MIC2145_05 Datasheet, PDF (9/15 Pages) Micrel Semiconductor – High Efficiency 2.5W Boost Converter

MIC2145
Bootstrap
A bootstrapped configuration is recommended for applica-
tions that require high efficiency at heavy loads (>70mA).
This is achieved by connecting the V_DD pin to V_OUT (see
Micrel, Inc.
Figure 7). For applications that require high efficiency at light
loads (<70mA), the V_DD pin is connected to the input voltage
(V_IN); this is referred to as the basic configuration (see Figure
6).
V_IN
3.6V
C1
10µF/6.3V
Murata
GRM42-6 X5R 106K 6.3
R1 R2
100k 10k
L1
10µH
Sumida
CR43-100
VDD
SW
EN
PGND
MIC2145
RSET
FB
SS
C2
0.01µF
SGND
D1
On Semiconductor
MBR0530T1
R4
1M
C3
100pF
R3
274k
Figure 6. Basic Configuration
V_OUT
5V/250mA
C4
10µF/6.3V
Murata
GRM42-6 X5R 106K 6.3
V_IN
3.6V
C1
10µF/6.3V
Murata
GRM42-6 X5R 106K 6.3
R2
10k
L1
10µH
Sumida
CR43-100
PGND
SW
D1
On Semiconductor
MBR0530T1
SGND
VDD
MIC2145
RSET
SS
EN
R1
FB ^100k
C2
0.01µF
C3
100pF
R4
1M
R3
274k
Figure 7. Bootstrap Configuration
V_OUT
5V/350mA
C4
10µF/6.3V
Murata
GRM42-6 X5R 106K 6.3
April 2005
9
M9999-042205