Batteries charger of nickel cadmium (Ni-cd) and nickel metal hidret (Ni-MH) of high efficiency with regulator LM2756 for up to 3A.
That charger has an overload protection, that circuit it is for being used with pack of batteries with 5 cells Ni-cd or Ni-MH (but it can be modified for other numbers of cells).
The circuit includes automatic power off, that happens when the temperature of the battery arises above 10° C of the temperature it adapts.
As the charger’s of batteries circuit works with lm2756
That batteries charger shown below in the image it was specifically developed for applications using batteries of nickel cadmium (Ni-cd) and nickel metal hidret (Ni-MH), that accepts a fast load of 3A, and it provides automatic power off of the discharge load current when the battery is level) it is used as ” maintenance ” load for avoiding load loss. The maxim and it holds load rate it is determined by the size and type of the battery.
Detecting the end of the load
There are several ways for determining the end of the load for batteries of Ni-cd and Ni-MH but a simple one and insurance is called ∆T detector. He measures the temperature it adapts and the temperature of the battery and it turns off the average discharge when the battery reaches an amount pre-set on the temperature it adapts. That circuit uses 10° C as power off point (that is recommended by most of the manufacturers of batteries), but it can be adjusted changing the value of the resistors easily. Cells of Ni-cd are perfectly functional for techniques of power off ∆T. Then those battery when it is totally loaded he elevates your temperature above 10° C of the temperature it adapts. For that the circuit counts with two sensor of temperature of precision lm35 one to measure the temperature adapts and other to measure the temperature of the battery.
For description it completes of the operation of the circuit it seeks for AN-946 High efficiency 3A battery chargers it uses LM2576 regulators of the national. The led1 indicates the battery situation with load it completes and situation of maintenance load.
Schematic of the charger’s Ni-Cd Ni-MH circuit with lm2576
High-Efficiency 3A Battery Chargers Uses LM2576 Regulators