When using the MINI USB connector to power the board, are D+D- short-circuited or floating?

CcKk

When using the MINI USB connector to power the board, are D+D- short-circuited or floating? [Copy link]

As shown in the picture, when the board is powered by a 5V to 3.3 converter from a power bank, should the D+D- on the USB connector be short-circuited or left floating? Why?

qwqwqw2088

What to charge?

The difference between Apple and Android

CcKk

qwqwqw2088 posted on 2019-12-13 09:35 What are the differences between charging Apple series and Android series

3.3V is only used to power the microcontroller, so how should D+D- be handled at this time? Since we mentioned charging the mobile phone, let's ask how to handle D+D- when charging Android and Apple.

dcexpert

Ordinary power banks do not have PD control. Device identification is processed at the power supply end, and the device end does not need to be processed, and D+/D- can be left floating. However, many power banks have a shutdown function, which will automatically cut off the output after a delay of a period of time when the current is less than tens of mA, which may cause problems in powering low-power devices.

chunyang

Never short-circuit the data path at any time. For some interface identification that needs to be performed, it is also achieved through data transmission or static biasing of the data line.

qwqwqw2088

CcKk posted on 2019-12-13 09:38 3.3V is only used to power the microcontroller, so how should D+D- be handled at this time? Since we mentioned charging the mobile phone, let's ask about D+D- when charging Android and Apple...

3.3V is only used to power the microcontroller, so it should be left floating.

As long as any device is plugged in, it will get power from the 5V and GND pins.

qwqwqw2088

qwqwqw2088 posted on 2019-12-13 13:43 3.3V is only used to power the microcontroller. If any device is left unconnected and plugged in, it will get power from the 5V and GND pins.

Apple series, for charging, adds voltage divider resistors on the two data pins D+ and D-, so that the charging device can read two voltages from these two data lines when charging. For details, please check Apple's relevant information on this.

hotsauce1861

What are the functions of pull-up, pull-down and floating?

For mobile devices, D+ or D- is used to distinguish the USB charging current. Generally, there are DCP, CDP, etc. The difference is that the charger chip of the mobile device will eventually set the charging current differently. For details, please refer to

"Battery Charging Specification Revision"

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