This paper presents a non-linear analysis of DC-shift induced by power supply noise in bandgap voltage references based on a diode connected PNP bipolar junction transistors (BJT) couple. The analysis is based on diode non-linear characteristic causing a variation of biasing currents involved in closed loop feedback. The observed effect is discussed, simulated, measured and compared with analytical derivation. A bandgap reference has been implemented in a CMOS 28 nm technology and used for successfully validating the proposed analysis.

This paper presents a 4.8 V tolerant circuit for reliably switching a startup load between a main power supply and a battery power supply. The circuit automatically switches the main power supply over to the battery in case the main line has been interrupted. The circuit includes a pair of back-to-back switch transistors for isolating the load from each power supply, a bias circuit for controlling the switch transistors, two independent current sources and two current subtraction units for deciding which supply to provide to the load. It consumes less than 1 μA per input and it can supply a startup circuitry up to 50 μA. The circuit has been implemented in a CMOS 28 nm technology, using only “low-voltage” devices and was successfully validated in the lab.

This paper presents an integrated bandgap reference circuit which is addressing low current consumption and a wide supply voltage range, using a current mode structure. Embedded in a sophisticated Power Management Unit (PMU) for a GNSS receiver, this bandgap reference has an output of 0.60 V and it can reach a temperature coefficient of 33 ppm/°C in the range from -40 °C to 125 °C. With a 1.4 V supply voltage, the power is only 3.5 μW and the PSRR is 57 dB at DC frequency. Occupying 0.125 mm2 chip area, this bandgap reference has been implemented in the CMOS 28 nm technology from Globalfoundries and successfully validated in the lab.

When passive RFID tags are used, RFID readers need to transmit a constant carrier, during uplink communication to provide sufficient operating power to the tag. This high power carrier with its associated noise, limits the receiver sensitivity and, hence, the possible reading range. This letter proposes a new way to cancel the received carrier. The topology, based on a directional coupler and a reflective vector modulator, has a very small area consumption and is very attractive to use with integrated reader ICs. The principle of operation as well as the noise contribution of the circuit itself are discussed.