Low pin count high voltage ultrasound transmitter and method therefor
View Patent ↗An integrated single channel or multi-channel ultrasound transmitter that minimizes the number of input connections to a controller such as an FPGA, field programmable gate array, or a custom integrated circuit in an ultrasound system. The method is accomplished by integrating, in low voltage logic, a means to store and or program the patterns required for the transmitter output. The number of logic input connections can be further reduced by further integrating, in low voltage logic, programmable individual time delays and frequency divider for each transmitter output.
1. An ultrasound transmitter comprising:
control logic circuitry having a single input trigger to switch to at least two different voltage levels, wherein the control circuitry comprises:
a shift register for each voltage level output of the transmitter, wherein the shift register defines a high voltage output pattern for each voltage level output of the transmitter; and
a latch coupled to the shift register for sending data to the shift register;
a high voltage output driver circuit coupled to the control logic circuitry;
a counter having an input coupled to the single input trigger and an output coupled to each shift register; and
a frequency divider having an input coupled to the single input trigger and an output coupled to the counter; and
wherein an oscillator signal is coupled to an input of the frequency divider and an input of the counter.
2. The ultrasound transmitter of claim 1 , wherein the control logic circuitry switches between two voltage levels, where the two voltage levels is one of: a positive voltage and ground, a negative voltage and ground, or a positive voltage and a negative voltage.
3. The ultrasound transmitter of claim 1 , wherein the control logic circuitry switches between three different voltage levels, the three different voltage levels being a positive voltage, a negative voltage, and ground.
4. The ultrasound transmitter of claim 1 , wherein the control logic circuitry switches between five different voltage levels, the five different voltage levels being a first positive voltage, a second positive voltage, a first negative voltage, a second negative voltage, and ground.
5. The ultrasound transmitter of claim 1 , wherein the control logic circuitry switches between seven different voltage levels, the seven different voltage levels being a first positive voltage, a second positive voltage, a third positive voltage, a first negative voltage, a second negative voltage, a third negative voltage, and ground.
6. The ultrasound transmitter of claim 1 , wherein the high voltage output circuit which outputs two voltage levels comprises:
a P-type transistor having a first terminal coupled to a first voltage level, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter; and
an N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to a second voltage level.
7. The ultrasound transmitter of claim 1 , wherein the high voltage output circuit which outputs three voltage levels comprises:
a first P-type transistor having a first terminal coupled to a first voltage level, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter;
a first N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to a second voltage level;
a second P-type transistor having a first terminal coupled to ground, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter;
a second N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to ground;
a first diode coupled to the third terminal of the second N-type transistor and to the output terminal of the ultrasound transmitter; and
a second diode coupled to the first terminal of the second N-type transistor and to the output terminal of the ultrasound transmitter.
8. The ultrasound transmitter of claim 1 , wherein the high voltage output circuit which outputs five voltage levels comprises:
a first P-type transistor having a first terminal coupled to a first voltage level, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter;
a first N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to a second voltage level;
a second P-type transistor having a first terminal coupled to a third voltage level, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter;
a second N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to a fourth voltage source;
a third P-type transistor having a first terminal coupled to ground, a second terminal coupled to the control logic circuitry, and a third terminal coupled to an output terminal of the ultrasound transmitter;
a third N-type transistor having a first terminal coupled to the output terminal of the ultrasound transmitter, a second terminal coupled to the control logic circuitry, and a third terminal coupled to ground;
a first pair of diodes coupled to the first P-type transistor and the first N-type transistor and the output terminal of the ultrasound transmitter;
a second pair of diodes coupled to the second P-type transistor and the second N-type transistor and the output terminal of the ultrasound transmitter; and
a third pair of diodes coupled to the third P-type transistor and the third N-type transistor and the output terminal of the ultrasound transmitter.