US20070110558A1

US20070110558A1 - Fan system and temperature-sensing module

Info

Publication number: US20070110558A1
Application number: US11/591,475
Authority: US
Inventors: Chien-Hua Chen; Chia-Pin Wei; Wen-Shi Huang
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2005-11-11
Filing date: 2006-11-02
Publication date: 2007-05-17
Also published as: TWI307999B; TW200719573A; JP2007134723A; JP4740824B2

Abstract

A fan system, which receives an input voltage from exterior, includes a first fan module, a second fan module, a first starting module, a second starting module, a temperature-sensing element and a first controlling module. The first starting module receives the input voltage and starts the first fan module. The second starting module, which is electrically connected to the second fan module, receives the input voltage. The temperature-sensing element produces a sensing signal in accordance with an ambient temperature. The first controlling module controls the second starting module in accordance with the sensing signal so as to start the second fan module.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 094139638 filed in Taiwan, Republic of China on Nov. 11, 2005, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention
The invention relates to a fan system and a temperature-sensing module and, in particular, to a fan system and a temperature-sensing module, which can start a plurality of fan modules according to the temperature difference.
2. Related Art
Generally speaking, a large electronic system is always equipped with a fan system to ensure that the electronic system can be kept at the normal working temperature such that the electronic system can operate normally.
FIG. 1 is a schematic illustration showing a conventional fan system 1. The fan system 1 receives an input voltage V_infrom exterior to serve as an operation voltage. The fan system 1 mainly has a plurality of fan modules 11 a to 11 ic and a plurality of starting modules 12 a to 12 c. After the starting modules 12 a to 12 c receive the input voltage V_in, the fan modules 11 a to 11 c are started simultaneously to dissipate the heat. However, when the fan modules 11 a to 11 c are started simultaneously, an extremely large start-up current and inrush current are generated at the moment of starting. Thus, the electronic system or the fan system 1 may crash or have unpredictable malfunction, or even the electronic system or the fan system 1 may be damaged.
In view of the above-mentioned problems, the prior art adopts an analog starting control chip 13 for starting the fan modules 11 a to 11 c sequentially, or a software module to control the starting sequence of the fan modules 11 a to 11 c. Thus, the prior art provides a protection mechanism for respectively starting the fan modules 11 a to 11 c at different time instants so as to avoid the malfunction caused when the fan modules 11 a to 11 c are simultaneously started. However, the analog starting control chip 13 has a high price, and the software module has a complicated architecture. Thus, the overall manufacturing cost of the conventional fan system 1 is too high. In addition, the analog starting control chip 13 only can delay the starting time of each of the fan modules 11 a to 11 c and cannot provide the function of soft-start.
Thus, it is an important subject of the invention to provide a fan system and a temperature-sensing module to overcome the above-mentioned problems.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a fan system and a temperature-sensing module for starting a plurality of fan modules at different time based on the temperature difference so as to avoid the malfunction caused when the fan modules are started simultaneously and to reduce the power consumption.
To achieve the above, a fan system of the invention is for receiving an input voltage from exterior. The fan system includes a first fan module, a second fan module, a first starting module, a second starting module, a temperature-sensing element and a first controlling module. The first starting module receives the input voltage and starts the first fan module. The second starting module, which is electrically connected to the second fan module, receives the input voltage. The temperature-sensing element produces a sensing signal in accordance with an ambient temperature. The first controlling module controls the second starting module in accordance with the sensing signal so as to start the second fan module.
To achieve the above, the invention also discloses a temperature-sensing module for receiving an input voltage from exterior and cooperating with a fan module. The temperature-sensing module includes a starting unit, a temperature-sensing element and a controlling unit. The starting unit is electrically connected with the fan module and receives the input voltage. The temperature-sensing element produces a sensing signal in accordance with an ambient temperature. The controlling unit controls the starting unit to start the fan module in accordance with the sensing signal.
As mentioned above, the fan system and the temperature-sensing module according to the invention include the temperature-sensing element for producing the sensing signal. Then, the controlling module can individually start the fan modules at different temperatures in accordance with the sensing signal so as to avoid the malfunction caused by the extremely large start-up current and inrush current, which are generated by instantaneously starting the fan modules. Compared with the prior art, the fan system and temperature-sensing module of the invention utilize the temperature-sensing element to sense the operating temperature and then correspondingly start sufficient fan modules. Therefore, the fan modules are started in a time-sharing manner to ensure that the fan system can operate normally, reduce the power consumption, and replace the analog starting control chip to reduce the overall manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:
FIG. 1 is a schematic illustration showing a conventional fan system;
FIG. 2 is a schematic illustration showing a fan system according to a preferred embodiment of the invention;
FIG. 3 is a circuit diagram showing a fan system according to the preferred embodiment of the invention; and
FIG. 4 is a schematic illustration showing a temperature-sensing module according to the embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
FIG. 2 is a schematic illustration showing a fan system 2 according to a preferred embodiment of the invention. As shown in FIG. 2, the fan system 2 receives an input voltage 91 from exterior to serve as an operation voltage. In the embodiment, the fan system 2 may be applied to an electronic system (not shown) in order to dissipate heat, and the input voltage 91 may be supplied from the electronic system.
The fan system 2 includes a plurality of fan modules 21 a to 21 c, a plurality of starting modules 22 a to 22 c, a plurality of controlling modules 23 a and 23 b, and a temperature-sensing element 24.
Each of the fan modules 21 a to 21 c has a fan. Of course, the user may dispose a plurality of fans in each of the fan modules 21 a to 21 c according to the heat dissipating requirement so as to enhance the heat dissipating effect.
The starting modules 22 a to 22 c receive the input voltage 91 and are electrically connected with the fan modules 21 a to 21 c, respectively.
The temperature-sensing element 24 produces a sensing signal V_tin accordance with an ambient temperature. The temperature-sensing element 24 may be a thermistor (thermal resistor). In this embodiment, the temperature-sensing element 24 is a negative temperature coefficient (NTC) thermistor. The ambient temperature may be the internal temperature of the electronic system, so that the temperature-sensing element 24 produces the sensing signal V_t, e.g. a voltage value, in accordance with the internal temperature. Based on the characteristic of the NTC thermistor in this embodiment, the resistance of the temperature-sensing element 24 decreases and the voltage of the sensing signal V_tdecreases when the internal temperature of the electronic system increases. On the contrary, the voltage of the sensing signal V_tincreases when the internal temperature of the electronic system decreases.
The controlling modules 23 a and 23 b are electrically connected with the starting modules 22 b and 22 c, respectively. In the embodiment, the starting module 22 a receives the input voltage 91 so as to start the fan module 21 a, and the controlling modules 23 a and 23 b control the starting modules 22 b and 22 c according to the sensing voltage V_tso as to start the fan modules 21 b and 21 c.
As shown in FIG. 3, each of the starting modules 22 a to 22 c includes a plurality of diodes D₁and D₂, a plurality of resistors R₁and R₂, two switch elements Q₁and Q₂and a capacitor C. Each of the first switch element Q₁and the second switch element Q₂may be a transistor or any other electronic element with the switch function. In this embodiment, the first switch element Q₁is a PMOS transistor, and the second switch element Q₂is an NMOS transistor.
In addition, the diodes D₁and D₂are connected in parallel. Each of the diodes D₁and D₂has a first terminal for receiving the input voltage 91. In this embodiment, each of the diodes D₁and D₂may be a Schottky diode for avoiding the reverse current. One terminal of the resistor R₁is electrically connected with a second terminal of each of the diodes D₁and D₂.
A source S of the first switch element Q₁is electrically connected with the second terminals of the diodes D₁and D₂, and a drain D of the first switch element Q₁is electrically connected with corresponding one of the fan modules 21 a to 21 c. A gate G of the first switch element Q₁is electrically connected with a drain D of the second switch element Q₂.
The drain D of the second switch element Q₂is electrically connected with a second terminal of the resistor R₁. A source S of the second switch element Q₂is grounded. A first terminal of the capacitor C is electrically connected with the source S of the first switch element Q₁and a first terminal of the resistor R₁. A first terminal of the resistor R₂is electrically connected with a second terminal of the capacitor C, and a second terminal of the resistor R₂is grounded.
The controlling modules 23 a and 23 b include a comparator U₁and a comparator U₂, respectively. Each of the comparators U₁and U₂has a first input terminal input₁, a second input terminal input₂and an output terminal output. The second input terminal input₂and the output terminal output are electrically connected with each other through a resistor R to provide the comparator U₁or U₂a precise temperature transition characteristic. The resistor R is set between the second input terminal input₂and the output terminal output of the comparator U₁for compensating the feedback voltage value. Therefore, the comparator U₁can precisely control the starting module 22 b to start the fan module 21 b. Accordingly, the precise temperature transition characteristic can be achieved. Similarly, in the controlling module 23 b, the resistor R is set between the second input terminal input₂and the output terminal output of the comparator U₂for compensating the feedback voltage value. Therefore, the comparator U₂can precisely control the starting module 22 c to start the fan module 21 c, so that the precise temperature transition characteristic can be achieved. In this embodiment, the first input terminal input₁is a noninverting input terminal and the second input terminal input₂is an inverting input terminal.
