Dynamic hysteresis for autofan control
US7394217B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 27, 2005 |
| Grant date | Jul 1, 2008 |
| Priority date | — |
| Expiry date | Feb 5, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B11/28
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A control signal value, such as a duty cycle value for a Pulse Width Modulated (PWM) generator output, for controlling and/or powering a fan may be calculated using an autofan function configured with dynamic hysteresis control (DHC). As part of the DHC, the PWM duty cycle value may be determined by applying a hysteresis component at every point of the autofan function relating the PWM duty cycle to temperature. The PWM duty cycle value may be computed based on two functions, each function relating the PWM duty cycle to temperature, the first function applied when the temperature is increasing, and the second function applied when the temperature is decreasing. When a newly computed PWM duty cycle value falls within a range of duty cycle values defined by the hysteresis value, the current duty cycle of the PWM generator output may remain unchanged, minimizing noise resulting from the fan changing speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.