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Original question:

DC/DC Converter that can sink current

LDO that can sink current

user4991603
Prodigy 140 points
Other Parts Discussed in Thread: LM5160, LP2952-N, LP2953

In addition to my previous question I would like to know if TI has an LDO which meets the same requirements.

You can find the question here:

https://e2e.ti.com/support/power-management/f/196/t/720299

  • 0
    TI__Genius 10200 points
    Hi user4991603,

    Conventional LDOs are not designed to sink current as the only path from the output to ground is typically through large feedback resistors. TI does have some LDOs capable of sinking current with a special active output discharge feature. However, these LDOs are not capable of sinking 1 A, and they do not support the input and output voltage range you require. Furthermore, depending on your load current, careful layout considerations would have to be taken to ensure that the LDO junction temperature does not exceed the maximum rating and push the regulator into thermal shutdown. Because of this and your current sinking requirement, the LM5160 seems to be the most appropriate for your application as it would offer the best efficiency and thermal performance.

    Thanks,
    Gerard
  • 0 in reply to Gerard Copeland
    Prodigy 140 points

    Hello Gerard,

    thanks for your reply! What about an LDO with a sink/supply capability of 300-500mA each? And how much current can these LDOs sink that you mentioned?

    I also thought of a LM7812/LM7912 combination or newer counterparts using one as the current source and the other as the current sink.

  • 0 in reply to user4991603
    TI__Genius 10200 points

    Hi Cienski,

    I apologize for a mistake in my earlier post. TI does have offer the LP2953 and LP2952-N LDOs with active output discharge that support 24 V input and 12 V output. The current sinking capability is 50 mA typical, and the device must be put in shutdown mode first to sink any current. Keep in mind that with a maximum of 3 W power dissipation , the PCB will have to be optimized for thermal performance to prevent the regulator from entering thermal shutdown. 

    Regarding negative output regulators - although current does travel from output to input, it's the input supply that will be sinking the current, not the LDO. If you are actually looking for negative rail LDOs that support a 300-500 mA load, TI has a wide selection. You can use the LDO parametric search on the TI website under the Products tab here:

    Thanks,

    Gerard