Preheat oven to 325º. Lightly grease two 6 count donut pans with cooking spray or vegetable oil.
Combine bananas, sugar, yogurt, butter and eggs in a large bowl; beat at medium speed of an electric mixer until well blended. Combine flour, baking powder, baking soda and salt; Add flour mixture to banana mixture, add cinnamon chips, stirring just until moistened.
Divide batter evenly into 12 donut cups, filling each about ¾ full. (Use a pastry bag or plastic bag with corner cut out to make filling the cups easier.)
Bake for 10-15 minutes, until a tester inserted into the center comes out clean.
While donuts are baking, in a small bowl combine sugar and cinnamon for topping.
When donuts are done, cool for a few minutes in the pan, remove from pan and dip donut top in cinnamon sugar mixture. Cool on a wire rack.