Abstract:
A detecting circuit for a number of fans includes a connector module and a controller. The connector module includes a number of connectors. Each connector outputs a first signal or a second signal depending on the connection or non-connection to a fan. The controller receives a speed signal of the fan upon receiving the first signal which indicates a connected state.

Description:
FIELD 
       [0001]    The present disclosure relates to a detecting circuit for fans. 
       BACKGROUND 
       [0002]    A number of fans are often employed to dissipate heat generated in a server. The fans can be coupled to connectors in the server, so as to be controlled by the baseboard management controller. A number of connectors may be predefined, so that additional fans can be employed to dissipate heat in the server. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Many aspects of the present disclosure can be better understood with reference to the following drawing(s). The components in the drawing(s) are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawing(s), like reference numerals designate corresponding parts throughout the several views. 
           [0004]      FIG. 1  is a block diagram of an embodiment of a detecting circuit for fans of the present disclosure. 
           [0005]      FIG. 2  is a circuit diagram of the detecting circuit of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
         [0007]      FIG. 1  illustrates an embodiment of a detecting circuit. The detecting circuit can comprise a fan module  10 , a connector module  20 , a controller  30 , and an indicator module  40 . In the embodiment, the connector module  30  can comprise a plurality of connectors, the fan module  10  can comprise a plurality of fans (not shown) to be respectively connected to the connectors. The fan module  10  can generate state information with respect to the plurality of fans. The controller  30  can be connected to the connector modules  20 , to obtain the state information. The controller  30  can further output control signals to the indicator module  40 , to indicate the status of the fans. 
         [0008]      FIG. 2  illustrates a circuit diagram of the detecting circuit. In the embodiment, the connector module  20  can comprise connectors J 1 -J 4 . Each connector can comprise a power pin  1  coupled to a power terminal P 5 V, a speed pin  2 , a ground pin  3  connected to ground, and a state pin  4 . The speed pin  2  of the connector can output a speed signal upon a condition that a fan is connected to the connector. In the embodiment, the connectors J 1  and J 2  are connected to fans and the connectors J 3  and J 4  are not connected to fans. In other embodiment, the connectors J 3  and J 4  can be connected to additional fans that may be employed to satisfy the need of dissipating heat of a server. 
         [0009]    The controller  30  can comprise four speed controlling pins RA 0 -RA 3 , four indicator pins RC 0 -RC 3 , four trigger pins RB 4 -RB 7 , and a power pin Vpp coupled to the power terminal P 5 V through a resistor R 1 . The speed controlling pins RA 0 -RA 3  can be connected to the speed pins of a connector through two resistors connected in series. For example, the speed controlling pin RA 0  is connected to the speed pin  2  of the connector J 1  through resistors R 2  and R 10  connected in series. The speed controlling pin RA 1  is connected to the speed pin  2  of the connector J 2  through resistors R 3  and R 11  connected in series. The speed controlling pin RA 2  is connected to the speed pin  2  of the connector J 3  through resistors R 4  and R 13  connected in series. The speed controlling pin RA 3  is connected to the speed pin  2  of the connector J 4  through resistors R 5  and R 14  connected in series. 
         [0010]    The indicator module  40  can comprise fourth light-emitting diodes (LEDs) L 1 -L 4 . In the embodiment, the LEDs L 1 -L 4  can be employed to indicate the states of the fans that are connected to the connectors J 1 - 14 , such as normal status or a malfunctioning status. The indicator pins RC 0 -RC 3  of the controller  30  are coupled to cathodes of the LEDs L 1 -L 4  through respective resistors R 6 -R 9 . Anodes of the LEDs L 1 -L 4  are coupled to the power terminal P 5 V. The trigger pins RB 4 -RB 7  are respectively coupled to the state pins  4  of the connectors J 4 -J 1 . 
         [0011]    In the embodiment, the state pin  4  of each connector can output logic-high signal, such as logic 1, upon the condition that the connector is connected to a fan, and output a logic-low signal, such as logic 0, upon a condition that the connector is not connected to a fan. For example, when the connector J 3  is not connected to a fan, the state pin  4  of the connector J 3  can output the logic-low level state signal to the trigger pin RB 7  of the controller  30 . Alternatively, when the connector J 3  is connected to a fan, the state pin  4  of the connector J 3  can output the logic-high level state signal to the trigger pin RB 7  of the connector  30 . 
         [0012]    Accordingly, the controller  30  can determine whether the connector is connected to a fan or not, according to the voltage level at the trigger pins. In an embodiment, when the controller  30  obtains the speed of the fan, the controller  30  can determine whether the state pin  4  of the connector is at a logic-high or a logic-low level. If the state pin  4  of the connector is at logic-high level, the controller  30  then receives the speed signal from the speed pin  2  of the connector. If the state pin  4  of the connector is at logic-low level, the controller  30  then does not receive the speed signal from the speed pin  2  of the connector. Hence, the controller  30  can obtain the speed signal from the connector that has been connected to a fan. The controller  30  can further determine whether the fan is working normally or malfunctioning according to the speed signal. If the fan is malfunctioning, the controller  30  can further output logic-low level control signal to the anode of the corresponding LED to turn off the LED, to show that the fan is malfunctioning. In at least one embodiment, if the fan is operating normally, the controller  30  can further output logic-high level control signal to the anode of the corresponding LED, to turn on the relevant LED. 
         [0013]    While the disclosure has been described by way of example and in terms of a preferred embodiment, it is to be understood that the disclosure is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the range of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.