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US5422597A
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Means and method of enhancing signal resolution and dynamic range extension in a pulse width modulation amplifier
Assignee: Motorola Solutions Inc
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Filing: 1994-05-31
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Granted: 1995-06-06
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Expires: 2014-05-31
Abstract
Abstract An amplifier (1) used with a pulse width modulated signal which improves the efficiency of a low level input signal comprises two or more switching devices (7,9) with common source/drain or emitter/collector connections. The gates or the bases of the devices are independently driven to optimize the efficiency of the various Rds (on) resistance values of the transistors (61, 63, 65, 89, 91, 93) used in the devices. The amplifier is operated so that during the highest output levels, select switching devices (61, 63, 65) are utilized to reduce in series resistance with the load (13). As output power decreases, devices (89, 91, 93) with higher Rds (on) resistance values are activated by a control signal which greatly improves DC to DC conversion efficiency with improved output voltage resolution, dynamic range and reduced electromagnetic interference potential.
Inventors
- 👤 Robert E. Stengel
- 👤 David L. Muri
- 👤 Enrique Ferrer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:58
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/217; H03F3/2173
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
119 words
An amplifier system used for amplifying a pulse width modulated signal input from a pulse width modulator, said pulse width modulated signal having either a low level or a high level, said amplifier system comprising: a first bridge driver for controlling the pulse width and amplitude of said pulse width modulated signal in a first predetermined range; a second bridge driver for controlling the pulse width and amplitude of said pulse width modulated signal in a second predetermined range; and whereby said first bridge driver and said second bridge driver are operated alternately depending on the pulse width and amplitude of said pulse width modulated signal to provide an increased output voltage resolution of said pulse width modulated signal.
Claim 2
Dependent Claim
119 words
An amplifier system used for amplifying a pulse width modulated signal input from a pulse width modulator, said pulse width modulated signal having either a low level or a high level, said amplifier system comprising: a first bridge driver for controlling the pulse width and amplitude of said pulse width modulated signal in a first predetermined range; a second bridge driver for controlling the pulse width and amplitude of said pulse width modulated signal in a second predetermined range; and whereby said first bridge driver and said second bridge driver are operated alternately depending on the pulse width and amplitude of said pulse width modulated signal to provide an increased output voltage resolution of said pulse width modulated signal.
Claim 3
Dependent Claim
35 words
The amplifier system according to claim 1 further comprising: a means for filtering connected to an output of said first bridge driver and said second bridge driver for filtering a predetermined range of frequency components.
Claim 4
Dependent Claim
17 words
The amplifier system according to claim 2 wherein said means for filtering is a low pass filter.
Claim 5
Dependent Claim
20 words
The amplifier system according to claim 2 further comprising: a load for terminating the output of said means for filtering.
Claim 6
Dependent Claim
24 words
The amplifier system according to claim 1 wherein said first predetermined range defines when said pulse width modulated signal is at said low level.
Claim 7
Dependent Claim
24 words
The amplifier system according to claim 1 wherein said second predetermined range defines when said pulse width modulated signal is at said high level.
Claim 8
Dependent Claim
37 words
The amplifier system according to claim 1 wherein said first bridge driver controls the pulse width and amplitude of said pulse width modulated signal during a period said pulse width modulated signal is at said low level.
Claim 9
Dependent Claim
37 words
The amplifier system according to claim 1 wherein said second bridge drier controls the pulse width and amplitude of said pulse width modulated signal during a period said pulse width modulated signal is at said high level.
Claim 10
Dependent Claim
33 words
The amplifier system according to claim 1 wherein said first bridge driver and said second bridge driver are switched from an off state to an on state using a least one control signal.
Claim 11
Dependent Claim
25 words
The amplifier system according to claim 1 wherein said first bridge driver and said second bridge driver are comprised of a plurality of switching devices.
Claim 12
Dependent Claim
16 words
The amplifier system according to claim 10 wherein said plurality of switching devices are N-channel MOSFET's.
