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[TPS1H100-Q1] For reverse current protection and power loss of power supply protection

Tomoaki Yoshida
Expert 2200 points

Hi,

I'm consider solenoid load system.

I saw an item in the reverse current protection and power loss of power supply in the data sheet.

I understood that it is recommended strongly GND network method, diode + resister networking,

and this method is certainly realized at low cost.

But, of influence and GND float, other also I fear come out various effects.

The first place I'm going to insert a fast recovery diode(FRD) in parallel with the solenoid.
  
For reverse connection protection, I will insert the Vs upstream diode as shown figure 41 in data sheet.
The combination of the upstream of the diode and parallel FRD, or effect would not be expected to loss of power?
If all the ineffective, it must consider putting something measures
If it may be effect can be expected rather than about GND networking method, and I would like to keep this configuration.
I want any advice.
Best regard.
  • 0
    TI__Intellectual 1150 points

    Hi,

    For the influence of GND network , we've considered the GND potential shift side effect when deisgning the device.

    Add a FRD is a right way for inductive recirculation.

    If you add a upstream block diode as Figure 41, the GND network diode can be removed. If you already add FRD diode, when loss of power, all the recirculation energy will be pulled through FRD rather than the device itself. It's OK for the combination of upstream diode and FRD diode.

    Let me know if any other questiones.

    Thanks,

    Alex, (alex.wang@ti.com)

     

     

  • 0 in reply to Alex Wang (LED)
    Expert 2200 points

    Hi Alex,

    Thank you for your reply.

    Since I put the FRD in parallel with the solenoid anyway, and upstream of the diode and the set without GND network.
    What is there something concern in this way?
    I want to know if it is that should be considered in advance. 
    Thanks.
  • 0 in reply to Tomoaki Yoshida
    TI__Intellectual 1150 points
    Hi,
    Thanks,
    I think that should be fine, widely used application.
  • 0 in reply to Alex Wang (LED)
    Expert 2200 points
    Hi Alex,

    I have additional question.
    In the case of usage GND network for ｒeverse current and reverse connection, the output of current sense is also affected by GND shift.
    I am concerned that it than not be able to keep the current sense of accuracy.
    Do you have something countermeasure against this problem?
    When the MCU likewise take GND, it will feel a it another problem occurs in the unlikely.

    Please tell me if there is a countermeasure.

    Thanks,
    Tomoaki yoshida
  • 0 in reply to Tomoaki Yoshida
    TI__Intellectual 1150 points

    Hi，

    Thanks,

    You're right! If GND network, the side effect is the CS voltage shift. The GND current smaller than 10mA, you can find the corresponding Vdiode through its document, then modify it in the MCU codes. It definitely has some effect on the current sense accuracy.

    I'm not sure if MCU GND network is workable. Since for device GND shift structure, the internal logic should be considered carefully, not sure whether the MCU can support this.

    Alex,