I will post the design tomorrow hopefully.
The fact is that, it does not even go upto 50%. I thought it is due to the Rt/Ct ratio (which also limits max. duty cycle) but even if i try the values given in datasheet, it does not give 1:2 output.
Having read the related posts, i tried a similar circuit on LTSpice using LT1242 IC, which is said to be similar with UC 384x, it works as it is expected.
In fact i need a 1:4 boost ratio and the reason i am working so hard on UC3852 that it has cycle by cycle current limit. However, since i will be charging a li-po battery, the topology becomes unstable for such high boost ratios. Anyway it seems that i will be needing cascading converters to achieve a stable circuit.