A high-voltage class D audio amplifier for dielectric elastomer transducers

2023

Sensors

An inverse Class-E power amplifier was designed for an ultrasound transducer. The proposed inverse Class-E power amplifier can be useful because of the low series inductance values used in the output matching network that helps to reduce signal distortions. Therefore, a newly designed Class-E power amplifier can obtain a proper echo signal quality. The measured output voltage, voltage gain, voltage gain difference, and power efficiency were 50.1 V, 22.871 dB, 0.932 dB, and 55.342%, respectively. This low voltage difference and relatively high efficiency could verify the capability of the ultrasound transducer. The pulse-echo response experiment using an ultrasound transducer was performed to verify the capability of the proposed inverse Class-E power amplifier. The obtained echo signal amplitude and pulse width were 6.01 mVp-p and 0.81 μs, respectively. The −6 dB bandwidth and center frequencies of the echo signal were 27.25 and 9.82 MHz, respectively. Consequently, the designed Class-E power amplifier did not significantly alter the performance of the center frequency of the ultrasound transducer; therefore, it could be employed particularly in certain ultrasound applications that require high linearity and reasonable power efficiency.

Section: Studies On Ultrasound Applicationsmentioning

confidence: 99%

An Inverse Class-E Power Amplifier for Ultrasound Transducer

2023

Sensors

“…In Figure 12 , a zero-voltage switching mechanism is used such that one MOSFET is turned on and another MOSFET is turned off during the 50% duty cycle [ 94 ]. The turn-on/off time is dependent on the values of the inductor (L 1 ), transistor parasitic drain-source parasitic capacitance (C DS ), and capacitor (C 1 ) [ 94 ]. An output gain of 43.5 dB, a resonant frequency of 0.1 kHz, and an efficiency of 42% was obtained from the Class-D power amplifier.…”

Section: Classifications Of Power Amplifiersmentioning

confidence: 99%

“…An output gain of 43.5 dB, a resonant frequency of 0.1 kHz, and an efficiency of 42% was obtained from the Class-D power amplifier. In Figure 12, a zero-voltage switching mechanism is used such that one MOSFET is turned on and another MOSFET is turned off during the 50% duty cycle [94]. The turn-on/off time is dependent on the values of the inductor (L 1 ), transistor parasitic drainsource parasitic capacitance (C DS ), and capacitor (C 1 ) [94].…”

Section: Class-d/de Power Amplifiermentioning

confidence: 99%

Power Amplifier Design for Ultrasound Applications

2023

Micromachines

A design analysis of the power amplifiers developed for ultrasound applications was conducted because ultrasound applications require different types of power amplifiers, which are one of the most critical electronic components in ultrasound systems. To generate acoustic signals using transducers, which are among the most important mechanical devices in ultrasound systems, an appropriate output voltage, current, or power signal must be produced by a power amplifier. Therefore, an appropriate design analysis of the power amplifier must be conducted to obtain the optimal performance from a transducer. In addition, because of new ultrasound research trends, such as ultrasound systems with other imaging modalities and wireless ultrasound systems, the selection of an appropriate power amplifier could improve the performance of an ultrasound system with other imaging and therapy modalities. This paper describes the design parameters of a power amplifier, including the gain, bandwidth, harmonic distortion, and efficiency. Each power amplifier has specific applications and limitations. Therefore, this review will assist design engineers and ultrasound researchers who need to develop or use power amplifiers in ultrasound applications.

“…A class-D power amplifier was developed to generate 2 kW of output power, resulting in better signal quality with a power piezoelectric load [17][18][19]. A class-D amplifier was developed to generate a maximum output voltage of 125 V rms for a dielectric elastomer transducer [20]. A 1010 kHz class-DE power amplifier with output power of 800 mW was designed to generate a piezoelectric ultrasound transducer that can be integrated with MRI machines [21,22].…”

Section: Introductionmentioning

confidence: 99%

Harmonic-Reduced Bias Circuit for Ultrasound Transducers

2023

Sensors

The gain of class-C power amplifiers is generally lower than that of class-A power amplifiers. Thus, higher-amplitude input voltage signals for class-C power amplifiers are required. However, high-amplitude input signals generate unwanted harmonic signals. Therefore, a novel bias circuit was proposed to suppress the harmonic signals generated by class-C power amplifiers, which improves the output voltage amplitudes. To verify the proposed idea, the input harmonic signals when using a harmonic-reduced bias circuit (−61.31 dB, −89.092 dB, −90.53 dB, and −90.32 dB) were measured and were found to be much lower than those when using the voltage divider bias circuit (−57.19 dB, −73.49 dB, −70.97 dB, and −73.61 dB) at 25 MHz, 50 MHz, 75 MHz, and 100 MHz, respectively. To further validate the proposed idea, the pulse-echo measurements were compared using the bias circuits. The peak-to-peak echo amplitude and bandwidth of the piezoelectric transducer, measured when using a harmonic-reduced bias circuit (27.07 mV and 37.19%), were higher than those achieved with a voltage divider circuit (18.55 mV and 22.71%). Therefore, the proposed scheme may be useful for ultrasound instruments with low sensitivity.