US4633164A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microprocessor controlled constant current circuit
Assignee: Rosemount Inc
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Filing: 1985-12-20
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Granted: 1986-12-30
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Expires: 2005-12-20
Abstract
Abstract Apparatus for generating a constant current, comprising a storage device for storing a voltage corresponding to the constant current, the storage device including a resistor-capacitor filter and having an input and an output; a Zener diode for supplying a constant voltage; a first high off-state impedance device for connecting the Zener diode to the input in response to a first actuation signal; a second high off-state impedance device for connecting the input to a source of discharge potential in response to a second actuation signal; a microprocessor for supplying the first actuation signal to the first high off-state impedance device for a first time interval and the second actuation signal to the second off-state impedance device thereafter for a second time interval, and then providing no first and second actuation signals for a third time interval much greater than the combined first and second time intervals; and a voltage-to-current converting circuit connected to the output and having a high input impedance, for converting the voltage stored in the storage device to the constant current.
Inventors
- 👤 Donald F. Kaiser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:22
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/468
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
131 words
Apparatus for generating a constant current, comprising: storage means for storing a voltage corresponding to said constant current, and having an input and an output; constant voltage supply means for supplying a constant voltage; first high off-state impedance means for connecting said constant voltage supply means to said input in response to a first actuation signal; second high off-state impedance means for connecting said input to discharge means in response to a second actuation signal; actuation means for supplying said first actuation signal to said first high off-state impedance means and said second actuation signal to said second high off state impedance means thereafter; and voltage-to-current conversion means connected to said output and having a high input impedance, for converting said voltage stored in said storage means to said constant current.
Claim 2
Dependent Claim
131 words
Apparatus for generating a constant current, comprising: storage means for storing a voltage corresponding to said constant current, and having an input and an output; constant voltage supply means for supplying a constant voltage; first high off-state impedance means for connecting said constant voltage supply means to said input in response to a first actuation signal; second high off-state impedance means for connecting said input to discharge means in response to a second actuation signal; actuation means for supplying said first actuation signal to said first high off-state impedance means and said second actuation signal to said second high off state impedance means thereafter; and voltage-to-current conversion means connected to said output and having a high input impedance, for converting said voltage stored in said storage means to said constant current.
Claim 3
Dependent Claim
56 words
Apparatus according to claim 1; wherein said actuation means includes a microprocessor for producing said first actuation signal and said second actuation signal, first switch means for supplying said first actuation signal to said first high off-state impedance means and second switch means for supplying said second actuation signal to said second high off-state impedance means.
Claim 4
Dependent Claim
54 words
Apparatus according to claim 2; wherein said first switch means is an opto-isolator which includes first light transmitting semiconductor means for producing a first light signal in response to said first actuation signal and first light receiving semiconductor means for receiving said first light signal and reproducing said first actuation signal in response thereto.
Claim 5
Dependent Claim
27 words
Apparatus according to claim 3; wherein said first light transmitting semiconductor means includes a light emitting diode and said first light receiving semiconductor means includes a phototransistor.
Claim 6
Dependent Claim
54 words
Apparatus according to claim 3; wherein said second switch means is an opto-isolator which includes second light transmitting semiconductor means for producing a second light signal in response to said second actuation signal and second light receiving semiconductor means for receiving said second light signal and reproducing said second actuation signal in response thereto.
Claim 7
Dependent Claim
27 words
Apparatus according to claim 5; wherein said second light transmitting semiconductor means includes a light emitting diode and said second light receiving semiconductor means includes a phototransistor.
Claim 8
Dependent Claim
46 words
Apparatus according to claim 1; wherein said first high off-state impedance means includes a first MOSFET having a gate terminal supplied with said first actuation signal, a drain terminal connected to a power supply and a source terminal connected to said input of said storage means.
Claim 9
Dependent Claim
20 words
Apparatus according to claim 7; wherein said constant voltage supply means includes a Zener diode connected to said drain terminal.
Claim 10
Dependent Claim
48 words
Apparatus according to claim 7; wherein said second high off-state impedance means includes a second MOSFET having a gate terminal supplied with said second actuation signal, a drain terminal connected to said input of said storage means and a source terminal connected to a source of discharge potential.
Claim 11
Dependent Claim
47 words
Apparatus according to claim 1; wherein said second high off-state impedance means includes a MOSFET having a gate terminal supplied with said second actuation signal, a source terminal connected to a source of discharge potential and a drain terminal connected to said input of said storage means.
Claim 12
Dependent Claim
38 words
Apparatus according to claim 1; wherein said storage means includes a resistor-capacitor filter including a resistor connected in series between said input and said output and a capacitor connected between said output and a source of discharge potential.
Claim 13
Dependent Claim
49 words
Apparatus according to claim 1; wherein said voltage-to-current conversion means includes an operational amplifier having an input connected to said storage means and an output, and transistor means having an input connected to said output of said operational amplifier and an output at which said constant current is produced.
Claim 14
Dependent Claim
36 words
Apparatus according to claim 12; wherein said transistor means includes a MOSFET having a gate terminal connected to said output of said operational amplifier and a drain terminal which constitutes said output of said transistor means.
Claim 15
Dependent Claim
172 words
Apparatus for generating constant current, comprising: storage means for storing a voltage corresponding to said constant current, said storage means including a resistor-capacitor filter and having an input and an output; Zener diode means for supplying a constant voltage; first high off-state impedance means for connecting said Zener diode means to said input in response to a first actuation signal; second high off-state impedance means for connecting said input to discharge means in response to a second actuation signal; microprocessor means for supplying said first actuation signal to said first high off-state impedance means for a first time interval and said second actuation signal to said second off-state impedance means thereafter for a second time interval, and then inhibiting the supply of said first and second actuation signals for a third time interval much greater than the combination of said first and second time intervals; and voltage-to-current conversion means connected to said output and having a high input impedance, for converting said voltage stored in said storage means to said constant current.
Claim 16
Dependent Claim
172 words
Apparatus for generating constant current, comprising: storage means for storing a voltage corresponding to said constant current, said storage means including a resistor-capacitor filter and having an input and an output; Zener diode means for supplying a constant voltage; first high off-state impedance means for connecting said Zener diode means to said input in response to a first actuation signal; second high off-state impedance means for connecting said input to discharge means in response to a second actuation signal; microprocessor means for supplying said first actuation signal to said first high off-state impedance means for a first time interval and said second actuation signal to said second off-state impedance means thereafter for a second time interval, and then inhibiting the supply of said first and second actuation signals for a third time interval much greater than the combination of said first and second time intervals; and voltage-to-current conversion means connected to said output and having a high input impedance, for converting said voltage stored in said storage means to said constant current.
Claim 17
Dependent Claim
60 words
Apparatus according to claim 14; wherein said first high off-state impedance means includes a MOSFET having a gate terminal supplied with said first actuation signal, a source terminal connected to said input of said storage means and a drain terminal connected to said Zener diode means for supplying said constant voltage to said storage means during said first time interval.
Claim 18
Dependent Claim
56 words
Apparatus according to claim 14; wherein said second high off-state impedance means includes a MOSFET having a gate terminal supplied with said first actuation signal, a source terminal connected to a source of discharge potential and a drain terminal connected to said input of said storage means for discharging said capacitor during said second time interval.
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) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |