Intelligent fan driver offers closed-loop control for fan speed, temperature

Andigilog, the fabless semiconductor company providing intelligent thermal management solutions, has expanded its product line with two new products. The aMC8520 is the first device in the industry to provide closed-loop speed control with thermal temperature compensation in a single device without the use of microcode. It provides a highly integrated solution for fans that run more quietly and reliably, increasingly important requirements in the PC market.

For PC applications as well as communications, consumer electronic and industrial systems requiring open loop performance, the Andigilog aMC8510 uniquely offers both analog and digital speed control of DC brushless fans to address the critical issues of managing system temperature, fan noise and power consumption. DC brushless fans using this device now can be run more efficiently due to intelligent speed management over the complete duty cycle, allowing the system to run cooler with less power and less noise.

“Power, reliability and acoustics continue to present challenges for designers and users of fans in applications in computing, consumer, communication and industrial areas,” noted Susie Inouye, research director and principal analyst at Databeans. “Andigilog's new intelligent fan controllers provide much- needed solutions to address these challenges.”

Andigilog thermal Management chips

Both new devices include Andigilog's QuietStart technology, which manages acoustic noise at fan start-up and while the fan runs. This technology saves power and improves reliability by eliminating current surges in the system. The new devices also reduce the bill of materials for fans by combining analog and digital speed control inputs through a single pin.

“Andigilog's innovative solutions for thermal management already are helping PC makers solve critical processor-based cooling issues,” said Bill Sheppard, CEO, Andigilog. “Our unique new devices give PC makers more ways to manage heat effectively while improving performance, reducing ambient noise and reducing power consumption.”

The aMC8520, a single-phase, closed-loop fan pre-driver, provides all required functions to implement closed-loop control of fan speed. The device is the industry's first to offer digital fan speed signal control with temperature sensor measurement compensation without the use of microcode. With these functions integrated in a single device, the bill of materials cost and component count can be reduced while improving performance, reliability and power savings. The benefit of a closed loop system to a thermal management system designer is that, regardless of the characteristics of the fan, the fan speed output will be linear across the operating range. With the inclusion of temperature compensation, fans built around the aMC8520 will be quieter and run more efficiently than standard fan controller systems. Other features include:

  • Andigilog's proprietary QuietStart Technology that guarantees the fan will start with a slow, gradual acceleration for minimizing acoustic impact and minimizing power usage
  • Integrated fault timer with auto start retry provides built-in support for detecting and attempting to remove fan blockages without additional components
  • Programmable minimum speed setting for continuous thermal management
  • Support for high voltage motors (12V and above) to address the high- performance requirements for servers, communications and industrial systems
  • Current limit, under voltage lockout and thermal shutdown protection, which help improve system safety and reliability

The aMC8510, a single-phase, open-loop fan pre-driver, provides all required functions to implement open-loop fan speed control. It offers the system designer a direct PWM input, which eliminates the need to convert the PWM speed control input from the host computer to a linear control voltage and reduces parts needed for the fan hub. In addition to these features, including QuietStart Technology, the aMC8510 has a selectable speed control slope function that enables the device to work within multiple system architectures. It also has a pinned-out 3.5 volt reference for system stability.

The aMC8510 and aMC8520 controllers are available in environmentally-friendly RoHS-compliant and Pb-free matte SN lead finish packaging.
General samples and an evaluation kit including a tuning board are available now with production planned for Q3 2007. The aMC8510 is priced at $1.50 per unit U.S. in 1K unit quantities. The aMC8520 is priced at $2.00 per unit U.S. in 1K unit quantities.

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