PI2007-EVAL1 Datasheet, PDF (6/10 Pages) Vicor Corporation – PI2007-EVAL1 48V Bus High Side Active ORing

Before initial power-up follow these steps to configure
the evaluation board for specific end application
requirements:
2. EN inputs:
2.1. The enable inputs (EN1 and EN2) were left
unconnected (open). PI2007 devices will be
enabled when the enable pins are open. To
disable the PI2007, connect the enable input to
return (Rtn) with a wire or with an active device
(Transistor or MOSFET). Leave EN1 and EN2
unconnected for the initial test.
3. Control Circuitry Bias:
3.1. The PI2007 control circuitry and the gate driver
for the MOSFET are biased through the VC pin.
An internal regulator clamps VC pin voltage
with respect to the PG pin (VC-PG), to 11.7V
typically. A bias resistor R_PG (R1 and R2) or a
Constant Current bias circuit is required if the
voltage at the VC pin is higher than the
minimum Voltage Clamp (V_VC-CLM, 11V). PI2007-
EVAL1 has both circuits laid out. The constant
current bias circuit components are installed
while R_PG is not installed.
3.2. If R_PG is desired instead of the constant current
bias circuit to save components: remove the
constant current bias circuit components from
the evaluation board. The constant current
bias circuit components for upper ORing (U1)
are Q7, R5, R7 and D7, the constant current
bias circuit components for lower ORing (U2)
are Q8, R6, R8 and D8. The R_PG value can be
selected using the following equations:
And R_PG maximum power dissipation is:
Where:
:
:
VC pin minimum applied voltage (Vin to
Rtn)
VC pin maximum applied voltage (Vin to
Rtn)
: Controller maximum clamp voltage,
12.5V
: Controller minimum clamp voltage, 11V
:
Controller maximum bias current, use
2.0mA
:
0.1mA is added for margin
R_PG calculation example
Vin (minimum) = 40V and Vin (maximum) = 50V
4. Hook Up of the Evaluation Board
4.1. Connect the positive terminal of PS1 power
supply to Vin1. Connect the ground terminal of
PS1 to its local Rtn. Set the power supply to 48V.
Keep PS1 output disabled, off.
4.2. Connect the positive terminal of PS2 power
supply to Vin2. Connect the ground terminal of
PS2 to its local Rtn. Set the power supply to 48V.
Keep PS2 output disabled, off.
4.3. Connect the logic power supply PS3 positive
terminal to VL1 and VL2. Connect the ground
terminal of this power supply to a Rtn terminal.
Set the power supply to the desired logic voltage
level, 3.3V or 5V. Keep PS3 output disabled, off.
4.4. Connect the electronic load to the output
between Vout and its local Rtn. Set the load
current to 5A.
4.5. Enable (turn on) PS1 power supply output.
4.6. Enable (turn on) PS3 power supply output.
4.7. Turn on the electronic load.
4.8. Verify that the electronic load voltage reading
increases to a few millivolts below 48V. This
verifies that the MOSFET Q1 is in conduction
mode.
Picor Corporation • picorpower.com
PI2007-EVAL1 User Guide Rev. 1.1 Page 6 of 10