Miscellaneous active electrical nonlinear devices – circuits – and – Specific input to output function – With compensation
Reexamination Certificate
2002-10-08
2003-12-23
Tran, Toan (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Specific input to output function
With compensation
C327S307000
Reexamination Certificate
active
06667650
ABSTRACT:
FIELD OF INVENTION
The present invention relates to amplifier circuits. More particularly, the present invention relates to a current leakage compensation circuit and method for providing a reference current to an amplifier circuit.
BACKGROUND OF THE INVENTION
The increasing demand for higher performance amplifier circuits has resulted in the continued improvement of the precision and accuracy of the various devices and components within the amplifier circuits, as well the inclusion of additional buffers and compensation circuits.
In the implementation of various amplifier circuits, losses in the integrity of referenced currents flowing through the various devices and components can be realized. As a result, the delivered current can be possibly more or less than the intended current to the amplifier circuit. The cause of current losses can be greatly attributed to the presence of current leakage elements as well as parasitic processing components/elements occurring within the circuit devices.
The current leakage elements most often comprise diodes, created by the N and P regions, of the transistor devices within the amplifier circuit. For example, with reference to
FIG. 1
, a circuit
100
comprising a differential pair of transistors Q
1
and Q
2
as may be used within a logarithmic amplifier circuit are illustrated. A first reference current I
C1
, is provided to the collector of transistor Q
1
, while a second reference current I
C2
is provided to the collector of transistor Q
2
. However, instead of currents I
C1
, and I
C2
flowing through transistors Q
1
and Q
2
, leakage currents I
LEAK1
and I
LEAK2
created by the N
1
/P
1
and N
2
/P
2
regions at the diode junctions are realized, i.e., leakage current flows from the N region into the P region. This loss of integrity in the referenced currents results in currents I
C1
−I
LEAK1
, and I
C2
−I
LEAK2
flowing through transistors Q
1
and Q
2
, which results in less accuracy during operation.
Accordingly, a need exists for addressing the leakage current resulting within devices and components of amplifier circuits.
SUMMARY OF THE INVENTION
In accordance with various aspects of the present invention, a leakage compensation circuit and technique is provided that compensates for losses in a referenced current of an amplifier circuit due to leakage elements. The leakage compensation circuit is configured to inject current substantially equal in magnitude to the leakage current into one or more junctions of the amplifier circuit to compensate for lost referenced current due to leakage. As a result, the amplifier circuit and various devices can realize the flow of the reference current as substantially intended without detrimental effects of leakage current, thus maintaining the integrity of the referenced current.
In accordance with an exemplary embodiment, the leakage compensation circuit comprises an array of compensation regions. The array of compensation regions is configured to approximate the collective loss that is created by the leakage elements and provide a compensation current substantially equal in magnitude to one or more junctions to compensate for lost referenced current. To facilitate the injecting of compensation current, the leakage compensation circuit can comprise a current mirror circuit for providing the compensation current to the amplifier circuit.
REFERENCES:
patent: 4613772 (1986-09-01), Young
patent: 5493246 (1996-02-01), Anderson
patent: 5691657 (1997-11-01), Hirano et al.
patent: 6501327 (2002-12-01), Tam
Doorenbos Jerry L.
Gammie David A.
Jones David M.
Parfenchuck Jeffrey B.
Brady W. James
Swayze, Jr. W. Daniel
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
Tran Toan
LandOfFree
Current leakage compensation circuit and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Current leakage compensation circuit and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Current leakage compensation circuit and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3109135