Linear Technology DC1771A Demo Manual page 3

RAIL TRACKING
Demonstration circuit 1771A is configured for an onboard
soft-start circuit. The soft-start ramp rate can be adjusted
by changing the value of C24. Demonstration circuit 1771A
Table 2. Output Tracking Options
CONFIGURATION
Soft-Start Without Tracking (Default)
VOUT Equals External Ramp
VOUT Tracking Scaled External Ramp
Figure 2. Measuring Input or Output Ripple Across Terminals or Directly Across Bulk Capacitor
can also be modified to track an external reference. Refer
to Table 1 for tracking options and to the data sheet for
more details.
TRK/SS RESISTORS AND CAPACITOR
R32 R35
0Ω Open
0Ω Open
Resistor Divider
90
80
70
60
50
40
30
20
10
0 3 6
9
LOAD CURRENT (A)
Figure 3. Measured Efficiency
DEMO MANUAL DC1771A
RAIL TRACKING
C24 TRK/SS PIN
0.1μF OPEN
Open External Reference Applied
Open External Reference Applied
V = 12V
IN
V = 1.5V
OUT
f = 400kHz
SW
CCM
BURST
P . S.
12 15
dc1771af
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