ADP2230

Data Sheet

Thermal Shutdown

In the event that the junction temperature of the ADP2230 rises

above 150°C, the thermal shutdown protection circuit turns off

the regulator. Extreme junction temperature can be the result of

high current operation, poor circuit board design, and/or high

ambient temperature. A 15°C hysteresis is included in the

protection circuit so that when a thermal shutdown occurs, the

device does not return to normal operation until the on-chip

temperature drops below 135°C. Upon exiting thermal shutdown,

the soft start sequences are initiated.

Soft Start

The ADP2230 has an internal soft start function that ramps the

output voltage in a controlled manner upon startup, thereby

limiting the inrush current. This prevents possible input voltage

drops when a battery or a high impedance power source is

connected to the input of the converter. Typical soft start time is

350 μs. The ADP2230 is also capable of starting up into a

precharged output capacitor. If soft start is invoked when the

output capacitor charge is greater than zero, the device delays

the start of switching until the internal soft start ramp reaches

the corresponding FB voltage. This feature prevents discharging

the output capacitor at the beginning of soft start.

Current Limit

The ADP2230 has protection circuitry that limits the direction

and amount of current that flows through the power switch and

synchronous rectifier, cycle by cycle. The positive current limit

of 1300 mA ( typical) on the power switch limits the amount of

current that can flow from the input to the output. In PWM, the

ADP2230 also has a negative current limit of 500 mA (typical),

on the synchronous rectifier that prevents the inductor current

from reversing direction and flowing out of the load.

100% Duty Cycle

The ADP2230 enters and exits 100% duty cycle smoothly. The

control loop seeks the next clock cycle while the high-side

switch is engaged. When this occurs, the clock signal is masked,

and the PMOS remains on. When the input voltage increases,

thus, the device stops skipping clock cycles and exits 100% duty

cycle.

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