BQ25720: disable input current limit

Hello Fred,

These two settings should effectively disable the Input Current limit. How did you confirm that the Input Current Limit is still there after these bits are set to 0?

Khalid

Hi Kahlid,

thanks got your feedback.

they said they check 0x3F and test on the board the verify,

BTW, is there a sequence between 0x12 and 0x31 to disable the current limit(including ILIM_HIZ)

for example 0x12 first, and then 0x31

so you mean 0x12[1] is enough to disable all the current limit including external ILIM, right?

Fred, 

That's correct.

Khalid

Hi Khalid,

they measured IADPT and found out that the current limit is not  disabled by 0x12 succesfully,

they said the IADPT value exactly correspond to the 0x3F

Hi Fred,

This bit will disable IINDPM. You can try to confirm on the EVM. They may be overwriting the bit, or something else is limiting the input current.

Khalid

customer condition is no battery,

I've tried it on the EVM without battery,

and you're right, 0x12 is enough.

is there any related cause that would overwrite the 0x12?

Hi Fred,

Can the customer read back 0x12 after they check IADPT? That would confirm if it is overwritten, we also need to monitor I2C read/write to see where it has been overwritten. The IC will not change this value back to "1" unless a POR condition occurs. Since you mentioned they are using no battery, when they remove the adapter this setting will be reset, so they need to set it every time they plug in the adapter.

Khalid

Hi Khalid,

as you can see, as the load increase, the Vout drop accordingly, and IADPT remain still.

and BQstudio shows the current limit is turned off at that moment (through EV2400)

HI Fred,

The ChargerStatus shows no IINDPM triggered. If the load is too high on the adapter the adapter voltage will drop. Is it possible the input adapter can't supply this current? Can they try a lower IINDPM setting and then disable IINDPM to see if they see the exact same behavior or not? 

Khalid

Hi Khalid,

see below , they tested again for us.

 0x12[1]=0,  but why charge status still show IINDPM triggered?

Fred,

Can you ask for the sequence so we can reproduce it? Did IINDPM trigger before they disable IINDPM?

Khalid

Hi Khalid,

you can see the E-load connect at charger output, SMbus is transmitted through EV2400.

under 4A load, the INDPM all show triggered whether 0x12[1]=0 or 1, I have video can share in Webex.

----------------------------- Start to Monitor I2C / SMBus / PMBus Protocol -----------------------------
----------------------------- All data will be monitored and display on screen ----------------------------
 [S] [P]
 [S] 12 12 1C F7 [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 00 00 [P]
 [S] 12 21 00 38 [P]
 [S] 12 22 00 00 [P]
 [S] 12 30 40 77 [P]
 [S] 12 31 37 E0 [P]
 [S] 12 32 3C 04 [P]
 [S] 12 33 81 2E [P]
 [S] 12 34 A8 48 [P]
 [S] 12 36 4C 18 [P]
 [S] 12 3D 00 00 [P]
 [S] 12 12 1C F7 [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 00 00 [P]
 [S] 12 21 00 38 [P]
 [S] 12 22 00 00 [P]
 [S] 12 30 40 77 [P]
 [S] 12 31 37 E0 [P]
 [S] 12 32 3C 04 [P]
 [S] 12 33 81 2E [P]
 [S] 12 34 A8 48 [P]
 [S] 12 36 4C 18 [P]
 [S] 12 3D 00 00 [P]
 [S] 12 3E 00 54 [P]
 [S] 12 3F 00 00 [P]
 [S] 12 14 00 00 [P]
 [S] 12 33 81 2E [P]
 [S] 12 15 90 33 [P]
 [S] 12 34 A8 2C [P]
 [S] 12 3E 00 7D [P]
 [S] 12 3F 00 40 [P]
 [S] 12 22 00 40 [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 90 33 [P]
 [S] 12 33 81 0E [P]
 [S] 12 34 A8 2C [P]
 [S] 12 3E 00 7D [P]
 [S] 12 33 81 0E [P]
 [S] 12 34 60 83 [P]
 [S] 12 3F 00 40 [P]
 [S] 12 22 00 40 [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 90 33 [P]
 [S] 16# [P]
 [S] 16# [P]
 [S] 16# [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 90 33 [P]
 [S] 12 14 00 00 [P]
 [S] 12 15 90 33 [P]

----------------------------- Stop to Monitor I2C / SMBus / PMBus Protocol -----------------------------

Hi Fred,

Per our meeting today please try the recommended steps and update us via email. We can schedule a follow-up meeting if necessary. I will close the thread and we can update via email.

Khalid

Hi Tiger,

they try use pure DC source to bypass PD and type-C , but still the same.

this issue is getting weird . please help think of other causes.

why the Vsys voltage (charger output) drop when they decrease the IN_HOST  under same load when 0X12[1] is disabled?

Fred,

As mentioned last Friday I would recommend the customer tries this with as many default settings on the IC as possible. I reviewed the register dump, a couple items stick out to me.

In ChargeOption2 the EN_PKPWR_IIN_DPM is enabled per the register settings. Please keep ChargeOption2() register default to rule out this interaction.

In ChargeOption3 the IL_AVG inductor current clamp is disabled. Please keep this register default (15A IL_AVG) to rule this out.

Khalid

1Hi Khalid,

good news, the current limit stop after they disable EN_PKPWR_IIN_DPM.

1. does that mean the original current limit is actually the level 2 ILIM2?

how can we explain the original current limit?

2. BTW,

ICRIT Prochot will not function as they disable EN_PKPWR_IIN_DPM now., they want  a PROCHOT trigger at 120% of INDPM, but  INOM PROCHOT is 110% of INDPM,

do they still have other options?

Regards,

Fred

Hello Fred,

Good to know. Regarding your questions - ILIM2 is defined as a % of ILIM1 (the value of IIN_DPM) depending on ProchotOption0 register setting.

I am a little confused, why can they not use PROCHOT_ICRIT if the EN_PKPWR_IIN_DPM is disabled?

Khalid

1.but why ILIM2 will valid, I thought it only last for Tovld duration?

is this condition different at battery removal?

2. you mean ICRIT PROCHOT and peak power mode are independent? 

Hi Fred,

As discussed I will check these out on E2E and try to confirm by Friday. As of today no update.

Khalid

got it

Hi Khalid,

let me organize three things for you,

1. why current limit still valid when peak power mode enable (longer than Tovud).

2.if this will be normal if we set EN_PKPWR_VSYS=1 as datasheet suggest?

3. is peak power mode independent with ICRIT?

Fred,

I will close and respond by email with the details of my findings. Please continue the conversation via email if any more info needed.

Khalid