Broadband Power Limiter

Abstract

A broadband power limiter having a distributed architecture of multiple segments of self-actuating, adjustable power limiters, where the limiter segments are separated from each other along a signal path by intermediate matching inductors. The intermediate matching inductors are chosen to form, in combination with the capacitances of the limiter segments, an impedance matched, low-loss, broadband transmission line. Optionally, limiter segments may be configured with different sizes and stack depths in a “tapered” architecture, such that different limiter segments have different power limiting response times and power handling capabilities. As each limiter segment initiates its power limiting action, power is reflected back toward the signal line, helping to trigger the power limiting action of the remaining limiter segments. Optionally, a power detector circuit may provide a more ideal limiting function by modulating the threshold power point of the limiter segments as a function of the transient signal voltage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application may be related to the following patent application, assigned to the assignee of the present invention, the entire disclosure of which is incorporated herein by reference as if set forth in full: U.S. patent application Ser. No. ______, filed Oct. 4, 2016, entitled “Adjustable Power Limiter with Integrated Power Detector”, Attorney Docket No. PER-204-PAP.BACKGROUND(1) Technical Field[0002]This invention relates to electronic circuitry, and more particularly to a broadband power limiter circuit.(2) Background[0003]Limiter circuits are used in electronic systems to limit power, voltage, or current to protect electrically connected “downstream” electronic devices from being damaged by excessive power, voltage, or current from a source, which may be an “upstream” power source, signal source, antenna, device being tested, etc. For example, radio frequency (RF) systems in particular must be designed to operate in the pres...

AI Technical Summary

Benefits of technology

The solution provides a broadband power limiter with fast response time, adjustable threshold, low limiting slope, and broad bandwidth, minimizing integrated circuit area and cost, while effectively handling high power and integrating control circuits, thus enhancing the protection of downstream electronic devices.

Problems solved by technology

Further, fast P-i-N diodes are not available in certain semiconductor implementation processes, such as standard bulk silicon, silicon-on-insulator (SOI), and silicon-on-sapphire (SOS) processes, and thus generally are not available for integration with other circuitry.

One drawback of adjustable limiters is that they often cannot limit as completely as fixed limiters.

Thus, while the adjustable limiter of FIG. 3 is flexible due to its adjustability and maintains the rapid response time of an ideal limiter, it has the disadvantage of higher power leakage than an ideal power limiter (comparing FIG. 4 to FIG. 2).

However, all known limiters share a short-coming of limited bandwidth for RF frequencies.

The limiters described above have some but not all of these characteristics, and all of them exhibit limits on their bandwidth caused by input mismatch to an RF source.

However, making FETs larger (1) increases their internal parasitic capacitances, thus increasing their response time, (2) consumes more integrated circuit die area, and thus increases cost, and (3) degrades input match, decreasing bandwidth and lowering linearity.

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