SW3518S

Dual Ports Fast Charge Application

Copyright © 2022, ZHUHAI ISMARTWARE TECHNOLOGY CO., LTD.

May, 2022 - DS031_v1.6

6

9. Functional Description

9.1. Synchronous Buck

The SW3518S integrates a high efficiency synchronous buck with output current up to 5A and

efficiency up to 95%(VIN=12V, VOUT=5V, IOUT=5A).

The synchronous buck works in PSM/PWM mode with switching frequency of 125KHz. It works in

PSM mode when in light load and in PWM mode in heavy load to make a better efficiency. It will

automatically change in these two modes base on output current.

The synchronous buck supports CC/CV mode. When output current is lower than CC limited current,

output voltage will keep constant. When output current reaches CC limited current, output voltage

will drop to keep output current constant. When single port outputs, CC limited current is set to

3.3A. When dual ports outputs, CC limited current is set to 2.7A for each port.

The synchronous buck supports wire drop compensation. Output voltage will linear increase

according to output current and the increased voltage is 65mV/A.

The synchronous buck integrates thermal regulation. When die temperature rises to 120℃, output

voltage will automatically fall down so as die temperature stop increasing. If die temperature still rises

to 150℃, buck will stop and turn off. When die temperature falls to thermal shutdown hysteresis, buck

will automatically restart.

The synchronous buck integrates input over voltage, input under voltage, output over current and short

protection.

Type-C

CC Current Source

ICC_SOURCE

Power Level=3.0A

310

330

350

uA

BC1.2

DP/DM Voltage

DP

Apple 2.4A Mode

2.55

2.7

2.85

V

DM

Apple 2.4A Mode

2.55

2.7

2.85

V

PE

Current Threshold

IREF

150

250

350

mA

Quit Time

tPLUG_OUT

160

200

240

mS

I2C

Rate

fCLK

100

400

Kbit/S

Thermal Shutdown

Thermal Shutdown Threshold

TSHDT

Temperature Rising

135

150

165

℃

Thermal Shutdown Hysteresis

TSHDT_HYS

Temperature Falling

35

50

65

℃