 1, 0x1A);
    Dp130Write(0x04, 1, 0x00);

    /* set upper & middle DPCD addr ... constant for writes below */
    LOG("1. set upper & middle DPCD addr");
    Dp130Write(0x1C, 1, 0x00);
    Dp130Write(0x1D, 1, 0x01);
    LOG(" ");

    /* link_bw_set: 5.4gbps */
    LOG("2. link_bw_set: 5.4gbps");
    Dp130Write(0x1E, 1, 0x00);
    Dp130Write(0x1F, 1, 0x0A);
    LOG(" ");

    /* lane_count_set: 4 */
    LOG("3. lane_count_set: 4");
    Dp130Write(0x1E, 1, 0x01);
    Dp130Write(0x1F, 1, 0x04);
    LOG(" ");

    /*
     * Force Link voltage level & pre-emphasis by writing each of the lane's
     * DPCD config registers 103-106h accordingly.
     */
    for (uint8_t i = 0x3; i < 0x7; i++) {
        LOG("DPCD %d: ", 100 + i);
        Dp130Write(0x1e, 1, i);
        Dp130Write(0x1f, 1, 0x10);
        LOG(" ");
    }

Hi Zach,

I get you，but our question is：

 What does this register represent, or does it mean that the DP130 anomaly causes a black screen when static electricity is applied? How to solve this problem？Could you give us some suggestions for our design？

Thanks 

Hello,

Register 0x19 is reserved for TI internal testing.

I have added a TI ESD team member to this ticket to suggest an alternate ESD devices you can use to see if those devices mitigate ESD concerns.

Thanks,

Zach

Hi Tian,

Can you provide me with the part number of the ESD device you're using?

PCB layout is also very important for dissipating large ESD currents, here is our ESD layout guide that goes over best practices for optimizing PCB layouts for ESD. 

Regards,

Sebastian 

Hi Tian,

Any updates on providing the information requested above so that we can further assist you?

Thanks,

Zach

Hi Zach,

The ESD device we're use is "SEMTECH_RCLAMP0524P";

After these day's test,we found that it when ESD testing,the BER of main link would be higher,cause the screen reconnect.

The signal transferred by the DP130 will have a black screen problem, and the main control directly drives the screen will not cause problem.

Here's our PCB design

Thanks

Hello, Tian, 

We are looking at the ESD device provided and will get back to you shortly.

Thanks,

Zach

Hi,Sebastian 

First of all thank you for your comments.

Here are the tests:

We use TPD4E05U06DQAR   instead, when ESD is applied to the whole machine still black screen;

While use ESD204DQAR instead,it will be flicker when work.

Wheater DP130 device can pass ESD test?

Thanks.