Signal level detection and overrange signal limiter and clamp for electronic circuits

Patent metadata

Field	Value
Publication number	US-10498303-B2
Application number	US-201815887544-A
Country	US
Kind code	B2
Filing date	Feb 2, 2018
Priority date	Feb 2, 2018
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

One embodiment is an apparatus including a detector circuit electrically coupled between a signal source and a second circuit, the signal source generating a first signal, the detector circuit detecting a level of the first signal and generating a first control signal when the detected level of the first signal exceeds a first threshold value, and a clamping switch electrically coupled to receive the first control signal from the detector circuit, the clamping switch including a multi-terminal active device. The first control signal controls a state of the clamping switch such that the clamping switch clamps a level of a signal applied to the second circuit when the level of the first signal exceeds the first threshold value.

First claim

What is claimed is:

1. An apparatus comprising:
a detector circuit electrically coupled to a signal source and a second circuit, the signal source generating a first signal, the detector circuit detecting a level of the first signal and generating a first control signal when the detected level of the first signal exceeds a first threshold value; and
a clamping switch electrically coupled to receive the first control signal from the detector circuit, the clamping switch comprising a multi-terminal active device;
wherein the first control signal controls a state of the clamping switch such that the clamping switch clamps a level of a signal applied to the second circuit when the level of the first signal exceeds the first threshold value; and
wherein the detector circuit comprises a peak detector circuit for detecting a peak value of the first signal, wherein the peak detector circuit comprises a first MOSFET device, a second MOSFET device coupled to the first MOSFET device, and a source follower coupled to the first and second MOSFET devices.

2. The apparatus of claim 1 , wherein the source follower comprises a third MOSFET device and a capacitor.

3. The apparatus of claim 2 , wherein the detector circuit comprises a comparator for comparing the detected peak value of the first signal with the first threshold value and generating the control signal when the detected peak value of the first signal exceeds the first threshold value.

4. The apparatus of claim 3 , wherein the comparator comprises an amplifier.

5. The apparatus of claim 1 , wherein the multi-terminal active device exhibits a variable impedance between first and second terminals thereof and a value of the variable impedance is controlled by a third terminal thereof.

6. The apparatus of claim 5 , wherein the first control signal is applied to the third terminal of the multi-terminal active device.

7. The apparatus of claim 1 , wherein the clamping switch comprises at least one of a p-channel metal oxide semiconductor field effect transistor (“PMOSFET”), an n-channel MOSFET (“NMOSFET”), a complementary MOSFET (“CMOSFET”), and a bi-polar junction transistor (“BJT”).

8. The apparatus of claim 1 , wherein bits corresponding to the first control signal are input to an Automatic Gain Control (“AGC”) system for adjusting a level of the first signal.

9. The apparatus of claim 1 , wherein the detector circuit further generates a second control signal when the level of the first signal exceeds a second threshold value.

10. The apparatus of claim 1 , wherein bits corresponding to the second control signal are input to an Automatic Gain Control (“AGC”) system for adjusting a level of the first signal.

11. An apparatus comprising:
a detector circuit electrically coupled between a signal source and a second circuit, the signal source generating a first signal, the detector circuit comparing the first signal with first and second threshold values and generating a control signal when the detected level of the first signal exceeds the first threshold value or falls below the second threshold value; and
a clamping switch electrically coupled to receive the control signal from the detector circuit, the clamping switch comprising a multi-terminal active device;
wherein the control signal controls a state of the clamping switch such that the clamping switch clamps a level of a signal applied to the second circuit when the detected level of the first signal exceeds the first threshold value or falls below the second threshold value;
wherein the detector circuit comprises a pair of cross-coupled fast amplifiers.

12. The apparatus of claim 11 , wherein a first one of the pair of cross-coupled fast amplifiers is configured to generate the control signal when the first signal exceeds the first threshold value.

13. The apparatus of claim 11 , wherein a second one of the pair of cross-coupled fast amplifiers is configured to generate the control signal when the first signal falls below the second threshold value.

14. The apparatus of claim 11 , wherein the multi-terminal active device exhibits a variable impedance between first and second terminals thereof and wherein a value of the variable impedance is controlled by the third terminal and wherein the control signal is applied to the third terminal of the multi-terminal active device.

15. The apparatus of claim 11 , wherein the clamping switch comprises at least one of a p-channel metal oxide semiconductor field effect transistor (“PMOSFET”), an n-channel MOSFET (“NMOSFET”), a complementary MOSFET (“CMOSFET”), and a bi-polar junction transistor (“BJT”).

16. The apparatus of claim 11 , wherein bits corresponding to the control signal are input to an Automatic Gain Control (“AGC”) system for adjusting a level of the first signal.

17. A method comprising:
comparing a level of a first signal generated by a signal source to a first threshold value;
generating a first control signal if the level of the first signal exceeds the first threshold value;
using the first control signal to activate a clamping switch comprising a multi-terminal active device, wherein the first control signal is provided to a first terminal of the multi-terminal active device and controls a value of a variable impedance between second and third terminals of the multi-terminal active device; and
providing bits corresponding to the first control signal to an Automatic Gain Control (“AGC”) system for adjusting a level of the first signal;
wherein activation of the clamping switch clamps a value of a signal applied to a circuit under protection (“CUP”) to approximately the first threshold value.

18. The method of claim 17 further comprising:
generating a second control signal when the level of the first signal exceeds a second threshold value.

19. The method of claim 17 further comprising:
providing bits corresponding to the second control signal to an Automatic Gain Control (“AGC”) system for adjusting a level of the first signal.

20. The method of claim 17 , wherein the clamping switch comprises at least one of a p-channel metal oxide semiconductor field effect transistor (“PMOSFET”), an n-channel MOSFET (“NMOSFET”), a complementary MOSFET (“CMOSFET”), and a bi-polar junction transistor (“BJT”).

Assignees

• Analog Devices Inc

Inventors

• Dinc Huseyin
• Gray Iii Ronald Bryce
• Ali Ahmed Mohamed Abdelatty

Classifications

• H03G11/00

  Limiting amplitude; Limiting rate of change of amplitude · CPC title

• H03G7/00

  Volume compression or expansion in amplifiers {(frequency dependent H03G9/025)} · CPC title

• H03F2200/441

  Protection of an amplifier being implemented by clamping means · CPC title

• H03F2200/435

  A peak detection being used in a signal measuring circuit in a controlling circuit of an amplifier · CPC title

• H03F3/45183

  Long tailed pairs (H03F3/4521, H03F3/45237 take precedence) · CPC title