Patent Publication Number: US-2017366176-A1

Title: Detection device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 201610460425.X filed in China on Jun. 21, 2016, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to a detection device, more particularly to a detection device integrated with an electrostatic protection device. 
     Related Art 
     Nowadays, integrated circuits are very sensitive to electrostatic discharge (ESD). In fabrication plants, when operators and technicians assemble devices, ESD might occur and cause damages on the integrated circuits of the devices. Thus, the operators and technicians of fabrication plants need to wear devices with ESD protection function to prevent the charges on human bodies being conducted to the device to be fabricated. 
     However, technicians may incorrectly wear ESD protection devices due to various reasons. For example, a technician wears ESD protection device indeed, but the loose port of device causes imperfect contact, the technician wears the protection device by a wrong method, or the technician is too busy to wear the protection device. Therefore, how to find out the above problems immediately and notify the person involved and the related department is an issue to be solved in modern fabrication plants. 
     SUMMARY 
     According to an embodiment, the disclosure provides a detection device, having a detecting port, a leakage port, an oscillation circuit and a detection circuit. The detecting port is used for pluggably coupled to the object to be measured. The leakage port is used for electrically coupled to the ground loop. The oscillation circuit is electrically coupled to the detecting port and the leakage port respectively, and is used for generating an oscillation signal. Also, when the detecting port is coupled to the object, the charges of the object will be transferred to the leakage port via the oscillation circuit. The detection circuit is used for determining whether the detecting port is coupled to the object based on the oscillation characteristic of the oscillation signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present disclosure and wherein: 
         FIG. 1  is a circuit diagram of a detection device in an embodiment; 
         FIG. 2  is a schematic diagram of a detection device in actual use in an embodiment; 
         FIG. 3A  is a timing diagram of an oscillation signal in an embodiment; 
         FIG. 3B  is a timing diagram of an oscillation signal in another embodiment; and 
         FIG. 4  is a functional block diagram of a detection device in an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings. 
     Please refer to  FIG. 1 , a circuit diagram of a detection device in an embodiment. As shown in  FIG. 1 , a detection device  1000  has a detecting port  1100 , a leakage port  1200 , an oscillation circuit  1300  and a detection circuit  1400 . Among them, the leakage port  1200  is electrically coupled to a ground loop ESD to contact to the ground terminal of whole environment GGND. The oscillation circuit  1300  is electrically coupled to the detecting port  1100  and the leakage port  1200  respectively. The detection circuit  1400  is electrically coupled to the oscillation circuit  1300 . 
     The oscillation circuit  1300  is used for generating the oscillation signal Vosc. More specifically, the oscillation circuit  1300  has an amplifier  1310 , a divided feedback and bleeder circuit  1320 , a resistor device  1330  and a harmonic oscillation unit  1340 . The amplifier  1310  has a first input  1311 , a second input  1313  and an output  1315 . The divided feedback and bleeder circuit  1320  has a first terminal  1321 , a second terminal  1323 , a first node  1325  and a second node  1327 . The first terminal  1321  of the divided feedback and bleeder circuit  1320  is coupled to the output  1315  of the amplifier  1310 . The second terminal  1323  of the divided feedback and bleeder circuit  1320  is coupled to the leakage port  1200 . The first node  1325  of the divided feedback and bleeder circuit  1320  is coupled to the detecting port  1100 . The second node  1327  of the divided feedback and bleeder circuit  1320  is coupled to the first input  1311  of the amplifier  1310 . The resistor device  1330  has a first terminal  1331  and a second terminal  1333 . The first terminal  1331  of the resistor device  1330  is coupled to the leakage port  1200 . The harmonic oscillation unit  1340  has a first terminal  1341 , a second terminal  1343  and a third terminal  1345 . The first terminal  1341  of the harmonic oscillation unit  1340  is coupled to the output  1315  of the amplifier  1310 . The second terminal  1343  of the harmonic oscillation unit  1340  is coupled to the input  1313  of the amplifier  1310 . The third terminal  1345  of the harmonic oscillation unit  1340  is coupled to the second terminal  1333  of the resistor device  1330 . In an embodiment, the oscillation signal Vosc, generated by the oscillation circuit  1300 , is not larger than 5 volt with respect to the voltage of the ground terminal GGND. 
     In an embodiment, the divided feedback and bleeder circuit  1320  is made up of a resistor R 11 , a resistor R 12  and a resistor R 13 , wherein the resistance of the resistor R 11  is 470 kilo ohm (kΩ), the resistance of the resistor R 12  is 910 kΩ, and the resistance of the resistor R 13  is 100 kΩ. Besides, the resistance of resistor device  1330  is no less than 10 kΩ. 
