DAA hook switch

Details DAA hook switch DAA hook switch

2006-11-21

2006-11-21

Swerdlow, Daniel (Department: 2615)

Telephonic communications

Substation or terminal circuitry

Hold circuit

C379S412000

Reexamination Certificate

active

07139391

ABSTRACT:
A hook switch circuit is shown wherein two high-voltage bipolar transistors, a PNP transistor Q1and a NPN transistor Q2. that are connected in a regenerative feedback manner to form a bi-stable latch. The regenerative structure permits the use of low beta transistors that may be turned on with a low control current, but still conduct a sufficient off-hook current. Also shown is a polarity steering regenerative switch (MP1, MP2) that provides a power supply voltage from a telephone line pair and may be adapted for a polarity signal and can be combined with a current mirror (MP7) to produce a current signal proportional to the line voltage (LV1).

REFERENCES:
patent: 4292595 (1981-09-01), Smith
patent: 4419543 (1983-12-01), Kelm et al.
patent: 4465903 (1984-08-01), Barber
patent: 4835486 (1989-05-01), Somerville
patent: 4991051 (1991-02-01), Hung
patent: 5105461 (1992-04-01), Tsurusaki et al.
patent: 5369666 (1994-11-01), Folwell et al.
patent: 5500895 (1996-03-01), Yurgelites
patent: 5633925 (1997-05-01), Handford et al.
patent: 5654984 (1997-08-01), Hershbarger et al.
patent: 5692041 (1997-11-01), Torazzina
patent: 5790656 (1998-08-01), Rahamim et al.
patent: 5870046 (1999-02-01), Scott et al.
patent: 5946393 (1999-08-01), Holcombe
patent: 5946394 (1999-08-01), Gambuzza
patent: 5991335 (1999-11-01), Price
patent: 6107948 (2000-08-01), Scott et al.
patent: 6137827 (2000-10-01), Scott et al.
patent: 6430229 (2002-08-01), Scott et al.
patent: 6498825 (2002-12-01), Dupuis et al.
patent: 6587560 (2003-07-01), Scott et al.
patent: 6654409 (2003-11-01), Scott et al.
patent: 6785383 (2004-08-01), Fan et al.
patent: 6876742 (2005-04-01), Sacca
patent: 2001/0033190 (2001-10-01), Bendall
patent: 2001/0033650 (2001-10-01), Wilson et al.
patent: 2002/0130801 (2002-09-01), Scott et al.
patent: 0 973 305 (2000-01-01), None
Allen et al., “CMOS Analog Circuit Design,” HRW Series in Electrical and Computer Engineering, Chapter 7, pp. 349-357, Holt, Rinehart and Winston (1987).

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