Detecting circuit for rotating speed of fan
A technology for detecting circuit and fan speed, applied in linear/angular velocity measurement, speed/acceleration/shock measurement, measurement device, etc., it can solve the problem that the counter cannot accurately detect the pulse signal, the counter cannot detect the fan speed, and the user mistakenly believes that the fan And other issues
Inactive Publication Date: 2013-04-03
HONG FU JIN PRECISION IND (SHENZHEN) CO LTD +1
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Problems solved by technology
However, when the duty cycle of the PWM signal is set to be low, the counter often cannot accurately detect the pulse signal output by the fan connector, so that the counter cannot detect the fan speed, which may easily cause users to mistake the fan as stopped working
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Embodiment Construction
[0011] see figure 1 , The fan speed detection circuit of the present invention is used to detect the fan speed. The fan speed detection circuit 100 includes a fan connector 10 , an integrating circuit 20 , a control circuit 30 , a level matching circuit 40 and a control chip 50 . The fan connector 10 is used for connecting the fan. The integration circuit 20 is electrically connected to the control chip 50 and receives the PWM digital control signal sent by the control chip 50 . The integration circuit 20 integrates the PWM digital control signal to form an analog control signal. The control circuit 30 is used to adjust the current input to the fan connector 10 in a positive phase and linear manner according to the change of the analog control signal, so as to adjust the rotation speed of the fan accordingly. The control chip 50 includes a rotational speed counter 51 for detecting the rotational speed of the fan. The level matching circuit 40 is used to convert the voltage...
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The invention relates to a detecting circuit for rotating speed of a fan. The detecting circuit comprises a control chip, an integral circuit, a fan connector, a control circuit and a level matching circuit, wherein the control chip has a rotating speed counter; the integral circuit is electrically connected with the control chip; the fan connector is electrically connected with the fan and the rotating speed counter; the control circuit is electrically connected between the integral circuit and the fan connector; the level matching circuit is electrically connected between the fan connector and the rotating speed counter; the integral circuit is used for receiving a digital control signal sent by the control chip and integrating the digital control signal into an analog control signal; the control circuit is used for normal-phase linearly adjusting the magnitude of the current inputted to the fan connector according to the change in the analog control signal so as to correspondingly adjust the rotating speed of the fan; and the level matching circuit is used for converting a voltage outputted to the rotating speed counter by the fan connector, so as to realize the matching of the level potential between the fan connector and the rotating speed counter.
Description
technical field [0001] The invention relates to a fan control circuit of electronic products such as computers and servers, in particular to a fan speed detection circuit. Background technique [0002] With the continuous development of computer technology, especially the continuous improvement of the frequency of the central processing unit, the heat generated during its work is also increasing accordingly. In order to fully dissipate the heat in time, a fan cooling device is generally used to dissipate heat from the central processing unit. . The rotational speed of the fan is generally controlled by a pulse width modulation (Pulse Width Modulation, PWM) signal, and the rotational speed of the fan can be controlled accordingly by changing the duty cycle of the PWM signal. Existing fan detection circuits generally use a counter to detect the rotational speed of the fan. After the fan rotates one revolution, the fan connector outputs a pulse to the counter, and the corresp...
Claims
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IPC IPC(8): F04D27/00G01P3/481
CPCG01P3/4805G01P3/48
Inventor 涂一新熊金良周海清
Owner HONG FU JIN PRECISION IND (SHENZHEN) CO LTD