CN102454621A

CN102454621A - Fan control circuit

Info

Publication number: CN102454621A
Application number: CN2010105144824A
Authority: CN
Inventors: 谢明志
Original assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2010-10-21
Filing date: 2010-10-21
Publication date: 2012-05-16

Abstract

The invention discloses a fan control circuit. The fan control circuit comprises a current sensing circuit, an analog-digital converter (ADC) and a processor; the current sensing circuit is used for sensing a current value which is output by a power supply; the ADC is used for converting the sensed current value into a digital signal and outputs the digital signal to the processor; and the processor is used for correspondingly adjusting rotation speed of a fan according to the received digital signal. The fan control circuit can avoid the delay caused by correspondingly adjusting the rotation speed of the fan by detecting the temperature value of a whole system.

Description

Fan control circuitry

Technical field

The present invention relates to a kind of fan control circuitry.

Background technique

The heat radiation of inside computer system generally is through the temperature in the thermistor sensing cabinet, and sends the rotating speed that corresponding pulse width modulating signal is adjusted fan according to the temperature value that is sensed by processor.But the temperature of heating element is still needed to cabinet through air conduction and wanted the regular hour, and is like this then cause that the heat radiation of heating element is had certain delay.

Summary of the invention

In view of above content, be necessary to provide a kind of fan control circuitry that can adjust rotation speed of the fan according to the power that power supply is exported.

A kind of fan control circuitry; Comprise a current sensing circuit, an analog digital converter and a processor; This current sensing circuit is used for the current value that sensing one power supply is exported; This analog digital converter is used for the current value that senses is converted into digital signal and exports to this processor, and this processor is used for the rotating speed according to the corresponding adjustment of received digital signal one fan.

The current value that the said fans control circuit is exported through current sensing circuit sensing power supply, with the performance number of learning that whole system will consume, thus the rotating speed of corresponding adjustment fan.Aforementioned fan control circuitry can be avoided coming the corresponding adjustment delay that rotation speed of the fan brought through the temperature value of detecting whole system.

Description of drawings

Fig. 1 is the skeleton diagram of the preferred embodiments of fan control circuitry of the present invention.

Fig. 2 is the circuit diagram of the preferred embodiments of Fig. 1 fan control circuit.

The primary component symbol description

Electronic equipment 2

Current-sensing circuit 10

Amplification circuit 12

ADC 15

CPU 16

Switching circuit 18

Power supply 20

Fan 22

Sensing resistor Rsen

Amplifier U1

Resistance R 1, R2, R3, R4, R5, R6

Field effect transistor Q1

Triode Q2

Embodiment

Below in conjunction with accompanying drawing and preferred embodiments the present invention is described in further detail:

See also Fig. 1; The preferred embodiments of fan control circuitry of the present invention comprises a current-sensing circuit 10, an amplification circuit 12, an analog digital converter (Analog Digital Converter; ADC) 15, one processor (Central Processing Unit, CPU) 16 and one switching circuit 18.

This current-sensing circuit 10 is used to detect the current value that power supply 20 is supplied with electronic equipment 2, and it is connected between power supply 20 and the electronic equipment 2.This amplification circuit 12 links to each other with this current-sensing circuit 10, is used to amplify this current-sensing circuit 10 resulting detection signals.This ADC 15 is used for after converting digital signal into through the detection signal that amplifies, being sent to CPU 16.16 pulse duration modulations corresponding according to the digital signal output that receives of this CPU (pulse width modulation, PWM) signal, with the working state of corresponding control switch circuit 18, thus can the corresponding rotating speed of controlling fan 22.

Please refer to Fig. 2, this current-sensing circuit 10 comprises a sensing resistor Rsen, and first end of this sensing resistor Rsen is connected in the negative pole and the ground connection of power supply 20, and second end links to each other with electronic equipment 2, and the positive pole of this power supply 20 then directly links to each other with electronic equipment 2.This power supply 20 is used to electronic equipment 2 power supplies, and this sensing resistor Rsen then is used for the current value that this power supply 20 of sensing is exported to electronic equipment 2.

This amplification circuit 12 comprises an amplifier U1 and two resistance R 1, R2; One end of this resistance R 1 links to each other with first end of this sensing resistor Rsen; The other end links to each other with the reverse input end of this amplifier U1; The reverse input end of this amplifier U1 also links to each other with its output terminal through resistance R 2, and positive input links to each other with second end of this sensing resistor Rsen, and output terminal also links to each other with the input end of this ADC 15.The output terminal of this ADC15 links to each other with this CPU 16.

