ADM4210 Analog Devices, ADM4210 Datasheet - Page 13

• Manufacturer Part Number: ADM4210
• Description: Low Voltage Hot Swap Controller in 6-pin TSOT Package
• Manufacturer: Analog Devices

Specifications of ADM4210

• Vin Min (v): 2.7V
• Vin Max (v): 16.5V
• Uv & Ov Detection: ON pin (UV)
• I Monitor Accuracy (+/-%): n/a
• Package: 6-ld TSOT

CIRCUIT BREAKER TIMING CYCLE
When the voltage across the sense resistor exceeds the circuit
breaker trip voltage, the 60 μA timer pull-up current is activated.
If the sense voltage falls below this level before the TIMER pin
reaches 1.3 V, the 60 μA pull-up is disabled and the 2 μA pull-
down is enabled. This is likely to happen if the overcurrent fault
is only transient, such as an inrush current. This is shown in
Figure 31. However, if the overcurrent condition is continuous
and the sense voltage remains above the circuit breaker trip
voltage, the 60 μA pull-up remains active. This allows the TIMER
pin to reach the high trip point of 1.3 V and initiate the GATE
shutdown. On the ADM4210-2, the TIMER pin continues pulling
up but switches to the 5 μA pull-up when it reaches the 1.3 V
threshold. The device can be reset by toggling the ON- CLR pin
or by manually pulling the TIMER pin low. On the ADM4210-1,
the TIMER pin activates the 2 μA pull-down once the 1.3 V
threshold is reached, and continues to pull down until it reaches
the 0.2 V threshold. At this point, the 100 μA pull-down is
activated and the GATE pin is enabled. The device keeps
retrying in the manner as shown in Figure 32.
The duty cycle of this automatic retry cycle is set to the ratio of
2 μA/60 μA, which approximates 3.8% on. The value of the
timer capacitor determines the on time of this cycle. This time
is calculated as follows:
t
t
Figure 32. ADM4210-1 Automatic Retry During Overcurrent Fault
ON
OFF
I
= 1.3 × C
V
RSENSE
= 1.1 × C
V
GSFET
TIMER
V
OUT
TIMER
TIMER
COMP2
/60 μA
SHORT-
CIRCUIT
EVENT
/2 μA
60µA
CYCLE
FAULT
100µA
2µA
COMP1
CYCLE
FAULT
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AUTOMATIC RETRY OR LATCHED OFF
The ADM4210 is available in two models. The ADM4210-1
has an automatic retry system whereby when a current fault is
detected, the FET is shut down after a time determined by the
timer capacitor, and it is switched on again in a controlled con-
tinuous cycle to determine if the fault remains (see Figure 32
for details). The period of this cycle is determined by the timer
capacitor at a duty cycle of 3.8% on and 96.2% off.
The ADM4210-2 model has a latch off system whereby when a
current fault is detected, the GATE is switched off after a time
determined by the timer capacitor (see Figure 33 for details).
Toggling the ON- CLR pin, or pulling the TIMER pin to GND
for a brief period, resets this condition.
I
RSENSE
V
V
Figure 33. ADM4210-2 Latch Off After Overcurrent Fault
GSFET
TIMER
V
OUT
COMP2
5µA
SHORT-
CIRCUIT
EVENT
60µA
COMP1
ADM4210