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TPS4H160-Q1: reverse current protection circuit

Shinichi Inoue
Guru 20896 points
Part Number: TPS4H160-Q1
Other Parts Discussed in Thread: TPS27S100

Dear Specialists,

MY customer is evaluating TPS4H160-Q1 and has a question.

I would be grateful if you could advise.

---

For reverse current protection, the circuit is installed both Figure 28 and Figure31.

In this case, when noise input from V+ the device malfunctioned a few ms.

I found two measures experimentally, Figure28 remove or add a capacitor.

Are they any problem for using reverse current protection. 

Is there any other concern?

Could you please see attached file.

---

I appreciate your great help in advance.

Best regards,

Shinichi 

Question about TPS4H160-Q1.pptx

  • 0
    TI__Mastermind 27280 points

    Hello, I am trying to better understand the situation. Please give inputs on these statements:

    1. DC supply voltage is applied between V+ and COM-.

    2. AC noise is applied between V+ and V-. What is the magnitude and the frequency?

    3. What is the back to back diodes between V+ and V- symbol represent?

    4. What is the TVS clamp voltage value?

    5. I understood if TVS is removed the circuit is working correctly with the actual ground network and 1nF

    6. TVS is installed the circuit works correctly but with 1uF in the ground network

    Regards

  • 0 in reply to Mahmoud Harmouch
    Guru 20896 points
    Hi Mahmoud,

    Thank you for your reply.

    Regarding your comment,
    I'll confirm and feedback to you.

    Could you please wait for a while.

    I appreciate your great help.

    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    Guru 20896 points
    HI Mahmoud,

    I could confirm the condition.
    Please see below.

    The customer only wants to confirm that there is no problem with the combination of TVS and diode as a circuit for countermeasures against inductive load connected to the output.

    I would appreciate if you could advise this point as soon as possible.

    1. DC supply voltage is applied between V+ and COM-.

    DC24V

    2. AC noise is applied between V+ and V-. What is the magnitude and the frequency?

    First transient burst noise 2.2kV (61000-4-4)
    Impulse noise 1.2kV
    （www.noiseken.co.jp/.../211.pdf）
    Conducted immunity　10V (61000-4-6)
    Surge 1.2kV (61000-4-5)
    ESD Direct 6.5kV (61000-4-2

    3. What is the back to back diodes between V+ and V- symbol represent?

    SM15T39CA

    4. What is the TVS clamp voltage value?

    SM15T39A has 39V minimun ,may be around 40V.

    5. I understood if TVS is removed the circuit is working correctly with the actual ground network and 1nF
    6. TVS is installed the circuit works correctly but with 1uF in the ground network

    Thank you for your understanding and support.

    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    TI__Mastermind 27280 points

    Hello Shinichi-san,

    For IEC61000-4, it is recommended to add 22nF on each output and 22nF on the ground network. We have tested the TPS27S100 but with no ground network. If you would like to review please check lit # SLVA957. I think 1uF is big and may cause high peak reverse current in case of reverse battery. 

    Regards, Mahmoud  

  • 0 in reply to Mahmoud Harmouch
    Guru 20896 points

    Hi Mahmoud,

    Thank you for your reply.

    Regarding for adding 22nF capacitor on each output and GND network,

    Is this possible to use pattern 1 for this noise immunity test?

    Is this possible to use pattern 2 for this noise immunity test?

    I made a daiagram by refering SLVA957A, so could you please confirm if there is mistake.

    I appreciate your great help.

    Best regards,

    Shinichi

    Additional question about TPS4H160-Q1.pptx

  • 0 in reply to Shinichi Inoue
    TI__Mastermind 27280 points

    Hello Shinichi-san, here is the rules:

    1. A good set of decoupling X7R cap(s) (C1) from VS input to  COM with short loop for RF currents needed for CP switching in the IC. This is to improve emissions.

    2. A good set of X7R caps (C2) from supply input on the board to V-. This cap need not (should not!) be close to the chip and chip GND. This is for RF immunity by shunting  RF current coming into the board to GND. 

    3. A large electrolytic cap (47u from V+ to V- in this case) to the board GND

    4. In addition X7R cap (optional) from IC GND to board GND will help with RF immunity.

    Pattern 1 and 2 follow the rule and I think it should work. In SLVA957A, ground network is not implemented and it is like pattern 1.

    Regards, Mahmoud

  • 0 in reply to Mahmoud Harmouch
    Guru 20896 points

    Hi Mahmoud,

    Thank you for your reply.

    I'll send your suggestion to the customer.

    I appreciate your great help.

    Best regards,

    Shinichi