Chapter Eight : Motherboard Hardware Support
67
Fan Speed Control
The motherboard must provide the necessary circuit that converts PWM pulses from the
MegaRAC M300V card output to an analog DC level that is then amplified to actually control the
fans. It is part of the fan speed control circuit. The illustration below shows the block diagram of
the fan speed control circuit. The one beneath it shows an example of the fan speed control PWM-
to-DC converter circuit. If the platform is using PWM controlled fans this circuitry is not required,
but proper hardware buffering might be required for directly routing the PWM signals to the fan
circuitry.
Fan Speed Control Circuit Block Diagram
Fan Speed Control PWM-to-DC Converter Circuit Example
Summary of Contents for MegaRAC M300V
Page 1: ...MegaRAC M300V Card Implementer s Reference and User s Guide MAN M300V 07 9 07 ...
Page 14: ...8 MegaRAC M300V Card Implementer s Reference and User s Guide ...
Page 16: ...10 MegaRAC M300V Card Implementer s Reference and User s Guide ...
Page 58: ...52 MegaRAC M300V Card Implementer s Reference and User s Guide ...
Page 62: ...56 MegaRAC M300V Card Implementer s Reference and User s Guide ...
Page 80: ...74 MegaRAC M300V Card Implementer s Reference and User s Guide ...
Page 87: ...Index 81 ...