BQ51013B: The circuit is designed for 500mA, but when I connected 150mA load Vout drops to app.3.2V.

Hi
The schematics only have page 1 of 4, could you repost?
Also coil that you are using will help?

First area to check for a current limit problem is ILIM pin to ground, this will set max output current. For 500mA should be 524 ohms or greater.

Hi, 

Coil I am using is with val 14uH.

7462.design1-500mA.pdf

Hello
Thanks for the schematic.
Can you provide more info on the coil, what size is it or p/n?

Some thing to try on the circuit:
1.) Add a 10k pull down resistor to AD pin
2.) Remove R19
3.) Reduce R16 and increase R17

Hi

I made the changes as per your suggestion.

But output is continuously toggling btw 1.6v - 6.6V

Hi
What RX coil are you using?
Can you send a scope shot of the Votlage at RECT?