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TPS922055: TPS922055: TPS922055: Leakage current when the driver is turned off, the output can not be completely turned off, and the leakage current causes the LED to light.

renjian Han
Prodigy 50 points
Part Number: TPS922055

Tool/software:

In the use of TPS922055 chip power supply 34V, drive 6 series of white LED, in the off state can not completely let the LED off, there is a weak light, there is leakage current, the load output can not be completely closed, please tell me how to set the configuration circuit, can achieve normal shutdown when the LED off.

[2] When inquiring historical questions, I found that other personnel had asked this question. May I ask whether this BUG has been fixed, and whether the new chip model has been upgraded?
​
And how to configure the resistance to limit the LED will not be completely extinguished due to leakage current when the chip is turned off.

e2e.ti.com/.../tps922055-leakage-current-issue-when-driver-is-in-off-state

  • 0
    TI__Mastermind 18140 points

    Hi Renjian,

    1. The easiest way to avoid the leakage current caused by UVP resistors is to leave the UVP pin floating (do not install any component for R45 and R46 in your schematic). You can refer to this [FAQ]. You can have a try with this method. If this method can solve the problem, then it can be deduced that the leakage current is caused by the UVP resistors. You can then decide whether to leave UVP pin floating / use larger UVP resistors / use an R_shunt resistor as is stated in the E2E thread you posted to avoid this leakage current.

    2. The problem mentioned in the previous E2E thread is caused by the design of the current prototype-version EVM. We will soon release a new EVM. The problem is not related to the chip itself, so there is no chip upgrade.

    renjian Han said:
    And how to configure the resistance to limit the LED will not be completely extinguished due to leakage current when the chip is turned off.

    For this question, do you want to know how to calculate the R_shunt? 

    Best Regards,

    Steven