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Temperature Monitoring

Temperature Monitoring Feature

August 23, 2010

Temperature Monitoring and Measurement Controller Cuts Power and Cooling Costs in Enterprise Systems

By Ashok Bindra, TMCnet Contributor

With the ever-increasing demand for computing and storage capacity, data center energy efficiency has become an important concern. The EPA estimates that data centers accounted for 1.5 percent of U.S. electricity consumption in 2006, and this demand is expected to nearly double by 2011, necessitating the development of an additional 10 power plants. Increasing data center energy efficiency through temperature monitoring can help avoid these infrastructural costs, while offering end users significant savings on their electricity bills.

To address this issue, analog and mixed-signal semiconductor manufacturer Maxim Integrated Products has readied a system management microcontroller chip that combines six temperature measurement channels with six channels of closed-loop fan control. By monitoring multiple temperature points throughout the system, the 16-bit MAX31782 enables enterprise system designers to implement highly precise zoned-cooling schemes. Thus, by individually adjusting the speed of each fan to deliver the exact amount of cooling required by each zone, Maxim’s microcontroller minimizes system power consumption and cooling costs. Plus, according to the supplier, it offers an added benefit of increased reliability through reduced fan wear, compensation for fan speed variances due to dust accumulation, and acoustic noise reduction.

A completely C-language programmable solution, the MAX31782 allows system designers to quickly and easily customize algorithms for precision zoned cooling in complex systems such as servers, network switches and routers, and base stations.

By monitoring multiple temperature nodes across the system, enterprise system designers can use a multichannel fan-controller IC to implement precision zoned cooling. This approach saves power by dynamically adjusting the speed of each cooling fan to meet the constantly changing thermal requirements of each zone, noted Maxim

Because fan power consumption is approximately equal to a square of its speed, reducing fan speed by just 30 percent can cut power consumption by as much as 50 percent. These power savings can provide significant cost savings for end users, while reducing the environmental footprint of the data center as a whole, added Maxim.

Furthermore, the supplier said that the conventional approach for implementing zoned cooling requires a microcontroller and an external multichannel temperature sensor. Compared to this multichip approach, the MAX31782 consumes 55 percent less board space and reduces cost by at least 25 percent, according to Maxim.

The MAX31782 can be directly connected to up to six remote thermal diodes, which are typically integrated on CPU, FPGA, and ASIC ICs. Using the on-chip master I2C interface, additional temperature points can be monitored with external digital temperature ICs, such as Maxim's high-accuracy DS7505. Based on the temperature information, the MAX31782 can control up to six cooling fans, each with an independent 16-bit PWM output and timer/tachometer input. It thus provides a complete closed-loop system for multiple fans, allowing accurate zoned cooling with minimum energy expended for fan power.

In addition, it incorporates a 6-channel, 12-bit analog-to-digital converter (ADC (News - Alert)) with a temperature-sensing analog front-end (AFE) that allows direct connection to thermal diodes. The AFE offers 0.125 °C resolution, series resistance cancellation for the entire external diode circuit, and configurable ideality factor to deliver the highest temperature measurement accuracy.

Based on a 16-bit MAXQ20 RISC microcontroller core, the MAX31782 provides ample space for programs and data with 32-kWord reprogrammable flash and 1-kWord RAM (News - Alert) for data storage. C-language and assembly-based programming is supported with the IAR Embedded Workbench for MAXQ, available in time-limited or code-limited versions for free product evaluation. This tool also accommodates in-circuit flash programming and code debugging through the MAX31782's integrated JTAG-compatible debug port.

Housed in a 6-mm x 6-mm, 40-pin TQFN package, the CMOS based MAX31782 is fully specified over the temperature range of -40 °C to +85 °C. Operating voltage is 2.7 V to 5.5 V. Typical current consumption is 4 mA at 3.3 V. Pricing starts at $2.95, in quantities of 10,000 and up.

Ashok Bindra is a veteran writer and editor with more than 25 years of editorial experience covering RF/wireless technologies, semiconductors and power electronics. To read more of his articles, please visit his columnist page.

Edited by Erin Monda