器件名称: TC647BEPA713
功能描述: PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense
文件大小: 662.92KB 共34页
简 介:M
Features
TC642B/TC647B
Description
The TC642B/TC647B devices are new versions of the existing TC642/TC647 fan speed controllers. These devices are switch mode, fan speed controllers that incorporate a new fan auto-restart function. Temperature-proportional speed control is accomplished using pulse width modulation. A thermistor (or other voltage output temperature sensor) connected to the VIN input supplies the required control voltage of 1.20V to 2.60V (typical) for 0% to 100% PWM duty cycle. Minimum fan speed is set by a simple resistor divider on the VMIN input. An integrated Start-Up Timer ensures reliable motor start-up at turn-on, coming out of shutdown mode or following a transient fault. A logic-low applied to VMIN (pin 3) causes fan shutdown. The TC642B and TC647B also feature Microchip Technology's proprietary FanSense technology for increasing system reliability. In normal fan operation, a pulse train is present at SENSE (pin 5). A missingpulse detector monitors this pin during fan operation. A stalled, open or unconnected fan causes the TC642B/ TC647B device to turn the VOUT output on full (100% duty cycle). If the fault persists (a fan current pulse is not detected within a 32/f period), the FAULT output goes low. Even with the FAULT output low, the VOUT output is on full during the fan fault condition in order to attempt to restart the fan. FAULT is also asserted if the PWM reaches 100% duty cycle (TC642B only), indicating that maximum cooling capability has ……