This switching circuit 18 comprises a field effect transistor Q1 and a triode Q2; The grid of this field effect transistor Q1 links to each other with this CPU 16 through resistance R 3; Source ground, drain links to each other with power supply 20 through resistance R 4, also links to each other with the base stage of triode Q2 through resistance R 5; The emitter of this triode Q2 links to each other with power supply 20, and collector electrode links to each other with fan 22.This CPU 16 also links to each other with power supply 20 through resistance R 6.

To the working principle of this fan control circuitry be described below:

When the voltage V that offers electronic equipment 2 when power supply 20 was definite value, the power (P=VI) that whole electric equipment 2 is consumed and 20 electric current I that offer electronic equipment 2 of power supply were directly proportional.When the current value I that is sensed as sensing resistor Rsen was big more, the power that whole electric equipment 2 is consumed was big more, and promptly the heat that produced of whole electric equipment 2 is big more; The current value I that is sensed as sensing resistor Rsen more hour, the power that whole electric equipment 2 is consumed is more little, promptly the heat that produced of whole electric equipment 2 is more little.

Principle according to amplification circuit 12 can be learnt, voltage V=I * Rsen that this amplifier U1 is exported * [1+ (R2/R1)].This voltage signal V exports to CPU16 after this ADC 15 converts digital signal into, the corresponding pwm signal of digital signal output that 16 bases of this CPU receive, and with the working state of corresponding control switch circuit 18, thus the rotating speed of corresponding control fan 22.

The artificer can be through measuring the received digital signal of CPU 16 and its pwm signal of exporting in advance the relation of dutycycle.So, the dutycycle of the pwm signal that this fan control circuitry can finally obtain according to the current value that sensing resistor Rsen is sensed being exported by CPU 16, thereby the rotating speed of corresponding this fan 22 of control.

When the relation between the rotating speed of fan 22 can be as shown in table 1 for the duty of the current value I that this sensing resistor Rsen is sensed, the magnitude of voltage V that amplification circuit 12 is exported, digital signal that this ADC 15 is exported, power P that whole electric equipment 2 is consumed, temperature value T that whole electric equipment 2 will reach, pwm signal that CPU 16 is exported:

Table 1

Can know that from table 1 when CPU 16 received digital signals were " 100 ", the dutycycle of the pwm signal of these CPU 16 outputs was 62.5%, is r5 (rpm) with the rotating speed of controlling fan 22.When CPU 16 received digital signals were " 111 ", the dutycycle of the pwm signal of these CPU 16 outputs was 100%, and this moment, the rotating speed of this fan 22 was r8 (rpm).

The said fans control circuit is through 20 output current values of current-sensing circuit 10 detecting power supplys; With the performance number of learning that whole system consumes; Thereby further learn the heat that distributes in advance; So can not be transmitted to the rotating speed that can adjust fan 22 when air makes that the product internal temperature transition raises in advance as yet at heat, the temperature of having avoided heating element is through the delay between air conduction to the product inside.

Claims

1. fan control circuitry; Comprise a current sensing circuit, an analog digital converter and a processor; This current sensing circuit is used for the current value that sensing one power supply is exported; This analog digital converter is used for the current value that senses is converted into digital signal and exports to this processor, and this processor is used for the rotating speed according to the corresponding adjustment of received digital signal one fan.

2. fan control circuitry as claimed in claim 1 is characterized in that: this current sensing circuit comprises a sensing resistor.

3. fan control circuitry as claimed in claim 1; It is characterized in that: said fan control circuitry also comprises an amplification circuit; This amplification circuit is arranged between current sensing circuit and the analog digital converter, so that the current value that is sensed is converted into corresponding voltage value and exports to this analog digital converter.

4. fan control circuitry as claimed in claim 3; It is characterized in that: this amplification circuit comprises one first resistance, one second resistance and an amplifier; One end of this first resistance links to each other with this current sensing circuit; The other end links to each other with the reverse input end of this amplifier; The reverse input end of this amplifier also links to each other with the output terminal of this amplifier through this second resistance, and the positive input of this amplifier links to each other with this current sensing circuit, and the output terminal of this amplifier also links to each other with this analog digital converter.

5. fan control circuitry as claimed in claim 1; It is characterized in that: said fan control circuitry also comprises a switching circuit; This switching circuit is connected between this processor and the fan; This processor is according to the corresponding output of the digital signal that receives one pulse width modulating signal, controlling the working state of this switching circuit, thereby adjusts the rotating speed of this fan.

6. fan control circuitry as claimed in claim 5; It is characterized in that: this switching circuit comprises a field effect transistor and a triode, and the grid of this field effect transistor links to each other source ground through one the 3rd resistance with this processor; Drain links to each other with this power supply through one the 4th resistance; Also link to each other with the base stage of triode through one the 5th resistance, the emitter of this triode links to each other with this power supply, and collector electrode links to each other with this fan.