Patent ID: 9362876
Filing Date: 2016-06-07
CPC Classification: H03F,H03G

Claim Text:
1. A digital controller for use with an ultrasound power amplifier circuit to increase linearity and efficiency of the ultrasound power amplifier circuit, wherein the digital controller comprises: a digital signal generator that has a first output and a second output; a digital to analog converter that has an output coupled to an input of the ultrasound power amplifier circuit and an input coupled to the first output of the digital signal generator; a memory unit that has a first input coupled to the second output of the digital signal generator, an output coupled to the input of the digital to analog converter, and the memory unit comprises a processor and a look-up table; a delay adjustment block coupled to the input of the digital to analog converter; a feedback circuit that has a first input comprising an analog to digital converter coupled to an output of the ultrasound power amplifier circuit, a second input coupled to the delay adjustment block, and an output coupled to a second input of the memory unit; and the processor obtains an output signal from the ultrasound power amplifier circuit through the feedback circuit and an ideal output signal from the digital signal generator that is delayed based on the delay adjustment block, and repeatedly operates in a calibration mode followed by an evaluation mode, wherein the processor: (i) calculates a value of error based on a difference between the delayed ideal output signal and the output signal obtained from the ultrasound power amplifier circuit, and stores the value of error in the look-up table in the calibration mode, and (ii) equalizes an input signal from the digital signal generator to reduce nonlinearity in the output signal of the ultrasound power amplifier circuit using the value of error stored in the look-up table in the evaluation mode.