# US 10,441,972 B2 · Transmission channel for ultrasound applications

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- Number: US 10,441,972 B2
- Document ID: US10441972B2
- Status: Granted
- Kind: B2
- Application number: 15/220,208
- Filed: 2016-07-26
- Published: 2016-11-17
- Granted: 2019-10-15
- Earliest claimed: 2014-12-17
- Assignees: STMicroelectronics S.r.l.
- Applicants: STMicroelectronics S.r.l.
- Inventors: Davide Ugo Ghisu; Sandro Rossi; Dario Bianchi
- Web page: https://patentgrep.com/patent/US10441972B2

## CPC

- B06B 1/0215: {for generating pulses, e.g. bursts of oscillations, envelopes}
- G05F 3/02: Regulating voltage or current
- H03K 3/356182: {with additional means for controlling the main nodes}
- H03K 17/0822: {in field-effect transistor switches}
- H03K 17/687: the devices being field-effect transistors
- H03K 19/018521: {of complementary type, e.g. CMOS}
- A61B 8/4483: {characterised by features of the ultrasound transducer}
- H03K 2217/0063: High side switches, i.e. the higher potential [DC] or life wire [AC] being directly connected to the switch and not via the load
- B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R)
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A transmission channel transmits high-voltage pulses in a transmission phase and receives echoes of the high-voltage pulses in a receiving phase. The transmission channel includes a buffer with anti-memory circuitry to couple drain conduction terminals of buffer transistors of a high-side of a buffer of the transmission channel to a low-side reference voltage of a low-side of the buffer and couple drain conduction terminals of buffer transistors of the low-side of the buffer to a high-side reference voltage of the high-side of the buffer during the clamping phase.

## Claims

### Claim 1

A method, comprising:
transmitting high-voltage pulses through a buffer of a transmission channel in a transmission phase, the buffer having:
a first branch having a first half-branch coupled between a first voltage reference node and a central buffer node and a second half-branch coupled between the central buffer node and a second voltage reference node; and
a second branch having a third half-branch coupled between a third voltage reference node and the central buffer node and a fourth half-branch coupled between the central buffer node and a fourth voltage reference node;
coupling, using one or more first high-voltage switches of the buffer of the transmission channel, drain conduction terminals of one or more buffer transistors of the first half-branch to at least one of the second voltage reference node and the fourth voltage reference node during a clamping phase;
coupling, using one or more second high-voltage switches of the buffer of the transmission channel, drain conduction terminals of one or more buffer transistors of the third half-branch to at least one of the second voltage reference node and the fourth voltage reference node during the clamping phase;
coupling, using one or more third high-voltage switches of the buffer of the transmission channel, drain conduction terminals of one or more buffer transistors of the second half-branch of the buffer to at least one of the first voltage reference node and the third voltage reference node during the clamping phase; and
coupling, using one or more fourth high-voltage switches of the buffer of the transmission channel, drain conduction terminals of one or more buffer transistors of the fourth half-branch to at least one of the first voltage reference node and the third voltage reference node during the clamping phase.

### Claim 2 (depends on 1)

The method of claim 1, comprising:
coupling the drain conduction terminals of the buffer transistors of the first and third half-branches of the buffer to at least one of the second voltage reference node and the fourth voltage reference node during a receiving phase; and
coupling the drain conduction terminals of the buffer transistors of the second and fourth half-branches of the buffer to at least one of the first voltage reference node and the third voltage reference node during the receiving phase.

### Claim 3 (depends on 2)

The method of claim 2, comprising:
coupling the drain conduction terminals of the buffer transistors of the first and third half branches of the buffer to at least one of the second voltage reference node and the fourth voltage reference node when a buffer transistor of the second or fourth half-branches is on; and
coupling the drain conduction terminals of the buffer transistors of the second and fourth half-branches of the buffer to at least one of the first voltage reference voltage node and the fourth voltage reference node when a buffer transistor of the first or third half-branches is on.

