US4178585A
Expired / Lapsed
US
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Analog-to-digital converter
Assignee: Hitachi Ltd
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Filing: 1978-08-22
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Granted: 1979-12-11
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Expires: 1998-08-22
Abstract
Abstract An analog-to-digital converter comprising a capacitor for storing an analog input signal, a constant current discharging circuit coupled with the capacitor for discharging the charge stored therein, a level detection circuit connected to the input terminal of the capacitor, a counter connected to the output terminal of the level detection circuit for counting the number of clock-pulses between the time of discharge start and the time when the voltage at the input terminal of the capacitor drops to a detection level of the level detection circuit, a bias voltage supply means connected in series with the capacitor for adding a bias voltage to the voltage at the input terminal of said capacitor, and a switch connected in parallel with the capacitor for short-circuiting the capacitor when the voltage at the input terminal of said capacitor drops to the detection level.
Inventors
- 👤 Katsuaki Takagi
- 👤 Toshiro Tsukada
- 👤 Hisashi Tsuruoka
- 👤 Michio Hara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:34
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/34; H03M1/38; H03M1/40; H03M1/403
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
100 words
An analog-to-digital converter comprising: (a) a storage means with an input terminal, to which an analog signal is applied, for storing said analog input signal, (b) a discharging circuit coupled with said storage means for discharging the charge stored therein, (c) a level detection circuit connected to said input terminal of said storage means, (d) a counting means connected to said level detection circuit for counting the number of clock-pulses in the period of discharging, (e) a bias voltage supply means connected in series with said storage means, and (f) a short-circuiting means connected in parallel with said storage means.
Claim 2
Dependent Claim
100 words
An analog-to-digital converter comprising: (a) a storage means with an input terminal, to which an analog signal is applied, for storing said analog input signal, (b) a discharging circuit coupled with said storage means for discharging the charge stored therein, (c) a level detection circuit connected to said input terminal of said storage means, (d) a counting means connected to said level detection circuit for counting the number of clock-pulses in the period of discharging, (e) a bias voltage supply means connected in series with said storage means, and (f) a short-circuiting means connected in parallel with said storage means.
Claim 3
Dependent Claim
21 words
An analog-to-digital converter according to claim 1, wherein said storage means is a capacitor, and a short-circuiting means is a switch.
Claim 4
Dependent Claim
19 words
An analog-to-digital converter according to claim 1 or 2, wherein said discharging circuit is a constant current discharging circuit.
Claim 5
Dependent Claim
34 words
An analog-to-digital converter according to claim 1 or 2, wherein said bias voltage supply means comprises a parallel circuit of a switch, and a series connection of a switch and a bias voltage source.
Claim 6
Dependent Claim
20 words
An analog-to-digital converter according to claim 1 or 2, wherein said level detection circuit comprises a multistage connection of inverters.
Claim 7
Dependent Claim
166 words
An analog-to-digital converter comprising: (a) an input terminal, to which an analog input signal is applied, (b) a storage means connected to said input terminal through a switch for storing said analog input signal, (c) a discharging circuit coupled with the storage means for discharging the charge stored therein, (d) a level detection circuit connected to the input terminal of said storage means and having a detection level, (e) a counter connected to said level detection circuit for counting the number of clock pulses in the period between the time at the start of discharge and the time when a voltage at said input terminal of said storage means reaches said detection level, (f) a bias voltage supply means connected in series with said storage means for supplying a vias voltage to said voltage at said input terminal of said storage means, and (g) a short-circuiting means connected in parallel with said storage means for short-circuiting said storage means at the time of finish of discharge.
Claim 8
Dependent Claim
166 words
An analog-to-digital converter comprising: (a) an input terminal, to which an analog input signal is applied, (b) a storage means connected to said input terminal through a switch for storing said analog input signal, (c) a discharging circuit coupled with the storage means for discharging the charge stored therein, (d) a level detection circuit connected to the input terminal of said storage means and having a detection level, (e) a counter connected to said level detection circuit for counting the number of clock pulses in the period between the time at the start of discharge and the time when a voltage at said input terminal of said storage means reaches said detection level, (f) a bias voltage supply means connected in series with said storage means for supplying a vias voltage to said voltage at said input terminal of said storage means, and (g) a short-circuiting means connected in parallel with said storage means for short-circuiting said storage means at the time of finish of discharge.
Claim 9
Dependent Claim
21 words
An analog-to-digital converter according to claim 6, wherein said storage means is a capacitor and a short-circuiting means is a switch.
Claim 10
Dependent Claim
32 words
An analog-to-digital converter according to claim 7, wherein said bias voltage supply means comprises a parallel circuit of a switch, and a series connection of a switch and a bias voltage source.
Claim 11
Dependent Claim
12 words
An analog-to-digital converter according to claim 8, wherein all switches are MOSFET's.
Claim 12
Dependent Claim
27 words
An analog-to-digital converter according to claim 6; comprising another input terminal to which a reference voltage is applied and connected to said storage means through a switch.
Claim 13
Dependent Claim
17 words
An analog-to-digital converter according to claim 6; comprising a switch connected between ground and said storage means.
Claim 14
Dependent Claim
12 words
An analog-to-digital converter according to claim 11, wherein all switches are MOSFET's.
References Cited (Backward Citations)
US3480948A
Cited
US4023160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-10 | 1983-06-11 | 1983-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-10 | 1987-06-11 | 1987-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-10 | 1991-06-11 | 1991-12-11 | $7700.00 | Window Closed / Lapsed |