AAT1230 Datasheet, PDF (17/21 Pages) Advanced Analogic Technologies – 18V 100mA Step-Up Converter

AAT1230
18V 100mA Step-Up Converter
I_PEAK =
I_OUT
1 - D_MAX
+
D_MAX · V_IN(MIN)
(2 · F_SW · L)
=
0.100
1 - 0.840
+
0.834 (2.7V)
2 · 0.8M · 2.2µH
= 0.625 + 0.640
= 1.265A = 1265mA
I_RMS = ^IPEAK = ¹²⁶⁵ = 730mA
3
3
For Coiltronics inductor SD3814-2R2, I_SAT = 1.90A, I_DC(MAX) = 1.90A and DCR = 77mΩ.
P_{LOSS(INDUCTOR)} = I_RMS2 · DCR
= (0.730)² (0.077)
= 0.041W
= 41mW
16V Output Capacitor
ΔV_OUT = 0.2V
C_OUT =
I_OUT · D_MAX
F_SW · ΔV_OUT
=
(0.1A) (0.84)
(0.8kHz) (0.1V)
= 1.05µF; use 2.2µF/25V MLC
AAT1230 Losses
I_RMS = I_PEAK ·
D_MAX
3
= 1.270
0.834
3
= 0.527A
= 527mA
1230.2006.03.1.0
17