TelCom Semiconductor Inc. (Mountain View, CA) recently announced two new additions to their proprietary line of fan controllers, the TC647 and TC649. The TC647 and TC649 are stand-alone, low-cost fan managers that integrate a pulse width modulation (PWM) fan speed controller with start-up timer and fan-fault detection circuitry. The fan speed control's PWM is claimed to reduce the acoustic noise of a fan, extend fan life and lower the average fan's operating current.
The TC647/649 can drive any standard two-wire fan through a low-cost transistor or logic level MOSFET. The devices take a temperature signal, generated with a NTC thermistor and resistor, as input. These fan controllers provide temperature-proportional fan-speed control, whereby the fan speed is increased linearly from 40-percent speed to 100-percent speed based on a user-programmed temperature range. The TC647 and TC649 differ from the TC642 and TC646 in one significant way, the TC647 and TC649 do not include an over-temperature fault alert.
The TC647/649 are available in standard eight-pin PDIP and SOIC packages, and are considered ideal for personal computer motherboards, power supplies and any other application that uses brushless dc fans for forced-air cooling. Both package options are available with commercial and industrial temperature ranges. In quantities of 1,000, pricing for the TC647 starts at $1.40, and pricing for the TC649 starts at $1.33.