Abstract:
The present invention provides a thermostat with GFCI which includes control module, keyboard module, communication module and display module, and it further includes a leakage detection module, and the control module includes the temperature sensor, and the leakage detection module is connected with the control module, keyboard module and display module respectively. The control module is connected with the controlled device by the leakage detection module. The thermostat monitors current status of output circuit while adjusting the temperature of room, so that it can ensure the safety of the output circuit in use. If leakage occurs to the controlled device, the thermostat can cut off the power and stop power supplying at once, and the alarm light illuminates in the meantime. After manual reset, the alarm light goes out. It works with a wide input voltage range and makes the thermostat normally work at multistage voltage, and it can detect the leakage current accurately, and cut off power in time and report to the system.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to a thermostat, particularly relates to a thermostat with GFCI (Ground-Fault Circuit Interrupter), which uses the electric load as the controlled object. 
       BACKGROUND OF THE INVENTION 
       [0002]    With the improved requirement of comfortable life, various modernize HVAC equipments have become more popular in the habitable environment, such as floor heating, cable heating, electro-thermal film heating, electric radiation panel, electric heater and so on. At the same time, it has generally applied in industry and agriculture. Therefore, it needs the advanced device or equipment to control temperature. Thermostat is the most ordinary device for controlling temperature at present. 
         [0003]    Thermostat belongs to the temperature controlling device, and it can control cold and heat sources device according to the contrast between the required temperature and current temperature. It can achieve the user&#39;s required temperature by increasing or decreasing temperature, so that it meets the purpose of comfort and energy-saving. 
         [0004]    In theory, there are many ways to realize above purpose. In fact, there are two series at present, mechanical thermostat and electronic-type intelligent thermostat. 
         [0005]    The early stage of thermostat is the mechanical thermostat which adopts the bi-metallic strip or the gas filled bellow to sense room temperature and realize control cold and heat source, and it can achieve the user&#39;s required temperature by increasing or decreasing temperature, Nowadays, the bimetallic strip thermostat has already been eliminated, it is only used in some occasions which is not higher requirement or in lower level occasion. Generally speaking, the function of mechanical-type thermostat is simple and it has big deviation for measuring temperature. 
         [0006]    The electronic-type intelligent thermostat belongs to the highly advanced product, and especially it is widely used in the fields of industry and agriculture, scientific research and daily life, so the number of thermostats is increasing. In recent 100 years, the development of thermostat has undergone the following stages:
       (1) Analog integrated mechanical-type thermostat;   (2) Electronic intelligent thermostat;   (3) Intelligentized and networking thermostat.       
 
         [0010]    However, the thermostat of the market is mainly applied to control the room temperature at present, but the controlled device works in the condition of commercial AC 220 v. Electric leakage is an important problem we should take into account, because it can cause danger and threat for the security of people, animals, as well as some devices. Recently, most of the thermostats of the market have no function of GFCI (Ground-Fault Circuit Interrupter), so they virtually have hidden troubles for the security of people and equipments. 
       SUMMARY OF INVENTION 
       [0011]    In order to solve the problems that the thermostat cannot differentiate whether it is leakage or not and it does not detect the current of the load circuit, the present invention solves said technologic problems and puts forward a new proposal. That is this thermostat can not only control temperature and equipment, but also it can detect the current of load circuit. It has the function of GFCI (Ground-Fault Circuit Interrupter), and can detect the current of load return circuit and its supply circuit. According to the requirements of the standard, it can rapidly detect and handle the corresponding detecting result, and ensure the security of users. 
         [0012]    A thermostat with GFCI for maintaining the temperature to a default value and includes control module, keyboard module and display module, which is characterized in that it further includes a leakage detection module, and the control module includes the temperature sensor, which is used to collect the external temperature, and the leakage detection module is connected with the control module, keyboard module and display module respectively, and the control module is connected with the controlled device by the leakage detection module. 
         [0013]    Said leakage detection module includes a leakage fault protection chip, a detection circuit, an output circuit and a signal reset circuit. 
         [0014]    Said output circuit includes two optical couplers which are used for separating input signal and output signal. 
         [0015]    Said detection circuit includes a circuit which is used for deciding whether leakage exists in the circuit or not by detecting whether the current of L line and N line of the current transformer is equal. Said current transformer is located near AC power source to detect whether leakage exists or not in the controlled device and the thermostat simultaneously. 
         [0016]    Said leakage detection module includes the indicator which is used for indicating circuit leakage. And it includes LED. 
