Datasheet

11
LTC1473
APPLICATIONS INFORMATION
WUU
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V
GG
Regulator Inductor and Capacitors
The V
GG
regulator provides a power supply voltage 8.5V
higher than any of the three main power source voltages
to allow the control of N-channel MOSFET switches. This
micropower, step-up voltage regulator is powered by the
highest potential available from the three main power
sources for maximum regulator efficiency.
BAT1 BAT2DCIN
V
GG
SWITCHING
REGULATOR
V
+
SW
GND
1473 F05
V
GG
L1*
1mH
C1
1µF
50V
C2
1µF
50V
TO GATE
DRIVERS
(8.5V + V
+
)
LTC1473
*COILCRAFT 1812LS-105 XKBC. [phone]
Figure 5. V
GG
Step-Up Switching Regulator
Three external components are required by the V
GG
regu-
lator: L1, C1 and C2, as shown in Figure 5.
L1 is a small, low current, 1mH surface mount inductor. C1
provides filtering at the top of the 1mH switched inductor
and should be at least 1µF to filter switching transients.
The V
GG
output capacitor, C2, provides storage and filter-
ing for the V
GG
output and should be at least 1µF and rated
for 50V operation. C1 and C2 can be ceramic capacitors.