Abstract:
A capacity detecting circuit detects battery voltage and load current, compares the load current to the battery voltage to determine whether the voltage of the battery is sufficient, displays both the current and the relative capacity of the batteries, and cuts off power to the load if the battery voltage is too low, the current is excessive, or if the battery capacity is too low in comparison with said current.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of a capacity detecting circuit for a battery, and especially to a capacity detection circuit with a function that allows it to detect the capacity of the battery and that will also be able to automatically cut off the power supply to the electric circuit of the drive controlling device when there is a mismatch of polarities, a short circuit, or even an over-discharge from the battery. 
     BACKGROUND OF THE INVENTION 
     According to the speedy progress of modern society, the living standard of people is improving day by day and the current scientific technology also makes progress at a tremendous pace, leaving more leisure time and increasing the demand for convenient transportation by developing all kinds of transportation vehicles such as a bicycle, motorcycle, automobile, train, airplane, vessel, etc. For example, it is now a common situation for people with personal taste in enjoying leisure time to own at least one or even several luxury cars. The images of free transportation, comfortable interior decoration, and a wide-range of fanciful daydreams make a car become an incredible enjoyment in everyone&#39;s mind, a place for taking refuge and a place for the people to run after their favorite models from every kind of media. 
     A car is not just the most convenient vehicle in the world. Whether in the form of a sedan, wagon . . . , etc., a car is the best thing for travelling, especially in the hot season in case of no vacant hotel room, in which case the vehicle itself will settle the big headache by serving as a place to sleep. 
     Even having all kinds of the benefits from vehicles, one problem of car-owners is that someone might forget to turn off the headlights of the vehicle, or turn on the stereo equipment, fan, or even high beam for a long period of time, and force the battery to over-discharge and hence have it burn down or die. Furthermore the huge current caused by a car accident or short circuit might not only burn down the battery but also caused serious fires etc., which tragedies could be prevented if there was a device on the vehicles which had the function of an auto-cut off. Solving this problem of modern people has become a very important topic in present-day living. 
     SUMMARY OF THE INVENTION 
     In light of the above matters and based on good experience in studying and researching the field of designing and manufacturing a vehicle&#39;s batteries for many years, the inventor has thus created the present invention in order to overcome the known problems of the battery, and so as to achieve a practical effect at the same time. 
     Therefore, the preferred purpose of the invention is to provide a capacity detecting circuit for a battery that allows detection of the capacity of the battery and cut off of the power supply when the battery capacity is either insufficient or the battery is overcharged. 
     Another preferred purpose of the present invention is to supply a capacity detecting circuit for a battery that has a simple structure and a special function of detecting the capacity under different loading conditions. 
     Thus, according to an embodiment of the invention, it is desired to provide a capacity detecting circuit for a battery that comprises a voltage detecting circuit, a current detecting circuit, a switching circuit, a capacity display circuit, a timing circuit, and a driving circuit etc., which are all fixed onto appropriate positions of the battery. The current detecting circuit and voltage detecting circuit are installed in parallel, and the switching circuit is actually one kind of electronic switch and is installed at a position between the current detecting circuit and the capacity display circuit. The capacity display circuit comprises more than one set of LEDs and resistances. The design for the timing circuit is to add and install a timing loop circuit in the voltage detecting circuit and, furthermore, in the driving circuit, there is also an extra driving loop circuit which is installed onto the voltage detecting circuit. 
     An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE ILLUSTRATIONS 
     FIG. 1 is a sketch-map for the current circuit wiring of the present invention. 
     FIG. 2 is a block diagram of the present invention. 
     FIG. 3 is a flow chart of the present invention. 
     FIG. 4 is a 4051 B Truth Table in common use. 
    