         [0017]    Preferably, the display module includes display symbol which is used for indicating circuit leakage. The control module is connected with and control the controlled device by relay. 
         [0018]    Compared to the existing technology, the thermostat with GFCI in accordance with the present invention has the following advantages:
       (1) The present invention use Ampere&#39;s law to detect the induction current produced in the current transformer caused by the unequal between the current in the L line and N line, and then delivers leakage signal to the control module after the processing by said leakage detection module. And the control module can delivers disconnection signal, so that it can protect human safety and property effectively.   (2) Structurally, the space-embedded type method is adopted to make the components compact and tidy. The thermostat can be smaller, nice and occupying less space;   (3) The display module adopts character-type LCD, and the operation of it is simple and convenient;   (4) The housing of the thermostat is made of engineering plastic, which has high temperature resistance and high strength;   (5) The thermostat has the function of communication, so it can report its status in time. The thermostat with GFCI (Ground-Fault Circuit Interrupter), in accordance with the present invention, monitors current status of output circuit while adjusting the temperature of room, so that it can ensure the safety of the output circuit in use. If leakage occurs to the controlled device, the thermostat can cut off the power and stop power supplying at once, and the alarm light illuminates in the meantime. After manual reset, the alarm light goes out. It works with a wide input voltage range and makes the thermostat normally work at multistage voltage, and it can detect the leakage current accurately, cut off power in time and report to the system.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a schematic circuit diagram of the present invention. 
           [0025]      FIGS. 2-1  and  2 - 2  describe a schematic circuit diagram of the leakage detection module of the present invention. 
           [0026]      FIG. 3  is a schematic circuit diagram of the keyboard module of the present invention. 
           [0027]      FIGS. 4-1  and  4 - 2  describe a schematic circuit diagram of the display module of the present invention. 
           [0028]      FIGS. 5-1 ,  5 - 2 ,  5 - 3  and  5 - 4  describe a schematic circuit diagram of the control module of the present invention (including communication part). 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    In order to make the technological means, creative feature, purpose and functions of the present invention clear, we will give in-depth illustration associated with the following figures. 
         [0030]    As shown in  FIG. 1 , a thermostat with GFCI includes control module  1 , keyboard module  2  and display module  3 , as well as a leakage detection module  4 , and control module  1  is connected with keyboard module  2 , display module  3  and leakage detection module  4  respectively, and leakage detection module  4  is connected with keyboard module  2  and display module  3  respectively, and control modules  1  is connected with the controlled equipment by leakage detection module  4 , and the required working power of the controlled device must be detected by leakage detection module  4 , and the working power of control module  1 , keyboard module  2  and display module  3  must be detected by leakage detection module  4 . 
         [0031]    Temperature sensor is set in the control module  1  to collect the external temperature signal, and then to deliver the signal to the control module  1 . The thermostat set temperature by control module  1  with keyboard module  2  according to actual needs. Control module  1  compares the temperature between external temperature, which is sensed by temperature sensor, and the temperature set by keyboard module  2  to deliver control signal and control the working status of the controlled device. In this embodiment, control module  1  is connected with and control the controlled device by the relay, and it can also use other means to control the controlled device, with out affecting achieving the purpose of the present invention. The controlled device can be the heating and air-conditioning equipment, such as heating cable, electro-thermal film and electric warmer, and it can provide working voltage with leakage detection module  4 . 
         [0032]    As shown in  FIGS. 2-1  and  2 - 2 , leakage detection module  4  includes a leakage fault protection chip IC 3 , a detection circuit  41  including current transformers, an output circuit  42  and a signal reset circuit  43 . 
         [0033]    Detection circuit  41  includes current transformer A, capacitor C 41 , C 43 , C 44 , C 48  and inductor L 1 , L 2 ; and PIN 2  of current transformer A is connected with PIN 1  of current transformer A by capacitor C 43 , and then it is connected with 220V+power by capacitor C 44 , and PIN 3  and PIN 4  are connected to PIN 3  and PIN 1  of leakage protection fault chip IC 3 , respectively, with the resonance circuit composed of inductor L 1 , L 2  and capacitor C 41  and C 48 , and PIN 1  of leakage protection fault chip IC 3  is connected with PIN 7  of leakage protection fault chip IC 3  by resistor R 41  and R 42 , and PIN 6  of leakage protection fault chip IC 3  is connected with 220V+power by resistor R 43 , and the PIN 4  of leakage protection fault chip IC 3  is connected with PIN 5  of leakage protection fault chip IC 3  by capacitor C 42 . 
