USB OTG

Transceiver

LM2775 (Host

Power)

Dual Role

Application

Processor

EN

ID

D+

D-

GND

USB Connector

OUTDIS

PFM

1E-5

0.0001

0.001

0.01

0.05

0.2 0.5

4.90

4.92

4.94

4.96

4.98

5.00

5.02

5.04

D003

LM2775

SNVSA57 – MAY 2015

www.ti.com

8.2.3 Application Curve

PFM = '0'

Figure 22. Load Regulation

8.2.4 USB OTG / Mobile HDMI Power Supply

Figure 23. USB OTG Configuration

8.2.4.1 Design Requirements

DESIGN PARAMETER

EXAMPLE VALUE

Input voltage range

2.7 V to 5.5 V

Output current range

8.2.4.2 Detailed Design Procedure

The 5-V output mode is normally used for the USB OTG / Mobile HDMI application. Therefore, the LM2775 can

be enabled/disabled by applying a logic signal on only the EN pin while grounding the OUTDIS pin. Depending

on the USB/HDMI mode of the application, the LM2775 can be enabled to drive the power bus line (Host), or

disabled to put its output in high impedance allowing an external supply to drive the bus line (Slave). In addition

to the high impedance-backdrive protection, the output current limit protection is 250 mA (typical), well within the

USB OTG and HDMI requirements.

16

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