Regarding to the controlling module 23 a, the first input terminal input₁of the comparator U₁receives a first reference signal V_ref1, and the second input terminal input₂receives the sensing signal V_t. The output terminal output is electrically connected with the gate G of the second switch element Q₂of the starting module 22 b for controlling the second switch element Q₂of the starting module 22 b. In the embodiment, when the sensing signal V_tis lower than the first reference signal V_ref1, the output terminal output delivers a positive voltage signal to start the second switch element Q₂of the starting module 22 b. Accordingly, the fan module 21 b is started.
Regarding to the controlling module 23 b, the first input terminal input₁of the comparator U₂receives a second reference signal V_ref2, and the second input terminal input₂receives the sensing signal V_t. The output terminal output is electrically connected with the gate G of the second switch element Q₂of the starting module 22 c for controlling the second switch element Q₂of the starting module 22 c. In the embodiment, when the sensing signal V_tis lower than the second reference signal V_ref2, the output terminal output delivers a positive voltage signal to start the second switch element Q₂of the starting module 22 c. Accordingly, if the second reference signal V_ref2is lower than the first reference signal V_ref1, the fan module 22 b is started when the internal temperature of the electronic system rises.
The operation principle of the fan system 2 will be described in the following. Once the fan system 2 is connected with the electronic system, it receives the input voltage 91. In this case, the diodes D1 and D2 of the starting module 22 a receive the input voltage 91 to start the switch element Q2 and to charge the capacitor C. When the voltage of the capacitor C reaches the starting voltage of the switch element Q1, the switch element Q1 is started to enable the fan module 21 a. To be noted, the capacitor C and the resistor R₂form a charging circuitry that enables the current flowing through the fan module 21 a to increase at a slow rate such that the effect of soft starting can be achieved.
Since the electronic system is just started, the internal temperature thereof is not raised too much. At this moment, the sensing signal V_tis not less than the first reference signal V_ref1and the second reference V_ref2, so the fan modules 21 b and 21 c are not started yet. After the electronic system has operated for a period of time, the internal temperature thereof begins to rise so that the voltage of the sensing signal V_tdecreases. If the sensing signal V_tis less than the first reference signal V_ref1, the controlling module 23 a will control the starting module 22 b to start the fan module 21 b.
If the internal temperature of the electronic system keeps rising, which leads to the sensing voltage V_tless than the second reference signal V_ref2, the controlling module 23 b will control the starting module 22 c to start the fan module 21 c. As a result, the fan modules 21 a to 21 c can be started in accordance with the different temperatures so as to avoid the malfunction caused by the extremely large start-up current and inrush current. Thus, the heat dissipation requirement and the power consumption issue can be achieved.
In addition, the fan system 2 of the embodiment provides the backup heat-dissipating device in advance, so that the backup heat dissipating device, such as the fan module, can be enabled to increase the heat dissipation efficiency as the load of the electronic system increases, which generates more heat. In this manner, the electronic system can operate normally.
For example, assuming that the electronic system needs only one fan module 22 a for normal operation, the preset two fan modules 22 b and 22 c can be used as the backup fan modules in the fan system 2 of the embodiment. Therefore, when the load of the electronic system increases, which leads to the higher internal temperature in the electronic system, the temperature-sensing element 24 will sense the temperature variation for starting the fan modules 22 b and 22 c. In this manner, the heat-dissipating efficiency can be enhanced for maintaining the normal operation of the electronic system.
With reference to FIG. 4, the invention further discloses a temperature-sensing module 3, which receives an input voltage 91 from exterior and cooperates with a fan module 31. The temperature-sensing module 3 includes a starting unit 32, a controlling unit 33, and a temperature-sensing element 34. In this embodiment, the fan module 31, the starting unit 32, the controlling unit 33, and the temperature-sensing element 34 have the same constructions and functions as those of the above mentioned fan module 21 b, the starting unit 22 b, the controlling unit 23 a, and the temperature-sensing element 24, so the detailed descriptions thereof will be omitted for concise purpose.
In summary, the fan system and the temperature-sensing module according to the invention include the temperature-sensing element for producing the sensing signal. Then, the controlling modules can individually start the fan modules at different temperatures in accordance with the sensing signal so as to avoid the malfunction caused by the extremely large start-up current and inrush current, which are generated by instantaneously starting the fan modules. Compared with the prior art, the fan system and temperature-sensing module of the invention utilize the temperature-sensing element to sense the operating temperature and then correspondingly start sufficient fan modules. Therefore, the fan modules are started in a time-sharing manner to ensure that the fan system can operate normally, reduce the power consumption, and replace the analog starting control chip to reduce the overall manufacturing cost. In addition, the fan system of the invention has the advantage of preparing the backup heat-dissipating devices in advance, which can enhance the flexibility in usage.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.

