Patent US6137273A successfully refreshed from Google Patents.
US6137273A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for supplying a high precision current to an external element
Assignee: EM Microelectronic Marin SA
•
Filing: 1998-10-15
•
Granted: 2000-10-24
•
Expires: 2018-10-15
Abstract
Abstract The present invention concerns a circuit (30; 50) for supplying a first current (I3) to an external element (3), this current having to be supplied with high precision at a desired nominal value. The current supply circuit includes a first transistor (T3) through which the first current flows, an operational amplifier (A2) to a first input of which a reference voltage (Vref) is supplied, and to an output of which a control signal from the first transistor is supplied, and an external resistor (Re1; Re2). These the circuit is characterized in that it further includes a second transistor (T4) through which a second current (I4; I4/m) flows, said second current also flowing through the external resistor. Such an arrangement of the circuit according to the present invention allow the value of the first current to be trimmed with great precision to its nominal value.
Inventors
- 👤 Tim Bales
- 👤 Serge Bitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:53
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
221 words
Current supply means for supplying a first current to an external element intended to be connected to said means, said current having to be supplied with high precision at a desired predetermined value or nominal value, said current supply means being connected to a power supply, and including: at least one first transistor provided with a control terminal intended to receive a control signal, said transistor being arranged so that said first current flows through it; and an operational amplifier having a first input terminal, to which a reference voltage is supplied by reference voltage supply means, and an output terminal to which is supplied the first transistor control signal, said current supply means being connected to an external resistor arranged for trimming the value of the first current to its nominal value independently of a change in said power supply, wherein said means further include a second transistor, connected in a feedback control loop of the operational amplifier, and arranged so that a second current proportional to said first current flows through it, wherein a current mirror circuit is connected to said second transistor so that the second current flows through it, and wherein said mirror current circuit supplies a third current, proportional to said second current, to said external resistor connected to a second input terminal of said amplifier.
Claim 2
Dependent Claim
221 words
Current supply means for supplying a first current to an external element intended to be connected to said means, said current having to be supplied with high precision at a desired predetermined value or nominal value, said current supply means being connected to a power supply, and including: at least one first transistor provided with a control terminal intended to receive a control signal, said transistor being arranged so that said first current flows through it; and an operational amplifier having a first input terminal, to which a reference voltage is supplied by reference voltage supply means, and an output terminal to which is supplied the first transistor control signal, said current supply means being connected to an external resistor arranged for trimming the value of the first current to its nominal value independently of a change in said power supply, wherein said means further include a second transistor, connected in a feedback control loop of the operational amplifier, and arranged so that a second current proportional to said first current flows through it, wherein a current mirror circuit is connected to said second transistor so that the second current flows through it, and wherein said mirror current circuit supplies a third current, proportional to said second current, to said external resistor connected to a second input terminal of said amplifier.
Claim 3
Dependent Claim
61 words
Current supply means according to claim 1, wherein said first and second transistors are field effect transistors connected so as to operate in saturation state, and wherein said first transistor is arranged so that the value of the first current which flows through said first transistor operating in saturation state is substantially equal to said nominal value of said first current.
Claim 4
Dependent Claim
41 words
Current supply means according to claim 1, wherein said second transistor is provided with a control terminal connected to that of said first transistor, so that the control signal allows both said first transistor and said second transistor to be controlled.
Claim 5
Dependent Claim
42 words
Current supply means according to claim 1, further including a plurality of identical first transistors, each transistor being provided with a control terminal, and wherein the control terminals of said transistors are all connected to the output terminal of said operational amplifier.
Claim 6
Dependent Claim
27 words
Current supply means according to claim 1, wherein said second transistor is made so that its active surface is substantially symmetrical to that of said first transistor.
Claim 7
Dependent Claim
41 words
Current supply means according to claim 2, wherein said mirror current circuit is connected between a drain terminal of said second transistor and an inverting input terminal of said operational amplifier, the non-inverting input terminal being connected to said reference voltage.
Claim 8
Dependent Claim
71 words
The current supply means according to claim 6, wherein said first and second transistors are N-channel transistors having gate terminals, controlled by the control signal, and source terminals connected to earth, wherein said mirror current circuit comprises P-channel transistors, and wherein the external resistor is connected between the inverting terminal of said operational amplifier and earth, the value of the reference voltage being independent of a change in the power supply.
Claim 9
Dependent Claim
15 words
The power supply according to claim 1, wherein said current supply means is an accumulator.
References Cited (Backward Citations)
US3962592A
Cited
US4150309A
Cited
US4292584A
Cited
US4349777A
Cited
US4399399A
Cited
US4700144A
Cited
US4706013A
Cited
US4808907A
Cited
US5107199A
Cited
US5124632A
Cited
US5291123A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-10-24 | 2004-04-24 | 2004-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-24 | 2008-04-24 | 2008-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-24 | 2012-04-24 | 2012-10-24 | $7700.00 | Window Closed / Lapsed |