Datasheet

LTC4253B
29
4253bf
applicaTions inForMaTion
Figure 13. Current Limit Behavior (All Waveforms Are Referenced to V
EE
)
(13a) Analog Current Limit Fault (13b) Fast Current Limit Fault
Figure 14. Soft-Start Timing (All Waveforms Are Referenced to V
EE
)
(14a) Without External C
SS
(14b) With External C
SS
1 212 34
TIMER
GATE
SENSE
V
OUT
SS
DRAIN
PWRGD1
TIMER
GATE
SENSE
V
OUT
DRAIN
PWRGD1
4253b F13
CB TIMES-OUT
V
TMRH
V
ACL
V
CB
V
ACL
V
FCL
V
CB
5µA
200µA + 8 • I
DRN
200µA + 8 • I
DRN
V
DRNCL
V
TMRH
12 34 5 6 7 7a 8 9 10 11
END OF INITIAL TIMING CYCLE
12 3 4 5 6 7 8 9 10 11
END OF INITIAL TIMING CYCLE
4253b F14
TIMER
GATE
SENSE
SS
DRAIN
PWRGD1
V
TMRH
V
ACL
V
CB
V
TMRL
V
TMRH
V
TMRL
V
GS(th)
V
GS(th)
20 • (V
ACL
+ V
OS
)
20 • (V
CB
+ V
OS
)
20 • V
OS
5µA
50µA
50µA
50µA
V
DRNCL
V
DRNL
V
IN
– V
GATEH
200µA + 8 • I
DRN
TIMER
GATE
SENSE
SS
DRAIN
PWRGD1
V
ACL
V
CB
20 • (V
ACL
+ V
OS
)
20 • (V
CB
+ V
OS
)
20 • V
OS
5µA
50µA
50µA
50µA
V
DRNCL
V
DRNL
V
IN
– V
GATEH
200µA + 8 • I
DRN