EnerChip CC CBC3105

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DS-72-21 Rev E

Page 10 of 12

Preliminary

Figure 7: CBC3105 Typical Circuit for Mode 2 Operation

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.

To determine the backup switchover hysteresis for Mode 2 operation, use Figure 9.

Figure 8: Mode 2 Resistor Selection Graph

Figure 9: Mode 2 Hysteresis as a Function of R2/R1

Battery Switchover Threshold Voltage vs. R2/R1

Ratio

0

1

2

3

4

5

6

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

Hysteresis in Battery Switchover Threshold

Voltage vs. R2/R1 Ratio

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

1 1.1

R2/R1 Ratio

Hysteresis

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.