BQ25890H: Plug in the charger slowly, it detects SDP mode

Lillian Liu(SH)

Part Number: BQ25890H

Hi team，

My customers use BQ25890H in their pad product, now they find that the pad plug in the Type-C charger slowly, it detects SDP mode in a high probability.

[name:bq2589x_charger&]Reg[0b] = 0x36

Log and waveform are attached.(green: DP; yellow: DM; orange: VBUS)

What's the reason for it?

SDP.txt

over 3 years ago

0 Ning T over 3 years ago

TI__Guru 57321 points

Hi,

The charger does not detect Type-C charger. What DPDM detection result do you expect?

Thanks,

Ning.

0 Lillian Liu(SH) over 3 years ago in reply to Ning T

TI__Expert 4620 points

Thanks Ning ,we think it detects DCP mode.

I know from my clients that this question only occurs at slow speeds when plug in, plug in normal speed detects DCP mode as below.

And I want to know Reg[0b] bit 1 reads 1 , is it normal?

0 Lillian Liu(SH) over 3 years ago in reply to Lillian Liu(SH)

TI__Expert 4620 points

Here is the DCP waveform when plug in at normal speed.

0 Ning T over 3 years ago in reply to Lillian Liu(SH)

TI__Guru 57321 points

Hi,

REG0B[1] is reserved. The bit does not matter.

Please read through 9.3.1.3.4 D+/D– Detection Sets Input Current Limit on BQ2419x d/s at https://www.ti.com/lit/ds/symlink/bq24192i.pdf. The primary detection is used to distinguish between USB host (Standard Down Stream Port, or SDP) and different type of charging ports (Charging Down Stream Port, or CDP, and Dedicated Charging Port, or DCP). If PD is attached to a USB host (SDP), the D– is low. If PD is attached to a charging port (CDP or DCP), the D– is high.

Thanks,

Ning.

0 Lillian Liu(SH) over 3 years ago in reply to Ning T

TI__Expert 4620 points

Hi Ning,

From the waveform and log above , when plug in slowly, it really detects SDP mode and can't recover. This problem will really affect the user experience. Do you have any ideas to solve this problem?

Thanks

Lillian

0 Ning T over 3 years ago in reply to Lillian Liu(SH)

TI__Guru 57321 points

Lillian,

Plugging in slowly impacts on the D+/D- resistance which may change the DPDM detection results. There's little to do on the charger side.

Thanks,

Ning.

Power management

Power management forum

BQ25890H: Plug in the charger slowly, it detects SDP mode