AAT1210
High Power DC/DC Boost Converter
with Optional Dynamic Voltage Programming
Functional Block Diagram
VIN
LIN
VP
Soft-Start
Timer
EN/SET
FB1
W
S
Control
VREF1
Output
Select
VREF2
FB2
SEL
GND
PGND
voltage. This allows the voltage loop to directly pro-
gram the required inductor current in response to
changes in the output load.
Functional Description
The AAT1210 consists of a DC/DC boost (step-up)
controller, an integrated slew rate controlled input
disconnect MOSFET switch, and a MOSFET power
switch. A high voltage rectifier, power inductor,
capacitors and resistor divider network are required
to implement a DC/DC boost converter. The mini-
mum output voltage must be 0.5V above the input
voltage and the maximum output voltage is 18V.
The operating input voltage range is 2.7V to 5.5V.
The switching cycle initiates when the N-channel
MOSFET is turned ON and current ramps up in the
inductor. The ON interval is terminated when the
inductor current reaches the programmed peak
current level. During the OFF interval, the input cur-
rent decays until the lower threshold, or zero induc-
tor current, is reached. The lower current is equal
to the peak current minus a preset hysteresis
threshold, which determines the inductor ripple cur-
rent. The peak current is adjusted by the controller
until the output current requirement is met.
Control Loop
The AAT1210 provides the benefits of current
mode control with a simple hysteretic feedback
loop. The device maintains exceptional DC regula-
tion, transient response, and cycle-by-cycle current
limit without additional compensation components.
The magnitude of the feedback error signal deter-
mines the average input current. The AAT1210
controller implements a programmed current
source connected to the output capacitor and load
resistor. There is no right-half plane zero, and loop
stability is achieved with no additional compensa-
tion components.
The AAT1210 modulates the power MOSFET
switching current in response to changes in output
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