Electronic isolator

Abstract

The present invention is an electronic isolator that provides low input to output insertion loss, high output to input insertion loss, and substantial asymmetric isolation between a source circuit and a load circuit. The invention actively reduces noise and reflected power appearing on the isolator output. In numerous embodiments, the invention operates in circuit applications from dc through millimeter wave. Multistage electronic isolator embodiments provide increased isolation and greater noise reduction. In other embodiments, the electronic isolator also removes noise appearing on its input. In another embodiment the invention is configured for high power applications. This embodiment includes circuitry for redirecting power away from the load into resistors or other dissipative elements. In another embodiment, the electronic isolator is configured to remove signal distortion produced by one or more power amplifiers in the system.

1 . An electronic isolator between a source stage and a load stage, including configuring means for configuring said isolator to appear as an infinite impedance to said source stage. 
   
   
       2 .- 4 . (canceled) 
   
   
       5 . The electronic isolator of  claim 1  wherein said configuring means is an operational amplifier with negative feedback. 
   
   
       6 . The electronic isolator of  claim 5  wherein said configuring means comprises a gain controlled stage. 
   
   
       7 . The electronic isolator of  claim 6  wherein said gain controlled stage is a divider network. 
   
   
       8 . The electronic isolator of claim  3  further including an input amplification circuit between an electrical input of said source stage and an attenuation circuit network. 
   
   
       9 . The electronic isolator of  claim 8  including means for configuring control signals for said controllable sources. 
   
   
       10 . The electronic isolator of  claim 9  wherein said control signals include reference signals and negative feedback signals. 
   
   
       11 . The electronic isolator of  claim 10  wherein said configuring means includes circuitry for determining the gain of an input amplification circuit. 
   
   
       12 . The electronic isolator of  claim 10  wherein said input amplification circuit gain controls said reference signal level. 
   
   
       13 . An electronic isolator between a source stage and a load stage comprising:
 an electrical input comprising at least one source electrical connection connected to the source stage, an electrical output comprising at least one load electrical connection to the load stage, at least one circuit path into which electrical noise is directed away from the source and load electrical connections.   
   
   
       14 . (canceled) 
   
   
       15 . The isolator of claim  3  wherein said isolator redirects noise present on the electrical output to a circuit path other than the electrical connections to the source stage. 
   
   
       16 .- 17 . (canceled) 
   
   
       18 . The electronic isolator of  claim 15  wherein at least one of said electrical input and said electrical output comprises at least one conductor pair conducting differential signals. 
   
   
       19 . The electronic isolator of  claim 18  further including an attenuation circuit network comprising at least one lattice attenuator network for each conductor pair. 
   
   
       20 .- 21 . (canceled) 
   
   
       22 . The electronic isolator of  claim 13  wherein said controllable source is an operational amplifier. 
   
   
       23 . The electronic isolator of  claim 13  wherein said controllable source is an amplifier circuit. 
   
   
       24 . The electronic isolator of  claim 19  wherein said amplifier circuit includes a Class A amplifier. 
   
   
       25 . The electronic isolator of  claim 24  wherein said amplifier circuit includes an emitter follower output stage. 
   
   
       26 . The electronic isolator of  claim 25  wherein said amplifier circuit includes a Class A amplifier. 
   
   
       27 . (canceled) 
   
   
       28 . The electronic isolator of  claim 13  wherein said attenuation circuit networks comprise circuitry providing the function of a networks of resistors. 
   
   
       29 . The electronic isolator of  claim 13  wherein said attenuation circuit networks include at least one active circuit that determines the impedance of at least one circuit path within at least one of said attenuation circuit networks. 
   
   
       30 . The electronic isolator of  claim 13  wherein at least one of said attenuation circuit networks contains circuits providing the function of frequency responsive passive components. 
   
   
       31 . The electronic isolator of  claim 13  wherein the frequencies of said noise redirected to said circuit paths other than the electrical connections to the source stage are limited by the operating frequency range of said controllable sources. 
   
   
       32 . The electronic isolator of  claim 31  wherein a plurality of said controllable sources are responsive to distinct, non-overlapping frequency bands. 
   
