# US 8,465,432 B2 · Active transducer probes and circuits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,432 B2 - Document ID: US8465432B2 - Status: Granted - Kind: B2 - Application number: 12/876,162 - Filed: 2010-09-05 - Published: 2012-03-08 - Granted: 2013-06-18 - Earliest claimed: 2010-09-05 - Assignees: Maxim Integrated Products, Inc. - Applicants: Luigi Franchini; Diego Maiocchi; Roberto Amadio - Inventors: Luigi Franchini; Diego Maiocchi; Roberto Amadio - Web page: https://patentgrep.com/patent/US8465432B2 ## CPC - H03F 1/52: Circuit arrangements for protecting such amplifiers {(monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74)} - H03F 1/0277: {Selecting one or more amplifiers from a plurality of amplifiers} - H03F 1/083: {in transistor amplifiers (H03F1/10 - H03F1/22 take precedence)} - H03F 3/72: Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal - H03G 1/0088: {using discontinuously variable devices, e.g. switch-operated} - G01S 15/8915: {using a transducer array} - H03F 2200/261: Amplifier which being suitable for instrumentation applications - H03F 2203/7215: the gated amplifier being switched on or off by a switch at the input of the amplifier - H03F 2203/7221: the gated amplifier being switched on or off by a switch at the output of the amplifier - H03F 2203/7236: the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers by (a ) switch(es) - H03F: AMPLIFIERS - H03G: CONTROL OF AMPLIFICATION - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract In an example embodiment, a method for bidirectional signal propagation comprises: a) sensing a voltage level of a first signal at a first port; b) coupling the first port to an output of an amplifier with a solid state switch if the voltage level of the first signal is less than a threshold voltage, whereby a second signal applied to a second port coupled to an input of the amplifier is propagated in a first direction from the second port to the first port; and c) bypassing the amplifier if the voltage level of the first signal is greater than the threshold voltage such that the first signal is propagated in a second direction from the first port to the second port. ## Claims ### Claim 1 A bidirectional multichannel circuit comprising: a first plurality of channel ports; a second plurality of channel ports; channel circuitry coupling the first plurality of channel ports to the second plurality of channel ports to provide a plurality of active channels, where each active channel includes, an amplifier having an input and an output; b) an amplifier output protector including a solid state switch coupling the output of the amplifier to a channel port of the first plurality of channel ports, the solid state switch having an open position and a closed position; and c) a controller coupled to the channel port of the first plurality of channel ports and to the amplifier output protector; whereby the controller is operative to control the solid state switch of the amplifier output protector. ### Claim 2 (depends on 1) A bidirectional multichannel circuit as recited in claim 1 wherein each active channel further comprises an amplifier input protector coupling a channel port of the second plurality of channel ports to the input of the amplifier. ### Claim 3 (depends on 2) A bidirectional multichannel circuit as recited in claim 2 wherein each active channel further comprises an amplifier bypass coupling the channel port of the first plurality of channel ports to the channel port of the second plurality of channel ports. ### Claim 4 (depends on 3) A directional multichannel circuit as recited in claim 3 wherein the controller includes a voltage detection circuit having an input coupled to the channel port of the first plurality of channel ports and an output coupled to the amplifier output protector. ### Claim 5 (depends on 4) A bidirectional multichannel circuit as recited in claim 4 wherein the voltage detection circuit is a window voltage detection circuit. ### Claim 6 (depends on 5) A bidirectional channel circuit as recited in claim 5 wherein when the solid state switch is closed the amplifier output protector has an impedance which is matched to an impedance of a transmission cable. ### Claim 7 (depends on 3) A bidirectional multichannel circuit as recited in claim 3 wherein the amplifier input protector comprises a capacitor. ### Claim 8 (depends on 7) A bidirectional multichannel circuit as recited in claim 7 further comprising a shunt coupled to at least one of the input of the amplifier and the output or the amplifier. ### Claim 9 (depends on 3) A bidirectional multichannel circuit as recited in claim 3 wherein the amplifier is a variable gain amplifier (VGA). ### Claim 10 (depends on 3) A bidirectional multichannel circuit as recited in claim 3 wherein the amplifier bypass includes a pair of reverse parallel coupled diodes. ### Claim 11 (depends on 3) A bidirectional multichannel circuit as recited in claim 3 wherein at least one of the amplifier input protector and the amplifier bypass comprises a solid state switch. ### Claim 12 (depends on 11) A bidirectional multichannel circuit as recited in claim 11 wherein both the amplifier input protector and the amplifier bypass comprises a solid state switch. ### Claim 13 (depends on 12) A bidirectional multichannel circuit as recited in claim 12 wherein the controller is further coupled to the amplifier input protector and the amplifier bypass, whereby the controller is further operative to control the amplifier input protector and the amplifier bypass. ### Claim 14 (depends on 3) A bidirectional multichannel circuit as recited in claim 3 wherein the amplifier output protector and the controller comprise a self resetting circuit breaker. ### Claim 15 (depends on 14) A bidirectional multichannel circuit as recited in claim 14 wherein the circuit breaker includes a series connection of a pair of transistors, a first threshold sensing transistor coupled to a first of the pair of transistors, and a second threshold sensor coupled to a second of the pair of transistors. ### Claim 16 (depends on 15) A bidirectional multichannel circuit as recited in claim 15 wherein a first end of the pair of transistors is coupled to the channel port of the first plurality of channel ports and a second end of the pair of transistors is coupled to the output of the amplifier, whereby the first threshold sensing transistor and the second threshold sensing transistor comprise a voltage window detector. ### Claim 17 An active ultrasonic probe comprising: a housing; a multichannel transducer disposed within the housing; and a bidirectional multichannel circuit disposed within the housing and including, (a) a first plurality of channel ports; (b) a second plurality of channel ports which are coupled to the multichannel transducer; (c) channel circuitry coupling the first plurality of channel ports to the second plurality of channel ports to provide a plurality of active channels, where each active channel includes: i) an amplifier having an input coupled to one of the second plurality of channel ports and an output; ii) an amplifier output protector including a solid state switch coupling the output of the amplifier to a channel port of the first plurality of channel ports, the solid state switch having an open position and a closed position; and iii) a controller coupled to the channel port of the first plurality of channel ports and to the amplifier output protector.