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A speaker driver applied to class G/class I with a single phase power supply is presented. Gain expanding and compressing technology are employed in the signal processing circuit to optimize power dissipation. The circuit is implemented in 0.18 m N-well CMOS. Experimental results show that the speaker driver has a good audio sound quality and power efficiency. Less than 0.006% THD at a low power range and less than 0.4% at a medium power range can be obtained with a 1 kHz sine wave signal. Maximum output power of 360 mW can be gained at a load of 8 . The power efficiency is about twice that of a traditional class AB driver at the power range of 80 mW and shows more than 18% improvement at the higher output power range.

Food toxins are a hidden threat that can cause cancer and tremendously impact human health. Therefore, the detection of food toxins in a timely manner with high sensitivity is of paramount importance for public health and food safety. However, the current detection methods are relatively time-consuming and not practical for field tests. In the present work, we developed a novel aptamer-chip-based sample-to-answer biosensor (ACSB) for ochratoxin A (OTA) detection via fluorescence resonance energy transfer (FRET). In this system, a cyanine 3 (Cy3)-labeled OTA-specific biotinylated aptamer was immobilized on an epoxy-coated chip via streptavidin-biotin binding. A complementary DNA strand to OTA aptamer at the 3′-end was labeled with a black hole quencher 2 (BHQ2) to quench Cy3 fluorescence when in proximity. In the presence of OTA, the Cy3-labeled OTA aptamer bound specifically to OTA and led to the physical separation of Cy3 and BHQ2, which resulted in an increase of fluorescence signal. The limit of detection (LOD) of this ACSB for OTA was 0.005 ng/mL with a linearity range of 0.01–10 ng/mL. The cross-reactivity of ACSB against other mycotoxins, ochratoxin B (OTB), aflatoxin B1 (AFB1), zearalenone (ZEA), or deoxynilvalenol (DON), was less than 0.01%. In addition, this system could accurately detect OTA in rice samples spiked with OTA, and the mean recovery rate of the spiked-in OTA reached 91%, with a coefficient of variation (CV) of 8.57–9.89%. Collectively, the ACSB may represent a rapid, accurate, and easy-to-use platform for OTA detection with high sensitivity and specificity.

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A 65-nm all-digital Class-S transmitter with an entire digital frontend (DFE) and a current-mode Class-D (CMCD) power amplifier (PA) is presented. To realize the high operation rate and performance of the DFE, which includes a 1-bit band-pass modulator, a mixer, and interpolation filters, approaches, such as time-interleaving algorithm and modified Manchester encoding, are adopted. The main blocks in the DFE are implemented using standard cells with electronic design automation tools for synthesis and place and route. A CMCD PA with an ON-chip transformer is designed and integrated. This Class-S transmitter exhibits a 40-MHz bandwidth at up to a 1.6 GHz output carrier frequency. Measurements with a 1-MHz channel-spacing π/4 quadrature phase shift keying signal show a power control range of −18.66 to −4.65 dBm, and the power consumption of the modulator core is 7 mW.