Active limiter with integrated sensor

1. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port; and

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal received on an input port comprising one of the first and second RF ports, and to couple first and second detector output signals, distinct from the input signal, to first and second ports of the limiter section, causing the limiter section to limit the input signal;

wherein the input signal may have a positive or negative voltage polarity at any instant, and wherein the difference between the first and second detector output signals at the first and second ports of the limiter section causes the limiter section to limit the input signal independently of the voltage polarity of the input signal.

2. The integrated circuit of claim 1 wherein the integrated circuit comprises a gallium-arsenide integrated circuit.

3. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port; and

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal received on an input port comprising one of the first and second RF ports, and to couple first and second detector output signals, distinct from the input signal, to first and second ports of the limiter section, causing the limiter section to limit the input signal;

wherein the limiter section comprises a plurality of biasable switch devices switched according to the difference between the first and second detector output signals at the first and second ports of the limiter section.

4. The integrated circuit of claim 3 wherein the plurality of biasable switch devices comprises diodes.

5. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port; and

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal received on an input port comprising one of the first and second RF ports, and to couple first and second detector output signals, distinct from the input signal, to first and second ports of the limiter section, causing the limiter section to limit the input signal;

wherein the limiter section comprises a plurality of diode stacks switched according to the difference between the first and second detector output signals at the first and second ports of the limiter section.

6. The integrated circuit of claim 1 wherein the detector section detects an RF power level of the input signal, said input signal having a frequency of at least 20 GHz.

7. The integrated circuit of claim 1 wherein the input signal detected by the detector section comprises an electrical overstress event.

8. The integrated circuit of claim 1 wherein the input signal detected by the detector section comprises an electro-static discharge (“ESD”).

9. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal received on an input port comprising one of the first and second RF ports; and

a first resistor disposed between the input port and the detector section and a second resistor disposed between the detector section and ground potential;

wherein the first resistor is connected directly to the second resistor.

10. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal;

a first limiter bias input port; and

a second limiter bias input port, wherein the limiter section comprises at least a first diode disposed between the first limiter bias input port and the RF signal path and a second diode disposed between the second limiter bias input port and the RF signal path;

and wherein bias voltages at the first and second limiter bias input ports are set according to a detector output signal.

11. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal; and

a differential amplifier disposed between the detector section and the limiter section;

wherein the differential amplifier couples an amplified output signal directly to the limiter section.

12. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal;

a first resistor coupled to ground potential;

a second resistor disposed between the first resistor and the first RF port;

a node between the first resistor and the second resistor; and

an amplifier disposed between the node and the detector section;

wherein the amplifier is connected directly to the node.

13. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal;

a first limiter bias input port; and

a second limiter bias input port, wherein the limiter section comprises at least a first diode disposed between the first limiter bias input port and the RF signal path and a second diode disposed between the second limiter bias input port and the RF signal path; and

a limiter drive circuit connected to the detector section and to the first and second bias input ports, such that the first and second diodes may be switched according to an output from the limiter drive circuit.

14. The integrated circuit of claim 13 further comprising an overpower indicator output signal.

15. An integrated circuit comprising:

a first RF port;

a second RF port;

a limiter section disposed between the first RF port and second RF port;

a detector section, coupled to the limiter section and coupled to an RF signal path between the first RF port and the second RF port, the detector section configured to detect a power level of an input signal received on an input port comprising one of the first and second RF ports; and

a directional device connected to the RF signal path and to the detector section, such that it couples a portion of the input signal if the input signal travels in one direction along the RF signal path to the detector section, but does not couple any portion of the input signal if the input signal travels in the opposite direction along the RF signal path;

wherein the input signal may have a positive or negative voltage polarity at any instant, and wherein the detector section detects the power level of the input signal independently of the voltage polarity of the input signal and couples first and second detector output signals, distinct from the input signal, to first and second ports of the limiter section, the difference between the first and second signals at the first and second ports of the limiter section causing the limiter section to limit the input signal independently of the voltage polarity of the input signal.

16. The integrated circuit of claim 15 wherein the directional device is one of a directional coupler and a directional bridge.