PI2126-EVAL1 Datasheet, PDF (5/8 Pages) Vicor Corporation – PI2126-EVAL1 30V/12A Full-Function High Side Active ORing

Before initial power-up follow these steps to configure
the evaluation board for specific end application
requirements:
2. Hook Up of the Evaluation Board
2.1. Connect the positive terminal of PS1 power
supply to Vin1+. Connect the ground terminal
of PS1 to Gnd. Set the power supply to 12V.
Keep PS1 output disabled, off.
2.2. Connect the positive terminal of PS2 power
supply to Vin2+. Connect the ground terminal
of PS2 to Gnd. Set the power supply to 12V.
Keep PS2 output disabled, off.
2.3. Connect the electronic load to the output
between Vout and Gnd. Set the load current to
5A.
2.4. Enable (turn on) PS1 power supply output.
2.5. Turn on the electronic load.
2.6. Verify that Vout+ voltage is a few millivolts
below 12V. This verifies that the PI2126 (U1)
internal MOSFET is in conduction mode.
2.7. Verify that Vin2+ is low. This verifies that the
PI2126 (U2) internal MOSFET is off.
2.8. Enable (turn on) PS2 output.
2.9. Verify that both PS1 and PS2 are sharing load
current evenly by looking at the supply current.
Power supplies output may need adjustment to
set current sharing between the supplies.
2.10. Disable (turn off) PS1, and PS2 outputs.
2.11. Enable (turn on) PS2 output.
2.12. Verify that the electronic load voltage reading is
few millivolts below 12V. This verifies that the
PI2126 (U2) internal MOSFET is in conduction
mode.
2.13. D2 should be off. This verifies that there is no
fault condition.
2.14. Verify that Vin1+ is low. This verifies that the
PI2126 (U1) internal FET is off.
Note: When the PI2126 internal MOSFET is in the on
state, it will not turn off unless a reverse current
greater than 1.1A is sensed in the MOSFET.
When both power supplies are enabled and both
PI2126 MOSFETs are in R_DS(on); if one of the sources
(Power supplies) removed or disabled both PI2126
stay on unless the disabled power supply sources
current greater than 1.1A when turned off.
3. Internal MOSFET R_DS(on) Measurement:
3.1. The internal MOSFET R_DS(on) can be measured
with a voltmeter between the S1 and D1 Kelvin
connection for U1 and between the S2 and D2
Kelvin connection for U2. The potential between
S1 and D1 is the voltage drop across the internal
MOSFET and:
Where:
:
:
Voltage drop across the internal MOSFET
Input current.
Note: The R_DS(on) value is temperature dependent and the
junction temperature increases directly
proportional to power dissipation.
4. Input short circuit test:
PI2126 has a very fast response (80ns) to a reverse current
(Input short) fault condition. Measuring a short period
event requires attention to the test set-up. Before
proceeding, consider the following:
4.1. To emulate a real application, the BUS supplies
for this test should have a solid output source
such as a DC-DC converter that supplies high
current and can be connected very close to the
evaluation board to reduce stray parasitic
inductance. Or use the prospective supply
sources of the end application where the PI2126
will be used. Typical bench power supplies have
slow response to output load change. In this test
when the power supply output is shorted and
then released, the bench power supply may
produce high output voltage with high current
capability that may damage the device under
test.
4.2. Do not install Input capacitors (C1 and/or C2) in
this test.
4.3. Output capacitor (C5) should be installed.
4.4. Place the scope probes very close to the PI2126 S
and D pins to measure Vin and Vout, and make
sure that the scope ground leads are very short.
You may use a close by ground pad for the scope
probe return, such as C1, C2, C3 and C4 return
pads.
4.5. Apply a short at one of the inputs (Vin1+ or Vin2+)
when both SiP’s (U1 and U2) are on, PS1 and PS2 are
enabled. The short can be applied electronically using
a MOSFET connected between Vin+ and Gnd or simply
by connecting Vin+ to Gnd. Then measure the
response time between when the short is applied and
the PI2126 internal MOSFET is disconnected (or
turned off). An example for the PI2126 response time
to an input short circuit is shown in Figure 4.
Picor Corporation • picorpower.com
PI2126-EVAL1 User Guide Rev. 1.0
Page 5 of 8