PRODUCT DATASHEET
AAT1276
SwitchRegTM
Boost Converter with USB Power Switch
Step-Up Converter Design Example
Specifications
VOUT = 5V
IOUT = 300mA
VIN = 2.7V to 4.2V (3.6V nominal)
TAMB = 50°C
Output Inductor
VOUT - VIN(MIN)
5V - 2.7V
DMAX
=
=
= 0.46
VOUT
5V
From the characterization curves, the switching frequency at room temperature with a 300mA load and 2.2μH inductor
is about 800kHz.
VIN(MIN) · DMAX
IPP
=
L · FS
IO
1 - D
IP =
IPP
2
IPK = IP +
IV = IP - IPP
IV = IP - IPP = 0.9A - 0.7A = 0.20A
2
IPK2 + IPK · IV + IV
0.9A2 + 0.9A · 0.2A + 0.2A2
3
IRMS
=
=
= 0.59A
3
For the Sumida CDRH2D14-2R2 inductor, ISAT = 1.0A, IDC(MAX) = 1.6A and DCR = 94mΩ.
PLOSS(INDUCTOR) = I2RMS · DCR = (590mA)2 · 94mΩ = 32mW
w w w . a n a l o g i c t e c h . c o m
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
