CN3722

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Mutil-Cells Battery Charge Mangement

  • CN3722 datasheet,

  • CN3722 Fb resistor setup

Features and Use Guide of CN3722

  • datasheet please see datasheet section below
  • Support multi-cells, 5A max.
  • Photovotaic MPPT Function
  • Trickle-current charge, CC and CV charging Mode


Board usage

  • Trickle - on board backside R9 resitor to pin8, can be used to enlarge the trickle-current charge current.
  • All following information from datasheet
  • Detect constant-current charge current = Ics, according to datasheet Ics = 200mV/Rcs, board example:
Ics = 200mV / ( 2 x parallel 0.33R = 0.17R ) = 1.17A
  • Detect Fb voltage = 2.416 * (1 + R7/R6) + (Ib x R7), in case (Ib x R7) is difference, Ib normally 50nA, we simply igore it first here, board example:
Vfb (Vbat) = 2.416 * (1 + R8/R9) = 2.416 * (1 + 13.7K/28K) = 3.589V, around 3.6V
  • MPPT voltage setup, board example
Vmppt = 1.04 x ( 1 + 220K / 13.7K)

Notice

  • Charge voltage VCC should be always 2V higher than stop voltage of battery, for example, if you have 3x 4.2V = 12.6, please supply 15V.
  • Parts selection guide, refer from datasheet
Header text Header text Header text
Example <2.5A 2.5A—5A
Diode D1 D2 30BQ015 50WQ03FN。
Mosfet AO3407A SI4435DY
  • Rcs, 1A -> 2ohm, 2A -> 1ohm, 3A -> 0.067ohm, 4A -> 0.05ohm, 5A -> 0.04ohm,
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