Fatih Kocer

A new transponder architecture with on-chip ADC for long-range telemetry applications

We present a new architecture for wireless power and data telemetry that recovers power and a system clock from a weak incident RF signal. A high-efficiency RF-DC converter generates a 3-VDC supply for the system from a -12.3-dBm incident RF signal, gathered by a commercial 50-/spl Omega/ antenna. A system clock is extracted from the same incident signal, by an injection-locked LC oscillator. Sub-harmonic injection-locking facilitates the separation of the incident and the transmit signal frequencies, without need for a PLL. The proposed architecture is used in a long-range telemetry device, incorporating an on-chip ADC, and employing active telemetry for data transmission. Data is transmitted through binary phase-shift-keying of a 900-MHz carrier. The prototype, implemented in 0.25-/spl mu/m CMOS, occupies less than 1 mm/sup 2/. A wireless operation range of more than 18 meters is indicated by anechoic chamber testing.

An RF-powered, wireless CMOS temperature sensor

We present a wireless, fully integrated CMOS temperature sensor that recovers power from a radio frequency (RF) signal, and returns data as a frequency-modulated 2.3-GHz signal to a base station. Power is recovered from a 450-MHz incident signal with the help of a low-threshold, high-efficiency, voltage rectifier-multiplier circuit. This technique decreases the minimum incident RF power required, compared to state-of-the-art wirelessly powered telemetry systems. The rectifier-multiplier can collect energy from a base station placed up to 18 m away. To further increase the range from the base, the device collects energy in a low power standby/charging mode. A mode selector circuit monitors the amount stored energy and decides if the system is transmitting data or is in the standby/charging mode. A bootstrapped reference generates a complementary to absolute temperature (CTAT) voltage with an R-squared regression of 0.9995 to a linear fit. This reference is used as the temperature sensor of the system, controlling a low-power, integrated, voltage-controlled LC oscillator (VCO). The oscillation frequency of the VCO is modulated by ambient temperature changes. The modulated carrier is transmitted by a fully integrated power amplifier. A temperature sensitivity of 126 ppm/degC is achieved and the entire sensor consumes 1.1 mA while transmitting data

Wireless, remotely powered telemetry in 0.25 /spl mu/m CMOS

This new architecture for wireless power and data telemetry recovers power and system clock from a weak incident RF signal. An efficient RF-DC converter rectifies and multiplies the received signal, generating a practical DC voltage, far higher than the incident RF signal amplitude, increasing the range between the base station and the transponder. An injection locked LC oscillator recovers the system clock from the incident signal. Super-harmonic or sub-harmonic locking facilitates the separation of the incident and telemetry frequency without the need for a PLL. Experimental data from a 900 MHz transponder and a remotely powered 2.3 GHz wireless temperature sensor are presented. Both prototypes, implemented in 0.25 /spl mu/m CMOS, occupy less that 1 mm/sup 2/.

An RF powered, wireless temperature sensor in quarter micron CMOS

We present a wireless CMOS temperature sensor that gathers power through RF power telemetry, and transmits data wirelessly at 2.3 GHz to a base station. Power is gathered by a low threshold voltage rectifier-multiplier circuit decreasing the minimum incident peak signal amplitude required at the receiving port compared to the state of the art power telemetry systems. A low power integrated LC voltage controlled oscillator (VCO) lies at the heart of the system. The oscillation frequency of the VCO is modulated by change in the ambient temperature, and is transmitted via an integrated power amplifier. The measured phase noise of the oscillator is -101 dBc/Hz (@1 MHz offset) while consuming 400 /spl mu/A, achieving a figure of merit of 171 dBc/Hz. A linear temperature sensitivity of 126 ppm//spl deg/C is achieved with a total sensor current consumption of 1.1 mA.

An injection locked, RF powered, telemetry IC in 0.25 /spl mu/m CMOS

This wireless transponder recovers power and a reference clock from an incident RF signal and returns data on a 900MHz carrier. A multi-stage voltage multiplier/rectifier converts the received low power RF signal to a useful DC voltage and stores the energy on a storage capacitor. The injection locking technique facilitates power efficient generation of a low phase noise 900MHz internal clock from the received 450MHz signal by employing a fully integrated low power LC oscillator. A fully integrated pseudodifferential power amplifier operating in class AB regime is used as the output stage of the system. The system dissipates an average of 5 /spl mu/A in standby mode and 1.1 mA during active operation.

A new transponder architecture for long-range telemetry applications

We present a transponder architecture for long range, remotely powered, sensor telemetry applications. Power and a reference clock are recovered from a 450 MHz incident RF signal, and data is modulated on a 900 MHz carrier. A high efficiency RF-DC converter generates a 3 V/sub DC/ supply from a -123 dBm incident RF signal. An LC oscillator, injection locked to this incident RF signal, generates a high purity clock for high data rate transmission. A wireless operation range of more than 18 meters is indicated by anechoic chamber testing. Two versions, one with BPSK modulation, and another with on-off keying modulation, are implemented in a 5-metal 0.25/spl mu/m CMOS process. These devices also incorporate an ADC and a temperature sensor. The total die is less than 1.1 mm/sup 2/.

A long-range RFID IC with on-chip ADC in 0.25 /spl mu/m CMOS

This 1 mm/sup 2/ wireless telemetry device recovers power and a reference clock from a 450 MHz incident RF signal and returns data as a binary phase shift keyed signal on a 900 MHz carrier. The device generates a 3 V/sub DC/ supply from the -12.3 dBm incident RF signal. This corresponds to an operating distance of more than 18 meters in the US. The transmit data includes the output of an on-chip 5-bit single-slope analog-to-digital converter (ADC) and a 3-bit ID tag. The entire IC dissipates 4mW while active.