Abstract:
A signal generating circuit for detecting ground status includes a power supply input unit (A), a step down rectified power supply or DC power supply unit (C) in series. The DC power supply required by a signal detection and process unit (D) is obtained by the power supply input unit (A) passing through the step down DC power supply unit (C), and then a ground status signal is obtained and outputted via a resistor unit (B) and the signal detection and process unit (D) connected in turn.

Description:
BACKGROUND OF THE PRESENT INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to a signal generating circuit, and more particularly to a signal generating circuit for detecting ground status. 
         [0003]    2. Description of Related Arts 
         [0004]    Signal generating circuit is a common circuit and widely applied to electrical or electronic industry, wherein the signal generating circuit comprises a signal outputting circuit, and a step down rectifier circuit or DC power supply unit. When the power cable or the electrical equipment is not grounded or grounded in an improper way, there are significant safety risks to the human bodies and the equipments. 
       SUMMARY OF THE PRESENT INVENTION 
       [0005]    An object of the present invention is to overcome the above drawbacks of the conventional technology, wherein the signal generating circuit for detecting ground status provides a security inspection for detecting its grounding status or detecting the grounding status of the power input cable or the electrical equipment. 
         [0006]    Accordingly, in order to accomplish the above object, the present invention provides a signal generating circuit for detecting ground status. 
         [0007]    The signal generating circuit comprises a power supply input unit A and a step down DC power supply unit C connected to the power supply input unit A. A power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0008]    The above object of the signal generating circuit for detecting ground status can further be achieved with the followings. 
         [0009]    The resistor unit B comprises one or more resistors connected with each other in parallel or in series. 
         [0010]    The resistor unit B comprises a resistor R A , a resistor R B , a resistor R C , and a resistor R D , wherein the resistor R A  is connected to R B  in series, wherein an input end of the resistors R A , R B  in series is connected to a hot wire (live wire) of the power supply input unit A, and an output end of the resistors R A , R B  in series is connected to an earth wire (ground wire) of the signal detection and process unit D. The resistors R C , R D  are connected in series, wherein an input end of the resistors R C , R D  in series is connected to a neutral wire (null line) of the power supply input unit A, and an output end of the resistors R C , R D  in series is connected to the ground wire of the signal detection and process unit D. 
         [0011]    The resistor unit B comprises a resistor R A , a resistor R B , wherein the resistor R A  is connected to R B  in series, wherein an input end of the resistors R A , R B  in series is connected to a hot wire of the power supply input unit A, and an output end of the resistors R A , R B  in series is connected to a ground wire of the signal detection and process unit D. 
         [0012]    The resistor unit B comprises a resistor R A , a resistor R B , a resistor R C , and a resistor R D , wherein the resistor R A  is connected to R B  in series, wherein an input end of the resistors R A , R B  in series is connected to a hot wire of the power supply input unit A, and an output end of the resistors R A , R B  in series is connected to an Vcc of the signal detection and process unit D. The resistors R C , R D  are connected in series, wherein an input end of the resistors R C , R D  in series is connected to the neutral wire of the power supply input unit A, and an output end of the resistors R C , R D  in series is connected to the Vcc of the signal detection and process unit D. 
         [0013]    The resistor unit B comprises a resistor R A , a resistor R B , a resistor R C , and a resistor R D , wherein the resistor R A  is connected to R B  in series, wherein an input end of the resistors R A , R B  in series is connected to a hot wire of the power supply input unit A, and an output end of the resistors R A , R B  in series is connected to an Vcc of the signal detection and process unit D. 
         [0014]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a resistor R 4 , a diode D 5 , a diode D 15 , a chip U 1 , wherein a positive pole of the diode D 15  is connected to a ground wire of the chip U 1 , and a negative pole of the diode D 15  is connected to a negative terminal (−) of the chip U 1 . A voltage divider of the connected in series resistors R 1 , R 2  is parallel connected to a voltage divider of the connected in series resistors R 3 , R 4  and the diode D 5 . A voltage divider connecting point  2  between the resistors R 1  and R 2  is connected to a position terminal (+) of the chip U 1 , wherein the other end of the resistor R 1  is connected to a Vcc of the chip U 1 , wherein the other end of the resistor R 2  is connected to a ground wire of the chip U 1 . A voltage divider connecting point  3  of the resistors R 3 , R 4 , and the diode D 5  is connected to the negative terminal of the chip U 1 , wherein one end of the resistor R 4  is connected to the Vcc of the chip U 1 , and the other end of the resistor R 4  is connected to a positive pole of the diode D 5 , wherein a negative pole of the diode D 5  is connected to the voltage divider connecting point  3 . One end of the resistor R 3  is connected to the ground wire of the chip U 1 , and the other end of the resistor R 3  is connected to the voltage divider connecting point  3 . An output end of the resistor unit B is connected to the negative terminal of the chip U 1 . A ground wire SGND of the power supply input unit A is connected to the negative terminal of the chip U 1 , and an output signal is connected to an output end of the chip U 1 . 
