PI5USB2546J

www.diodes.com

November 2020

Document Number DS43167 Rev 1-2

13

© Diodes Incorporated

PI5USB2546J

DCP-1.2V Charging Scheme

DCP-1.2V charging scheme is used by some handheld devices to enable fast charging at 2.0A. PI5USB2546J supports this

scheme in the DCP-Auto mode before the device enters BC1.2 shorted mode. To simulate this charging scheme D+/D- lines are

shorted and pulled-up to 1.2V for fixed duration then device moves to DCP shorted mode as defined in BC1.2 spec. This is

shown as Figure 3.

Figure 3. DCP-1.2V Charging Scheme

DCP Auto Mode

As mentioned above the PI5USB2546J integrates an auto-detect state machine that supports all the above DCP charging

schemes. It starts in Divider-1A scheme, however if a BC1.2 or YD/T 1591-2009 compliant device is attached, the PI5USB2546J

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 releases the data line, in which case it goes back to Divider-1A scheme.

When a Divider-1A compliant device is attached the PI5USB2546J will stay in Divider-1A state.

Also, the PI5USB2546J will automatically switch between the Divider-1A and Divider-2A schemes based on charging current

drawn by the connected device. Initially the device will set the data lines to Divider-1A scheme. If charging current of the device

>750mA is measured by the PI5USB2546J, it switches to Divider-2A scheme and test to see if the peripheral device will still

charge at a high current. If it does then it stays in Divider-2A charging scheme otherwise it will revert to Divider-1A scheme.

Figure 4. DCP_Auto Mode

D-

D+

PI5USB2546J

BC1.2 CDP

BC1.2 DCP

/DCP-1.2V

Divider-1A/

Divider-2A

To

USB

2.0

Host

Controlled by

CTL pins settings

GND

USB

Connector

2.0V

1.2V

2.7V

CDP

Detect

Auto

Detect

D-

D+

D- OUT

D+OUT

PI5USB2546J

VBUS

USB

Host/Hub