This thesis presents an energy-efficient high-accuracy temperature sensor that combines a BJT front-end with a continuous-time readout circuit. Its front-end is based on PNP transistors, which, compared to NPNs, are more widely available in CMOS processes and less sensitive to stress. In this design, proportional-to-absolute-temperature (PTAT) and complementary-toabsolute-temperature (CTAT) currents are created by forcing ΔVBE and VBE over two resistors
of the same type, after which their ratio is digitized by a continuous-time Delta-Sigma Modulator (CTDSM). As a result, the sampling noise present in traditional switched-capacitor (SC) modulators is eliminated, which improves the sensor’s energy efficiency. High accuracy is achieved by the liberal use of chopping and dynamic element matching techniques. Fabricated in a 0.18µm CMOS process, the sensor achieves a 0.15°C (3σ) inaccuracy over the industrial temperature range (-45°C to 85°C) after a 1-point temperature calibration. It also achieves a 1.24mK resolution in 56.3ms, while consuming only 16µW. This corresponds to a state-of-theart resolution Figure-of-Merit (FoM) of 1.4pJ°C2.

In recent years the field of wireless charging has seen remarkable developments. More and more devices like mobile phones and laptops can be charged wirelessly, and larger equipment like electric vehicles are likely to follow the same path. The air gaps over which the power can be transferred keeps increasing, as do the
amount of power that can be transferred and the power transfer efficiency. Though combining these three key requirements has turned out to be a problem, since there always seems to be a trade off. This thesis will focus on the design process and the result of a wireless charger for hand held devices like mobile phones. This thesis will only describe the receiver side of the wireless power transfer system. The requirements were an output of 5V at 5W, over an as large as possible air gap with an efficiency of at least 60%. After the complete circuit had been designed and assembled an efficiency of 67.8% at a distance of 2.5cm had been obtained, which satisfies the requirements.