         [0015]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a resistor R 4 , a diodes D 5 , a voltage regulator diode (Zener diode) ZD 1 , and a chip U 1 , wherein a negative pole of the voltage regulator diode ZD 1  is connected to a Vcc of the chip U 1 , and a positive pole of the voltage regulator diode ZD 1  is connected to a positive terminal of the chip U 1 . A voltage divider of the connected in series resistors R 1 , R 2  is parallel connected to a voltage divider of the connected in series resistors R 3 , R 4  and the diode D 5 . A voltage divider connecting point  2  between the resistors R 1  and R 2  is connected to a negative terminal of the chip U 1 , wherein the other end of the resistor R 1  is connected to a Vcc of the chip U 1 , wherein the other end of the resistor R 1  is connected to a ground wire of the chip U 1 . A voltage divider connecting point  3  of the resistors R 3 , R 4 , and the diode D 5  is connected to the positive terminal of the chip U 1 , wherein one end of the resistor R 4  is connected to the Vcc of the chip U 1 , and the other end of the resistor R 4  is connected to a positive pole of the diode D 5 , wherein a negative pole of the diode D 5  is connected to the voltage divider connecting point  3 . One end of the resistor R 3  is connected to the ground wire of the chip U 1 , and the other end of the resistor R 3  is connected to the voltage divider connecting point  3 . An output end of the resistor unit B is connected to the Vcc of the chip U 1 . A ground wire SGND of the power supply input unit A is connected to the positive terminal of the chip U 1 , and an output signal is connected to an output end of the chip U 1 . 
         [0016]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a diodes D 1 , a diodes D 2 , and a chip U 1 , wherein one end of the resistor R 1  is connected to a ground wire SGND of the power supply input unit A, and the other end of the resistor R 1  is connected to one of the I/O pins of the chip U 1  through the connecting point  1  and  2  respectively. A voltage divider of the connected in series resistors R 2 , R 3  is parallely connected to the connected in series diode D 1  and D 2 , wherein the other end of the resistor R 2  and an positive pole of the diode D 2  are connected to a ground wire GND pin  4  of the chip U 1 , and the other end of the resistor R 3  and a negative pole of the diode D 1  are connected to a power Vcc pin  8  of the chip U 1 . An output end of the resistor unit B is connected to the ground wire GND pin  4  of the chip U 1 . 
         [0017]    The present invention has the following advantages in comparison with the conventional technology. 
         [0018]    Applying the above signal generating circuit is simple in structure and practical. The signal generating circuit can effectively detect the importation of power cables or electrical equipment grounding status, so as to ensure the safety of human bodies and the operation of the equipments. 
         [0019]    These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a block diagram of the signal generating circuit for detecting the ground status according to the present invention. 
           [0021]      FIG. 2  is a schematic signal generating circuit for detecting the ground status according to a first preferred embodiment of the present invention. 
           [0022]      FIG. 3  is a schematic signal generating circuit for detecting the ground status according to a second preferred embodiment of the present invention. 
           [0023]      FIG. 4  is a schematic signal generating circuit for detecting the ground status according to a third preferred embodiment of the present invention. 
           [0024]      FIG. 5  is a schematic signal generating circuit for detecting the ground status according to a fourth preferred embodiment of the present invention. 
           [0025]      FIG. 6  is a schematic signal generating circuit for detecting the ground status according to a fifth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    It will combine the accompany drawings to further describe the present invention as follows. 
         [0027]    Referring to  FIGS. 1 and 2  of the drawings, a first preferred embodiment of the present invention is illustrated. 
         [0028]    Referring to the accompany drawings, the signal generating circuit for detecting ground status comprises a power supply input unit A and a step down DC power supply unit C, wherein the power supply input unit A is connected to the step down DC power supply unit C, wherein a power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0029]    The resistor unit B comprises a resistor R A , a resistor R B , a resistor R C , and a resistor R D , wherein the resistor R A  is connected to the resistor R B  in series, wherein an input end of the resistors R A , R B  in series is connected to a hot wire of the power supply input unit A, and an output end of the resistors R A , R B  in series is connected to a ground wire of the signal detection and process unit D. The resistors R C , R B  are connected in series, wherein an input end of the resistors R C , R D  in series is connected to the neutral wire of the power supply input unit A, and an output end of the resistors R C , R D  in series is connected to the ground wire of the signal detection and process unit D. 