### Claim 4 (depends on 1)

The method of claim 1, comprising:
coupling the drain conduction terminals of the buffer transistors of the first and third half-branches of the buffer to at least one of the second voltage reference node and the fourth voltage reference node when a buffer transistor of the second or fourth half-branches is on; and
coupling the drain conduction terminals of the buffer transistors of the second and fourth half-branches of the buffer to at least one of the first voltage reference node and the third voltage reference node when a buffer transistor of the first or third half-branches is on.

### Claim 5 (depends on 3)

The method of claim 3 wherein:
the first branch includes:
a first buffer transistor having a source terminal coupled to the first voltage reference node;
a first buffer diode coupled between a drain terminal of the first buffer transistor and the central buffer node;
a second buffer transistor having a source terminal coupled to the first voltage reference node; and
a second buffer diode coupled between a drain terminal of the second buffer transistor and the central buffer node; and
the second branch includes:
a third buffer transistor having a source terminal coupled to the third voltage reference node;
a third buffer diode coupled between a drain terminal of the third buffer transistor and the central buffer node;
a fourth buffer transistor having a source terminal coupled to the fourth voltage reference node; and
a fourth buffer diode coupled between a drain terminal of the fourth buffer transistor and the central buffer node.

### Claim 6 (depends on 1)

The method of claim 1 wherein,
a source conduction terminal of a buffer transistors of the first half-branch of the buffer is coupled to the first voltage reference voltage node; and
a source conduction terminal of a buffer transistors of the second half-branch of the buffer is coupled to the second voltage reference node.

### Claim 7 (depends on 6)

The method of claim 6 wherein,
a source conduction terminal of a buffer transistors of the third half-branch of the buffer is coupled to the third voltage reference node; and
a source conduction terminal of a buffer transistors of the fourth half-branch of the buffer is coupled to the fourth voltage reference node.

### Claim 8

A system, comprising:
means for transmitting high-voltage pulses in a transmission phase, the means for transmitting including a buffer having:
a first side including a first buffer transistor coupled between a first reference voltage terminal and a central buffer node and a second buffer transistor coupled between a second reference voltage terminal and the central buffer node;
a second side including a third buffer transistor coupled between a third reference voltage terminal and the central buffer node and a fourth buffer transistor coupled between a fourth reference voltage terminal and the central buffer node; and
means for coupling the buffer transistors of the first side of the buffer to at least one of the third and fourth reference voltage terminals of the second side of the buffer and coupling the buffer transistors of the second side of the buffer to at least one of the first and second reference voltage terminals of the first side of the buffer during a clamping phase.

### Claim 9 (depends on 8)

The system of claim 8 wherein the means for coupling is configured to:
couple drain conduction terminals of the buffer transistors of the first side of the buffer to at least one of the third and fourth reference voltage terminals of the second side of the buffer during a receiving phase; and
couple drain conduction terminals of the buffer transistors of the second side of the buffer to at least one of the first and second reference voltage terminals of the first side of the buffer during the receiving phase.

### Claim 10 (depends on 8)

The system of claim 8 wherein the means for transmitting comprises:
a first buffer diode coupled between a conduction terminal of the first buffer transistor and a central buffer node;
a second buffer diode coupled between a conduction terminal of the second buffer transistor and the central buffer node; and
a third buffer diode coupled between a conduction terminal of the third buffer transistor and the central buffer node; and
a fourth buffer diode coupled between a conduction terminal of the fourth buffer transistor and the central buffer node.

### Claim 11 (depends on 10)

The system of claim 10 wherein the means for coupling comprises:
a first switch coupled between the conduction terminal of the first buffer transistor and the second third voltage reference terminal;
a second switch coupled between the conduction terminal of the second buffer transistor and the third voltage reference terminal;
a third switch coupled between the conduction terminal of the third buffer transistor and the first voltage reference terminal; and
a fourth switch coupled between the conduction terminal of the fourth buffer transistor and the first voltage reference terminal.

