Preventing power-on audio output noise in a wireless...

Details Preventing power-on audio output noise in a wireless... Preventing power-on audio output noise in a wireless...

2006-08-01

2006-08-01

Nguyen, Khanh V. (Department: 2817)

Amplifiers

Combined with automatic amplifier disabling switch means

C330S010000

Reexamination Certificate

active

07084701

ABSTRACT:
A wireless telephone (10) including audio amplifier circuitry (20) that produces reduced “pop” noise in speakers such as in handsfree headsets (HS) is disclosed. The audio amplifier circuitry (20) includes an audio amplifier (22) that drives the headset speaker (HSS). A first transistor (26) has its source-drain path connected between an output (HSO) of the audio amplifier (22) and a power supply voltage (Vdd), and a second transistor (28) has its source-drain path connected between the amplifier output (HSO) and a reference voltage such as ground. The first and second transistors (26, 28) are controlled by control logic (24), in response to the state of various register locations (30) that indicate the powered-up and enabled state of the audio amplifier circuitry (20). Normal and automatic modes for the precharge control are available, with the automatic mode eliminating the need for the precharge enable register location (30d) being written during operation.

REFERENCES:
patent: 5199079 (1993-03-01), Anderson et al.
patent: 5537081 (1996-07-01), Naokawa et al.
patent: 5682121 (1997-10-01), Naokawa et al.
patent: 6118336 (2000-09-01), Pullen et al.
patent: 6605991 (2003-08-01), Midya et al.
patent: 6734724 (2004-05-01), Schell et al.
patent: 0 678 975 (1995-10-01), None
patent: 0785 501 (1997-07-01), None

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