AT1605
High-Side Power Switch IC
Function Description
Enable Control
Digital logic of EN provides an electrical ON/OFF control of the power supply. Connecting this pin to
ground or to any voltage less than EN input threshold will completely turn OFF the Bias. In this state,
current drain from the input supply is less than 1µA; the internal reference, comparators, and biasing
circuitry turn off. EN works as a simple on/off control. Drive EN high to enable the device, or drive EN
low for shutdown.
Charge Pump
The higher of supply battery powers the internal charge pump. The charge pump provides power to the
current limit amplifier and allows the N-MOS gate voltage to be higher the battery supply voltage. A
gate voltage that is higher than the source voltage is necessary to turn on the N-MOS.
Under-Voltage Lockout (UVLO)
The under voltage lockout prevents the device from misoperation at low input voltage.
Soft-Start
Soft-start is built-in on chip. When power up, the soft-start function is immediately active to nominal
voltage by a constant current. During this time, the soft-start voltage directly controls the N-MOS
on-time to reduce input surge currents. The maximum load current is available after the soft-start cycle
is completed.
Over-Current Limit
The AT1605 provides cycle-by-cycle over-current protection. Current limit is accomplished using a
separate dedicated comparator. The current limit signals control logic block to limit current of N-MOS
in event that the current of flowing N-MOS is greater than the current limit value. The current-limit
feature protection against a hard short or over-current fault at the output.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipation in the AT1605. When the junction
temperature exceeds Tj=130°C, a thermal sensor activates the thermal protection, which shuts down the
IC, allowing the IC to cool. Once the device cools down by 20°C, IC will automatically recover normal
operation. For continuous operation, do not exceed the absolute maximum junction-temperature rating
of Tj=150°C.
7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300, Taiwan, R.O.C.
Tel: 886-3-563-0878
4/26/2006 REV:1.1
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
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AIMTRON [ AIMTRON TECHNOLOGY ]