         [0030]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a resistor R 4 , a diode D 5 , a diode D 15 , and a chip U 1 , wherein a positive pole of the diode D 15  is connected to a ground wire of the chip U 1 , and a negative pole of the diode D 15  is connected to a negative terminal of the chip U 1 . A voltage divider of the connected in series resistors R 1 , R 2  is parallel connected to a voltage divider of the connected in series resistors R 3 , R 4  and the diode Ds. A voltage divider connecting point  2  between the resistors R 1  and R 2  is connected to a positive terminal of the chip U 1 , wherein the other end of the resistor R 1  is connected to a Vcc of the chip U 1 , wherein the other end of the resistor R 2  is connected to a ground wire of the chip U 1 . A voltage divider connecting point  3  of the resistors R 3 , R 4 , and the diode D 5 , which is located in between the resistor R 3  and the resistor R 4 , diode D 5 , is connected to the negative terminal of the chip U 1 , wherein one end of the resistor R 4  is connected to the Vcc of the chip U 1 , and the other end of the resistor R 4  is connected to a positive pole of the diode D 5 , wherein a negative pole of the diode D 5  is connected to the voltage divider connecting point  3 . One end of the resistor R 3  is connected to the ground wire of the chip U 1 , and the other end of the resistor R 3  is connected to the voltage divider connecting point  3 . An output end of the resistor unit B is connected to the negative terminal of the chip U 1 . A ground wire SGND of the power supply input unit A is connected to the negative terminal of the chip U 1 , and an output signal is connected to an output end of the chip U 1 . 
         [0031]    Referring to  FIGS. 1 and 3  of the drawings, a second preferred embodiment of the present invention is illustrated. 
         [0032]    Referring to the accompany drawings, the signal generating circuit for detecting ground status comprises a power supply input unit A and a step down DC power supply unit C, wherein the power supply input unit A is connected to the step down DC power supply unit C, wherein a power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0033]    The resistor unit B comprises a resistor R A , wherein an input end of the resistor unit B is connected to a hot wire of the power supply input unit A, and an output end of the resistor unit B is connected to a Vcc of the signal detection and process unit D. 
         [0034]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a resistor R 4 , a diodes D 5 , a voltage regulator diode ZD 1 , and a chip U 1 , wherein a negative pole of the voltage regulator diode ZD 1  is connected to a Vcc of the chip U 1 , and a positive pole of the voltage regulator diode ZD 1  is connected to a positive terminal of the chip U 1 . A voltage divider of the connected in series resistors R 1 , R 2  is parallel connected to a voltage divider of the connected in series resistors R 3 , R 4  and the diode D 5 . A voltage divider connecting point  2  between the resistors R 1  and R 2  is connected to a negative terminal of the chip U 1 , wherein the other end of the resistor R 1  is connected to the Vcc of the chip U 1 , wherein the other end of the resistor R 2  is connected to a ground wire of the chip U 1 . A voltage divider connecting point  3  of the resistors R 3 , R 4 , and the diode D 5  is connected to a positive terminal of the chip U 1 , wherein one end of the resistor R 4  is connected to the Vcc of the chip U 1 , and the other end of the resistor R 4  is connected to a positive pole of the diode D 5 , wherein a negative pole of the diode D 5  is connected to the voltage divider connecting point  3 . One end of the resistor R 3  is connected to the ground wire of the chip U 1 , and the other end of the resistor R 3  is connected to the voltage divider connecting point  3 . An output end of the resistor unit B is connected to the Vcc of the chip U 1 . A ground wire SGND of the power supply input unit A is connected to the positive terminal of the chip U 1 , and an output signal is connected to an output end of the chip U 1 . 
         [0035]    Referring to  FIGS. 1 and 4  of the drawings, a third preferred embodiment of the present is illustrated. 
         [0036]    Referring to the accompany drawings, the signal generating circuit for detecting ground status comprises a power supply input unit A and a step down DC power supply unit C, wherein the power supply input unit A is connected to the step down DC power supply unit C, wherein a power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0037]    The resistor unit B comprises a resistor R A  and a resistor R B , wherein the resistors R A , R B  are connected in series, wherein an input end of the resistor unit B is connected to a hot wire of the power supply input unit A, and an output end of the resistor unit B is connected to a ground wire of the signal detection and process unit D. 
         [0038]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a diodes D 1 , a diodes D 2 , and a chip U 1 , wherein one end of the resistor R 1  is connected to a ground wire SGND of the power supply input unit A, and the other end of the resistor R 1  is connected to one of the I/O pins of the chip U 1  through the voltage divider connecting point  1  and  2  respectively. A voltage divider of the connected in series resistors R 2 , R 3  is parallely connected to the connected in series of the diode D 1  and the D 2 , wherein the other end of the resistor R 2  and an positive pole of the diode D 2  are connected to a ground wire GND pin  4  of the chip U 1 , and the other end of the resistor R 3  and a negative pole of the diode D 1  are connected to a power Vcc pin  8  of the chip U 1 . An output end of the resistor unit B is connected to the ground wire GND pin  4  of the chip U 1 . 
