A GaN-Based Wireless Monitoring System for High-Temperature Applications

Abstract

A fully-integrated data transmission system based on gallium nitride (GaN) high-electron-mobility transistor (HEMT) devices is proposed. This system targets high-temperature (HT) applications, especially those involving pressure and temperature sensors for aerospace in which the environmental temperature exceeds 350 °C. The presented system includes a front-end amplifying the sensed signal (gain of 50 V/V), followed by a novel analog-to-digital converter driving a modulator exploiting the load-shift keying technique. An oscillation frequency of 1.5 MHz is used to ensure a robust wireless transmission through metallic-based barriers. To retrieve the data, a new demodulator architecture based on digital circuits is proposed. A 1 V amplitude difference can be detected between a high-amplitude (data-on) and a low-amplitude (data-off) of the received modulated signal. Two high-voltage supply levels (+14 V and −14 V) are required to operate the circuits. The layout of the proposed system was completed in a chip occupying 10.8 mm2. The HT characterization and modeling of integrated GaN devices and passive components are performed to ensure the reliability of simulation results. The performance of the various proposed building blocks, as well as the whole system, have been validated by simulation over the projected wide operating temperature range (25–350 °C).

Circuit Techniques in GaN Technology for High-Temperature Environments

“…Recently, we had investigated the possibility of using GaN500 HEMT technology to implement HT ICs [15][16][17][18][19] at the Polystim Laboratory [20]. The results reported in [15] confirmed the stability of tested GaN devices from room temperature up to 400 • C. In [16], basic digital circuits were implemented using GaN500 and off-chip resistors achieving HT operation up to 400 • C. In addition, three demodulators were demonstrated to recover data from an LSK-based modulated signal.…”

“…The functionality of the demodulators was validated by simulations. The modulation/demodulation system proposed in [17] was the first GaN500-based integrated data transmission system. This modulation system was based on a simplified delta-sigma modulation technique, and a fully digital demodulator was implemented to recover data from a modulated signal.…”

A Versatile SoC/SiP Sensor Interface for Industrial Applications: Implementation Challenges

“…Besides, non-silicon processes such as GaN 500, offered by the Canadian National Research Council (NRC) can be considered. This process has technology files that support design operating up to 350 • C [74] and was shown to work reliably up to 600 • C [67]. Some key features of these different high-voltage processes are summarized and compared in Table 4.…”

Mathematical Model-Based Analysis and Mitigation of GaN Switching Oscillations

“…GaN can effectively overcome carrier freeze-out issues due to its polarizationinduced doping, in contrast to other technologies, including doped silicon, which are significantly impacted by this problem [7]. GaN has already been widely adopted in fast chargers, data centers, wireless charging and electric transportation due to its physical superiority over Si and SiC for power applications [8]. Improvements in these applications might include enhancing the switching frequency to several megahertz, significantly reducing the volume or further enhancement in efficiency.…”