Server Fan Power Switching for S5 Standby Cooling
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Solution Overview
Problem
Server systems face inadequate heat dissipation in the soft off state (S5) due to fans only operating in the on state (S0), leading to insufficient cooling as demand for data processing increases.
Innovation Solution
A fan control system comprising a first and second monitoring and protection chip, a switch, and a complex programmable logic device (CPLD) that switches fans between standby and operating power levels based on the server's state, allowing fans to run at a lower power level in shutdown state (S5) and a higher power level in working state (S0), with the CPLD activating appropriate chips and controlling the switch to manage power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fans operate only in the on state (S0), then energy consumption is reduced in shutdown state (S5), but heat dissipation capability becomes insufficient when components need to operate in S5
Solution Approach 1:
The fan control system dynamically adjusts fan operation based on server state. In S0 state, fans operate at normal power level for full cooling capability. In S5 state, fans operate at standby power level providing reduced but sufficient cooling. This dynamic adaptation resolves the contradiction by matching fan performance to actual cooling needs in each state, reducing energy consumption while maintaining adequate heat dissipation.
Solution Approach 2:
The system changes the power supply parameter to the fans based on server state. The switch controller receives power supply signals indicating S0 or S5 state and accordingly connects fans to different power levels (normal power vs. standby power). This parameter change enables fans to provide appropriate cooling capability for each state, resolving the contradiction between energy savings and heat dissipation requirements.
2Temperature
If fans operate at normal power level in shutdown state (S5), then heat dissipation is sufficient, but energy waste increases
Solution Approach 1:
In S5 shutdown state, the system applies partial action by operating fans at standby power level rather than full normal power level. This partial operation provides just enough cooling for the reduced load in shutdown state, avoiding the excessive energy consumption that would result from running fans at full capacity. The switch controller enables this partial action by controlling the power level based on detected server state.
3Device complexity
If a single monitoring chip is used, then device complexity is reduced, but reliability decreases due to inability to monitor both operating and standby power states
Solution Approach 1:
The monitoring function is segmented into two specialized chips: a first monitoring chip for operating power state (S0) and a second monitoring chip for standby power state (S5). Each chip is optimized for its specific power state, ensuring reliable detection and monitoring. The switch controller receives signals from both chips and coordinates fan operation accordingly. This segmentation resolves the contradiction by maintaining high monitoring reliability for both states while keeping each individual monitoring chip relatively simple.
Solution Approach 2:
The switch controller serves multiple functions: it receives power supply signals from both monitoring chips, determines current server state (S0 or S5), controls the switch to connect fans to appropriate power levels, and manages the overall fan control logic. This multi-functionality allows the system to achieve reliable comprehensive monitoring without proportionally increasing device complexity, as one component handles multiple critical tasks.
Data Source
AI summary
A fan control system for use in a server system is disclosed. The fan control system includes a first monitoring and protection chip, a second monitoring and protection chip, a switch, a plurality of fans and a complex programmable logic device (CPLD). In a shutdown state of the server system, the switch is switched under control of the CPLD so that the fans are connected to the second monitoring and protection chip, receive standby power therefrom and run at a standby power level. When the server system is switched to a working state, the switch is switched under control of the CPLD so that the fans are connected to the first monitoring and protection chip, receive operating power therefrom and run at a higher working power level. This design can address different heat dissipation needs of various applications.