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Original question:

LM5170-Q1: Single phase operation

LM5170-Q1: LM5170-Q1: Single phase operation

user6390484
Prodigy 20 points
Part Number: LM5170-Q1
Other Parts Discussed in Thread: LM5170

Hi,

Since the power I use is small, I want to use only the single channel of LM5170, but how should the pin of channel 2 be connected?he answer to the previous question (https://e2e.ti.com/support/power-management/f/196/t/619955?tisearch=e2e-sitesearch) and TINA simulation can be run, but the channel 1 in the actual PCB experiment does not work, and the nFAULT pin is actually measured as low voltage, and I have connected a 10k resistor to the SYNCOUT pin. My personal guess is that HB2 and SW2 may not be directly grounded and other connection methods are needed. Have you ever actually done experiments with only a single channel? Do you have relevant documents? Attached my TINA file, but channel 1 does not run in the PCB experiment, hope to help me solve this problem.

Thankssnvmb002.tsc

  • 0
    TI__Guru* 78070 points

    Hi User,

    Thank you for posting.  Please try to following to disable the 2nd channel: You need to remove components related to second phase.

    • EN2 grounded
    • RAMP2 grounded
    • COMP2 can left open
    • LO2 grounded
    • HO2 grounded
    • SW2 grounded
    • HB2 grounded  
    • CSA2 and CSB2 shorted and grounded
    • IOUT2 left open

    Hope this clarifies.

    Thanks,

    Youhao Xi, Applications Engineering

  • 0 in reply to Youhao Xi
    Prodigy 20 points

    Hi,

    I did related experiments, but the PCB cannot be run. The TINA simulation of the connection method you mentioned will report an error (irregular circuit). If HO, LO are connected to the ground. Below I am attaching the simulation software that I connected according to your method. Actually, my PCB is connected according to yours, and it still can’t run. Have you actually done a single-channel experiment? Do you have relevant documents for the actual single-channel operation? 

    Also, can you recommend if there is an IC control chip similar to LM5170, but with only one channel and used for low-power (24V-12V, 80W) bidirectional DCDC to charge and discharge the battery?

    Thanks6735.snvmb002.tsc

  • 0 in reply to user6390484
    TI__Guru* 78070 points

    Hi,

    I looked into your model.  The modification that I recommended earlier is for actual hardware circuit not for simulation.  As you may know the sim model does not like any open circuit node or some conflicting grounding.  For your TINA model, please do the following changes:

    • EN2 grounded
    • RAMP2 100k to GND
    • COMP2 100k to GND
    • LO2 100k to GND
    • HO2 100k to GND
    • SW2 100k to GND
    • HB2 100k to GND
    • CSA2 and CSB2 shorted and grounded
    • IOUT2 100k to GND
    • nFAULT  1G to GND

    Now, you should be able to simulate.  

    Regarding your other question: yes we actually have customer using single channel and leaves the 2nd channel as I mentioned yesterday.   The LM5170 is our current solution for bidirectional operation.

    Thanks,

    Youhao