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TPS2H000-Q1: Increased quiescent current with Diagnostic enabled and No load connected

Dušan Vaverka
Prodigy 10 points
Part Number: TPS2H000-Q1

Hi,

I am observing unexpected power loss in at TPS2H000A chip. It is around 0,5 Watt and the conditions are following: 
t(a)=22 deg.C, V(VS)=24,0 Vdc, V(IN1)=V(IN2)=0 V, No load at OUT1, OUT2 (nets VAC_V1, VAC_V2 left open), pull-ups for no load detection=20 kOhm, steady state the consumption from PSU +24V is measured around 23 mA. I was not able find any information about this idle current in TPS2H000A datasheet. Or is it there and hidden to my eyes? 

I am sure with the current measurement, it is related to IC and the open load det. bias clearly, because I measured it at location of L500 which was desoldered for this measurement.

My next finding is that when at least one of outputs is slightly loaded e.g. Rload=1 kOhm (while control input still left inactive/off) the output voltage drops below the open load threshold V(ol,off) 1,6 V(min) then the current consumption falls to around 4 mA which is fine because it corresponds with datasheet parameter I(off,diag)=3 mA(max) and open load det. bias +24V->R500(20kOhm)->Rload(1kOhm)->GND.

Otherwise the IC is working fine. But why there flows such "significant" idle quiescent current is a mystery to me.

If anyone can comment this situation, I would appreciate it.

@support.TI: May be if this IC behavior is normal in such conditions, there could be some datasheet information added.

Thanks to everyone in advance.

Note1: Datasheet I have downloaded,
https://www.ti.com/lit/ds/symlink/tps2h000-q1.pdf?ts=1670248674151&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS2H000-Q1

Note2: My observation is based on eight IC occurrences (I have 2 boards, each assembled with 4 TPS2H000A)

Schematic1: My application of TPS2H000A:

  • +1
    TI__Mastermind 32650 points

    Hi Dusan,

    In this device, during a open load fault in the internal circuit pulls a fault current. This lines up with the current that you are seeing in the open load state and is expected behavior. 

    To reduce this current consumption, the DIAG_EN pin can be PWM'd to drop overall current consumption. This current value is similar to the specification for ICS(H). 

    Thank you for your feedback. We will look to improve the detail level on the datasheet for future devices as well.

    Best,

    Shreyas