Buck/Boost converter IC

[max91]

Hi guys,

For one of my projects I need a buck-boost converter IC which would take 12-14V as an input and would output a voltage between 5V and 20V with a maximum current of 300mA. I should be able to control the output voltage from a microcontroller, so I have to be able to adjust it either by using a PWM signal or by I2C, SPI,...

Does anybody know of an IC that would satisfy this requirements? It would be best if as few external components as possible would be needed, as size is a constraint. I tried searching for something suitable for the past couple of hours, but with no luck.
In case there isn't such a circuit, is it ok to cascade a boost converter IC with a buck converter IC? I could first boost my voltage to 22V and then use a digitally controlled buck converter to obtain the needed voltage.
Thanks!

[Cliff Matthews]

Have you gone to the product selection pages? Here's one from TI:
http://www.ti.com/lsds/ti/power-management/buck-boost-converter-products.page