A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally.

To efficiently scavenge ambient vibration energy and wind energy at the same time, a low-frequency piezoelectric harvester was designed, fabricated and tested. A lumped-parameter model of the cantilevered piezoelectric energy harvester with a proof mass was established and the closed-form expressions of voltage and power on a resistance load under base acceleration excitation were derived. After effects of the lengths of the proof mass and electrodes on output power were analyzed, a MEMS harvester was optimally designed. By using aluminum nitride as piezoelectric layer, a MEMS energy harvester was fabricated with bulk micromachining process. Experimental results show that the open-circuit frequency of the MEMS harvester is about 134.8 Hz and the matched resistance is about 410 k . Under the harmonic acceleration excitation of ± 0.1 g, the maximum output power is about 1.85 μW, with the normalized power density of about 6.3 mW cm −3 g −2 . The critical wind speed of the device is between 12.7 and 13.2 m s −1 when the wind direction is from the proof mass to the fixed end of the cantilever. The maximum output power under 16.3 m s −1 wind is about 2.27 μW.

A process of failure analysis of a COMS chip damaged by Electro-Static Discharge (ESD) is presented. The method of the thermal image was used to locate the failure spot. To find out the root of the failure, the circuit principle and the layout of the chip were analyzed, and it was found that the layout design was not unreasonable. An ESD test was carried out to confirm the analysis. This work has reference significance for the failure analysis and reliability improvement of the integrated circuit product.

No abstract

A failure analysis process of a circuit with AC (alternating current) noise in the output signal is presented. To find out the root of the failure, the circuit principle and the layout of the circuit were analyzed, and it was found that the layout design was not unreasonable. Specifically, the output signal wire is too close to the clock signal wire, which results in the coupling crosstalk. To eliminate the coupling crosstalk, serval measures including the filter design, replacement of resistor, and layout optimization were adopted. This work has reference significance for the anti-interference design of circuits.