Amplifier with built in time gain compensation for ultrasound applications
An ultrasound circuit comprising a trans-impedance amplifier (TIA) with built-in time gain compensation functionality is described. The TIA is coupled to an ultrasonic transducer to amplify an electrical signal generated by the ultrasonic transducer in response to receiving an ultrasound signal. The TIA is, in some cases, followed by further analog and digital processing circuitry.
1. An ultrasound apparatus, comprising:
an ultrasonic transducer to provide an analog electrical signal;
an amplifier having time gain compensation (TGC) functionality coupled to the ultrasonic transducer and configured to receive and amplify the analog electrical signal by a time-dependent amount;
wherein:
the amplifier comprises amplification circuitry and feedback circuitry with a variable impedance; and
the feedback circuitry comprises a plurality of resistors in a series arrangement, and wherein a subset of the plurality of resistors have respective resistance values that increase sequentially in a logarithmic fashion.
2. The ultrasound apparatus of claim 1 , wherein the amplifier is a trans-impedance amplifier (TIA).
3. The ultrasound apparatus of claim 1 , wherein the amplifier is a trans-conductance amplifier.
4. The ultrasound apparatus of claim 1 , wherein the amplifier is a low noise amplifier (LNA).
5. The ultrasound apparatus of claim 1 , wherein the ultrasonic transducer is a first ultrasonic transducer and the amplifier is a first amplifier, the ultrasound apparatus comprising a plurality of ultrasonic transducers including the first ultrasonic transducer and a plurality of respective amplifiers coupled to the respective ultrasonic transducers, the plurality of respective amplifiers including the first amplifier, wherein the ultrasound apparatus further comprises an averaging circuit coupled to the plurality of respective amplifiers.
6. The ultrasound apparatus of claim 5 , wherein the averaging circuit comprises TGC circuitry distinct from the TGC functionality of the amplifier.
7. The ultrasound apparatus of claim 1 , wherein the ultrasonic transducer and the amplifier are integrated on a same substrate to form an integrated electronic device.
8. The ultrasound apparatus of claim 1 , wherein the amplifier is configured to receive a plurality of control signals, and wherein the time-dependent amount of gain is determined based on at least one control signal of the plurality of control signals.
9. The ultrasound apparatus of claim 8 , wherein the at east one control signal represents a signal from a charge pump.
10. The ultrasound apparatus of claim 9 , wherein the charge pump comprises a capacitor.
11. The ultrasound apparatus of claim 1 , wherein the analog electrical signal comprises ultrasound image data.
12. The ultrasound apparatus of claim 1 , further comprising a switch coupled between the ultrasonic transducer and the amplifier.
13. An ultrasound circuit, comprising:
an ultrasonic transducer;
an analog signal processing chain coupled to the ultrasonic transducer; and
an analog-to-digital converter (ADC), wherein the analog signal processing chain is coupled electrically between the ultrasonic transducer and the ADC, wherein the analog signal processing chain includes a combined trans-impedance amplifier (TIA) and time gain compensation (TGC) circuit; and
a plurality of ultrasonic transducers including the ultrasonic transducer and a plurality of respective combined TIA and TGC circuits coupled to respective ultrasonic transducers, the plurality of respective combined TIA and TGC circuits including the combined TIA and TGC circuit, wherein the ultrasound apparatus further comprises an averaging circuit coupled to the plurality of respective combined TIA and TGC circuits.
14. The ultrasound circuit of claim 13 , wherein the analog signal processing chain lacks a distinct TGC circuit between the combined TIA and TGC circuit and the ADC.
15. The ultrasound circuit of claim 13 , further comprising a switch coupled between the ultrasonic transducer and the combined TIA and TGC circuit.
16. The ultrasound circuit of claim 13 , wherein the averaging circuit comprises a TGC circuit.
17. The ultrasound circuit of claim 13 , wherein the combined TIA and TGC circuit is configured to apply a time varying amount of gain to an analog electrical signal from the ultrasonic transducer.
18. The ultrasound circuit of claim 17 , wherein the combined TIA and TGC circuit is configured to receive a plurality of control signals determining a magnitude of the time varying amount of gain.
19. The ultrasound system of claim 18 , further comprising charge pump circuitry configured to delay logic level transitions of at least one control signal of the plurality of control signals.
20. The ultrasound circuit of claim 18 , further comprising switching circuitry configured to receive a plurality of switching signals, the switching circuitry configured to assert the plurality of control signals in a sequential order.
21. The ultrasound circuit of claim 18 , further comprising selectable resistive segments configured to be selected by the plurality of control signals to increase the magnitude of the time varying amount of gain by logarithmically scaled increments.