PI2003 View Datasheet(PDF) - Vicor
Part Name
Description
MFG CO.
'PI2003' PDF : 16 Pages View PDF
Typical application Example 1:
Requirement:
Redundant Bus Voltage = -48V (-36V to -60V, 100V
for 100ms transient)
Load Current = 5A load (assume through each
redundant path)
Maximum Ambient Temperature = 60°C
Solution:
A single PI2003 with a suitable MOSFET for each
redundant -48V power source should be used and
configured as shown in figure 13. The VC is biased
from the return line through a bias resistor.
Select a suitable N-Channel MOSFET: Select the
N-Channel MOSFET with voltage rating higher than
the input voltage, Vin, plus any expected transient
voltages, with a low Rds(on) that is capable of
supporting the full load current with margin. For
instance, a 100V rated MOSFET with 10A current
capability is suitable. An exemplary MOSFET
having these characteristic is Si4486EY from Vishay
Siliconix.
From Si4486EY datasheet:
• N-Channel MOSFET
• VDS= 100V
• ID = 23A continuous drain current at 125°C
• VGS(MAX) = ± 20V
• RθJA= 50°C/W
• RDS(on)=20mΩ typical at VGS=10V, TJ=25°C
Reverse current threshold is:
Is.reverse = Vth.reverse = − 6mV = −300mA
Rds(on) 20mΩ
Power dissipation:
Rds(on) is 25mΩ maximum at 25°C and will
increase as the temperature increases. Add 40°C to
maximum ambient temperature to compensate for
the temperature rise due to power dissipation. At
100°C (60°C + 40°C) Rds(on) will increase by 63%.
Rds(on) = 25mΩ∗1.63 = 41mΩ maximum at 100°C
Maximum Junction temperature
TJ
max
=
60°C
+
⎜⎛
⎝
50°C
W
∗
(5.0
A)2
∗
41mΩ⎟⎞
⎠
=
111°C
Recalculate based on calculated Junction
temperature, 115°C.
At 115°C Rds(on) will increase by 72%.
Rds(on) = 25mΩ∗1.72 = 43mΩ maximum at 115°C
TJ
max
=
60°C
+
⎜⎛
⎝
50°C
W
∗
(5.0
A)2
∗
43mΩ⎟⎞
⎠
=
113°C
FT pin: Connect the FT pin to to the logic power
supply or to the VC pin via a resistor (RFT). Make
RFT large (120KΩ) to lower FT sink current.
I FT −Sink
= VC
R FT
= 11.0V = 92μA
120KΩ
VC: Connect each controller to the return path with
a separate bias resistor, Rbias.
Rbias = Vbusmin − VCclampMax
ICmax + I FT −Sink
Rbias = 36V − 12V = 11.47KΩ , or 11.5KΩ,
2.0mA + 0.092mA
1%
Rbias maximum power dissipation is at maximum
input voltage and minimum clamp voltage.
Pd Rbias
= (Vbusmax − VCclampMIN ) 2
Rbias
= (60V − 12V )2
11.5KΩ
= 200mW
Figure 13: PI2003 in low side -48V application.
Picor Corporation • picorpower.com
PI2003
Rev 1.0
Page 12 of 16
Share Link: 
