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LM5175: maximum output current

JeffYC Yang
Expert 1290 points
Part Number: LM5175


Hi,

I would like to know LM5175 is possible to output maximum 50A Iload?

or can use 2 or 3 LM5175 in parallel output?

My customer wants used in below condition.

Input :  DC 11~16V

Output : DC 12~15V

Output current : Max. 50A

Thanks!

Jeff

  • 0
    TI__Guru* 78630 points
    What is the min load?
  • 0 in reply to Youhao Xi
    Expert 1290 points

    Hi Youhao,

    Should be around 1A.

    Thanks!

    Jeff

  • 0 in reply to JeffYC Yang
    TI__Guru* 78630 points
    Hi Jeff,
    1A to 50A is too wide to design with appropriate current sense resistor. The current signal will be too small at 1A and noise can affect the operation. Also, we do not recommend to parallel the LM5175. We are going to release a new device soon and it can be used to achieve higher power by paralleling.

    Thanks,
    Youhao Xi, System and Applications Engineering, APP-BMC-BCS, TI
  • 0 in reply to Youhao Xi
    Prodigy 50 points
    Hi Youhao Xi!
    I am also looking for more or less the same specifications as Jeff are looking for. Let’s hope its ok to come with some additional questions in this thread.

    In our case, we are looking for different options to design a battery charger that boost the charging from the main battery in a vehicle to a secondary battery. A normal step-up won’t work because we need to be able to turn off the output fully and block current to flow in any direction when the device is off/idle. The charger should run in constant current mode until we reach a specified voltage level. Then it runs in constant voltage mode. Our Idea is to use one more resistor on the FB connected to a DAC output. In this way, we should be able to adjust the output voltage, or do you have any other suggestions.

    Concerning the Rsense, would it be possible to use several sense resistors in parallel together with an FET in series for each resistor (except the first one) to be able to change the Rsense value. As you mention it will be difficult to have a good noise level on low currents. Then are we able to adjust the sensitivity in different current ranges.

    Would it be possible to replace the Rsns resistor with an LEM module for current measurement? In this case ISNS(-) would be connected to GND and ISNS(+) to the output of the LEM that will give the 50mV at our required current limit.

    I have just ordered the LM5175EVM-HP, for testing, this board is prepared to add one more switch in parallel, how many do you think is possible to add? Not in the EVM-HP but when we make our own design without getting to big switching losses? (If we use the recommended Infinion switches)

    In page 11 in the EVM-HP specification, the placement drawing are unreadable, is it possible to have this one with better resolution?
    www.ti.com/.../snvu465.pdf

    Sorry again putting a lot of questions in Jeffs thread.

    As a short summery of my questions:
    1: Is it possible to use a DAC to adjust the output voltage?
    2: Is it possible to use several Rsense resistors with an FET?
    3: Is it possible to use an LEM module instead for the Rsns?
    4: How many switches will the outputs be able to drive?
    5: Placement drawings for the LM5175EVM-HP?

    You are free to email the answers to me if that is better!

    Thanks, in Advance!

    BR
    Stefan
    CEO Solarit AB in Sweden