Four independent charging single battery automatic charger circuit

  
10 hours using the constant current charging, use more convenient, the circuit shown in FIG. Electricity through the secondary transformer T stepped down, all the way from the
Four independent charging single battery automatic charger circuit - schematic

rear VD1 rectifier, R1, C1 filtering, VD4 regulated by R2, C2 secondary filter output 4.6V regulated voltage control circuit for four; another route VD2 It provides four half-wave rectified pulse current for charging. Only one is shown the way in which the control circuit, the remaining three are the same way. Control manifold with four comparator LM339, its non-inverting input voltage 1.46V to stabilize, which is on the R3, the power indicator LED LED1 get 1.9V stabilized voltage by R4, R5 partial pressure provided by R12; and a comparator inverting input is reflected in the change in voltage of a rechargeable battery, since the input of the comparator does not consume current, R9, no voltage drop on R12, the comparator can truly reflect the comparison voltage size. When charging the battery voltage is low, the potential of high-inverting input terminal, a control MOSFET V1, the charging circuit is formed. At the same time charging indicator light emitting diode LED2 lights; When the rechargeable battery voltage reaches 1.46V, the comparator output low potential, V1 off, cut off the charging circuit and the battery voltage begins to fall, due to VD3, R11 branch influence, more has a certain hysteresis, comparator avoid oscillation state. Only the battery voltage drop is large, and the output of the comparator was a high potential so that V1 conduction, charging resumes. Such state of charge of the battery is intermittent, LED2 blinking, the battery is charged with the increase in intermittent time getting longer, LED2 blinking with increasing frequency is low, keeping the last in a long time off status indicates battery is fully charged. R10 comparator output load resistance. Out of control when the battery is bad R8 prevented. R4 Adjustable Quad voltage comparator threshold comparator can also be fine-tuning their own based on the age of the battery being charged. Charge current with the charging voltage increases and decreases, the measured maximum of 110mA, the current size by changing R6 to fine-tune.




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