General Description
●The TC646 is a switch mode, fan speed controller for use with brushless DC fans. Temperature proportional speed control is accomplished using pulse width modulation (PWM). A thermistor (or other voltage output temperature sensor) connected to the VIN input furnishes the required control voltage of 1.25V to 2.65V (typical) for 0% to 100% PWM duty cycle. The TC646
●automatically suspends fan operation when measured temperature (VIN) is below a user programmed minimum setting (VAS). An integrated Start-up Timer ensures reliable motor start-up at turn-on, coming out of shutdown mode, auto-shutdown mode or following a transient fault.
●Features
●• Temperature Proportional Fan Speed for Acoustic Control and Longer Fan Life
●• Efficient PWM Fan Drive
●• 3.0V to 5.5V Supply Range:
●\- Fan Voltage Independent of TC646 Supply Voltage
●\- Supports any Fan Voltage
●• FanSense™Fault Detection Circuits Protect Against Fan Failure and Aid System Testing
●• Shutdown Mode for "Green" Systems
●• Supports Low Cost NTC/PTC Thermistors
●• Space Saving 8-Pin MSOP Package
●• Over-temperature Indication
●Applications
●• Power Supplies
●• Computers
●• File Servers
●• Portable Computers
●• Telecom Equipment
●• UPS, Power Amps
●• General Purpose Fan Speed Control