     In an embodiment, as shown in  FIG. 1 , the harmonic oscillation unit  1340  has a resistor R 2 , a first capacitor C 1  and a second capacitor C 2 . The resistor R 2  is coupled to the first terminal  1341  of the harmonic oscillation unit  1340  and the second terminal  1343  of the harmonic oscillation unit  1340  respectively. The first capacitor C 1  is coupled to the first terminal  1341  of the harmonic oscillation unit  1340  and the third terminal  1345  of the harmonic oscillation unit  1340  respectively. The second capacitor C 2  is coupled to the third terminal  1345  of the harmonic oscillation unit  1340  and the second terminal  1343  of the harmonic oscillation unit  1340  respectively. In this embodiment, the resistance of the resistor R 2  is 470 kΩ, the capacitances of the first capacitor C 1  and the second capacitor C 2  are both 470 pico Farad pF. However, the above description is just for example. Person having ordinary skill in the art can determine the value of every electronic component based on the spirit of this disclosure and this disclosure does not intend to limit the value of these electronic components. 
     Please refer to  FIG. 1  and  FIG. 2 , wherein  FIG. 2  is a schematic diagram of a detection device in actual use in an embodiment. As shown in  FIG. 2 , a personnel  2000  wears an electrostatic protection wristband  3000 , the electrostatic protection wristband  3000  is plugged in the detecting port of the detection device  1000  (not clearly shown in the figure). The electrostatic charges on the personnel  2000  are transferred via the detecting port  1100 , the divided feedback and bleeder circuit  1320  of the oscillation circuit  1300  in the detection device  1000  to the leakage port  1200 . Afterwards, the charges flow from the leakage port  1200 , via the ground loop ESD, to the ground terminal GGND. 
     More specifically, the inner margin of the electrostatic protection wristband  3000  has an exposed conducting loop. When the electrostatic protection wristband  3000  is plugged in the detecting port  1100 , the conducting loop is electrically coupled to the detecting port. Thus, when the personnel  2000  wears the electrostatic protection wristband  3000  correctly, the charges on the hand of the personnel  2000  are transferred to the detecting port  1100  via the exposed conducting loop, and are finally transmitted to the ground terminal GGND. If the electrostatic protection wristband  3000  is plugged in the detecting port  1100  incorrectly or the eversion of the inner margin of the electrostatic protection wristband  3000  makes the conducting loop disconnect with the hand of the personnel  2000 , the charges on the hand of the personnel  2000  are not transmitted to the ground terminal GGND. 
     Please refer to  FIG. 3A  and  FIG. 3B , wherein  FIG. 3A  is a timing diagram of an oscillation signal in an embodiment, and  FIG. 3B  is a timing diagram of an oscillation circuit in another embodiment. In an embodiment, when the personnel  2000  is not really electrically coupled to the detection device  1000 , the oscillation signal generated by the oscillation circuit  1300  is shown in  FIG. 3A . In another embodiment, when the personnel  2000  is correctly electrically coupled to the detection device  1000 , the oscillation signal generated by the oscillation circuit  1300  is shown in  FIG. 3B . More specifically, please back to  FIG. 2 . Because there is a parasitic capacitor CP for the personnel  2000  with respect to the ground terminal, when the personnel  2000  is correctly electrically coupled to the detection device  1000 , the existence of the parasitic capacitor CP breaks the oscillation conditions of the oscillation circuit based on Barkhausen stability criterion. The result is shown in  FIG. 3B , wherein in time interval TP 1 , the personnel  2000  doesn&#39;t wear the electrostatic protection wrist band  3000 , and in time interval TP 2 , the personnel  2000  correctly wears the electrostatic protection wristband  3000 . Thus, in time interval TP 2 , the amplitude of the oscillation signal must become smaller and smaller, and finally stop oscillating. 
     The detection circuit  1400  is electrically coupled to the output  1315  of the amplifier  1310  of the oscillation circuit  1300 . Therefore, the detection circuit  1400  can detect the oscillation characteristic of the oscillation signal Vosc to determine whether the personnel  2000  is correctly electrically coupled to the detecting port  1100  of the detection device  1000 . More specifically, when the detection circuit  1400  detects no periodic voltage change of the oscillation signal Vosc, based on the theory mentioned before, the detection circuit  1400  determines that the personnel  2000  is correctly electrically coupled to the detecting port  1100 . In other words, the personnel  2000  uses a right method to wear the electrostatic protection wristband  3000 , and the electrostatic protection wristband  3000  is well plugged in the detecting port  1100  of the detection device  1000 . Moreover, according to embodiments in  FIG. 3A ,  FIG. 3B  and  FIG. 1 , followed by the voltage restriction of the oscillation signal Vosc, because the value of the current flowing from the oscillation circuit  1300  to human body is very tiny, the current won&#39;t affect the electrostatic protection of the personnel  2000  by the detection device  1000 . Besides, when the electrostatic protection wristband  3000  is correctly coupled to the detection device  1000 , the oscillation signal Vosc will decay fast and converge to smaller than 5 volt. The ESD protection of the detection device  1000  for the personnel  2000  is not affected in the aforementioned situation. 
