"24V DC Cooling Fan" on power-up, shutdown and restart recovery mode after a transient fault, integrated on-chip starting a timer to ensure reliable fan motor starts. In VMIN (Pin 3) applying a logic low causes fan shutdown mode. TC642 also features Microchip Technology's FanSenseTM patented technology to improve system reliability. Fan normal operation, the missing pulse detector pulse sequence SENSE pin (pin 5) on the monitor. This circuit is normally no problem, as the temperature rises, the faster the fan speed, the fan voltage applied to the larger drop fan full speed when only about 0.1-0.2V. Incredibly small. And with simulation tools are not able to simulate the effect.