PI2061 Datasheet, PDF (10/16 Pages) Vicor Corporation – High Side High Voltage Load Disconnect Switch Controller IC

Not Recommended for New Designs
Schottky Diodes Selection: D1 and D2
Diode D1 (See Figure 1 & Figure 14.) must be a low reverse
leakage Schottky diode capable of supporting 4A of peak
gate discharge current for 10ns. Diode D2 must be a low
reverse leakage Schottky diode capable of supporting 1A
peak. Both diodes will have a reverse voltage of 13V
during normal operation.
Recommended diode for D1 and D2: PMEG4005EJ from
NXP
Sense Resistor Selection: Rs
In typical load switch application the sense resistor is
based on minimum trip current to allow maximum normal
load current without interruption. Calculate Rs value at
minimum Low Range Overcurrent Threshold voltage
(V_OC-THL):
Where:
:
: Minimum Low Range Overcurrent
Threshold voltage, 63mV
Required minimum trip current
Enable Input Circuit: EN
EN pin can be tied directly to VC OR LEFT FLOATING if
PI2061 should be enabled when the power is applied. If
the user wants to control the device enable function, then
EN pin can be pulled low with a resistor and signal FET,
signal transistor or open collector logic as shown in Figure
12. Note that the enable control signal phase must be
inverted.
Use an enable resistor (R_EN) value between 300k and
400k with voltage rating that meets maximum input
voltage.
Vin
RS
Vout
RVC
26
7
GATE SP SN
VC ³ VC
5 _{EN PI2061}
REN
4 _SGND
EN
QEN
RTN
Figure 12: Enable circuit
PGND
1
RPG
D2 D1

Fault Indication: FT
FT is an open collector output and its return is referenced
to SGND. When the SGND pin is floating on a bias resistor
(R_PG) or in a constant current circuit, a level shift circuit can
be added to create an output referenced to the system
ground. See Figure 13.
Vin
RS
Vout
RVC
26
7
VC
GATE SP
SN
3 _VC
5 _EN
PI2061
FT
4 _SGND
PGND
1
RPG
RTN
Figure 13: FT level shift circuit
VC
D2 D1
100k
Q1
100k
100k
FT
Q2
15k
Alternative Bias Circuit: Constant current circuit for high
voltage application.
In a wide operating input voltage range the size of R_VC and
R_PG may be become large to support power dissipation. A
simple constant current circuit, shown in Figure 14 can be
used instead of R_VC and R_PG to allow the circuit to operate
between 18V and 80V (100V/100ms transient) with low
power dissipation components. Please refer to Picor
application notes for more details on how to design a
floating bias with the constant current circuit.
IRF7853PbF
10m
Vin
50k
M1
RS
Q1
1k ^{FJV1845 2 6}
7
6.8V _2k
GATE SP SN
3 _VC
CVC ^{5 EN PI2061}
1µF
4 _{SGND PGND}
50k
1
Q2
FJV1845
6.8V
2.6k
RTN
Figure 14: Constant current bias circuit
Vout
D1 D2
Picor Corporation • picorpower.com
PI2061
Rev 1.4
Page 10 of 16