US3560768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit for a low-frequency amplifier
Assignee: Grundig EMV Elektromechanische Versuchsanstalt Max Grundig GmbH
•
Filing: 1968-04-11
•
Granted: 1971-02-02
•
Expires: 1988-04-11
Abstract
Abstract A low-frequency input voltage is fed to a voltage divider consisting of a fixed resistor and a pair of diodes connected in parallel but with opposite polarity with respect to AC but series-connected with respect to DC The output voltage is derived from the DC common point of the two diodes and is thus a function of the impedance of said diodes. The impedance of the diodes is controlled as follows: A voltage proportional to the input voltage, after passing a threshold stage, is used to charge a capacitor. The capacitor circuit has a short charging time and a long discharge time. The capacitor voltage constitutes the voltage at the gate of a field effect transistor, the voltage at whose drain electrode is used to control the impedance of the diodes. A circuit for compensating for temperature effects on the impedance of the diodes by inserting a DC voltage in the diode circuit is also shown.
Inventors
- 👤 Hans-Georg Rimkus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:09
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/301; H03G3/3015
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
218 words
A transistorized regulating circuit for furnishing a regulated output voltage at an output terminal in response to a varying input voltage applied at a first input terminal, comprising, in combination, a second input terminal; means connected between said output terminal and said second input terminal for furnishing a second voltage proportional to said output voltage at said second input terminal; a charging capacitor having a capacitor voltage proportional to the charge thereon; Unidirectional charging means connected between said second input terminal and said charging capacitor, in such a manner that said capacitor charges in a short-charging time in response to said second voltage, but has a long discharge time; high input impedance transistor means having a control electrode connected to said charging capacitor for furnishing a transistor output voltage at a transistor output terminal as a function of said capacitor voltage; and voltage divider means comprising fixed impedance means and variable impedance means connected at a common point, said voltage divider means interconnecting said first input terminal, said output terminal and said transistor output terminal in such a manner that the impedance of said variable impedance means caries as a function of said transistor output voltage, and that said output voltage corresponds to a portion of said input voltage determined by the impedance of said variable impedance means.
Claim 2
Dependent Claim
218 words
A transistorized regulating circuit for furnishing a regulated output voltage at an output terminal in response to a varying input voltage applied at a first input terminal, comprising, in combination, a second input terminal; means connected between said output terminal and said second input terminal for furnishing a second voltage proportional to said output voltage at said second input terminal; a charging capacitor having a capacitor voltage proportional to the charge thereon; Unidirectional charging means connected between said second input terminal and said charging capacitor, in such a manner that said capacitor charges in a short-charging time in response to said second voltage, but has a long discharge time; high input impedance transistor means having a control electrode connected to said charging capacitor for furnishing a transistor output voltage at a transistor output terminal as a function of said capacitor voltage; and voltage divider means comprising fixed impedance means and variable impedance means connected at a common point, said voltage divider means interconnecting said first input terminal, said output terminal and said transistor output terminal in such a manner that the impedance of said variable impedance means caries as a function of said transistor output voltage, and that said output voltage corresponds to a portion of said input voltage determined by the impedance of said variable impedance means.
Claim 3
Dependent Claim
51 words
A circuit as set forth in claim 1, wherein said high impedance transistor means comprise a field effect transistor having a gate and a drain and a source electrode, and wherein said gate is connected to said charging capacitor and the voltage at said drain electrode constitutes said transistor output voltage.
Claim 4
Dependent Claim
46 words
A circuit as set forth in claim 2, wherein said variable impedance means comprises a first and second diode, DC series connected at said common point, said series connection having a first and second terminal; and connecting means connecting said first terminal to said drain electrode.
Claim 5
Dependent Claim
53 words
A circuit as set forth in claim 3, also comprising means for furnishing a DC voltage varying as a function of temperature; and means for applying said DC voltage to said second terminal of said DC series-connected diodes, thus causing the effective impedance of said diode circuit to become substantially independent of temperature.
Claim 6
Dependent Claim
24 words
A circuit as set forth in claim 1, also comprising means for compensating for changes in said variable impedance means caused by temperature changes.
Claim 7
Dependent Claim
29 words
A circuit as set forth in claim 1, further comprising a threshold stage connected to said second input terminal and responsive to a predetermined magnitude of said second voltage.
Claim 8
Dependent Claim
21 words
A circuit as set forth in claim 1, wherein the capacitance of said charging capacitor is substantially equal to one microfarad.
References Cited (Backward Citations)
DE235596C
Cited
US3178619A
Cited
US3193709A
Cited
US3188554A
Cited
US3239723A
Cited
US3454789A
Cited
US3428884A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |