MP2681 – CC/CV CONTROLLER WITH FULL PROTECTION

MP2681 Rev.1.01

www.MonolithicPower.com

10

12/25/2013

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Table 1 is a summary of all the charge voltage

setting for the MP2681. The real ID voltage

threshold for every battery

pack is about ±65mV wider than the ones listed

in the table taking in consideration

reference

variations, comparator offsets and hysteresis.

Table1: Charge Voltage Setting Summary

ID resistor

Detect Voltage

Operation Mode

Battery Spec

Output Voltage

Float

Sleep Mode

Unknown

3.2V/cell

73.2k

3S1P

12.45V

28.7k

3S2P

12.45V

13k

4S1P

16.6V

7.87k

4S2P

16.6V

3.9k

5S1P

20.75V

1.62k

Automatic Mode

5S2P

20.75V

Short

Sleep Mode

Unknown

3.2V/cell

If the ID pin voltage is detected out of range

based on the values specified in Table 1 possibly

caused by the insertion of a wrong battery pack

configuration, the MP2681 will detect this fault

condition and cutoff the external MOSFET to stop

charging and protect the battery. Under this

condition the output voltage is set to a default

value of 3.2V/cell and the MP2681 enters sleep

mode. The MP2681 also provides a fault

indication.

The MP2681 compares the VFB voltage to its

internal voltage reference in order to keep

voltage regulation. If this voltage is higher than

2.075V, the output of the voltage loop operational

amplifier will decreases. The opto-coupler current

increases reducing the output voltage of the

PWM controller.

Figure 3 shows the CC and CV control circuit.

Figure 3 — CC/CV Control Circuit of MP2681