Need a NiMH battery charger CKT

[spkirankumar]

tea1104 schematic

I want to use a contant current source to charge 2 NiMH batteries (1.2V each) which are connected in series, using 5V input voltage. I want to control the charging current using PWM of the frequency 100 HZ from microcontroller. Please reply me with the circuit....

 

[IanP]

Here is a circuit that, using PWM, sinks 4-20mA:

It can be easily modified to become constant current battery charger ..

Regards,
IanP

 

[vaibhav.k]

Why dont use chargers for it.
U can use NXP's TEA1104 or Texas bq2000.

 

[spkirankumar]

Why dont use chargers for it.
U can use NXP's TEA1104 or Texas bq2000.

I can use this IC's for NiMH charging. But my requirement is to build a constant current source using transistor and to vary the output current using pulse width. I am using PIC microcontroller in my application. So i am using same PIC to sense the battery voltage, according battery voltage i like to vary the charging current. If i get any IC, in which output current can be controlled by PWM, is OK.

 

[shoaibali]

Check out MAX712/713 and DS2715.
These seem to provide simple NiMH battery charging solutions.