Datasheet

14
LTC4210-1/LTC4210-2
421012f
Autoretry After Current Fault (LTC4210-1)
Figure 8 shows the waveforms of the LTC4210-1 (autoretry
version) during a circuit breaker fault. At time point B1, the
TIMER trips the COMP2 threshold of 1.3V. The GATE pin
pulls to ground while TIMER begins a “cool-off” cycle with
a 2µA pull-down to the COMP1 threshold of 0.2V. At time
point C1, the TIMER pin pulls down with approximately a
7k resistor to ground and a GATE start-up cycle is initiated.
If the fault persists, the fault autoretry duty cycle is
approximately 3.8%. Pulling the ON pin low for more than
30µs will stop the autoretry function and put the LTC4210
in reset mode.
Latch-Off After Current Fault (LTC4210-2)
Figure 9 shows the waveforms of the LTC4210-2 (latch-off
version) during a circuit breaker fault. At time point B, the
TIMER trips the COMP2 threshold. The GATE pin pulls to
ground while the TIMER pin is latched high by a 5µA pull-
up. The TIMER pin eventually reaches the soft-clamped
voltage (V
CLAMP
) of 2.3V. To clear the latchoff mode, the
user can either pull the TIMER pin to below 0.2V externally
or cycle the ON pin low for more than 30µs.
APPLICATIO S I FOR ATIO
WUUU
Figure 8. Automatic Retry After Overcurrent Fault
A1
V
TIMER
V
GATE
V
OUT
I
LOAD
4210 F08
B1 C1 A2 B2
COMP2
COMP1
CB
FAULT
CB
FAULT
NORMAL
MODE
COOL OFF
CYCLE
COOL OFF
CYCLE
60µA
100µA
2µA
2µA
60µA
REGULATING AT 50mV/R
SENSE
NORMAL
MODE
LATCHED OFF CYCLE
CB
FAULT
60µA
V
TIMER
V
GATE
V
OUT
I
LOAD
AB C
V
CLAMP
COMP2
COMP1
0V
0V
2410 F09
REGULATING AT 50mV/R
SENSE
Figure 9. Latchoff After Overcurrent Fault