Preliminary
EnerChip CC CBC3105
Mode 2 Operation
Figure 7 shows the circuitry for user-selectable switchover threshold to a value between 2.5 and 5.0 volts. Use
Figure 8 to determine the value of R1. To determine the amount of hysteresis from the EnerChip switchover
threshold, use Figure 9.
Figure 7: CBC3105 Typical Circuit for Mode 2 Operation
EnerChip charging and backup power switchover threshold for 2.5 to 5.5 volt operation is selected by changing
the value of R2 (see Figure 7). To determine the backup switchover point, set the value of R1 to 200kΩ and
choose the value of R2 according to Figure 8. For example, to set a 3.0V trip point: If R1=200 kΩ then R2 = R1
x 0.72 = 144kΩ. Figure 7 shows a Mode 2 circuit with standard value resistors of 200kΩ and 143kΩ.
To determine the backup switchover hysteresis for Mode 2 operation, use Figure 9.
Battery Switchover Threshold Voltage vs. R2/R1
Ratio
Hysteresis in Battery Switchover Threshold
Voltage vs. R2/R1 Ratio
6
5
4
3
2
1
0
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
Trip point
Hysteresis
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
1
1.1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
1
1.1
R2/R1 Ratio
R2/R1 Ratio
Figure 9: Mode 2 Hysteresis as a Function of R2/R1
Figure 8: Mode 2 Resistor Selection Graph
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-21 Rev E
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