US3870964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sound volume control circuit with sound level output linearly related to volume control potentiometer setting
Assignee: National Semiconductor Corp
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Filing: 1973-07-16
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Granted: 1975-03-11
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Expires: 1993-07-16
Abstract
Abstract An integrated circuit sound level control wherein a resistance potentiometer is utilized to produce a voltage output linearly related to the potentiometer setting, the voltage output serving to produce a current in a differential amplifier which is linearly related to the potentiometer voltage, the linear current of the differential amplifier being converted by a diode circuit coupled thereto into a log function voltage, the log function voltage serving to drive a transistor in an attenuator circuit coupled between the audio signal input stage and the audio signal output, said transistor responding to said log function signal drive to produce a change in the audio signal output linearly related to said potentiometer voltage. Temperature compensation is included in the circuit.
Inventors
- 👤 Thomas B Mills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:27
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/02; H03G3/04; H03G3/10; H03G1/00; H03G1/0005; H03G1/0017; H03G1/0023
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
223 words
A sound volume control system comprising: an attenuator circuit for controlling the level of transmission of an incoming audio signal to an audio signal output, said attenuator circuit comprising: a pair of transistors, the emitter-collector circuits of said transistors being coupled in parallel and being coupled to receive said incoming audio signal, one of said emitter-collector circuits having said audio output coupled thereto, a potentiometer for producing a linear voltage output change responsive to movement thereof, first circuit means responsive to said linear voltage change from said potentiometer for producing a current change linearly related to said voltage change, said first circuit means comprising: a differential amplifier including a pair of transistors, and means for applying a reference voltage to the base of one of said latter transistors, said voltage from said potentiometer being applied to the base of the other of said latter transistors, second circuit means for converting said linear current change to a log function change, said second circuit means comprising: diodes in each of the emitter-collector circuitS of said differential amplifier transistors, said diodes being coupled to the bases of said transistors in said attenuator circuit, and third circuit means in said attenuator circuit for converting said log function voltage change to a changing audio signal current flow to said audio output linearly related to said potentiometer voltage change.
Claim 2
Dependent Claim
223 words
A sound volume control system comprising: an attenuator circuit for controlling the level of transmission of an incoming audio signal to an audio signal output, said attenuator circuit comprising: a pair of transistors, the emitter-collector circuits of said transistors being coupled in parallel and being coupled to receive said incoming audio signal, one of said emitter-collector circuits having said audio output coupled thereto, a potentiometer for producing a linear voltage output change responsive to movement thereof, first circuit means responsive to said linear voltage change from said potentiometer for producing a current change linearly related to said voltage change, said first circuit means comprising: a differential amplifier including a pair of transistors, and means for applying a reference voltage to the base of one of said latter transistors, said voltage from said potentiometer being applied to the base of the other of said latter transistors, second circuit means for converting said linear current change to a log function change, said second circuit means comprising: diodes in each of the emitter-collector circuitS of said differential amplifier transistors, said diodes being coupled to the bases of said transistors in said attenuator circuit, and third circuit means in said attenuator circuit for converting said log function voltage change to a changing audio signal current flow to said audio output linearly related to said potentiometer voltage change.
Claim 3
Dependent Claim
223 words
A sound volume control system comprising: an attenuator circuit for controlling the level of transmission of an incoming audio signal to an audio signal output, said attenuator circuit comprising: a pair of transistors, the emitter-collector circuits of said transistors being coupled in parallel and being coupled to receive said incoming audio signal, one of said emittercollector circuits having said audio output coupled thereto, a potentiometer for producing a linear voltage output change responsive to movement thereof, first circuit means responsive to said linear voltage change from said potentiometer for producing a current change linearly related to said voltage change, said first circuit means comprising: a differential amplifier including a pair of transistors, and means for applying a reference voltage to the base of one of said latter transistors, said voltage from said potentiometer being applied to the base of the other of said latter transistors, second circuit means for converting said linear current change to a log function change, said second circuit means comprising: diodes in each of the emitter-collector circuitS of said differential amplifier transistors, said diodes being coupled to the bases of said transistors in said attenuator circuit, and third circuit means in said attenuator circuit for converting said log function voltage change to a changing audio signal current flow to said audio output linearly related to said potentiometer voltage change.
Claim 4
Dependent Claim
223 words
A sound volume control system comprising: an attenuator circuit for controlling the level of transmission of an incoming audio signal to an audio signal output, said attenuator circuit comprising: a pair of transistors, the emitter-collector circuits of said transistors being coupled in parallel and being coupled to receive said incoming audio signal, one of said emittercollector circuits having said audio output coupled thereto, a potentiometer for producing a linear voltage output change responsive to movement thereof, first circuit means responsive to said linear voltage change from said potentiometer for producing a current change linearly related to said voltage change, said first circuit means comprising: a differential amplifier including a pair of transistors, and means for applying a reference voltage to the base of one of said latter transistors, said voltage from said potentiometer being applied to the base of the other of said latter transistors, second circuit means for converting said linear current change to a log function change, said second circuit means comprising: diodes in each of the emitter-collector circuitS of said differential amplifier transistors, said diodes being coupled to the bases of said transistors in said attenuator circuit, and third circuit means in said attenuator circuit for converting said log function voltage change to a changing audio signal current flow to said audio output linearly related to said potentiometer voltage change.
Claim 5
Dependent Claim
63 words
A sound system as claimed in claim 1 including a current source coupled to the emitter-collector circuits of said differential amplifier transistors, a pair of resistors, each emitter-collector circuit of said differential amplifier containing one of said resistors, and a fourth circuit means including a third resistor for setting the level of the current flow from said current source to said differential amplifier.
References Cited (Backward Citations)
GB1236928A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |