Power chip

The NCT7491 is a 2-wire serial programmable hardware supervisor. It monitors 2 remote temperature zones and its own ambient temperature. PECI 3.0 single-wire interface supports NCT7491 to monitor CPU temperature. The NCT7491 can also implement an SMBus-compatible host, allowing it to automatically read data from thermal sensors on the SMBus. NCT7491 adopts PWM control, which can automatically control the speed of 3 fans and monitor the speed of 4 fans. There are 4 analog inputs for measuring 12 V, 5 V, 2.5 V and Vccp channels. The NCT7491 supply voltage and PECI VTT voltage are also monitored. The individual measured temperature, voltage, and fan speed values ​​are compared to programmable limits and if any channel exceeds the programmable limits, an interrupt signal is generated via the ALERT output pin. A high temperature output is also available for fail-safe high temperature control. Up to 3 GPIO pins are available for digital control or signal transmission. Communication with the NCT7491 is via the SMBus/I2C interface, which is compatible with industry standard protocols. The SMBus address is set by two address select pins. The NCT7491 features a 24-lead QFN or QSOP encapsulation and operates from 3.0 V to 3.6 V.