Thanks a lot your help.
I figured it out, where the extra power is getting consumed. On Beaglebone Black, HDMI and LAN remain active even though we put system in deep sleep mode.
After removing power to HDMI and LAN, The total current board use is 18mA with 5V. So, total standby power we can achieve on Beaglebone Black board is around 0.1W
HDMI alone consume 21mA. LAN consumes 11mA.
Just thought of sharing it. Can be useful for some body.
Thanks and Regards
Ajay Kar