A contrast control circuit for a display apparatus includes third and fourth resistors, a first transistor, a second transistor, serially connected resistors and a Darling circuit. The third and fourth resistors each has one end connected to the terminals of a positive supply voltage. The first transistor...http://www.google.de/patents/US20010035864?utm_source=gb-gplus-sharePatent US20010035864 - Contrast control circuit for display apparatus
