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US 6,274,991 B1Granted
Method and circuit configuration for detecting the rotational speed of electronically commutated fans
AssigneePCS PC-Systeme Entwicklungs-und Produktionsgesellschaft mbH & Co. KG
InventorPeter Busch
Life of this patent
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Abstract
A method and a circuit configuration for detecting the rotational speed of electronically commutated fans include measuring maximum current gradients of current fluctuations caused by the fan on its power supply lines, and adapting an amplification range and switching threshold of a comparator used as an input stage for a pulse former.
Claims8
A method for detecting the rotational speed of electronically commutated fans, which comprises:
- indicating a rotational speed of an electronically commutated fan with a clock signal having a corresponding number of clock pulses per unit time;
- forming the clock pulses of the clock signal with a pulse former having a comparator serving as an input stage;
- measuring maximum current gradients of current fluctuations caused by the fan on power supply lines of the fan as a function of the rotational speed;
- and
- automatically adapting an amplification range and switching threshold of the comparator in dependence on a result of the measurement.
2 more elements
A circuit configuration for detecting the rotational speed of electronically commutated fans, comprising:
- a device for producing a clock signal with a corresponding number of clock pulses per unit time corresponding to a rotational speed of an electronically commutated fan having power supply lines;
- a pulse former forming the clock pulses of the clock signal;
- a comparator serving as an input stage for said pulse former;
- a device for detecting maximum current gradients of current fluctuations caused by the fan on the power supply lines;
- and
- a device for automatically adapting an amplification range and switching threshold of said comparator.
3 more elements
Dependencies are inferred from the claim text.