LTC3788-1 Datasheet, PDF (25/28 Pages) Linear Technology – 2-Phase, Dual Output Synchronous Boost Controller

LTC3788-1
APPLICATIONS INFORMATION
for inductive coupling between C_IN, Schottky and the top
MOSFET components to the sensitive current and voltage
sensing traces. In addition, investigate common ground
path voltage pickup between these components and the
SGND pin of the IC.
An embarrassing problem, which can be missed in an
otherwise properly working switching regulator results
when the current sensing leads are hooked up backwards.
The output voltage under this improper hook-up will still
be maintained, but the advantages of current mode control
will not be realized. Compensation of the voltage loop will
be much more sensitive to component selection. This
behavior can be investigated by temporarily shorting out
the current sensing resistor—don’t worry, the regulator
will still maintain control of the output voltage.
R_B1
232k
1%
R_A1
12.1k, 1%
C_ITH1, 220pF
C_ITH1, 15nF
R_ITH1
8.66k
C_SS1, 0.1μF
C_SS2, 0.1μF
C_ITH2, 15nF
R_ITH2
2.7k
C_ITHA2, 100pF
R_A2
12.1k
R_B2
110k
SENSE1^–
SENSE1⁺ PGOOD1
VFB1
TG1
SW1
BOOST1
LTC3788-1
ITH1
BG1
100k
INTV_CC
C_B1, 0.1μF
D1
SS1
VBIAS
INTV_CC
PLLIN/MODE
SGND
EXTV_CC
RUN1
RUN2
FREQ
PGND
BG2
BOOST2
C_INT
4.7μF
D2
C_B1, 0.1μF
SS2
SW2
ITH2
TG2
VFB2
SENSE2⁺
SENSE2^–
MTOP1
L1
3.3μH
R_SENSE1
4mΩ
C_OUTA1 ⁺
22μF
s4
V_OUT1
24V, 5A
C_OUTB1
220μF
MBOT1
MBOT2
V_IN
5V TO 24V
C_INA ⁺ C_INB
22μF
220μF
s4
L2
R_SENSE2
1.25μH _3mΩ
MTOP2
C_OUTA2 ⁺
22μF
s4
V_OUT2
12V, 10A
C_OUTB2
220μF
C_INA, C_OUTA1, C_OUTA2: SANYO, 50CE220AX
C_INB, C_OUTB1, C_OUTB2: TDK C4532X5R1E226M
L1: PULSE PA1494.362NL
L2: PULSE PA1294.132NL
MBOT1, MBOT2, MTOP1, MTOP2: RENESAS HAT2169H
37881 F09
Figure 9. High Efficiency Dual 12V/24V Boost Converter
37881f
25