Claim 13
Dependent Claim
181 words
A pulse width modulated amplifier having at least one input for receiving pulse width modulated signals, said pulse width modulated signals having a plurality of states, said plurality of states having either a high level or a low level, said amplifier comprising: a first driver which is controlled by at least one first control signal for switching and amplifying said pulse width modulated signal when said pulse width modulated signal is at said low level; a second driver which is controlled by at least one second control signal for switching and amplifying said pulse width modulated signal when said pulse width modulated signal is at said high level; a filter attached to an output of both said first driver and said second driver for removing undesired AC signal components from an amplified signal produced by said first driver and said second driver; and wherein said first driver and said second driver are selectively actuated using said at least one first control signal and said at least one second control signal to enhance the signal resolution of said pulse width modulated signal.
Claim 14
Dependent Claim
181 words
A pulse width modulated amplifier having at least one input for receiving pulse width modulated signals, said pulse width modulated signals having a plurality of states, said plurality of states having either a high level or a low level, said amplifier comprising: a first driver which is controlled by at least one first control signal for switching and amplifying said pulse width modulated signal when said pulse width modulated signal is at said low level; a second driver which is controlled by at least one second control signal for switching and amplifying said pulse width modulated signal when said pulse width modulated signal is at said high level; a filter attached to an output of both said first driver and said second driver for removing undesired AC signal components from an amplified signal produced by said first driver and said second driver; and wherein said first driver and said second driver are selectively actuated using said at least one first control signal and said at least one second control signal to enhance the signal resolution of said pulse width modulated signal.
Claim 15
Dependent Claim
22 words
A pulse width modulated amplifier as in claim 12 further comprising a speaker connected to said filter for providing an audio output.
Claim 16
Dependent Claim
63 words
A pulse width modulated amplifier as in claim 12 wherein said first driver and said second driver include a plurality of switching transistor which are controlled using said at least one first control signal and said at least one second control signal for selecting the duration upon which said first and second driver means are used to amplify said pulse width modulated signal.
Claim 17
Dependent Claim
30 words
A pulse width modulated amplifier as in claim 12 wherein said plurality of switching transistors used in said first driver are N-channel MOSFET's having a substantially low Rds (on) resistance.
Claim 18
Dependent Claim
30 words
A pulse width modulated amplifier as in claim 12 wherein said plurality of switching transistors used in said second driver are N-channel MOSFET's having a substantially high Rds (on) resistance.
Claim 19
Independent Claim
89 words
A method of increasing the dynamic range of a pulse width modulated amplifier comprising the steps of: providing a pulse width modulated input signal; directing said pulse width modulated signal to at least two bridge drivers connected in parallel; and switching said pulse width modulated signal between said two bridge drivers depending on the amplitude of said pulse width modulated input signal to improve DC to DC conversion efficiency of said pulse width modulated amplifier for improving output voltage resolution and dynamic range of said pulse width modulated signal.
Claim 20
Independent Claim
89 words
A method of increasing the dynamic range of a pulse width modulated amplifier comprising the steps of: providing a pulse width modulated input signal; directing said pulse width modulated signal to at least two bridge drivers connected in parallel; and switching said pulse width modulated signal between said two bridge drivers depending on the amplitude of said pulse width modulated input signal to improve DC to DC conversion efficiency of said pulse width modulated amplifier for improving output voltage resolution and dynamic range of said pulse width modulated signal.
Claim 21
Dependent Claim
41 words
A method of increasing the dynamic range of a pulse width modulated amplifier as in claim 17 further comprising the step of including at least one transistor in said at least two bridge drivers with a substantially high Rds (on) resistance.
Claim 22
Dependent Claim
41 words
A method of increasing the dynamic range of a pulse width modulated amplifier as in claim 17 further comprising the step of including at least one transistor in said at least two bridge drivers with a substantially low Rds (on) resistance.
Claim 23
Dependent Claim
71 words
A method of increasing the dynamic range of a pulse width modulated amplifier as in claim 17 wherein said switching step includes the steps of selecting a first bridge driver of said at least two bridge drivers during periods when said amplitude is at or above a predetermined level and selecting a second bridge driver of said at least two bridge drivers during periods said amplitude falls below said predetermined level.
References Cited (Backward Citations)
US4446440A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-05 | 2002-12-05 | 2003-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-05 | 2006-12-05 | 2007-06-06 | $7700.00 | Window Closed / Lapsed |