Patent US3750041A successfully refreshed from Google Patents.
US3750041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Active bootstrap circuit
Assignee: Motorola Solutions Inc
•
Filing: 1972-02-17
•
Granted: 1973-07-31
•
Expires: 1992-02-17
Abstract
Abstract A high input impedance linear amplifier is disclosed. The amplifier circuit has an input impedance resistance which is designed for proper DC biasing, but is too low to accommodate an AC input from a high impedance source. The circuit, through a voltage divider and a semiconductor, effectively provides a very high dynamic impedance to the incoming AC signal.
Inventors
- 👤 M Gay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:00
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
177 words
A high input impedance integrated circuit amplifier having input means for receiving an input alternating current signal, and output means for supplying an output alternating current signal, comprising: a. current source means; b. a transistor having at least first and second main electrodes and a control electrode, the first main electrode being connected to the current source means and the control electrode being connected to the input means to permit the transistor to be responsive to the input signal; c. input impedance means, connected at one end to the input means, and at the other end to a first junction with the current source means; d. voltage dividing means, connected to the second main electrode of the transistor at one end and to a voltage source at the other end, having at least one terminal at a second junction for supplying a pre-determined portion of the voltage across the dividing means; and e. unilateral semiconductive voltage transfer means for transferring the voltage at the second junction to the first junction to effectively increase the dynamic input impedance.
Claim 2
Dependent Claim
177 words
A high input impedance integrated circuit amplifier having input means for receiving an input alternating current signal, and output means for supplying an output alternating current signal, comprising: a. current source means; b. a transistor having at least first and second main electrodes and a control electrode, the first main electrode being connected to the current source means and the control electrode being connected to the input means to permit the transistor to be responsive to the input signal; c. input impedance means, connected at one end to the input means, and at the other end to a first junction with the current source means; d. voltage dividing means, connected to the second main electrode of the transistor at one end and to a voltage source at the other end, having at least one terminal at a second junction for supplying a pre-determined portion of the voltage across the dividing means; and e. unilateral semiconductive voltage transfer means for transferring the voltage at the second junction to the first junction to effectively increase the dynamic input impedance.
Claim 3
Dependent Claim
65 words
The invention of claim 1 further comprising: f. negative feedback means having an input terminal connected to the first main electrode of the transistor and an output terminal connected to the second main electrode of the transistor for providing an alternating current signal at the second main electrode in phase with the alternating current signal on the control electrode to minimize the control electrode current.
Claim 4
Dependent Claim
37 words
The invention of claim 2 wherein the current source means further comprise a first constant current source connected to the first main electrode of the transistor and a second constant current source connected to the first junction.
Claim 5
Dependent Claim
34 words
The invention of claim 2 wherein the current source means further comprise a current control connected to the first main electrode of the transistor and a constant current source connected to the first junction.
Claim 6
Dependent Claim
14 words
The invention of claim 1 wherein the unilateral voltage transfer means comprise a diode.
Claim 7
Dependent Claim
15 words
The invention of claim 4 wherein the unilateral voltage transfer means comprise a diode-connected transistor.
Claim 8
Dependent Claim
14 words
The invention of claim 6 wherein the negative feedback means comprise a current amplifier.
Claim 9
Dependent Claim
73 words
The invention of claim 7 wherein the input impedance means comprise a resistor designated R1 and the voltage divider meanS comprise a first resistor designated R2, connected between the second main electrode of the transistor and the second junction, and a second resistor, designated R3, connected between the second junction and the voltage reference, all operatively connected to approximate the dynamic input impedance designated Zin, in accordance with the equation: Zin R1 (R2+R3/R2)
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |