Electric lamp and discharge devices: systems – Periodic switch in the supply circuit – Impedance or current regulator in the supply circuit
Reexamination Certificate
2001-11-08
2003-02-18
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Periodic switch in the supply circuit
Impedance or current regulator in the supply circuit
C315S224000, C327S382000, C333S032000
Reexamination Certificate
active
06522083
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to driver circuitry. More particularly, this invention relates to circuits and methods for providing driver circuitry with a tuned output impedance.
In the past, the semiconductor industry has utilized various configurations of “driver circuitry” for supplying power to loads that are external to an integrated circuit. Common examples of such external loads include transmission lines, communication systems, and electric motors. One characteristic of driver circuitry that is of concern to system designers is output impedance. As a general principle, it is desirable to match the output impedance of the driver circuitry as closely as possible to the input impedance of the load to maximize power transfer and minimize signal reflections.
In certain applications, such as those involving power transmission or lighting systems, a closely matched impedance is not critical. Other applications, however, such as high speed communications systems, often rely on near-perfect impedance matches to properly function.
Historically, impedance matching has been accomplished by coupling a precision resistor between the driver circuit and the load to provide proper line termination. One deficiency of this approach, however, is that it fails to account for the output capacitance associated with the driver circuit. Because the response time of the driver circuitry is directly dependent on output capacitance, it is generally desirable to minimize this value to approximate a substantially resistive output characteristic. This is particularly desirable in applications that involve high speed data transfer.
Thus, in view of the foregoing, it would therefore be desirable to provide circuits and methods that compensate for the effects of output capacitance on driver circuit performance.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide circuits and methods that compensate for the effects of output capacitance on driver circuit performance.
This and other objects are accomplished in accordance with the principles of the present invention by providing driver circuitry with a tuned output impedance. The tuning function of the present invention is provided by an isolation circuit and matching network coupled to an output of the driver circuit. The isolation circuit isolates the capacitance associated portions of the driver circuit thereby reducing overall output capacitance. The matching network substantially compensates for reactive impedances associated with other portions of the driver circuit. Employing these circuits simultaneously allows the driver circuit to overcome intrinsic reactance and exhibit a substantially resistive output impedance characteristic.
Furthermore, the components used in the isolation circuit and matching network may be selected so that the output impedance of the driver circuit substantially matches that of an external load such as a transmission line or light emitting element. This solution eliminates the need for external damping components and provides significantly improved high frequency performance.
REFERENCES:
patent: 3573644 (1971-04-01), Evel
patent: 4451766 (1984-05-01), Angie et al.
patent: 5111065 (1992-05-01), Roberge
patent: 5121075 (1992-06-01), Roach
patent: 5939909 (1999-08-01), Callahan, Jr.
patent: 6130563 (2000-10-01), Pilling et al.
patent: 6140885 (2000-10-01), Abadeer et al.
patent: 6343024 (2002-01-01), Zabroda
patent: 6362679 (2002-03-01), Wile
Addis, John, “Three technologies on one chip make a broadband amplifier”,Electronics The International Magazine of Electronics Technology, Jun. 5, 1972, pp. 103-107.
Ahuja, B.K., “Implementation of Active Distributed RC Anti-Aliasing/Smoothing Filters”,IEEE Journal of Solid-State Circuits, vol. SC-17, No. 6, pp. 339-342.
AMCC Product Brief 1.0/1.25GBPSVCELDRIVER, May 10, 1999, pp. 1-3.
Khoury, John, M., “Synthesis of Arbitrary Rational Transfer Funtions is S Using Uniform Distributed RC Active Circuits”, IEEE Transactions on Circuits and Systems, vol. 37, No. 4, Apr. 1990, pp. 464-472.
Khoury, John, M., “On the Design of Constant Settling Time AGC Circuits”,IEEE Transactions on Circuits and Systems, vol. 45, No. 3, Mar. 1998, pp. 283-294.
Sackinger, Eduard, et al., “A 3GHz, 32dB CMOS Limiting Amplifier for SONET OC-48 Receivers”,IEEE International Solid-State Circuits Conference, 2000, pg. 158.
Summit Microelectronics, Inc. “Dual Loop Laser Diode Adaptive Power Controller with Look Up Table” (SML2108), Oct. 3, 2001, pp. 1-21.
Swartz, R.G. et al., “An Integrated Circuit for Multiplexing and Driving Injection Lasers”,IEEE Journal of Solid-State Circuits, vol. SC-17, No. 4, Aug. 1982, pp. 753-760.
Dascher, David J., “Measuring Parasitic Capacitance and Inductance Using TDR”,Hewlett-Packard Journal, Apr. 1996, pp. 1-19.
Ikäläinen, Pertti K., “An RLC Matching Network and Application in 1-20 GHZ Monolithic Amplifier”,IEEE, 1989, pp. 1115-1118.
Maxium, “Interfacing Maxim Laser Drivers with Laser Diodes”, May 2000, pp. 1-12.
Alemu Ephrem
Fish & Neave
Linear Technology Corp.
Shanahan Michael E.
Wong Don
LandOfFree
Driver circuitry with tuned output impedance does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Driver circuitry with tuned output impedance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Driver circuitry with tuned output impedance will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3177191