Abstract: A short-circuit protected line driver circuit is particularly adapted for use in a differential line driver system, where one line driver circuit provides a true output signal and another line driver circuit provides a complementary false output signal. A short-circuit is sensed by measuring current through a secondary pull-up transistor and disabling a primary pull-up transistor if a short-circuit fault occurs which exceeds a predetermined current level for a predetermined time.

Abstract: A three-voltage level detector include an input terminal for receiving an input logic signal having either a high level, mid-level or low level voltage. A first level sensing buffer is responsive to the input logic signal for generating a first output sense voltage indicative of whether the input logic signal is either at the (a) high level voltage or (b) mid-level or low level voltage. A second level sensing buffer is responsive to the input logic signal for generating a second output sense voltage indicative of whether the input logic signal is either at the (a) high level or mid-level voltage or (b) low level voltage.