William R Chester

US Patent:

7522433, Apr 21, 2009

Filed:

Mar 20, 2007

Appl. No.:

11/688835

Inventors:

Cary L. Delano - Los Altos CA, US
William R. Chester - Morgan Hill CA, US

Assignee:

Fairchild Semiconductor Corporation - South Portland ME

International Classification:

H02M 3/18

US Classification:

363 60, 363 59

Abstract:

A voltage reference generation circuit having switch pairs coupled to systematically commutate a flying capacitor among adjacent pairs of voltage rail outputs. The circuit requires only a single flying capacitor, N+1 switch pairs, and N storage capacitors, to generate N intermediate voltage references between VDD and GND. A signal generator produces N+1 non-overlapping switch enable signals to systematically enable the switch pairs and commutate the single flying capacitor between the rail pairs. The flying capacitor remains charged to VDD/(N+1). The N storage capacitors hold their respective reference outputs at VDD*N/(N+1), VDD*(N−1)/(N+1), VDD*(N−2)/(N+1), and so forth.

US Patent:

8081785, Dec 20, 2011

Filed:

Mar 20, 2007

Appl. No.:

11/688830

Inventors:

Cary L. Delano - Los Altos CA, US
William R. Chester - Morgan Hill CA, US

Assignee:

Fairchild Semiconductor Corporation - South Portland MA

International Classification:

H04R 5/02
H04R 25/00

US Classification:

381300, 381150, 381370

Abstract:

An audio amplifier system having improved power efficiency by wasting less power in its bias voltage circuit. An amplifier provides a voice signal to a first (+) input of a loudspeaker and a high efficiency converter provides a bias voltage to a second (−) input of the loudspeaker. In multi-loudspeaker systems, a single high efficiency converter can bias all the loudspeakers at a common node. The high efficiency converter can be a charge pump or a buck converter or the like, and has greater than 90% efficiency.

US Patent:

20070222522, Sep 27, 2007

Filed:

Mar 10, 2006

Appl. No.:

11/308200

Inventors:

Cary Delano - Los Altos CA, US
William Chester - Morgan Hill CA, US

Assignee:

PORTAL PLAYER, INC - San Jose CA

International Classification:

H03F 3/04

US Classification:

330296000

Abstract:

A system for driving a plurality of loads each connected to respective signal terminals and to a shared common load terminal. Multiple conventional signal amplifiers each provide a content signal at one of the signal terminals. The signal amplifiers each have a primary-power upper terminal, to receive a first voltage (V) from a first power supply, and a primary-power lower terminal, to receive a second voltage (V) from the first power supply. A bias amplifier biases the common load terminal, and has a secondary-power upper terminal to receive a third voltage (V) from a second power supply and a secondary-power lower terminal to receive a fourth voltage (V) from the second power supply, wherein V≦V