Ultrasound capacitive T/R switch device, circuit
An ultrasound image system has a plurality of channels. At least one of the plurality of channels has a capacitive T/R switch.
1. An ultrasound image system comprising:
a plurality of channels, wherein at least one of the plurality of channels has a capacitive T/R switch and a piezo transducer element coupled to the capacitive T/R switch.
2. The ultrasound imaging system of claim 1 , wherein the capacitive T/R switch comprises:
a pair of capacitive diodes; and
a pair of bleed resistors coupled to the pair of capacitive diodes.
3. The ultrasound system of claim 1 , wherein the capacitive T/R switch comprises:
a first variable capacitive diode, a terminal of the first variable capacitive diode forming a first terminal of the T/R switch;
a second variable capacitive diode, a terminal of the second variable capacitive diode forming a second terminal of the T/R switch; and
a pair of bleed resistors coupled to the first variable capacitive diode and the second variable capacitive diode.
4. The ultrasound imaging system of claim 1 , further comprising a bias control device coupled to the capacitive T/R switch.
5. The ultrasound imaging system of claim 3 , further comprising a bias control device coupled to a third terminal of the capacitive T/R switch.
6. The ultrasound imaging system of claim 1 , wherein the at last one channel comprises:
a Tx pulser;
a pair of isolation diodes coupled to the Tx pulser;
and
an Rx circuit coupled to a second terminal of the capacitive T/R switch;
wherein the piezo transducer element is coupled to the pair of isolation diodes and to a first terminal of the capacitive T/R switch.
7. The ultrasound imaging system of claim 6 , wherein the Rx circuit comprises:
a pair of diode protectors coupled to the second terminal of the capacitive T/R switch;
a coupling capacitor coupled to the pair of diode protectors; and
a low noise preamplifier coupled to the coupling capacitor.
8. The ultrasound imaging system of claim 1 , wherein the capacitive T/R switch generates a C-V curve having a rapidly capacitance falling area between near zero and knee point of voltages.
9. The ultrasound imaging system of claim 1 , wherein the capacitive T/R switch is a semiconductor device comprising:
an N-type substrate having a plurality of trenches formed therein;
a P-type poly-Silicon material formed within each of the plurality of trenches; and
metal layers applied to the N-type substrate and the P-type poly-Silicon to form terminals of the capacitive T/R switch.
10. The ultrasound imaging system of claim 1 , wherein the capacitive T/R switch is a semiconductor device comprising:
a P-type substrate having a plurality of trenches formed therein;
a N-type poly-Silicon material formed within each of the plurality of trenches; and
metal layers applied to the P-type substrate and the N-type poly-Silicon to form terminals of the capacitive T/R switch.
11. The ultrasound imaging system of claim 9 , wherein a junction capacitance of at least two of the trenches changes with a terminal voltage.
12. The ultrasound imaging system of claim 9 , wherein a junction capacitance of at least two of the trenches changes with a terminal voltage, the junction capacitance having a C-V curve having a rapid dC/dV turning knee point.
13. An ultrasound image system comprising:
a plurality of channels, wherein each channel comprises:
a Tx pulser;
a pair of isolation diodes coupled to the Tx pulser;
a piezo transducer element coupled to the pair of isolation diodes
a T/R switch having a first terminal coupled to the piezo transducer; and
an Rx circuit coupled to a second terminal of the T/R switch;
wherein the T/R switch of at least one of the plurality of channels is a capacitive T/R switch.
14. The ultrasound imaging system of claim 13 , wherein the capacitive T/R switch comprises:
a pair of diodes; and
a pair of bleed resistors coupled to the pair of diodes.
15. The ultrasound imaging system of claim 13 , wherein the capacitive T/R switch comprises:
a first variable capacitive diode, an anode of the first variable capacitive diode forming a first terminal of the T/R switch;
a second variable capacitive diode, an anode of the second variable capacitive diode forming a second terminal of the T/R switch; and
a pair of bleed resistors coupled to the first variable capacitive diode and the second variable capacitive diode.
16. The ultrasound imaging system of claim 13 , further comprising a bias control device coupled to a third terminal of the capacitive T/R switch.
17. The ultrasound imaging system of claim 13 , wherein the capacitive T/R switch generates a C-V curve having a rapidly capacitance falling area between near zero and knee point of voltages.
18. The ultrasound imaging system of claim 12 , wherein the capacitive T/R switch is a semiconductor device comprising:
an N-type substrate having a plurality of trenches formed therein;
a P-type poly-Silicon material formed within each of the plurality of trenches; and
metal layers applied to the N-type substrate and the P-type poly-Silicon to form terminals of the capacitive T/R switch.
19. The ultrasound imaging system of claim 12 , wherein the capacitive T/R switch is a semiconductor device comprising:
n P-type substrate having a plurality of trenches formed therein;
a N-type poly-Silicon material formed within each of the plurality of trenches; and
metal layers applied to the P-type substrate and the N-type poly-Silicon to form terminals of the capacitive T/R switch.
20. The ultrasound imaging system of claim 18 , wherein a junction capacitance of at least two of the trenches changes with a terminal voltage.
21. A capacitive T/R switch comprising:
a pair of capacitive diodes; and
a pair of bleed resistors coupled to the pair of capacitive diodes.
22. The capacitive T/R switch of claim 21 , wherein the pair of diodes comprises:
a first variable capacitive diode, a terminal of the first variable capacitive, diode forming a first terminal of the T/R switch; and
a second variable capacitive diode, a terminal of the second variable capacitive diode forming a second terminal of the T/R switch.