AW32901/AW32902/AW32905/

AW32909/AW32910/AW32912

Apr. 2018 V1.0

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Copyright © 2016 SHANGHAI AWINIC TECHNOLOGY CO., LTD

FUNCTIONAL DESCRIPTION

Device Operation

If the AW329xx is enabled and the input voltage is between UVLO and OVP threshold, the internal charge pump

begins to work after debounce time, the gate of the nFET switch will be slowly charged high till the switch is fully

on.

ACOK will be driven low about 30ms after VIN valid, indicating the switch is on with a good power input. If

the input voltage exceeds the OVP trip level, the switch will be turned off in about 50ns. If

EN is pulled high, or

input voltage falls below UVLO threshold, or over-temperature happens, the switch will also be turned off.

Surge Protection

The AW329xx integrates a clamp circuit to suppress input surge voltage. For surge voltages between VIN_OVLO

and VIN_CLAMP, the switch will be turned off but the clamp circuit will not work. For surge voltages greater than

VIN_CLAMP, the internal clamp circuit will detect surge voltage level and discharge the surge energy to ground.

The device can suppress surge voltages up to 120V.

Over-Voltage Protection

If the input voltage exceeds the OVP rising trip level, the switch will be turned off in about 50ns. The switch will

remain off until VIN falls below the OVP falling trip level.

OVP Threshold Adjustment

If the default OVP threshold is used, OVLO pin must be grounded. If OVLO pin is not grounded, and by

connecting external resistor divider to OVLO pin as shown in the typical application circuit, between IN and GND,

the OVP threshold can be adjusted as following:

VIN_OVLO =

R1+R2

R2

VOVLO_TH

For example, if we select R1 = 1M

Ω and R2 = 100kΩ, then the new OVP threshold calculated from the above

formula is 13.2V. The OVP threshold adjustment range is from 4V to 20V. When the OVLO pin voltage VOVLO

exceeds VOVLO_SEL (0.26V typical), VOVLO is compared with the reference voltage VOVLO_TH (1.2V typical) to judge

whether input supply is over-voltage.

ACOK Output

The device features an open-drain output

ACOK, it should be connected to the system I/O rail through a pull-

up resistor. If the device is enabled and VIN_UVLO < VIN < VIN_OVLO,

ACOK will be driven low indicating the switch

is on with a good power input. If OVP, UVLO, or OT occurs, or

EN is pulled high, the switch will be turned off

and

ACOK will be pulled high.

USB On-The-Go (OTG) Operation

If VIN = 0V and OUT is supplied by OTG voltage, the body diode of the load switch conducts current from OUT

to IN and the voltage drop from OUT to IN is approximately 0.7V. When VIN > VIN_UVLO, internal charge pump

begins to open the load switch after debounce time (about 15ms). After switch is fully on, current is supplied

through switch channel and the voltage drop from OUT to IN is minimum.