    
     BRIEF DESCRIPTION OF THE SYMBOLS 
     
       
         
               
               
               
               
             
           
               
                   
               
             
             
               
                 10 
                 Voltage detecting circuit 
                 RL1 ˜ RL6 
                 Resistance 
               
               
                 11 
                 Current detecting circuit 
                 R51 ˜ R54 
                 Resistance 
               
               
                 12 
                 Switching circuit 
                 R61 ˜ R64 
                 Resistance 
               
               
                 13 
                 Capacity display circuit 
                 R71 ˜ R74 
                 Resistance 
               
               
                 14 
                 Timing circuit 
                 R81 ˜ R84 
                 Resistance 
               
               
                 15 
                 Driving circuit 
                 R91 ˜ R94 
                 Resistance 
               
               
                 16 
                 Manual switch 
                 R101 ˜ R104 
                 Resistance 
               
               
                 A01 ˜ A10 
                 Operational amplifier 
                 X0 
                 No-loading 
               
               
                 V01 ˜ V10 
                 The input-port of 
                 X1 
                 Light-loading 
               
               
                   
                 Operational amplifier 
                 X3 
                 Heavy-loading 
               
               
                 VC0, VC1 
                 The input-port of 
                 X4 
                 Over-loading 
               
               
                   
                 Operational amplifier 
                 INH 
                 Whether the  
               
               
                   
                   
                   
                 switching 
               
               
                   
                   
                   
                 circuit 
               
               
                 Vref1 
                 Constant voltage 
                   
                 is acting 
               
               
                 Vref2 
                 Reference voltage 
                 LED1 ˜ LED9 
                 Lamp set 
               
               
                 Z1 ˜ Z2 
                 Zener diode 
                 C1 * R2 
                 Timing loop 
               
               
                   
                   
                   
                 circuit 
               
               
                 R1 ˜ R6 
                 Resistance 
                 A,B,C 4051B 
                 output control 
               
               
                 R01 ˜ R02 
                 Resistance 
                 D1 ˜ D13 
                 diode 
               
               
                 R21 ˜ R22 
                 Resistance 
                 I/O 4051B 
                 Input/Output 
               
               
                 R31 ˜ R32 
                 Resistance 
               
               
                 R41 ˜ R42 
                 Resistance 
               
               
                 RF 
                 Resitiance 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
     Firstly, with reference to both FIGS. 1 and 2, the present invention is a capacity detecting circuit for a battery, including a voltage detecting circuit  10 , a current detecting circuit  11 , a switching circuit  12 , a capacity display circuit  13 , a timing circuit  14 , and also a driving circuit  15  etc. 
     By utilizing the Operational Amplifier A 0 , the voltage detecting circuit  10  will analyze the energy by comparing it with an output voltage value and then will prohibit the voltage from being supplied to a controlling device if the value of the output voltage is lower than the protection voltage, and according to the following details: 
     (1) Resistance R 5  and constant voltage diode (Zener diode) Z 1  will provide a constant operating voltage Vref 1 . 
     (2) Resistance R 6  and constant voltage diode (Zener diode) Z 2  will provide a constant reference voltage Vref 2 . 
     (3) When the value of V01 is larger than the value of reference voltage Vref 2 , the actual voltage of the battery is higher than the value of the protection voltage so that the voltage detecting circuit is in a normal operating condition. (V01 utilizes the voltage divided from both resistance R 01  and R 02 .) 
     (4) At the time when the value of V01 is smaller than the value of reference voltage Vref 2 , the voltage of the battery is lower than the value of the protection voltage so that it will cut off the load automatically. (V01 utilizes the voltage divided from both resistance R 01  and R 02 .) 
     Furthermore, the current detecting circuit  11  and voltage detecting circuit  10  are installed in parallel and arranged so that they will provide the necessary current signals when the battery is under the condition of checking the respective circuits and proceeding with operation according to a constant current controlling procedure. In addition, the two detecting circuits utilize a Hall Effect current sensor together with an isolation function in order to get the necessary current signals without causing interference between the controlling circuit and the electric power circuit while the said battery is under a discharging condition. Assuming that the value of rated current is 100 amperes and the ratio of the winding coils is {fraction (1/1000)}, if a current of 1 ampere passes through the one time winding coil unit, then a current of 0.001 ampere will appear between the ends of the double-wound coil unit. Moreover when the current passes through a resistance of 100 ohm which is connected serially to the double-wound coil unit, a voltage of 0.1 volt will be accordingly provided. After including the effect of the amplification provided by the Operational Amplifier (AF=(R 4 +RF)/R 4 ), the current sensor will be able to measure the value of a voltage corresponding value of the current and then the current detecting circuit  12  will utilize Operational Amplifier A 1  to create a direct current VC 1  with the same effective value, which will be transferred into a current grading circuit for grading and finer analysis (such as for 10 amperes, 20 amperes,  50  amperes . . . ): 
     1. At the time the value of current is less than 10 amperes, the Operational Amplifier A 2  will output a negative value signal of “−”, and Operational Amplifier A 3  will output a negative value signal of “−” as well; 
     2. At the time the value of current is between 10 amperes and 20 amperes, the Operational Amplifier A 2  will output a positive signal “+”, and Operational Amplifier A 3  will output a negative value signal of “−” instead; 
     3. At the time the value of current is up to 20 amperes, the Operational Amplifier A 2  will output a positive value signal of “+”, and Operational Amplifier A 3  will output a positive value signal of “+” as well; 
     4. At the time the value of current reaches 50 amperes, then the Operational Amplifier A 4  will output a negative value signal of “−”, and hence it will cut off the power supply automatically from the battery to the load drive controlling device. 
     The switching circuit  12  installed in a position between the current detecting circuit  11  and the capacity display circuit  13  is actually a multiplexer which includes no-load X 0 , light-load X 1 , and heavy-load X 3  outputs together with the corresponding lamp sets LED 7 , LED 8 , LED 9 , (Please also refer to FIG. 4 of the 4051 Truth Table): 
     1. At the time the value of current is less than 10 amperes, input A=“−”, input B=“−”, then no-load output X 0 =“+”, and thus LED 7  will turn on automatically; 
     2. At the time the value of current is between 10 amperes and 20 amperes, input A=“+”, input B=“−”, then light-load output X 1 =“+”, and thus LED 8  will turn on automatically; 
     3. At the time the value of current is between 10 amperes and 50 amperes, input A=“+”, input B=“+”, then heavy-load output X 3 =“+”, and thus LED 9  will turn on automatically. 
     4. At the time the signals of no-load output X 0 , light-load output X 1 , and heavy-load output X 3  are all “+”, then all of the LED 7 , LED 8 , and LED 9  lamps will turn on, meaning that the value of current is still within the normal range; 
     5. At the time the value of current is over 50 amperes and A 4  shows “−”, there is a condition of over-loading at the output labeled IN/OUT, so that the battery will automatically cut off the power supply for driving the controlling device. 
     The capacity display circuit comprises more than one set of LED and resistance, and under the different loading conditions, will refer to switching circuit  12  for the status of no-load output X 0 , light-load output X 1  and heavy-load output X 3 , and after the value of the voltage in the battery has been divided will provide a divided voltage with different impedances to corresponding input ports V 05 , V 06 , V 07 , V 08 , V 09 , V 10  located on each Operational Amplifier A 5 , A 6 , A 7 , A 8 , A 9 , A 10  to provide voltages V 05 ˜V 10  as follows: 
     1. At the time the value of V 05  is less than the reference voltage Vref 2 , the relevant LED 1  will turn on a red lamp signal in order to send a message of warning that the capacity in the battery is insufficient and that the discharging operation will be prohibited accordingly; 
