EVAL-ADP2311 User Guide
UG-653
USING THE EVALUATION BOARD
POWERING UP THE EVALUATION BOARD
The
ADP2311
evaluation board is supplied fully assembled and
tested. Before applying power to the evaluation board, follow the
procedures in this section.
Jumper J20 Setting (Enable)
Jumper J20 is used to control the
ADP2311
. Use one of the
following methods to enable or to disable the device:
•
To enable the
ADP2311
, short the middle pin of J20 (EN)
to high.
•
To disable the
ADP2311
, short the middle pin of J20 (EN)
to low.
Input Power Source
If the input power source includes a current meter, use that meter
to monitor the input current. Connect the positive terminal of
the power source to J4 (VIN) of the evaluation board, and
connect the negative terminal of the power source to J6 (GND) of
the evaluation board.
If the power source does not include a current meter, connect a
current meter in series with the input source voltage. Connect the
positive lead (+) of the power source to the positive (+) ammeter
terminal, the negative lead (−) of the power source to J6 (GND),
and the negative lead (−) of the ammeter to J4 (VIN).
Output Load
Before connecting the load, ensure that the board is turned off.
Connect an electronic load or resistor to set the load current.
To connect a load to the output of Channel 1, connect the
positive terminal of the load to J5 (VOUT1) of the evaluation
board and connect the negative terminal of the load to J7 (GND).
To connect a load to the output of Channel 2, connect the
positive terminal of the load to J12 (VOUT2) of the evaluation
board and connect the negative terminal of the load to J13 (GND).
Input and Output Voltmeter
Measure the input and output voltages using voltmeters. Make
sure that the voltmeters are connected to the appropriate terminals
of the evaluation board and not to the load or power source. If
the voltmeters are not connected directly to the evaluation
board, the measured voltages are incorrect due to the voltage drop
across the leads and/or connections between the evaluation
board, the power source, and/or the load.
To measure the input voltage, connect the positive terminal of
the voltmeter to J1 (VIN_S) and the negative terminal to J9
(GND_S). Likewise, to measure the output voltage, connect the
positive terminal of the voltmeter to J3 (VOUT1_S) or
J11 (VOUT2_S) and the negative terminal to J8 (GND1_S) or
J14 (GND2_S).
Turning On the Evaluation Board
When the power source and load are connected to the evaluation
board, it can be powered for operation.
To turn on the evaluation board, perform the following steps:
1.
Ensure that the power source voltage is >4.5 V and <18 V.
2.
Ensure that EN is high and monitor the output voltage.
3.
Turn on the load, check that it is drawing the proper load
current, and verify that the output voltage maintains its
regulation.
MEASURING EVALUATION BOARD PERFORMANCE
Measuring the Switching Waveform
To observe the switching waveform with an oscilloscope, place the
oscilloscope probe tip at Test Point J2 (SW1) and J10 (SW2) with
the probe ground at GND. Set the scope to dc with the appropriate
voltage and time divisions. The switching waveform must alternate
approximately between 0 V and the input voltage.
Measuring Load Regulation
Load regulation can be tested by observing the change in the
output voltage with increasing output load current.
Measuring Line Regulation
Vary the input voltage and examine the change in the output
voltage with a fixed output current.
Line Transient Response
Generate a step input voltage change and observe the behavior
of the output voltage using an oscilloscope.
Load Transient Response
Generate a load current transient at the output and observe the
output voltage response using an oscilloscope. Attach the current
probe to the wire between the output and the load to capture
the current transient waveform.
Measuring Efficiency
The efficiency, η, is measured by comparing the input power with
the output power.
IN
IN
OUT
OUT
I
V
I
V
η
×
×
=
Measure the input and output voltages as close as possible to the
input and output capacitors to reduce the effect of voltage drop.
Measuring Inductor Current
The inductor current can be measured by removing one end of
the inductor from its pad and by connecting a current loop in
series. A current probe can be connected onto this wire.
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