ACE345

Adjustable USB Load Current Switch

VER 1.2

6

Block Diagram

Detailed Description

Operation

The ACE345 is a current limited switch that protects systems and loads which can be damaged or

disrupted by the application of high currents. The core of each device is a 0.10

Ω P-channel MOSFET and

a controller capable of functioning over a wide input operating range of 2.6-5.5V. The controller protects

against system malfunctions through current limiting, undervoltage lockout and thermal shutdown. The

current limit is adjustable from 0.15A to 1.5A through the selection of an external resistor.

On/Off control

The ON pin controls the state of the switch. When ON is high, the switch is in the on state. Activating ON

continuously holds the switch in the on state so long as there is no fault. An undervoltage on VIN or a

junction temperature in excess of 155°C overrides the ON control to turn off the switch. The ACE345 does

not turn off in response to an over current condition but instead remains operating in a constant current

mode so long as ON is active and the thermal shutdown or undervoltage lockout have not activated. The

ON pin control voltage and VIN pin have independent and recommended operating ranges. The ON pin

voltage can be driven by a voltage level higher than the input voltage.