Identification of hotspots on FPGA using Time to Digital Converter and distributed tiny sensors

Abstract

Fully digital time-domain temperature sensors are designed and placed at five different positions within FPGA. Five tiny pulse-generators are used as five temperature sensors. Using manual floor-planning four sensors are placed at four different corners and one at centre. Single 9-bit Time to Digital Converter is utilized for digital output coding. Vernier Time to Digital Converter with 6 picoseconds resolution is presented here. The overall design utilizes 184 logical elements of FPGA i.e. less than 1.5% of the total resources. Implemented temperature sensors give nearly 0.5°C resolution and maximum of ±1.5 LSB nonlinearity is observed over the range.