US4465967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current supply circuit
Assignee: Hitachi Ltd
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Filing: 1982-01-26
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Granted: 1984-08-14
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Expires: 2002-01-26
Abstract
Abstract A current supply circuit comprises a DC power feed circuit exhibiting a constant current characteristic for a power source and a constant resistance characteristic for a load, a first detecting circuit for detecting a load current or a load voltage, a DC-DC converter circuit inserted between the power source and the DC power feed circuit, a second detecting circuit for detecting an output voltage from the DC-DC converter circuit; and an operation circuit coupled at the input with the output of the first detecting circuit and the output of the second detecting circuit for controlling the DC-DC converter circuit by the output thereof. The DC-DC converter circuit is so controlled as to produce a voltage representative of the sum of a voltage drop across the load and a fixed voltage necessary for the operation of the DC power feed circuit.
Inventors
- 👤 Michio Tokunaga
- 👤 Junjiro Kitano
- 👤 Akio Sagawa
- 👤 Toshio Hayashi
- 👤 Kazuo Hamazato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:00
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/001; H04M19/008
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
195 words
A current supply circuit with a constant resistance power feed characteristic for connecting a power source to a load so that said current supply circuit appears to be a constant resistance to said load comprising: a. a load current detecting circuit for detecting a load current flowing through the load; b. a DC power feed circuit operable independently of said power source and having an equivalent internal resistance and an equivalent internal power supply; c. a DC-DC converter circuit inserted in series between the power source and said DC power feed circuit including means for generating an output voltage independently from a voltage output of said power source; d. a voltage detecting circuit connected to said DC-DC converter circuit for detecting the output voltage of said DC-DC converter circuit; and e. operation circuit means connected to receive the output of said load current detecting circuit and said voltage detecting circuit for controlling said DC-DC converter circuit so as to produce a voltage representative of the sum of a voltage drop across said load and a voltage necessary for allowing said DC power feed circuit to operate in accordance with a change of the load resistance.
Claim 2
Dependent Claim
195 words
A current supply circuit with a constant resistance power feed characteristic for connecting a power source to a load so that said current supply circuit appears to be a constant resistance to said load comprising: a. a load current detecting circuit for detecting a load current flowing through the load; b. a DC power feed circuit operable independently of said power source and having an equivalent internal resistance and an equivalent internal power supply; c. a DC-DC converter circuit inserted in series between the power source and said DC power feed circuit including means for generating an output voltage independently from a voltage output of said power source; d. a voltage detecting circuit connected to said DC-DC converter circuit for detecting the output voltage of said DC-DC converter circuit; and e. operation circuit means connected to receive the output of said load current detecting circuit and said voltage detecting circuit for controlling said DC-DC converter circuit so as to produce a voltage representative of the sum of a voltage drop across said load and a voltage necessary for allowing said DC power feed circuit to operate in accordance with a change of the load resistance.
Claim 3
Dependent Claim
19 words
A current supply circuit according to claim 1, wherein said DC-DC converter circuit is of the self-oscillation switching type.
Claim 4
Dependent Claim
20 words
A current supply circuit according to claim 1, wherein said DC-DC converter circuit is of the separate excitation switching type.
Claim 5
Dependent Claim
196 words
A current supply circuit with a constant resistance power feed characteristic for connecting a power source to a load so that said current supply circuit appears to be a constant resistance to said load comprising: a. a first voltage detecting circuit for detecting a load voltage across the load; b. a DC power feed circuit operable independently of said power source and having an equivalent internal resistance and an equivalent internal power supply; c. a DC-DC converter circuit inserted in series between the power source and said DC power feed circuit including means for generating an output voltage independently from a voltage output of said power source; d. a second voltage detecting circuit connected to said DC-DC converter circuit for detecting the output voltage of said DC-DC converter circuit; and e. operation circuit means connected to receive the output of said first voltage detecting circuit and said second voltage detecting circuit for controlling said DC-DC converter circuit so as to produce a voltage representative of the sum of a voltage drop across the load and a voltage necessary for allowing said DC power feed circuit to operate in accordance with a change of the load resistance.
Claim 6
Dependent Claim
196 words
A current supply circuit with a constant resistance power feed characteristic for connecting a power source to a load so that said current supply circuit appears to be a constant resistance to said load comprising: a. a first voltage detecting circuit for detecting a load voltage across the load; b. a DC power feed circuit operable independently of said power source and having an equivalent internal resistance and an equivalent internal power supply; c. a DC-DC converter circuit inserted in series between the power source and said DC power feed circuit including means for generating an output voltage independently from a voltage output of said power source; d. a second voltage detecting circuit connected to said DC-DC converter circuit for detecting the output voltage of said DC-DC converter circuit; and e. operation circuit means connected to receive the output of said first voltage detecting circuit and said second voltage detecting circuit for controlling said DC-DC converter circuit so as to produce a voltage representative of the sum of a voltage drop across the load and a voltage necessary for allowing said DC power feed circuit to operate in accordance with a change of the load resistance.
Claim 7
Dependent Claim
92 words
A current supply circuit according to claim 4, wherein said first voltage detecting circuit includes: a. a resistor circuitry having a plurality of series-connected high resistors, which is connected in parallel with the load; b. a complementary current amplifier having two complementary input terminals inserted in series in said resistor circuitry and two complementary output terminals one of which is connected to ground; c. a current proportional to a load voltage being produced from the other output terminal of said complementary current amplifier by detecting a current flowing through said resistor circuitry.
Claim 8
Dependent Claim
115 words
A current supply circuit according to claim 4, wherein said first voltage detecting circuit includes: a. a resistor circuitry having a series connection of a plurality of high resistors, which is connected in parallel with the load; b. a complementary current amplifier having two complementary input terminals inserted in series in said resistor circuitry and two complementary output terminals; c. a current inverter for inverting the current produced from one of the output terminals of said complementary current amplifier; d. the output current from said current inverter and the current derived from the outer output terminal of said complementary current amplifier being added to each other to provide a current proportional to the load voltage.
Claim 9
Dependent Claim
97 words
A current supply circuit according to claim 4, wherein said first voltage detecting circuit comprising: a. a resistor voltage divider having a series connection of a plurality of high resistors, which is connected in parallel with the load; b. a differential amplifier for converting voltage pproduced from said resistor voltage divider into a voltage proportional to a load voltage; c. a voltage-current converter for converting the voltage from said resistor voltage divider into a voltage proportional to the load voltage; and d. a voltage-current converter for converting the output voltage from said differential amplifier into a current.
Claim 10
Dependent Claim
53 words
A current supply circuit according to claim 6, wherein said complementary current amplifier is provided with a single common terminal, a mid point potential generator is provided for providing a voltage half of the output voltage of said DC-DC converter circuit, and said common terminal is connected to said mid point potential generator.
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) | 1987-08-14 | 1988-02-13 | 1988-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-14 | 1992-02-13 | 1992-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-14 | 1996-02-13 | 1996-08-14 | $7700.00 | Window Closed / Lapsed |