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Constant Current Configuration #2: (PI3740-00-EVAL1 Board)
High Side Current Sense Using R
SENSE
For customers who prefer high-side current sense, this configuration senses the current through R
SENSE
and uses the internal Imon amplifier and the LGH pin of the PI3740. The LGH pin is the inverting
input to an amplifier which has a 0.1V reference. Including R
SENSE
, only 4 components are required
for the current control loop.
V
OUT
minimum is 8V due to the common mode range of the IMON
amplifier. This configuration cannot be used for super cap charging
.
Install jumpers as shown.
Install: JISP, JISN connecting RSENSE to IS+ and IS-, J200 connecting IMON to LGH, JTRK.
Charging Current:
The LGH amplifier has a reference of 100mv nominally. The Imon amplifier has a
gain of 20. So the voltage across R
SENSE
will be 5mv when the circuit is active. Therefore, the current will
be approximately 5mv/R
SENSE
.
Figure 4
Jumper Placement for
Constant Current Operation
Configuration #2 (EVAL1)