Product category:
Power Supply ICs and Controllers
News Release from: Zetex | Subject: ZXBM2004
Edited by the Electronicstalk Editorial
Team on 25 September 2003
Controller takes charge of cooling fans
The ZXBM2004 variable-speed two-phase motor controller provides flexible thermal control for electronic equipment requiring forced air-cooling, such as PCs, servers and set top boxes.
For electronic equipment requiring forced air-cooling, such as PCs, servers and set top boxes, the ZXBM2004 variable-speed two-phase motor controller from Zetex provides added flexibility in thermal control Controlling brushless DC fans and blowers up to 100W in size in response to either NTC thermistor, voltage or PWM input signals, the ZXBM2004 governs motor speed, power consumption and audible noise in direct relation to ambient temperature conditions
This article was originally published on Electronicstalk on 6 Feb 2002 at 8.00am (UK)
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Chip takes control of brushless fans and blowers
The ZXBM2000 series of controller ICs offers a complete variable speed control solution for two-phase, DC brushless fan and blower motors up to 100W.
By substituting the ZXBM2004 variable speed controller for a motor's fixed internal speed controller, the need for a separate PWM driver IC and power mosfet stage is also removed, so reducing component count and overall system cost as a result.
The minimum speed setting function of the ZXBM2004 is particularly useful when a fan starts up under cold conditions.
A user-defined minimum speed setting prevents the fan from running unduly slowly or not being able to start at all.
The addition of an external resistor guards against supply voltage fluctuations enabling fan speed and therefore air flow to be maintained at the required level.
To detect fan rotation and speed, a built-in Hall amplifier enables Hall sensors to be wired directly to the controller.
Compatible with virtually any type of Hall-effect sensor, the ZXBM2004 removes the need for external signal conditioning circuitry.
The motor controller provides two separate diagnostic outputs: a pulsed rotor speed output and a locked rotor alarm output.
When an obstruction in the fan blade or a seized bearing causes a locked rotor condition, the controller ensures that phase drive outputs go into a safe mode to protect the transistor pair and motor windings.
Automatic restart is dependent on the setting of a single capacitor.
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