bq25890 / Input current limit for DCP at disabling adjustable high voltage adapter handshake

S.Satoshi

Other Parts Discussed in Thread: BQ25890

Hi Everyone,

Please let me ask about input current limit for DCP at disabling adjustable high voltage adapter handshake.

Is it set to 3.25A at both enable and disable adjustable high voltage adapter handshake? I'm asking it just to make sure because the Fig.9 in full datasheet show that the DCP arrow is output through Ajustable High Voltage Adapter Handshake box.

Best Regards,

Sonoki / Japan Disty

over 8 years ago

0 Smriti B over 8 years ago

TI__Expert 5565 points

Satoshi-san,

I'm not sure I fully understand the question. If high voltage adapter handshake is disabled, then the D+/D- detection scheme stops at CDP detection (with max input current limit at 1.5A). If the high voltage adapter handshake is enabled, then the input current could be set to 3.25A if a DCP is detected.

0 SamW2000 over 8 years ago in reply to Smriti B

TI__Intellectual 1910 points

Satoshi-san,
For adjustable high voltage adapter, it would initially looks like a DCP. Therefore the algorithm must first identify it is (and set to 1.5A) or is not HVDCP before DCP (3.25A) can be identified.

0 S.Satoshi over 8 years ago in reply to SamW2000

Guru 21675 points

Hi Bhuyan, Sam,

I tried to disable adjustable high voltage adapter handshake (HVDCP_EN =0, MAXC_EN = 0) and connect USB adapter, then the result was IINLIM = 3.25A, not 1.5A and VBUS_STAT showed 011: USB DCP as attached. Please ask your designer again and let me know if the IINLIM is set to 3.25A regardless adjustable high voltage adapter handshake setting.

bq25890EVM IINLIM setting at DCP adapter_20150629.pdf

Best Regards,

Sonoki

0 Smriti B over 8 years ago in reply to S.Satoshi

TI__Expert 5565 points

Satoshi-san,

Do you have D+ and D- shorted on the EVM? If JP5 is shorted on the EVM, then the IC thinks it's connected to a DCP and sets the current limit to 3.25A because there is no accurate detection on D+/D-.

0 S.Satoshi over 8 years ago in reply to Smriti B

Guru 21675 points

Hi Bhuyan,

Now I'm talking about "DCP" case, not CDP. Do you mean that the IINLIM is always set to 3.25A when DCP is connected?

Best Regards,
Sonoki

0 Smriti B over 8 years ago in reply to S.Satoshi

TI__Expert 5565 points

Satoshi-san,

Is JP5 shorted on the EVM? If you look at table 3 on page 17 of the datasheet, USB DCP = 3.25A for input current limit.

0 S.Satoshi over 8 years ago in reply to Smriti B

Guru 21675 points

Hi Bhuyan,

I'll check the JP5 condition tomorrow and get back to you.

Best Regards,
Sonoki

0 S.Satoshi over 8 years ago in reply to S.Satoshi

Guru 21675 points

Hi Bhuyan,

I confirmed that the JP5 is shorted, so I tried to retest with opened JP5. Then the 3.25A for all HVDCP_EN and MAXC_ENwas setting, so the result was the same with my previous result. I understand that bq25890 set IINLIM to 3.25A when DCP source is connected regardless adjustable high voltage adapter handshake setting.

Best Regards,

Sonoki

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bq25890 / Input current limit for DCP at disabling adjustable high voltage adapter handshake