### Claim 12 (depends on 11)

The system of claim 11 wherein,
the first buffer transistor is a P-MOS transistor and the conduction terminal of the first buffer transistor is a drain of the first buffer transistor;
the third buffer transistor is an N-MOS transistor and the conduction terminal of the third buffer transistor is a drain of the third buffer transistor;
the second buffer transistor is a P-MOS transistor and the conduction terminal of the second buffer transistor is a drain of the second buffer transistor; and
the fourth buffer transistor is an N-MOS transistor and the conduction terminal of the fourth buffer transistor is a drain of the fourth buffer transistor.

### Claim 13 (depends on 11)

The system of claim 11 wherein the means for coupling comprises:
a controller, which, in operation, generates control signals to:
close the first, second, third and fourth switches during a clamping phase of operation; and
close the first, second, third and fourth switches during a receiving phase of operation.

### Claim 14 (depends on 13)

The system of claim 13 wherein the controller, in operation, generates control signals to:
close the first, second and fourth switches when the third buffer transistor is closed;
close the first, second and third switches when the fourth buffer transistor is closed;
close the second, third and fourth switches when the first buffer transistor is closed; and
close the first, third and fourth switches when the second buffer transistor is closed.

### Claim 15 (depends on 10)

The system of claim 10 wherein the means for coupling comprises:
a first switch having a first conduction terminal coupled to the third voltage reference terminal;
a first control diode coupled between a second conduction terminal of the first switch and the conduction terminal of the first buffer transistor;
a second control diode coupled between the second conduction terminal of the first switch and the conduction terminal of the second buffer transistor;
a second switch having a first conduction terminal coupled to the fourth voltage reference terminal;
a third control diode coupled between a second conduction terminal of the second switch and the conduction terminal of the first buffer transistor;
a fourth control diode coupled between the second conduction terminal of the second switch and the conduction terminal of the second buffer transistor;
a third switch having a first conduction terminal coupled to the first voltage reference terminal;
a fifth control diode coupled between a second conduction terminal of the third switch and the conduction terminal of the third buffer transistor;
a sixth control diode coupled between the second conduction terminal of the third switch and the conduction terminal of the fourth buffer transistor;
a fourth switch having a first conduction terminal coupled to the second voltage reference terminal;
a seventh control diode coupled between a second conduction terminal of the fourth switch and the conduction terminal of the third buffer transistor; and
an eighth control diode coupled between the second conduction terminal of the fourth switch and the conduction terminal of the fourth buffer transistor.

### Claim 16 (depends on 15)

The system of claim 15 wherein,
the first buffer transistor is a P-MOS transistor and the conduction terminal of the first buffer transistor is a drain of the first buffer transistor;
the third buffer transistor is an N-MOS transistor and the conduction terminal of the third buffer transistor is a drain of the third buffer transistor;
the second buffer transistor is a P-MOS transistor and the conduction terminal of the second buffer transistor is a drain of the second buffer transistor; and
the fourth buffer transistor is an N-MOS transistor and the conduction terminal of the fourth buffer transistor is a drain of the fourth buffer transistor.

### Claim 17 (depends on 10)

The system of claim 10 wherein the means for coupling comprises:
a first resistor coupled between the conduction terminal of the first buffer transistor and the third voltage reference terminal;
a second resistor coupled between the conduction terminal of the third buffer transistor and the first voltage reference terminal;
a third resistor coupled between the conduction terminal of the second buffer transistor and the third voltage reference terminal; and
a fourth resistor coupled between the conduction terminal of the fourth buffer transistor and the first voltage reference terminal.

