CMOS temperature sensor with ring oscillator for mobile DRAM self-refresh control

—This paper presents novel low-cost CMOS temperature sensor for controlling the self-refresh period of a mobile DRAM. In the proposed temperature sensor, the temperature dependency of poly resistance is used to generate a temperature-dependent bias current, and a ring oscillator driven by this bias current is employed to obtain the digital code pertaining to on-chip temperature. This method is highly areaefficient, simple and easy for IC implementation as compared to traditional temperature sensors based on bandgap reference. The proposed CMOS temperature sensor was fabricated with an 80nm 3-metal DRAM process, which occupies extremely small silicon area of only about 0.016 with under 1uW power consumption for providing 0.7 effective resolution at 1 sample/sec processing rate. This result indicates that as much as 73% area reduction was obtained with improved resolution as compared to the conventional temperature sensor in mobile DRAM.

• Type: Conference
• Year: 2008
• Where: ISCAS
• Authors: Chan-Kyung Kim, Bai-Sun Kong, Chil-Gee Lee, Young-Hyun Jun
• Keywords: CMOS Temperature Sensor, Hardware, ISCAS 2008, Mobile Dram, Temperature Sensor