Fan rotating speed controlling circuit

Abstract

The invention relates to a fan rotating speed controlling circuit for controlling the rotating speed of a fan. The fan rotating speed controlling circuit comprises a driving integrated circuit (IC) and a temperature controlling module electrically connected with the driving IC, wherein the temperature controlling module comprises a comparator, a first switching circuit and a second switching circuit; the comparator can output a first comparison signal or a second comparison signal; the first switching circuit is provided with a first thermistor which is electrically connected with the comparator and the driving IC; the second switching circuit is electrically connected with the comparator, the driving IC and the first switching circuit; when the comparator outputs the first comparison signal, the first switching circuit is connected, and the second switching circuit is cut off, so that the fan generates a first fan rotating speed; and when the comparator outputs the second comparison signal, the second switching circuit is connected, and the first switching circuit is cut off, so that the fan generates a second fan rotating speed, wherein the second fan rotating speed is higher than the first fan rotating speed.

Description

technical field [0001] The invention relates to a fan speed control circuit, in particular to a fan speed control circuit capable of controlling the fan speed in sections. Background technique [0002] see Figure 6 As shown, it shows a conventional fan speed control circuit 200, the fan speed control circuit 200 is used to receive a target speed signal Starget to control the speed of a fan 300, the fan speed control circuit 200 includes a temperature measurement module 210, A speed regulation module 220 electrically connected to the temperature measurement module 210 and a fan drive module 230 electrically connected to the speed regulation module 220, the temperature measurement module 210 can be a sensing element (such as a thermistor ) to measure the temperature of the environment where the fan 300 is located to generate a temperature value, and the impedance of the thermistor changes with the system or ambient temperature to change the drive power input to the fan. The s...

AI Technical Summary

Problems solved by technology

[0002] see Image 6 As shown, it shows a conventional fan speed control circuit 200, the fan speed control circuit 200 is used to receive a target speed signal Starget to control the speed of a fan 300, the fan speed control circuit 200 includes a temperature measurement module 210, A speed regulation module 220 electrically connected to the temperature measurement module 210 and a fan drive module 230 electrically connected to the speed regulation module 220, the temperature measurement module 210 can be a sensing element (such as a thermistor ) to measure the temperature of the environment where the fan 300 is located to generate a temperature value, and the impedance of the thermistor changes with the system or ambient temperature to change the drive power input to the fan. The speed adjustment module 220 A fan control signal can be generated according to the temperature value and the target speed signal, and the fan drive module 230 can generate a drive signal Sdrive according to the fan control signal to achieve the purpose of controlling the fan speed. The increase of the temperature value increases, however, the variation curve of the fan speed and the temperature of the conventional fan speed control circuit 200 is roughly linear, so the effect of segmental control of the fan speed change cannot be achieved.

[0003] It can be seen that the above-mentioned existing fan speed control circuit obviously still has inconvenience and defects in structure and use, and needs to be further improved urgently.

In order to solve the above-mentioned problems, the relevant manufacturers have tried their best to find a solution, but for a long time no suitable design has been developed, and the general product has no suitable structure to solve the above-mentioned problems. This is obviously the relevant industry. Urgent problem

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