MAX77751

3.15A USB-C Autonomous Charger

for 1-Cell Li+ Batteries

www.maximintegrated.com

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Applications Information

Fast-Charge Current Setting

When a valid input source is present, the battery charger attempts to charge the battery with a fast-charge current

Table 3. Fast-Charge Current Settings

RESISTANCE (kΩ)

24.9

3150

22.6

3000

20.5

2800

18.7

2500

16.9

2400

15.4

2200

14

2000

12.4

1800

11

1500

9.53

1400

8.2

1200

6.65

1000

5.23

800

3.6

600

2.4

500

Top-Off Current Setting

The top-off charging current is programmed by an external resistor connected from ITOPOFF to GND (RTOPOFF).

Table 4 shows the resistance values which correspond to the target ITOPOFF values.

Table 4. Top-Off Current Settings

D+/D- Multiplexing

The USB D+/D- lines, which are used for BC1.2 and proprietary adapter detection, can be used for data communication.

If an MCU handles this communication in the target system, the D+/D- lines can be connected to the MAX77751 and the

MCU, as shown in Figure 11. The switchers are required for each D+ and D- lines to guarantee high impedance state for

the MCU connections to avoid incorrect adapter detection. It is recommended to connect the MAX77751’s INOKB to the

MCU in this configuration so that the MAX77751 can signal that detection is complete to the MCU. When the MCU

receives a valid INOKB signal, it can switch the D+/D- lines from the MAX77751 to the MCU for data communication.

RTOPOFF (kΩ)

ITOPOFF (mA)

24.3

350

19.6

300

16.5

250

13.3

200

10.2

150

8.06

100