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User manual for APPEB1002 Revision 2.1, Oct 2019
General Purpose CAP-XX Supercapacitor Evaluation Board
Figure 6: three charging modes with APPEB1002
Cell balancing options
When a dual cell supercapacitor or two GY series cells are used, cell balancing is strongly
recommended, refer to CAP-XX Application Note AN1002 Cell Balancing Rev1.0 available on
our
website.
When using single cell supercapacitor, all cell balancing option must be disabled. For more
information regarding cell balancing, please refer to CAP-XX Application Note AN1002_Cell
balancing on
our
website.
No cell balancing
When the board is fitted with a single cell supercapacitor resistors R7 and R8 must be left
unpopulated and solderable jumpers marked as Active Balance POWER (SJ3) and Balance output
ENABLE (SJ4) must be left open circuit.
Resistor balance
To use resistor balance, please solder two identical resistors to R7 and R8, highlighted on the PCB
with the marking Resistive balance. Their landing pads can accommodate SMD 0603 or 5mm pitch
through hole resistors. Solderable jumpers marked as Active Balance POWER (SJ3) and Balance
output ENABLE (SJ4) must be left open circuit as shown on the left of figure 7.
CAP-XX recommends the maximum resistance for R7 and R8 to be 39KΩ. At higher temperatures
lower value resistors should be used.
Active OPAMP balance
R4, R5, IC2 and R6 is the active cell balancing sub circuit. IC2 TLV8801 is a low quiescent current
general purpose OPAMP, configured as a unity gain buffer. R4 and R5 set the reference voltage
for the buffer and R6 limits the OPAMP output current and guarantees op amp stability into a
capacitive load. To use the active balancing option resistors R7 and R8 must be removed or left
unpopulated and the solderable jumpers marked as Active Balance POWER (SJ3) and Balance
output ENABLE (SJ4) must be bridged with solder as shown on the right of figure 7. The quiescent
current from this circuit is ~750nA excluding the supercapacitor leakage current.
For more information regarding cell balancing, please refer to CAP-XX Application Note
AN1002_Cell balancing on
our
website.
Figure 7: cell balance options, Left- resistor balance, Right – active balance
© CAP-XX Pty Limited 2019 | Tel +61 2 9420 0690 | www.cap-xx.com
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