     2. At the time the value of V 05  is larger than the reference voltage Vref 2 , LED 1  will turn off to indicate that the capacity in the battery is probably sufficient and thus it will be necessary to observe the status of LED 2  in order to confirm whether the battery capacity is sufficient; 
     3. At the time the value of V 06  is larger than the reference voltage Vref 2 , LED 2  will turn on a yellow lamp signal in order to indicate a warning that the capacity in the battery is on the edge of draining off very soon; 
     4. At the time the value of V 06  is less than the reference voltage Vref 2 , LED 2  will not light up any signal to indicate that the battery needs to be charged soon; 
     5. At the time the value of V 07  is larger than the reference voltage Vref 2 , LED 3  will turn on a green lamp signal in order to show that the capacity of the battery is sufficient; 
     6. At the time the value of V 07  is less than the reference voltage Vref 2 , LED 3  will not light up, thereby indicating that the capacity in the battery will drain off soon; 
     7. Same as the above condition (5), at the time the value of V 08 , V 09 , V 10  are all larger than the reference voltage Vref 2 , lamps LED 3 , LED 4 , LED 5 , LED 6  will all turn on green lamp signals in order to indicate that the capacity in the battery is quite sufficient (The more lamps light up the more sufficient capacity it has); 
     8. Same as the above condition (6), at the time the value of V 08 , V 09 , V 10  are all smaller than the reference voltage Vref 2 , lamps LED 3 , LED 4 , LED 5 , LED 6  will not light up any signal, thereby indicating that the capacity in the battery is insufficient; 
     In light of the above, it is very easy to determine whether the capacity in the battery is sufficient just by observing the status of LED 1 , LED 2 , LED 3 , LED 4 , LED 5  and also LED 6 ; and furthermore the capacity display circuit  13  also may be operated manually in order to observe the capacity of the battery while it is under different loading conditions. 
     The design for timing circuit  14  is to add and install a timing loop circuit C 1 *R 2  in the voltage detecting circuit  10 . The timing circuit  14  is installed with the voltage detecting circuit  10  and current detecting circuit  11  at the same time, i.e., in parallel, and thus when a voltage V 01  is input into the system (V 01  utilizes the voltage divided from the resistance R 01 , R 02 ) and the voltage of the battery is higher than the reference voltage Vref 2 , the battery will be connected, but when the setting time is over and the voltage of the battery is lower than the reference voltage Vref 2 , the battery will automatically cut off the power supply for driving the controlling device. 
     1. Similar to the above, in the structure of driving circuit  15  there is also an extra driving loop circuit which is installed in the voltage detecting circuit  10 , so that the driving circuit  15  is installed with the voltage detecting circuit  10  and current detecting circuit  1   1  at the same time; and hence while the voltage of the battery is less than the reference voltage Vref 2 , the battery will automatically cut off the power supply circuit for driving the controlling device when the setting time on timing circuit  14  is equalled or exceeded and the current detecting circuit  11  is detecting the output on A 4  as “−” (which means the status of current is abnormal). 
     In view of the above, preferably all of the respective configurations for the circuits installed according to the present invention are fixed properly onto the battery. 
     Finally, relying on the above structure and with reference to FIG. 3 which is a flow chart for the present invention, the following functions may be carried out: 
     1. According to the special functions provided by the present invention, the voltage detecting circuit  10  will detect the battery automatically and try to find out whether the voltage in the battery is in a normal condition or not: 
     (1) At the time voltage detecting circuit  10  detects that a value of voltage is much lower than the normal value (or a status of breakdown while it is abnormal), then it will switch into timing circuit  14 , and hence stop the power supply at once if it is over the setting time, or will supply the power accordingly only after the voltage value reverts to a normal condition. 
     (2) At the time voltage detecting circuit  10  detects a normal condition, then the current detecting circuit  11  will force the driving circuit  15  to detect the status of the current automatically. 
     2. When the setting time on the timing circuit  14  has elapsed, the power supply will be stopped at once, and then will return to voltage detecting circuit  10  system once it has reverted properly. 
     3. The current detecting circuit  11  is able to treat the current into different grades such as no-load, light-load, heavy-load and over-load, as follows: 
     (1) At the time the status of the current is overflow, the current detecting circuit will be able to test automatically whether it is allowable to supply the power again, will switch into the timing circuit  14  if it has determined that it is still not suitable, and also will stop supplying the power when it is over the setting time, but will supply the power again when it has reverted properly. 
     (2) At the time everything is in normal status, then the current detecting circuit  11  will drive capacity display circuit  13  by means of switching circuit  13 . 
     4. It is possible to find out whether the capacity in the battery is sufficient or not in order to supply the power just be means of the capacity display circuit  13 . 
     Preferably, with the above-described special functions, the present invention detects the exact capacity in the battery, and hence it is very easy for the user to find out whether the capacity in the battery is sufficient or not. Furthermore, the invention will isolate both the battery and load when it is mismatched in polarity, in a condition of short circuit, or even when the battery is discharging excessively. 
     While a particular embodiment of the present invention has been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of the present invention.