ISL6144 Intersil Corporation, ISL6144 Datasheet - Page 17

• Manufacturer Part Number: ISL6144
• Description: High Voltage ORing MOSFET Controller
• Manufacturer: Intersil Corporation

charge pump circuitry starts functioning as the input voltage
at the V
depends on the load current (as explained in previous
sections), The maximum gate voltage will be clamped to a
maximum of V
be handled with 20mV across the source-drain terminals.
Overall, it takes less than 1ms to reach the load-dependant
final gate voltage value. Note that the Input voltage cannot
be hot swapped and has to rise slowly. A rise time of at least
one ms is recommended for the voltage at VIN pin.
V
V
V
HV
5V/DIV
0A
IN1
0A
IN1
IN
FIGURE 19. FIRST FEED V
REF(Vz)
= 48V; RESISTIVE LOAD = 4A, C
, V
,V
IN
G1
G1
20V/DIV
5A/DIV
,I
, I
pin reaches a value around 8V. The gate voltage
IN1
V
IN1
20V/DIV
I
OUT
IN1
and HV
GQP
V
and V
G1
WHEN V
3V to 4V, GATE CHARGE PUMP ACTION STARTS
WHEN V
AND HVREF REACHES 3V TO 4V
GATE CHARGE PUMP ACTION STARTS
2A/DIV
10V/DIV
when load current becomes too high to
OUT
REF(VZ)
I
IN1
V
IN
G1
WAVEFORMS
IN
REACHES ~ 8V AND HVREF REACHES
WAVEFORMS
REACHES ~ 8V
17
IN1
V
10V/DIV
GSEXT
START-UP (48V CASE)
IN1
= 33nF
V
20V/DIV
IN1
4A
4A
ISL6144
The start-up tests were done with the addition of an external
gate to source capacitor to demonstrate start-up time with a
total equivalent gate-source capacitance around 39nF.
SECOND (CONSECUTIVE) FEED START-UP
In this case, the ISL6144 for the second (consecutive) feed
(U4) already has output bias voltage as the first parallel feed
has been turned on and V
bus. As V
with respect to GND). When V
Gate 2 is turned. Second feed gate turn-on is faster than the
first feed as the HVREF capacitor (C
charged.The second or consecutive power supply to be
started can be turned on faster than the first power supply, a
rise time of at least 200µs of the second rail is
recommended.
FIGURE 21. SECOND (CONSECUTIVE) FEED V
RELATED DELAY
V
POWER SUPPLY
SECOND GATE TURNS ON ONLY
IN
FIGURE 20. FIRST FEED V
= 48V; RESISTIVE LOAD = 4A, C
WHEN V
IN2
rises, V
V
IN2
IN
= 12V; RESISTIVE LOAD = 5A, C
REACHES V
IN THIS CASE GATE VOLTAGE IS MEASURED
G2
2A/DIV
rises with it (V
5V/DIV
OUT
I
BETWEEN GATE2 AND GND
5A/DIV
IN2
V
IN1
IN1
I
IN1
IN2
IN1
is present on the common
GS(EXT)
approaches V
START-UP (12V CASE)
20V/DIV
20V/DIV
3
V
V
) is already
G2
V
5V/DIV
G2
IN2
= 33nF
OUT
20V/DIV
is GATE2 voltage
V
OUT
GSEXT
IN2
5V/DIV
February 15, 2007
IN1
V
START-UP
G1
= 33nF
value,
FN9131.3