MAX77751

3.15A USB-C Autonomous Charger

for 1-Cell Li+ Batteries

www.maximintegrated.com

Maxim Integrated | 29

ENBST For Reverse Boost

ENBST is an input control signal for the reverse boost mode with an external logic signal. If ENBST is driven high, the

reverse boost is enabled and the BYP-to-

CHGIN path is closed. ENBST has an internal 235kΩ pulldown resistor. When

ENBST sets to high,

the MAX77751 disconnects Rd from the CC line and provides a 180μA current source.

USB BC1.2 Charger Detection

Features

• D+/D- Charging Signature Detector

• USB BC1.2 Compliant SDP, DCP, and CDP Detection

• Proprietary Charger Types Detection

• Apple 500mA, 1A, 2A, 2.4A

• Samsung 2A

Description

The USB charger detection is USB BC1.2 compliant with the ability to automatically detect some common proprietary

charger types.

The Charger Detection State Machine follows USB BC1.2 requirements and detects SDP, CDP, and DCP types. In

addition to the USB BC1.2 State Machine, the IC also detects a limited number of proprietary charger types (Apple and

Samsung). The IC automatically sets the CHGIN input current limit based on the charger type detection results. If charger

type detection results are an unknown charger type or D+/D- are found as open, the input current limits are set to 3A max.

Table 1. USB BC1.2 Detected Charger Type

INPUT CURRENT LIMIT

CHARGER DETECTED

500mA

SDP

1.5A

CDP

1.5A

DCP

Table 2. Detected Proprietary Charger Type

INPUT CURRENT LIMIT

CHARGER DETECTED

500mA

Apple

1A

Apple

2A

Apple

2.4A

Apple

2A

Samsung

3A

All others