HarryRai,
Try the SEPIC converter. The x'fer function is:
Vout/Vin = D/(1-D), where D = duty cycle
The circuit needs 2 inductors, and, the control loop is harder to stabilize than a regular buck or boost.
Bhuvan
I've used this circuit for years using a single comparator to generate triangle waves. By adjusting resistors R1, R6, R5 & R10, a sawtooth can easily be synthesized.
Bhuvanhttp://files.engineering.com/getfile.aspx?folder=90811bbb-7ad9-47cc-a758-45b304740ffd&file=multivibrator_2.pdf