Does anyone has experience with nmhi cel chargers.
I do need to incorporate on my pcb a charger capable of charging 8 nhmi cells 4/AH from a 13Vdc power source @ 0.5 Amp approx.
Some test with the lt1513-2 where not satisfactory and an other chip should be used however I was not able to find one.
Maybe one of you guys has an answer.
Picbuster

 

The LT1513-2 seems eminently suitable for the task. What about it was not satisfactory?

 

the calculations and by lt given values and calculations are not in line with product.
it's a simple circuit only 3 resistors needed two defining the vbatt float and one the current.
take r2=12.4K and use for r1 12.4*(vbatt-1.245)/( 1.245+ 12.4 * 0.0003) = 104.87 K
The unit will not produce an output.( 20K change on R1 has no effect)
By reducing r2 to 3k5 ( vbatt= 11.8V) the unit start to operate however the charge current never stops.
One of the strange effect is that the current is defined by R2 (pin 2) and the serial resistor 0,010 Ohm.
This give me the impression that product and manual lt1513 differs from lt1513-2.
Question where to obtain info for the lt1513-2 ? LT support indicate that this an old chip maybe you should use an other one.
So I end up on a big heap crying in the corner.
I do not want to reinvent the wheel by taking a pic and build it myself.
Maxim DS2715 is now in the picture I will use the weekend to study DS2715 possibilities.
But again I am open to any suggestion.

Picbuster


I

 

This covers both LT1513 and LT1513-2. You need to check through the datasheet noticing the difference between the two types.
http://www.linear.com/docs/3570

Page 6 includes this:
The LT1513-2 option removes the feedback resistors
around the IFB amplifier and connects its output to the FB
signal. This provides a ground referenced current sense
voltage suitable for external current programming and
makes amplifier input and output available for external
loop compensation