Teledyne LeCroy PCIBX64-X - Manual (Page 5)

3
CURRENT MEASUREMENT
Measurement may be taken using software commands or external voltmeter.
Voltmeter: To measure the current being drawn by the Unit-Under-Test, just connect a voltmeter to J3. Every Volt read by
the meter represents one Amp. So if the voltmeter reads 0.35, it represents that the Unit -Under-Test is drawing 350
milliampere of current. J3 terminals are marked for Ground, +5I, +3.3I and +12I.
NOTE: If the VIO and +5V are on the same plane on your board, you need to remove JP10 jumper, located on the extender
board, in order to get an accurate current measurement for the +5V.
Software: The voltage and current to the UUT may also be measured by software, please see instructions in the
"Programming Guide".
CURRENT LIMIT CIRCUITRY
Red LEDs, when illuminated, indicate a short or a very low voltage. Green LEDs when illuminated, indicate voltages at their
corresponding outputs. +5V, +12V, +3.3Vare electronically protected. +VIO and -12V are protected by resetable fuses.
INCREASE CURRENT LIMIT
1- To increase the +5V current limit remove the resistor at location R23 and follow the steps below.
A: To change the current limit to 8 Amps install a 10K resistor at location R22 and 6.2K resistor at location R23.
B: To change the current limit to 10 Amps install a 10K resistor at location R22 and 10K resistor at location R23.
2- To increase the +3.3V current limit the system must be supplying the +3.3V and not the on board regulator.
A: To change the current limit to 8 Amps install a 4.7K resistor on top of existing R57.