   
       33 . The electronic isolator of  claim 32  wherein at least one of said controllable sources is an operational amplifier. 
   
   
       34 . The electronic isolator Of  claim 32  wherein said controllable sources are connected in series driving one of said electrical noise redirection circuit path. 
   
   
       35 . The electronic isolator of  claim 32  wherein said controllable sources drive separate noise redirection circuit paths wherein said noise redirection circuit paths are connected to a common node. 
   
   
       36 .- 40 . (canceled) 
   
   
       41 . The electronic isolator of  claim 13  including means for configuring the control signals for said controllable sources. 
   
   
       42 . The electronic isolator of  claim 41  wherein said configuring means include a reference signal. 
   
   
       43 . The electronic isolator of  claim 42  wherein said reference signal is adjusted to compensate for signal loss occurring, in part of said attenuation circuit networks. 
   
   
       44 . The electronic isolator of  claim 43  wherein said reference signal adjustment is made using at least one resistor divider network. 
   
   
       45 . The electronic isolator of  claim 44  wherein said resistor divider networks are connected to said electrical input. 
   
   
       46 . The electronic isolator of  claim 43  wherein said reference signal adjustment is made using an active circuit which tracks and scales said electronic isolator input signals. 
   
   
       47 . The electronic isolator of  claim 41  wherein said configuring means includes at least one negative feedback signal. 
   
   
       48 . The electronic isolator of  claim 47  wherein said negative feedback signal originates at a circuit node into which said electrical noise is redirected away from said electrical input. 
   
   
       49 . The electronic isolator of  claim 48  wherein at least one of said controllable sources is an operational amplifier connected as a voltage follower. 
   
   
       50 . The electronic isolator of  claim 13  further including an input amplification circuit between said electrical input and said attenuation circuit networks. 
   
   
       51 . The electronic isolator of  claim 50  including means for configuring control signals for said controllable sources. 
   
   
       52 . The electronic isolator of  claim 51  wherein said control signals include reference signals and negative feedback signals. 
   
   
       53 . The electronic isolator of  claim 52  wherein said configuring means includes circuitry for determining the gain of said input amplification circuit. 
   
   
       54 . The electronic isolator of  claim 52  wherein said input amplification circuit gain controls said reference signal level. 
   
   
       55 . The electronic isolator of  claim 52  including means for reducing said negative feedback signals. 
   
   
       56 . The electronic isolator of  claim 13  wherein said controllable sources redirect noise appearing on the electrical input away from the electrical output and into said noise redirection circuit paths. 
   
   
       57 . (canceled) 
   
   
       58 . The electronic isolator of  claim 13  including means for detecting conditions of anomalous operation. 
   
   
       59 . The electronic isolator of  claim 58  including means for producing at least one control signal to said source stage to determine the electrical power entering said electronic isolator electrical input. 
   
   
       60 . The electronic isolator of  claim 59  including means for producing a time delay between the time of detection of one said conditions of anomalous operation and the production of said control signals. 
   
   
       61 . The electronic isolator of  claim 59  wherein controllable source is configured so as to absorb the maximum, peak, source stage generated, electrical signal power present under said conditions of anomalous operation during the time between the time of detection of one of said conditions of anomalous operation and said determination of said electronic isolator electrical input. 
   
   
       62 . The electronic isolator of  claim 58  including means for switching said electronic isolator electrical output away from said load stage. 
   
   
       63 . The electronic isolator of  claim 62  including means for dissipating the electrical input power to said electronic isolator in at least one dummy load resistor. 
   
   
       64 . The electronic isolator of  claim 63  wherein said at least one dummy resistor is internal to said electronic isolator. 
   
   
       65 . The electronic isolator of  claim 62  wherein said switching means is a circuit including at least one relay. 
   
   
       66 . The electronic isolator of  claim 62  wherein said switching means is a circuit including at least one bipolar transistor. 
   
   
       67 . The electronic isolator of  claim 62  wherein said switching means is a circuit including at least one field effect transistor. 
   
   
       68 . The electronic isolator of  claim 62  wherein said switching means is a diode, RF switching circuit.