         [0034]    Output circuit  42  includes optical coupler U 5 , U 6 , LED D 1 , resistor R 44 , R 45 , R 46 , controlled silicon Q 3 , capacitor C 45 . The PIN 6  of leakage protection fault chip IC 3  is connected with PIN 1  of Optical coupler U 6  by resistor R 44  and LED D 1 . The PIN 5  of leakage protection fault chip IC 3  is connected with control terminal of controlled silicon Q 3 . The PIN 5  of leakage protection fault chip IC 3  is connected with cathode of controlled silicon Q 3  by capacitor C 42 . The anode of Q 3  is connected with PIN 4  of optical coupler U 5 . The PIN 2  of optical coupler U 6  is connected with PIN 3  of optical coupler U 5 . The PIN 1  of optical coupler U 5  inputs high level signal GFCI_STANDBY. The PIN 1  of optical couplers U 5  are respectively connected with resistance R 45 , R 46 , capacitor C 45  and PIN 3  of optical coupler U 6 . The PIN 4  of optical coupler U 6  is connected with the other end of capacitor C 45  and grounded. The other end of resistor R 45 , R 46  are connected with each other and with power supply VCC. The PIN 3  of optical coupler U 6  outputs low level leakage signal LOSS_E. 
         [0035]    The signal reset circuit  43  includes transistor Q 4 , resistor R 47 , R 48 , R 49 , R 50 , and capacitor C 46 , C 47 . The resistor R 47 , R 48  are connected with each other and input a BACKPOW signal on the joint of resistor R 47  and R 48 . The other end of resistor R 47  is connected with capacitor C 46  and power supply VCC 2 . The other end of resistor R 48  is connected with resistance R 50 , the emitter of transistor Q 4  and capacitor C 47 , and grounded. The other ends of capacitor C 46  and resistor R 50  are together connected with the base of transistor Q 4 . The collector of transistor Q 4  outputs a RESET signal. The other end of capacitor C 47  is connected with power supply VCC by resistor R 49 . 
         [0036]    One skilled in the art will comprehend, that the optical coupler U 5  and U 6  are used for separating input signal and output signal, so that output signal has no influence on input terminal, and it gets high anti-interference ability, and it makes the circuit working steadily. Similarly, one skilled in the art will also comprehend, that current transformer A is located near AC power source, so it can detect whether the controlled device or the thermostat in accordance with the present invention has leakage or not, to get better leakage detection results. 
         [0037]    As shown in  FIG. 3 , the keyboard module  2  includes touch screen  1 , resistor R 20 -R 27  and button switch S 2 . PIN 1 - 8  of touch screen are respectively connected with R 20 -R 27  by signal KEY 0 -KEY 7 . The other ends of R 20 -R 27  are connected with each other and with signal VCC. One end of button S 2  is connected with signal KEY 8 ; and the other end of button S 2  is connected with signal GND. 
         [0038]    As shown in  FIGS. 4-1  and  4 - 2 , the display module  3  includes control chip IC 2 , display board LCD and auxiliary circuit. PIN 1 - 9 , PIN 18 - 48  of control chip IC 2  are connected with PIN 1 - 40  of display board LCD by bus. PIN 10  of control chip IC 2  is connected with signal VCC by resistor R 31 . The other end of resistor R 31  is connected with PIN 14  of control chip IC 2  and with signal GND by resistor R 32 . The PIN 11  of control chip IC 2  is connected with PIN 14  of control chip and with signal VCC by capacitor C 31 . PIN 12  and PIN 13  of control chip are connected with each other and with PIN 14  of control chip IC 2 . PIN 15  of control chip IC 2  is connected with LCD_SCL. PIN 16  of control chip IC 2  is connected with signal LCD_SDA. PIN 17  of control chip IC 2  is connected with signal RESET. 
         [0039]    As shown in  FIGS. 4-1  and  4 - 2 , one skilled in the art will comprehend, that the indicator for the circuit leakage is set in the display module. Specifically, when leakage occurs, the display module would show the indicating sign, symbol or feature code indicating leakage, accordingly. 
         [0040]    As shown in  FIGS. 5-1 ,  5 - 2 ,  5 - 3  and  5 - 4 , the control module  1  includes control chip U 1 , ISP interface module P 3 , communication module U 3  and the auxiliary circuit. PIN 29 - 37  of control chip U 1  is orderly connected with capacitor C 1 -C 6  and resistor R 11 -R 17  by bus. The other end of capacitor C 1 -C 6  is connected with each other and grounded GND. The other end of resistor R 11  is connected with the other end of resistor R 15  and with FLOOR, and with HOST by resistor R 8 , R 9 . The other end of resistor R 12  is connected with the other end of resistor R 116  and resistor NTC 2 . The other end of resistor R 13  is connected with other end of resistor R 17  and NTC 1 . The other end of resistor R 14  is connected with resistor R 18  and resistor R 1 . The other end of resistor NTC 2 , NTC 1  and R 1  are connected with each other and grounded GND. The other end of resistor R 18  is connected with power supply VCC. 
