PI2007 Datasheet, PDF (13/19 Pages) Vicor Corporation – Universal High Side Active ORing Controller IC

Typical application Example 1:
Requirement:
Redundant Bus Voltage = 12V (±10%, 10.8V to
13.2V)
Load Current = 15A (assume through each redundant
path)
Maximum Ambient Temperature = 75°C
Solution:
A single PI2007 with a suitable external MOSFET for
each redundant 12V power source should be used,
configured as shown in the circuit schematic in Figure
16.
Select a suitable N-Channel MOSFET: Most
industry standard MOSFETs have a Vgs rating of +/-
12V or higher. Select an N-Channel MOSFET with a
low R_DS(on) which is capable of supporting the full load
current with some margin, so a MOSFET capable of
at least 18A in steady state is reasonable. An
exemplary MOSFET having these characteristic is the
FDS6162N7 from Fairchild.
From FDS6162N7 datasheet:
 N-Channel MOSFET
 V_DS= 20V
 I_D = 23A continuous drain current
 I_D(Pulse) = 60A Pulsed drain current
 VGS(MAX)= 12V
 R_θJA= 40°C/W when mounted on a 1in² PCB
pad of 2 oz copper
 R_DS(on)=2.9mΩ typical and 3.5mΩ maximum at
I_D=23A, V_GS≥4.5V, T_J=25°C
Reverse current threshold is:
Is.reverse  ^Vth.reverse  ^{ 6mV}  2.07 A
Rds(on) 2.9m
Power dissipation:
R_DS(on) is 3.5mΩ maximum at 25°C & 4.5Vgs and will
increase as the temperature increases. Add 25°C to
maximum ambient temperature to compensate for the
temperature rise due to power dissipation. At 100°C
(75°C + 25°C) R_DS(on) will increase by 28%.
R_DS(on)  3.5m 1.28  4.48m maximum at 100°C
Trise  Rth_JA  Is²  R_DS(on)
Maximum Junction temperature
T_{J max}  T_A  Trise

T_J
max

75C
 

40C
W
 (15A)²
 4.48m

 115C
Recalculate based on increased
temperature, 115°C.
At 115°C R_DS(on) will increase by 32%.
R_DS(on)  3.5m 1.32  4.62m
Junction
T_J
max

75C
 

40C
W
 (15A)²
 4.62m

 116.5C
VC Bias: Vin maximum input is 13.2V, this is higher
than the 11V VC Clamp Voltage (V_VC-SGND) minimum.
Use the high side PI2007 internal resistor between VR
pin and VC pin will fit for this application.
Since the MOSFET requires only 4.5V for full
enhancement then the PI2007 internal resistor
between VR pin and VC pin will fit for this application.
Connect VR to Vin at the source of the MOSFET and
connect a 1μF ceramic capacitor between VC pin and
SGND pin.
Fault Indication:
Connect FT pin to the logic input and to the logic
power supply via a 10KΩ resistor.
Figure 16: PI2007 in 12V bus high side Active ORing
configuration
Picor Corporation • picorpower.com
PI2007
Rev 1.3
Page 13 of 19