TPS2546: TPS2546: Charging interrupted & Delayed.

cyan zhou

Expert 1500 points

Part Number: TPS2546

Hi TI Expert,

Please help to confirm whether it is a normal phenomenon.

We now use Tps2546 for a laptop charging port.

When we run DCP_Auto mode （CL1=0; CL2=0; CL2=3.3V）, there will be a delay seem from charging wave as below.

the delay time is about 2 seconds.

Please help to confirm whether it is a normal phenomenon.

below is the waveform：

CH2 BLUE: DP_IN

CH3 PINK: DM_IN

CH4 GREEN: OUT

downstream device is Iphone 6S A1700

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downstream device is HUAWEI MATE20

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BELOW IS SCHEMATIC:

0 Adam Mc Gaffin over 3 years ago

Hello,

Yes this is normal behavior

0 cyan zhou over 3 years ago in reply to Adam Mc Gaffin

Expert 1500 points

Hi Adam

Thanks.

Do you know why there will be a delay about 2 seconds?

0 Adam Mc Gaffin over 3 years ago in reply to cyan zhou

Hi Cyan,

The answer can be found in section 8.4.1 of the datasheet. This is an excerpt from that section

As mentioned above the TPS2546 integrates an auto-detect state machine that supports all the above DCP charging schemes. It starts in Divider1 scheme, however if a BC1.2 or YD/T 1591-2009 compliant device is attached, the TPS2546 responds by discharging OUT, turning back on the power switch and operating in 1.2 V mode briefly and then moving to BC1.2 DCP mode. It then stays in that mode until the device releases the data line, in which case it goes back to Divider1 scheme. When a Divider1 compliant device is attached the TPS2546 stays in Divider1 state.

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