Claims

1. A fan system for receiving an input voltage from exterior, the fan system comprising:

a first fan module;

a second fan module;

a first starting module for receiving the input voltage so as to start the first fan module;

a second starting module electrically connected with the second fan module for receiving the input voltage;

a temperature-sensing element for producing a sensing signal in accordance with an ambient temperature; and

a first controlling module for controlling the second starting module to start the second fan module in accordance with the sensing signal.

2. The fan system according to claim 1, wherein both the first starting module and the second starting module comprise:

a first switch element having a terminal for receiving the input voltage to start the corresponding one of the first fan module and the second fan module; and

a second switch element electrically connected with the first switch element for controlling the first switch element.

3. The fan system according to claim 2, wherein both the first starting module and the second starting module further comprises a capacitor having a terminal for electrically connected with the first switch element.

4. The fan system according to claim 2, wherein both the first starting module and the second starting module further comprise at least one diode having a first terminal for receiving the input voltage and a second terminal for electrically connecting with the first switch element.

5. The fan system according to claim 2, wherein both the first switch element and the second switch element are a transistor.

6. The fan system according to claim 1, wherein the first controlling module further comprises a first comparator having a first input terminal for receiving a first reference signal, a second input terminal for receiving the sensing signal, and an output terminal electrically connected with the second starting module for controlling the second starting module to start the second fan module.

7. The fan system according to claim 6, wherein the output terminal and the second input terminal of the first comparator are connected with each other through a resistor.

8. The fan system according to claim 1, wherein the temperature-sensing element is a thermistor or a negative temperature coefficient (NTC) thermistor.

9. The fan system according to claim 1, further comprising:

a third fan module;

a third starting module electrically connected with the third fan module and receiving the input voltage; and

a second controlling module for controlling the third starting module to start the third fan module in accordance with the sensing signal.

10. The fan system according to claim 9, wherein the second controlling module comprises a second comparator having a first input terminal for receiving a second reference signal, a second input terminal for receiving the sensing signal, and an output terminal electrically connected with the third starting module for controlling the third starting module to start the third fan module.

11. The fan system according to claim 10, wherein the output terminal and the second input terminal of the second comparator are connected with each other through a resistor.

12. A temperature-sensing module for receiving an input voltage from exterior and cooperating with a fan module, the temperature-sensing module comprising:

a starting unit electrically connected with the fan module and receiving the input voltage;

a controlling unit for controlling the starting unit to start the fan module in accordance with the sensing signal.

13. The temperature-sensing module according to claim 12, wherein the starting unit comprises:

a first switch element having a terminal for receiving the input voltage to start the fan module; and

14. The temperature-sensing module according to claim 13, wherein the starting unit further comprises a capacitor having a terminal for electrically connected with the first switch element.

15. The temperature-sensing module according to claim 13, wherein the starting unit further comprises at least one diode having a first terminal for receiving the input voltage and a second terminal for electrically connecting with the first switch element.

16. The temperature-sensing module according to claim 13, wherein both the first switch element and the second switch element are a transistor.

17. The temperature-sensing module according to claim 12, wherein the controlling unit comprises a comparator having a first input terminal for receiving a reference signal, a second input terminal for receiving the sensing signal, and an output terminal electrically connected with the starting unit for controlling the starting unit to start the fan module.

18. The temperature-sensing module according to claim 17, wherein the output terminal and the second input terminal of the comparator are connected with each other through a resistor.

19. The temperature-sensing module according to claim 12, wherein the temperature-sensing element is a thermistor or a negative temperature coefficient (NTC) thermistor.