         [0041]    PIN 5 ,  17 ,  38  of control chip U 1  are connected with each other and connected to power supply VCC. PIN 27  of control chip U 1  is connected with the PIN 5  of control chip U 1  and connected to power supply VCC by resistor R 4 . PIN 28  of control chip U 1  is grounded. PIN 6 ,  18 ,  39  of control chip are connected with each other and connected to the PIN 5  of communication module U 3 . Signal KEY 0  is connected with PIN 40  of control chip U 1 . Signal KEY 1  is connected with PIN 41  of control chip U 1 . Signal KEY 2  is connected with PIN 42  of control chip U 1 . Signal KEY 3  is connected with PIN 43  of control chip U 1 . Signal KEY 4  is connected with PIN 44  of control chip U 1 . Signal BACKPOW is connected with the PIN 12  of control chip U 1 . Signal RELAY_EN is connected with the PIN 13  of control chip U 1 . Signal GFCI_STANDBY is connected with the PIN 15  of control chip U 1 . Signal LOSS_E is connected with the PIN 16  of control chip U 1 . Signal RESET is connected with the PIN 4  of control chip U 1 . 
         [0042]    PIN 2  of ISP interface module P 3  is connected with power supply VCC. PIN 4 ,  6 ,  8 ,  10  of ISP interface module P 3  are connected with each other and grounded. PIN 1  of ISP interface module P 3  is connected with PIN 1  of control chip U 1  by signal KEY 5 . PIN 7  of ISP interface module P 3  is connected with PIN 3  of control chip U 1  by signal KEY 7 . PIN 9  of ISP interface module P 3  is connected with PIN 2  of control chip U 1  by signal KEY 6 . PIN 5  of ISP interface module P 3  is connected with PIN 4  of control chip U 1 . 
         [0043]    Reset circuit including diode D 3 , capacitor C 9 , C 10 , resistor R 2 , R 3 , transistor Q 1  and Switch S 1 , delivers the reset signal RESET to PIN 4  of control chip U 1 . 
         [0044]    Clock circuit includes crystal Y and capacitor C 7 , C 8 , and it is respectively connected with PIN 7 ,  8  of control chip, and provides clock signal for control chip U 1 . 
         [0045]    Communication circuit includes communication module U 3 , resistor R 6 , R 7 , capacitor C 11 -C 16  and port J 1 , and communication circuit U 3  communicates with outside equipment by port J 1 . 
         [0046]    The other circuits of control module  1  are circuit of the existing technology, so we don&#39;t repeat it. 
         [0047]    On the basis of the thermostat of the existing technology, the thermostat with GFCI in accordance with the present invention further includes independent leakage detection module  4  and has no special requirements about the type. 
         [0048]    When leakage occurs, the current in front line L and zero curve N of the current transformer A of leakage detection module  4  would be unequal, and the induction current would be produced in current transformer A and then be delivered to leakage fault protection chip IC 3  to be operated and amplified, to make the SCR terminal of the leakage fault protection chip IC 3  output high level voltage after comparing with the set temperature, and to make triggers Q 3  to conduct; and LED D 1  conducts and illuminates by optical coupler U 5 , U 6  and controlled silicon Q 3 , and indicates the circuit leakage; and the optical coupler U 6  conducts and outputs a low level voltage leakage signal LOSS_E to control module  1 , and control module  1  sends signal RELAY_EN to relay after receiving leakage signal and cuts it off. 
         [0049]    Because controlled silicon Q 3  can cut off it only by cutting off the anode current, control module  1  inputs high level voltage signal GFCI_STANDBY to optical coupler U 5  to make the U 5  stop its output. Then controlled silicon Q 3  cuts off and LED D 1  goes out. 
         [0050]    The above shows and describes the basic principles, main features and the advantages of the present invention. One skilled in the art will comprehend that, the present invention should not be confined to the embodiments shown and described, and the implementation and description only describe the theory of this invention, and the foregoing and other changes in forms and details, which these fall within the scope of the appended claims, may be made without departing from the spirit and scope of the present invention. The protection range of this invention is defined by the claims and other equivalents.