US 5,513,361 A · Method and apparatus for reducing power consumption of a fan in a computer system

Abstract

A circuit for controlling power consumption of a fan within a computer system having a central processing unit (CPU) is described. The circuit includes a filter circuit coupled to receive a periodical pulse signal for detecting duty cycle of the periodical pulse signal by converting the periodical pulse signal into an analog signal. The analog signal has a voltage level proportional to the duty cycle of the periodical pulse signal. The periodical pulse signal is generated to control the CPU to be operational between predetermined intervals when the CPU is in an inactive state. A comparator circuit is coupled to the filter circuit for comparing the voltage level of the analog signal with a predetermined voltage level. When the voltage level of the analog signal is below the predetermined voltage level, the comparator circuit generates a switching signal. A switching circuit is coupled to (1) a power supply, (2) the fan, and (3) the comparator circuit for disconnecting the power supply from the fan when the switching signal is generated by the comparator circuit so as to substantially reduce the power consumption of the fan in the computer system when the CPU is in the inactive state. A computer system having the circuit for controlling power consumption of a fan in the system and a method for controlling power consumption of a fan in a computer system are also described.

Claims19

Dependent claims

A circuit for controlling power consumption of a fan within a computer system having a central processing unit (CPU), comprising:

(A) a filter circuit coupled to receive a periodical pulse signal for detecting duty cycle of the periodical pulse signal by converting the periodical pulse signal into an analog signal, wherein the analog signal has a voltage level proportional to the duty cycle of the periodical pulse signal;
(B) a comparator circuit coupled to the filter circuit for comparing the voltage level of the analog signal with a predetermined voltage level to generate a switching signal when the voltage level of the analog signal is below the predetermined voltage level;
and
(C) a switching circuit coupled to (1) a power supply, (2) the fan, and (3) the comparator circuit for disconnecting the power supply from the fan when the switching signal is generated by the comparator circuit so as to substantially reduce the power consumption of the fan in the computer system.

1 more element

A computer system, comprising:

(a) a central processing unit (CPU);
(b) a fan for dissipating heat generated within the computer system;
(c) a power managing logic coupled to the CPU for detecting operational state of the CPU and for generating a periodical pulse signal that varies depending on the operational state of the CPU;
and
(d) a control circuit coupled to (1) the power managing logic, (2) the fan, and (3) a power supply for controlling power consumption of the fan in the computer system by determining duty cycle of the periodical pulse signal, wherein the control circuit further comprises
(i) a filter and comparison circuit coupled to the power managing logic for converting the periodical pulse signal into an analog signal with a voltage level proportional to the duty cycle of the periodical pulse signal, and for comparing the voltage level of the analog signal with a predetermined voltage level to generate a switching signal, wherein the filter and comparison circuit deasserts the switching signal when the periodical pulse signal is not applied to the filter and comparison circuit;
and
(ii) a switching circuit coupled to the power supply and the fan for disconnecting the power supply from the fan when the switching signal is asserted by the filter and comparison circuit so as to substantially reduce the power consumption of the fan in the computer system.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for reducing power consumption of a fan in a computer system

Life of this patent

Method and apparatus for reducing power consumption of a fan in a computer system

Life of this patent

Abstract

Claims19