Quick Answer
Brown sugar does not use the same grams-to-cups value as every other ingredient. Using a practical US cup reference, 220 grams of brown sugar is about 1 cup.
That means 100 grams of brown sugar is about 0.45 cups, while 200 grams is about 0.91 cups.
Brown sugar is usually packed in measuring cups, so packing level matters more here than with loose sugar.