Patents Represented by Attorney Volker R. Jacobs et al., "Touch-Tone Decoder Chip Mates Analog Filters with Digital Logic", Electronics, Feb. 15, 1979, pp. 105-112. Ulbrich
  • Patent number: 4375619
    Abstract: A differential input stage is connected to a push-pull output stage with a complementary MOS output pair (30, 32) in a common-source configuration. The gates of the output transistors (30, 32) are each driven by the output of one of a pair of auxiliary transistors (38, 42) which have their gates coupled to the signal. A separate bias current source (41, 44) is connected between the output of each of the auxiliary transistors and a supply node (26). The bias current sources (41, 44) draw current in proportion to the ratio of the transconductances of the auxiliary drive transistors (42, 38) for establishing the voltage across a coupling resistor (36) connecting the output transistor (30, 32) gates and thereby determining the crossover current of the output stage (50). Also disclosed is a frequency response compensation network circuit section (74) which is phase-inverting and provides a local negative feedback loop for the tandem arrangement of intermediate stage (48) and the output stage (50).
    Type: Grant
    Filed: June 26, 1980
    Date of Patent: March 1, 1983
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Veikko R. Saari