In next-generation integrated systems, high power densities and thermal issues can dramatically degrade performance, reliability, leakage current, and system robustness. Allocating heat conduction paths and specialized cooling systems can help protect from overheating, but these systems must be supported with a temperature aware capability to allocate and properly respond to critical hot spots. This can be achieved by distributing a large number of on-chip thermal sensors that are small in size, low power, high speed, sensitive, accurate over a wide temperature range, and appropriately placed to accurately capture local hot spots. The use of only a few thermal sensors placed in the vicinity of the integrated system, however, limits the ability to fully monitor the significant spatial and dynamic temperature variations across an integrated system. Existing thermal aware systems are able to manage the located distributed thermal sensor nodes around an integrated circuit (IC), dynamically controlling the system workload, but they utilize a software-based management system which does not respond to individual thermal sensor nodes. In addition, the response time of these software solutions is long and consumes significant power; hence hardware solutions are desirable.
This invention is a hybrid spintronic/CMOS-based analog thermal sensor based on the high temperature sensitivity of the magnetic tunnel junction (MTJ) antiparallel resistance. Multiple thermal sensor nodes are distributed across an IC and associated circuitry and communicate with a centralized sensing unit, which collects temperature information from the network of individual sensor nodes and produces a thermal map of the system. The sensor node voltage is compared with a reference voltage to set a threshold temperature, and thus the thermal network provides the monitored system with dynamic real-time thermal information about the location of the critical hot spots.
This sensor nodes have a very small footprint, utilize extremely low power, and have a high linearity of 0.9 and a high sensitivity of 4.8 mv/K over a temperature range of -55°C to 125°C. This system of 1,045 thermal sensors distributed in a 32 x 32 grid structure consumes approximately 500 pJ, providing a low energy and high sensitivity thermal aware system for improved thermal control of next-generation integrated systems.
Integrated systems