LTC4253 LINER [Linear Technology], LTC4253 Datasheet - Page 31

• Manufacturer Part Number: LTC4253
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
Power Limit Circuit Breaker
Figure 16 shows the LTC4253A in a power limit circuit
breaking application. The SENSE pin is modulated by board
voltage V
same as the lowest operating voltage, V
If the goal is to have the high supply operating voltage,
V
V
SUPPLY(MAX)
SUPPLY(MIN)
R4
R3
RESET
(LONG PIN)
– 48V RTN
(LONG PIN)
– 48V RTN
(SHORT PIN)
– 48V
(LONG PIN)
=
V
SUPPLY
30.1k
SUPPLY(MAX)
392k
1%
1%
R2
R1
, then resistors R3 and R4 are selected by:
= 71V give the same power as available at
V
CB
. The D1 Zener voltage, V
C1
10nF
0.1μF
C
C
SS
SQ
33nF
15k(1/4W)/6
C
0.68μF
DDZ13B*
OV
UV
RESET
SS
SQTIMER
TIMER
T
D
2.5k
R
LTC4253A
IN
IN
††
V
V
IN
EE
PWRGD1
PWRGD2
PWRGD3
SENSE
DRAIN
GATE
BZV85C43
Figure 16. Power Limit Circuit Breaker Application
EN3
EN2
SUPPLY(MIN)
1μF
C
Z
IN
V
IN
D1
, is set to be the
R3
31.6k
10nF
R4
22
C
C
= 43V.
R5
5.6k
R
D
(16)
1M
R
10Ω
C
†
Q1
IRF530S
R
0.02Ω
S
If R4 is 22Ω, then R3 is 31.6k. The peak circuit breaker
power limit is:
when V
R6
5.6k
POWER(MAX) =
EN2
†
SUPPLY
V
†
IN
R7
5.6k
100μF
C2
†
= 0.5 • (V
= 57V
= 1.064 • POWER AT V
+
•POWER AT V
R8
LTC4253/LTC4253A
(
4 • V
0.1μF
V
SUPPLY(MIN)
C3
POWER
MODULE 1
OUTPUT
SUPPLY(MIN)
SUPPLY(MIN)
EN3
MODULE 1
EN
POWER
*DIODES, INC.
†
††
MOC207
RECOMMENDED FOR HARSH ENVIRONMENTS.
SUPPLY(MIN)
+ V
• V
SUPPLY(MAX)
+ V
V
†
IN
SUPPLY(MAX)
SUPPLY(MIN)
MODULE 2
EN
MODULE 2
SUPPLY(MAX)
OUTPUT
POWER
POWER
R9
4253 F16
)
2
31
MODULE 3
EN
425353afe
POWER
)
(17)