### Claim 18 (depends on 10)

The system of claim 10 wherein the means for coupling, in operation:
couples the conduction terminal of the first buffer transistor to at least one of the third voltage reference terminal and the fourth voltage reference terminal;
couples the conduction terminal of the second buffer transistor to at least one of the third voltage reference terminal and the fourth voltage reference terminal;
couples the conduction terminal of the third buffer transistor to at least one of the first voltage reference terminal and the second voltage reference terminal; and
couples the conduction terminal of the fourth buffer transistor to at least one of the first voltage reference terminal and the second voltage reference terminal.

### Claim 19 (depends on 8)

The system of claim 8 wherein the means for coupling comprises:
a first resistor having a first terminal coupled to the third voltage reference terminal;
a first control diode coupled between a second terminal of the first resistor and the conduction terminal of the first buffer transistor;
a second control diode coupled between the second terminal of the first resistor and the conduction terminal of the second buffer transistor;
a second resistor having a first terminal coupled to the fourth voltage reference terminal;
a third control diode coupled between a second terminal of the second resistor and the conduction terminal of the first buffer transistor;
a fourth control diode coupled between the second terminal of the second resistor and the conduction terminal of the second buffer transistor;
a third resistor having a first terminal coupled to the first voltage reference terminal;
a fifth control diode coupled between a second terminal of the third resistor and the conduction terminal of the third buffer transistor;
a sixth control diode coupled between the second terminal of the third resistor and the conduction terminal of the fourth buffer transistor;
a fourth resistor having a first terminal coupled to the second voltage reference terminal;
a seventh control diode coupled between a second terminal of the fourth resistor and the conduction terminal of the third buffer transistor; and
an eighth control diode coupled between the second terminal of the fourth resistor and the conduction terminal of the fourth buffer transistor.

### Claim 20 (depends on 9)

The system of claim 9 wherein the means for coupling is configured to:
couple the drain conduction terminals of the buffer transistors of the first side of the buffer to at least one of the third and fourth reference voltage terminals of the second side of the buffer when a second-side buffer transistor is on; and
couple the drain conduction terminals of the buffer transistors of the second side of the buffer to at least one of the first and second reference voltage terminals of the first side of the buffer when a first-side buffer transistor is on.

### Claim 21

A system, comprising:
a transmission channel, which, in operation, transmits high-voltage pulses in a transmission phase, the transmission channel including:
a buffer including:
a first branch having a first half-branch coupled between a first reference voltage node and a central buffer node and a second half-branch coupled between the central buffer node and a second reference voltage node; and
a second branch having a third half-branch coupled between a third reference voltage and the central buffer node and a fourth half-branch coupled between the central buffer node and a fourth reference voltage node; and
coupling circuitry including switching transistors, wherein the coupling circuitry, in operation;
couples the first half-branch of the buffer to at least one of the second reference voltage node and the fourth voltage reference node during a clamping phase;
couples the second half-branch of the buffer to at least one of the first reference voltage node and the third voltage reference node during the clamping phase;
couples the third half-branch of the buffer to at least one of the second reference voltage node and the fourth voltage reference node during the clamping phase; and
couples the fourth half-branch of the buffer to at least one of the first reference voltage node and the third voltage reference node during the clamping phase.

### Claim 22 (depends on 21)

The system of claim 21 wherein the coupling circuitry, in operation:
couples drain conduction terminals of buffer transistors of the first and third half-branches of the buffer to at least one of the second reference voltage node and the fourth reference voltage node during a receiving phase; and
couples drain conduction terminals of buffer transistors of the second and fourth half-branches of the buffer to at least one of the first reference voltage node and the third reference voltage node during the receiving phase.

### Claim 23 (depends on 22)

The system of claim 22, comprising:
a transducer, which in operation is coupled to the transmission channel.

### Claim 24 (depends on 22)

The system of claim 22 wherein
a source conduction terminal of a buffer transistor of the first half-branch is coupled to the first reference voltage node; and
a source conduction terminal of a buffer transistor of the second half-branch is coupled to the second reference voltage node.