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Constant Voltage Operation (EVAL1)
For constant voltage operation install JLGH, JPG, JISP, JISN as shown in Figure 1. The regulated output
voltage can be adjusted by changing REA1 per the following equation.
V
FLOAT
= (1.5887*REA1) + 1.7 where REA1 is in k
Ω
. With the present values, the output
voltage is about 24V.
Note:
During constant voltage operation, short VSP to VDR to ensure the PI3740 internal amplifier does not affect
performance.
Constant Current Operation (EVAL1, EVAL2)
Constant Current mode is required for battery and super capacitor charging applications. Both EVAL1
and EVAL2 can be configured for constant current operation. EVAL1 should be the default board for
all constant current applications with the exception of high side current sense applications where V
OUT
can drop below 8V. Both evaluation boards can be configured to operate in a typical CC/CV charging
scheme where the regulator output starts out in CC mode and then transitions to CV mode as soon as
the battery voltage reached a predetermined float voltage.
Constant Current Float Voltage Adjustment
The float voltage or the voltage where the converter transitions to constant voltage mode, can be
adjusted by changing REA1 per the following equation.
Vfloat = (1.5887*REA1) + 1.7 where REA1 is in k
Ω
. The board is shipped with REA1 = 14k
Ω
which
sets the float voltage to 24V. The board is also shipped for easy configuration for V
OUT
values
of 48V and 12V.
To configure for one of these preset values simply remove REA1 and place a jumper on J302 for 48V
OUT
or J303 for 12V
OUT
.
Figure 1
Jumper Placement for Constant
Voltage Operation (EVAL1)
Figure 2
Jumper Locations for Preset
J302 48V
OUT
(shown)
or J303 12V
OUT