aoz1312 Alpha & Omega Semiconductor, aoz1312 Datasheet - Page 7

• Manufacturer Part Number: aoz1312
• Description: Single Channel Usb Switch
• Manufacturer: Alpha & Omega Semiconductor

Detailed Description
The AOZ1312 is a member of Alpha and Omega
Semiconductor’s single-channel power-distribution
switches family. The AOZ1312 is intended for
applications where heavy capacitive loads and
short-circuits are likely to be encountered. Gate drive is
provided by an internal charge pump designed to control
the power-switch rise times and fall times to minimize
current surges during switching. The charge pump
requires no external components and allows operation
from supplies as low as 2.7 V.
Power Switch
The power switch is a N-channel MOSFET with a low
on-state resistance capable of delivering 1 A of
continuous current. Configured as a high-side switch,
the MOSFET will go into high impedance when disabled.
Thus, preventing current flow from OUT to IN and IN to
OUT.
Charge Pump
An internal charge pump supplies power to the circuits
and provides the necessary voltage to drive the gate of
the MOSFET beyond the source. The charge pump is
capable of operating down to a low voltage of 2.7 Volts.
Driver
The driver controls the voltage on the gate to the power
MOSFET switch. This is used to limit the large current
surges when the switch is being turned On and Off.
Proprietary circuitry controls the rise and fall time of the
output voltages.
Rev. 1.1 July 2011
www.aosmd.com
Enable
The logic enable disables the power switch, charge
pump, gate driver, logic device, and other circuitry to
reduce the supply current. When the enable receives a
logic high the supply current is reduced to approximately
1 μA. The enable input is compatible with both TTL and
CMOS logic levels.
Over-current
The over-current open drain output is asserted
(active low) when an over-current condition occurs.
The output will remain asserted until the over-current
condition is removed. A 15 ms deglitch circuit prevents
the over-current from false triggering.
Thermal Shut-down Protection
When the output load exceeds the current-limit threshold
or a short is present, the device limits the output current
to a safe level by switching into a constant-current mode,
pulling the overcurrent (OC) logic output low.
During current limit or short circuit conditions, the
increasing power dissipation in the chip causing the die
temperature to rise. When the die temperature reaches a
certain level, the thermal shutdown circuitry will shutdown
the device. The thermal shutdown will cycle repeatedly
until the short circuit condition is resolved.
AOZ1312
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