EnerChip CC CBC3112
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.
Battery Switchover Threshold Voltage vs. R2/R1
Ratio
6
Switchover Threshold Voltage (Volts)
5
4
3
2
1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
R2/R1 Ratio
Trip point
Figure 8: Mode 2 Resistor Selection Graph
To determine the backup switchover hysteresis for Mode 2 operation, use Figure 9.
Hysteresis in Battery Switchover Threshold
Voltage vs. R2/R1 Ratio
0.09
0.08
0.07
Hysteresis (Volts)
0.06
0.05
0.04
0.03
0.02
0.01
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
R2/R1 Ratio
1
1.1
Hysteresis
Figure 9: Mode 2 Hysteresis as a Function of R2/R1
DS-72-04 Rev C
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