Hello,
I'm using current source LM234 chip to output constant 1mA current, the load vary from 1K to 30K. The V+ of LM234 is provide by +32V from DCDC.
The output of LM234 can only drive the load below 15K, when the load above 15K, the output voltage will not increase equal proportion, the max output voltage is only about 17V. So when the load is 30K, the output voltage is only 17V, the current is only about 0.566mA(17/30). Any one can help me to solve this issue? Thanks very much.
Below is my schematic and reference circuit from TI datasheet, VDD is 32V, load is below W4 and W3.
Thanks and Regards
Yanjun