Picor Corporation • picorpower.com
PI2161-EVAL1 User Guide Rev. 1.0 Page
5 of 8
3.
Control Circuitry Bias:
As described in the Functional Description section in
PI2161 datasheet; in a floating application it is
required to place low side bias resistor R
PG
(
R3
)
between the PG pin and system ground. R
PG
creates
an offset voltage at the PG pin to regulate VC with
respect to PG when the MOSFET is enabled.
The R
PG
resistor can be calculated using the following
expression:
Please refer to application section in the PI2161
datasheet for more details.
4.
Enabling PI2161
: PI2161-EVAL1 is set with two
enabling options.
4.1.
Mechanical switch (SW1) option
. Moving SW1
knob to On position to enable (turn on MOSFET
if conditions are met) PI2161, or moving SW1
knob to Off position to disable (turn off
MOSFET) PI2161.
4.2.
Logic input terminal (EN) option
: to use this
option slide WS1 knob to Off position. Apply
logic high voltage (>2V) to enable PI2161 and
logic low (<1V) to disable PI2161.
5.
Hook Up of the Evaluation Board
5.1.
Connect the positive terminal of PS1 power
supply to Vin+. Connect the ground terminal of
PS1 to Vin-. Set the power supply to 48V.
Keep
PS1 output disabled, off.
5.2.
Connect the electronic load to the output
between Vout+ and Vout-. Set the load current
to 5A
5.3.
Position SW1 knob to On
5.4.
Enable (turn on) PS1 power supply output.
5.5.
Turn on the electronic load
5.6.
Verify that the load voltage (Vout) is few
millivolts below 48V. This verifies that the
PI2161 MOSFET is in conduction mode.
5.7.
Measure VO with respect to Vin-, it should be
10% of Vout, 4.5V.
5.8.
Slide SW1 to Off position to disable the output.
5.9.
Verify that the load voltage (Vout) is off, about
0V. This verifies that the M1 MOSFET is turned
off. VO voltage should be at 0V.
6.
Over current trip point:
PI2161 has a very fast response (120ns) to over current
fault condition. Measuring a fast disconnect after high
current buildup requires attention to the test set-up. Before
proceeding, consider the following:
6.1.
To emulate a real application, the BUS supply for
this test should have a solid output source such
as a DC-DC converter that supply’s high current
and can be connected very close to the
evaluation board. This will reduce stray parasitic
inductance. Or use the prospective supply
sources of the end application where the PI2161
will be used. Typical bench power supplies have
slow response to output load change. In this test
when the output load is shorted, a high pulse of
Figure 4
:
Layout configuration for a typical Load Disconnect Switch application test using PI2161.
