TPS53667: READ_IOUT error

Peter vK

Part Number: TPS53667

Hi,

I dont seem to be reading the correct value for READ_IOUT using a TPS53667 wired up for 5 phase operation. CSP6 is connected to V3R3.

RImon is 49k9, and R's for F-IMAX are 33k2/30k1. Register 0xDA (MFR_SPECIFIC_10) is reading as 121, so seems that F-IMAX is correct.

The 0x8C register is reading as 0xB800.

I would guess that Iout is something like 5A. Vin and Iin are reading correctly. 0x39 (IOUT_CAL_OFFSET) is also reading as 0.

Thoughts? Happy to share schems offline.

Thanks,

Peter

over 6 years ago

0 Weidong Zhu over 6 years ago

TI__Expert 5965 points

Hi Peter,

Can you measure the voltage on IMON pin and see how much it reads? It supposed to be Iout*0.85/IccMax. If it's not right then we need to measure individual CSP voltage to see if they meet expectation. Thanks.

Regards,
Weidong

0 Peter vK over 6 years ago in reply to Weidong Zhu

Prodigy 70 points

Hi Weidong,

Thanks for the reply. Pls see attached, sorry about the terrible quality...

If I squint and use my imagination I think I can see a repeating pattern at about 500k of 5 pulses which I guess makes sense. Looks like the largest pulse is approx 10mV.

Regards,

Peter

0 Weidong Zhu over 6 years ago in reply to Peter vK

TI__Expert 5965 points

Hi Peter,

I assume the measurement is the voltage on IMON pin? I can not tell exactly but looks like the DC level is close to 0. This matches the READ_IOUT which also translate to 0 A. In this case, can you measure the CSP voltage voltage with meter? It is possible there can be offset on the CSP input from power stage, which may cause lower READ_IOUT reading. Also how did you measure the load current?

Regards,
Weidong

0 Peter vK over 6 years ago in reply to Weidong Zhu

Prodigy 70 points

Hi Weidong,

I added a much larger load and can now read the current output successfully. Perhaps the current reads as zero at very low IOUT? ~ <5% IMAX ? Anyway, thanks for your help.

Peter

0 Qian Chen over 6 years ago in reply to Peter vK

TI__Mastermind 24075 points

Hi Peter,

Thanks for the update. We will close this case.

Thanks
Qian

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TPS53667: READ_IOUT error