ltc3862gn-1 Linear Technology Corporation, ltc3862gn-1 Datasheet - Page 32

• Manufacturer Part Number: ltc3862gn-1
• Description: Multi-phase Current Mode Step-up Dc/dc Controller
• Manufacturer: Linear Technology Corporation

LTC3862-1
APPLICATIONS INFORMATION
4. A ripple current of 40% is chosen so the peak current
32
in each inductor is:
I
IN(PK)
1.5nF
Figure 25b. Output Current vs Input Voltage
2.5
2.0
1.5
1.0
0.5
0
100pF
45.3k
45.3k
0.1μF
0
=
=
V
OUT
n
2
1
1
• 1–
• 1+
5.62k
Figure 25a. A 8.5V to 36V Input, 72V/2A Output 2-Phase Boost Converter Application Circuit
324k
10
INPUT VOLTAGE (V)
2
0.4
2
20
•
D
SLOPE
BLANK
PHASEMODE
FREQ
SS
ITH
FB
SGND
CLKOUT
SYNC
PLLFLTR
MAX
1– D
•
I
O(MAX)
1– 0.669
LTC3862-1
1.5A
MAX
30
SENSE1
SENSE1
SENSE2
SENSE2
INTV
38621 F25b
GATE1
GATE2
PGND
RUN
3V8
= 2.7A
V
CC
IN
40
+
–
–
+
24.9k
4.7μF
1nF
1μF
10nF
10nF
150k
8.5V TO 36V
V
IN
5. The inductor ripple current is:
6. The inductor value is therefore:
7. For a current limit value 30% higher than the maximum
6.8μF 50V
load current:
The saturation current rating of the inductors must
therefore exceed:
10Ω
PA2050-583
PA2050-583
I
10Ω
L =
I
ΔI
O(CL)
L(SAT)
58μH
58μH
6.8μF 50V
6.8μF 50V
= 59.5µH
L1
L2
L
V
=
ΔI
IN(MIN)
= 1.3 • I
χ
n
L
=
•
• f
n
1
2
1
1– D
I
• 1+
• 1+
MURS320T3H
MURS320T3H
O(MAX)
Q1
HAT2267H
0.020Ω
1W
0.020Ω
1W
Q2
HAT2267H
• D
O(MAX)
MAX
D1
D2
MAX
2
0.4
100V
100V
47μF
47μF
2
=
=
•
= 1.3 • 1.5A = 1.95A
+
+
0.4
0.9A • 300kHz
1.3 •I
2
•
2.2μF
1– D
100V
1.3 • 1.5A
1– 0.669
×6
•
1– 0.669
24V
O(MAX)
38621 F25a
MAX
1.5A
= 3.5A
V
72V
2A (MAX)
OUT
= 0.9A
• 0.669
38621f