         [0039]    Referring to  FIGS. 1 and 5  of the drawings, a fifth preferred embodiment of the present invention is illustrated. 
         [0040]    Referring to the accompany drawings, the signal generating circuit for detecting ground status comprises a power supply input unit A and a step down DC power supply unit C, wherein the power supply input unit A is connected to the step down DC power supply unit C, wherein a power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0041]    The resistor unit B comprises a resistor R A , a resistor R B , a resistor R C , and a resistor R D , wherein the resistor R A  is connected to R B  in series, wherein an input end of the resistors R A , R B  connected in series is connected to a hot wire of the power supply input unit A, and an output end of the resistors R A , R B  connected in series is connected to an Vcc of the signal detection and process unit D. The resistors R C , R D  are connected in series, wherein an input end of the resistors R C , R D  in series is connected to the neutral wire of the power supply input unit A, and an output end of the resistors R C , R D  in series is connected to the Vcc of the signal detection and process unit D. 
         [0042]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a resistor R 4 , a diodes D 5 , a voltage regulator diode ZD 1 , and a chip U 1 , wherein a negative pole of the voltage regulator diode ZD 1  is connected to a Vcc of the chip U 1 , and a positive pole of the voltage regulator diode ZD 1  is connected to a negative terminal of the chip U 1 . A voltage divider of the connected in series resistors R 1 , R 2  is parallel connected to a voltage divider of the connected in series resistors R 3 , R 4  and the diode D 5 . A voltage divider connecting point  2  between the resistors R 1  and R 2  is connected to a positive terminal of the chip U 1 , wherein the other end of the resistor R 1  is connected to a Vcc of the chip U 1 , wherein the other end of the resistor R 2  is connected to a ground wire of the chip U 1 . A voltage divider connecting point  3  of the resistors R 3 , R 4 , and the diode D 5  is connected to the negative terminal of the chip U 1 , wherein one end of the resistor R 4  is connected to the Vcc of the chip U 1 , and the other end of the resistor R 4  is connected to a positive pole of the diode D 5 , wherein a negative pole of the diode D 5  is connected to the voltage divider connecting point  3 . One end of the resistor R 3  is connected to the ground wire of the chip U 1 , and the other end of the resistor R 3  is connected to the voltage divider connecting point  3 . An output end of the resistor unit B is connected to the Vcc of the chip U 1 . A ground wire SGND of the power supply input unit A is connected to the negative terminal of the chip U 1 , and an output signal is connected to an output end of the chip U 1 . 
         [0043]    Referring to  FIGS. 1 and 6  of the drawings, a fifth preferred embodiment of the present invention is illustrated. 
         [0044]    Referring to the accompany drawings, the signal generating circuit for detecting ground status comprises a power supply input unit A and a step down DC power supply unit C, wherein the power supply input unit A is connected to the step down DC power supply unit C, wherein a power source is inputted into the power supply input unit A to pass through the step down DC power supply unit C to obtain a DC power source, which is for the need of a signal detection and process unit D, and then connecting to a resistor unit B and the signal detection and process unit D respectively to obtain and output a ground status signal. 
         [0045]    The resistor unit B comprises a resistor R A  and a resistor R B , wherein the resistors R A , R B  are connected in series, wherein an input end of the resistor unit B is connected to a hot wire of the power supply input unit A, and an output end of the resistor unit B is connected to a Vcc of the signal detection and process unit D. 
         [0046]    The signal detection and process unit D comprises a resistor R 1 , a resistor R 2 , a resistor R 3 , a voltage regulator diode ZD 1 , and a chip U 1 , wherein one end of the resistor R 1  is connected to a ground wire SGND of the power supply input unit A, and the other end of the resistor R 1  is connected to a I/O pin  1  of the chip U 1  through the connecting point  1  and  2  respectively. The voltage regulator diode ZD 1  is parallely connected to the resistor R 3 , wherein a negative pole of the voltage regulator diode ZD 1  is connected to a power Vcc pin  8  of the chip U 1 , and a positive pole of the voltage regulator diode ZD 1  is connected to a I/O pin  1  of the chip U 1 . The resistor R 2  and the resistor R 3  are connected in series to form a voltage divider, wherein one end of the resistor R 2  is connected the voltage divider connecting point  1 , and the other end of the R 2  is connected to a ground wire GND pin  4 , and connected to the I/O pin  1  of the chip U 1 . 
         [0047]    One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
         [0048]    It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.