For this month's instalments I researched two ICs that provide stand-alone functionality as fan-speed controllers. This can be very handy when you have a system which is dissipating a lot of power, but is also built into some kind of enclosure. This makes forced-cooling with a fan a necessity. If you would like to make the control of this fan dependent on the temperature, but don't want to delegate this task to the existing microcontroller, then a separate control IC will be very useful. You only need to connect a sensor and a fan. One striking detail is that the ICs presented here do not follow the standard 4-pin, 25 kHz PWM fan speed control, but switch the power supply voltage directly at much lower frequencies.