|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

|||||||||||||||||

All trademarks are property of their respective owners 2014-08-0001

www.pericom.com

PT0516

8/27/14

9

PI5USB2549

USB Charging Port Controller and Load Detection Power Switch

DCP Auto Mode

PI5USB2549 integrates an auto-detect state machine that supports all the below DCP charging schemes. It starts in Divider-1A

scheme, however if a BC1.2 or YD/T 1591-2009 compliant device is attached, the PI5USB2549 responds by discharging OUT,

turning back on the power switch and operating in 1.2Vmode briefly and then moving to BC1.2 DCP mode. It then stays in that

mode until the device is done charging or removed, in which case it goes back to Divider-1A scheme. When a Divider-1A

compliant device is attached the PI5USB2549 will stay in Divider-1A state.

Also, the PI5USB2549 will automatically switch between the Divider-1A and Divider-2A (or Divider-2.4A) schemes based on

charging current drawn by the connected device. Initially the device will set the DP_IN/DM_IN to Divider-1A scheme. If

charging current of the device >900mA is measured by the PI5USB2549, it switches to Divider-2A scheme and test to see if the

peripheral device will still charge at a high current. With MODE_SEL=’HIGH’, if charging current of the device >1.8A is

measured by PI5USB2549 or PI5USB2549, it will switches to Divider-2.4A charging mode. If it does then it stays in Divider-

2A or Divider-2.4A charging scheme otherwise it will revert to Divider-1A scheme.

Figure 1, DCP_Auto Mode

DCP BC1.2 and YD/T 1591-2009

Both standards define that the D+ and D- data lines should be shorted together with a maximum series impedance of 200Ω.

This is shown as Figure 1.

Figure 2, DCP mode

GND

USB

Connector

2.0V

1.2V

2.7V

Auto

Detect

D-

D+

PI5USB2549

VBUS

D-

D+

PI5USB2549

BC1.2 DCP

/DCP-1.2V

Divider-1A

/2A /2.4A