     If the detection circuit  1400  detects the periodic voltage change of the oscillation signal Vosc, the detection circuit  1400  will determine that the personnel  2000  is incorrectly electrically coupled to the detecting port  1100 . In other words, the result is from either the incorrect wearing of the electrostatic protection wristband  3000  of the personnel  2000 , or imperfect contact between the electrostatic protection wristband  3000  and the detecting port  1100  of the detection device  1000 . 
     In an embodiment, due to the differences in body size and gender of each person, the value of the capacitor on a person with respect to the ground terminal GGND of environment varies from person to person. In order to accurately detect whether the personnel  2000  correctly wears the electrostatic protection wristband  3000  or not, the oscillation circuit  1300  needs calibrating appropriately. As shown in  FIG. 1 , the resistor device  1330  includes a variable resistor Rad. When the detection device  1000  is used by the personnel  2000  in the first time, the personnel  2000  has operated the detection device  1000  to adjust the value of the variable resistor Rad until the detection circuit  1400  of the detection device  1000  produces a correct determining result of the personnel  2000  and the detection device  1000 . Hence, the calibration is completed. 
     In an embodiment, please back to  FIG. 1 . The detection device  1000  is further electrically coupled to a bus network  4000 , for example, an inter-integrated circuit, RS-485 or other similar master-slave architecture bus. Besides, the detection circuit  1400  sends the determining result to the bus network  4000 . 
     More specifically, the detection device  1000  further has an interface circuit  1500 . The interface circuit  1500  is respectively electrically coupled to the detection circuit  1400  and the bus network  4000 . Thus, when the detection circuit  1400  runs normally, the interface circuit  1500  receives the determining result from the detection circuit  1400  and sends to the bus network  4000 . When the detection circuit  1400  is failed, in an embodiment, the detection circuit  1400  sends the same determining result repeatedly. If the interface circuit  1500  gets the constant determining result from the detection circuit  1400  continuously, the interface circuit  1500  will not send this repeat determining result to the bus network  4000 . In the protocol architecture of the bus network  4000 , if one of the multiple detection devices connected by the bus network  4000  malfunctions, the problems, including the defect detection device occupying the bus network  4000  continuously and the signal confliction of the bus network  4000 , can be avoided because of the function of the interface circuit  1500 . 
     In an embodiment, as shown in  FIG. 4 , the detection device  1000  further has a first enabling circuit  1600  electrically connected to the oscillation circuit  1300  and the detection circuit  1400 . The first enabling circuit  1600  is used for selectively disabling the oscillation circuit  1300 . More specifically, the first enabling circuit  1600  is used for selectively decreasing the electric potential of the power terminal VCC of the amplifier  1310  in order to make the amplifier  1310  functioning abnormally. Thus, the oscillation signal Vosc generated by the oscillation circuit  1300  is blocked from oscillating, and the detection circuit  1400  is blocked from sending the abnormal determining result. In practice, when the personnel  2000  temporarily leave the seat and does not need to wear the electrostatic protection wristband  3000 , the personnel  2000  operates the detection device  1000  to make the first enabling circuit  1600  disable the oscillation circuit  1300 . At this moment, the first enabling circuit  1600  also sends out the signal to inform the detection circuit  1400 . Therefore, the detection circuit  1400  sends the information that the detection device  1000  stops detecting to the bus network  4000 . When the personnel  2000  is back to the seat and operates the detection device  1000 , the first enabling circuit  1600  will enable the oscillation circuit  1300  again. Then, the detection circuit  1400  also restarts detecting, and sends the information detected to the bus network  4000 . 
     In another embodiment, as shown in  FIG. 4 , the detection device  1000  further has a second enabling circuit  1700  electrically connected to the detection circuit  1400 . And, the second enabling circuit  1700  is used for selectively adjust the determining result. In brief, in this embodiment, when the personnel  2000  temporarily leave the seat and does not need to wear the electrostatic protection wristband  3000 , the personnel  2000  operates the detection device  1000  to make the second enabling circuit  1700  notify the detection circuit  1400 . So, the detection circuit  1400  will not detect the oscillation signal Vosc practically, and the detection circuit  1400  will send the information that the detection device  1000  stops detecting to the bus network  4000 . When the personnel  2000  is back to the seat and operate the detection device  1000 , the second enabling circuit  1700  will notify the detection circuit  1400  to restart detecting, and send the information detected to the bus network  4000 . 
     As set forth above, the detection device provided in this disclosure can detect whether the detecting port is coupled to the object (personnel), and at the same time, transmit the charges on the object to the leakage port via the oscillation circuit. As a result, the detection device provided in this disclosure practically has the function of electrostatic discharge protection.