Brick wall current limit protection

Tsukui Yusuke

Guru 21930 points

Other Parts Discussed in Thread: TPS62125, TPS62120, TPS25200, TPS2662

Hi,

Customer wants the power supply to perform the following operations.

Customer condition ;
・Vin=6～12V
・Vout=5V
・Iout=200mA

Desired operation;
・Customers want to limit current at 200 mA.
　(Do not exceed 200mA.)
・If it exceeds 200 mA, the customer wishes to lower the output voltage.
　(Image of Brick wall current limit protection operation.)
ex,Iout=200mA→Vout=5V Iout=250ｍA→Vout=2～4V

Could you tell me the recommended products?

Best Regards,
Yusuke/Japan Disty

over 8 years ago

0 Chris Glaser over 8 years ago

TI__Guru**** 152370 points

Hi Yusuke-san,

The TPS62125 is an appropriate device for your power level. When overloaded, Vout will drop and the current will be limited. However, this limit is higher than 200 mA.

For a precise and adjustable current limit, have you looked at eFuses, hot swap ICs, or load switches?

0 Tsukui Yusuke over 8 years ago in reply to Chris Glaser

Guru 21930 points

Chris-san,

Thank you for your support.
It can not exceed 200mA.

I posted it on the e-fuse forum at the same time.
However, there is no introduction of switches and e-fuse yet.
http://e2e.ti.com/support/power_management/power_interface/f/204/p/661961/2433359#2433359

I would like to meet customers' requirements with a combination of DCDC and switches.
Could you give me your advice?

Best Regards,
Yusuke/Japan Disty

0 Chris Glaser over 8 years ago in reply to Tsukui Yusuke

TI__Guru**** 152370 points

The TPS62120/2's current limit specification limits the peak inductor current to 400 mA. Its current limit technique requires the inductor current to return to 0, once the current limit is triggered. So, this gives a 200 mA output current at most. Above this, Vout will drop.

0 Rakesh over 8 years ago in reply to Chris Glaser

TI__Guru** 107781 points

Hi Yusuke-san,

Please look at TPS25200 device and Figure 18 in the datasheet for configuring the current limit threshold. This device clamps the output voltage to 5.4V till input voltage of 7.6-V, beyond that it responds as overvoltage lockout.

The other option is new device TPS2662, which will be released soon.

Please let us know if you have follow up questions on the above.

Best Regards,
Rakesh

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Brick wall current limit protection