CN1437030A - Storage battery power detection device and method - Google Patents

Abstract

The invention relates to a device and a method for detecting the electric quantity of a storage battery, which utilize the charging time of the storage battery to a capacitor of an RC circuit and a table look-up mode to calculate the electric power degree of the storage battery.

Description

Storage battery power detection device and method

technical field

The present invention relates to a power detection device and method, more specifically, the present invention relates to a battery power detection device and method.

Background of the invention

As for the device and method for detecting battery power, in the prior art, the terminal voltage of the battery is mostly measured by the principle of voltage division, and the voltage at the detection point is sent to the microprocessor for comparison, so as to detect the power of the battery. Please refer to FIG. 1 , which shows an embodiment of a power detection device in the prior art. The voltage source Vcc of the storage battery in the figure provides the working power of the microprocessor 11, and the terminal voltage V _R2 of the voltage dividing terminal is taken out through the resistors R1 and R2. When the terminal voltage of the storage battery drops, the voltage of the voltage dividing terminal _VR2 also increases with the decline of; the input detection pin I of the microprocessor 11 is mainly used to receive the voltage of the voltage divider terminal _VR2 , when the terminal voltage _VR2 received by the detection pin is lower than the lower threshold voltage of the microprocessor 11, that is The detection pin changes from the high level (H) of the logic circuit to the low level (L) of the logic circuit, which means that the power of the battery is insufficient. The power of the battery can be simply detected by the aforementioned method, but this detection circuit using resistor voltage division will cause leakage current 12 on the battery terminal voltage circuit, and consume extra power of the battery.

In addition, please refer to FIG. 2A and FIG. 2B , which show another embodiment of the power detection device in the prior art. Since the detection circuit in the prior art shown in FIG. 1 will cause a leakage current, in order to overcome this problem, another prior art proposes to transfer the ground terminal (GND) of the resistor R2 to the output terminal of the microprocessor 11 Pin O; the detection device uses programming to set the initial value of the output pin O of the microprocessor 11 to a high level (the potential of logic H is Vcc), so that the resistance circuit of the detection will not leak current, and when the microprocessor 11 is to measure the electric quantity of the storage battery, the output terminal pin O of the microprocessor 11 is converted into a low level (i.e. grounding) by the high level planning, so that the input terminal pin I of the microprocessor 11 That is to detect the electric quantity of the storage battery according to the above-mentioned divided voltage, after the measurement is completed, the pin O of the output terminal is restored to a high level. As shown in Figure 2B, the battery power detection device has the function of segmented power detection. The microprocessor 11 further uses a number of input terminal pins I ₁ , I ₂ , and I ₃ to measure the voltage of the battery terminals respectively. The voltage drops to varying degrees of power.

Although the power detection device shown in FIG. 2A and FIG. 2B can effectively avoid the generation of leakage current, the use of more pins of the microprocessor 11 makes the microprocessor 11 use more resources to measure the power of the storage battery. , and relatively, the functions of the microprocessor 11 cannot be effectively and fully utilized.

Contents of the invention

The main purpose of the present invention is to provide a battery power detection method that uses the charging time of the RC and cooperates with the table look-up method to detect the working voltage and power.

Another object of the present invention is to provide a battery power detection device, which uses the combination of RC circuit and microprocessor, only uses a single pin of the microprocessor and uses the working state of the detection pin to continuously measure the battery power.

In view of the shortcomings of the battery power detection device in the prior art that would cause leakage current and occupy more I/O pins of the microprocessor, the present invention proposes a method for battery power detection, which is to use the battery to The charge of the RC circuit reflects the electric quantity of the storage battery by the charging time. The method at least includes: forming a discharge circuit of the capacitor in the RC circuit until the capacitor is discharged to zero potential; and starting to calculate the charging of the storage battery to the RC circuit until the capacitor is charged to The time required for a preset potential to obtain the current capacity of the storage battery.

According to the aforementioned method of the present invention, a storage battery power detection device includes an RC loop formed by a storage battery, a resistor R and a capacitor C; and a microprocessor, wherein the microprocessor uses a pin that can be programmed to work Measure the capacitor C of the RC loop. When the microprocessor wants to measure the power of the storage battery, the microprocessor designates the pin as an output mode, and the pin outputs a low level to make the capacitor C form a discharge circuit until the capacitor is discharged to zero potential; after that, the microprocessor again Design the pin as the input mode, and start to calculate the time required for the pin to change from low level to high level, that is, the charging time required for the capacitor of the RC circuit to charge from zero potential to high level, so as to obtain the power of the battery .

According to a preferred embodiment of the present invention, a battery power detection method includes an RC loop formed by a battery, a resistor R, and a capacitor C and utilizes a microprocessor with pins that can be programmed to work. The method includes:

Turn the pin of the microprocessor from the input mode to the output mode; the pin of the planned output mode outputs a low level, so that the capacitor of the RC circuit is discharged to zero potential through this pin; then the pin of the microprocessor is The pin transitions from output mode to input mode: and the microprocessor starts to calculate the time required for the pin to transition from low level to high level, that is, the charging time required for the capacitor of the RC circuit to charge from zero potential to high level, To obtain battery power.

The advantage of the storage battery power detection device of the present invention is that the principle of charging and discharging the capacitor through the RC circuit prevents the occurrence of leakage current and avoids the loss of battery power, and uses the charging time of the capacitor and the setting of the corresponding table to calculate and compare it. Obtain the power of the battery; at the same time, by detecting the transition of the pin, only a single detection pin can be used to complete the detection of the power level of the battery, effectively reducing the occupation of the microprocessor pin.

Description of drawings

Fig. 1 is the storage battery power detection circuit of known technology;

FIG. 2A and FIG. 2B are another embodiment of the battery power detection circuit of the known technology;

Fig. 3 is a flow chart of the method for detecting battery power of the present invention;

FIG. 4 is a structural diagram of the battery power detection device of the present invention;

FIG. 5 is a characteristic curve diagram of the corresponding table in the application program;

FIG. 6 is a characteristic diagram of a Schmitt trigger circuit.

Microprocessor-11 Leakage current-12 Detect pin transition state-101

Capacitor discharge-102 Detect pin re-transition-103 Look-up table-104

Detailed ways

The present invention proposes a method for detecting battery power, which is to use the battery to charge an RC circuit to reflect the battery's power from the charging time. The method at least includes: forming a discharge circuit for the capacitor in the RC circuit until the capacitor is discharged to zero potential; and start to calculate the time required for the battery to charge the RC circuit until the capacitor is charged to a preset potential, so as to obtain the current capacity of the battery.

To further explain, the capacitor system has the ability to store and discharge capacity, and the charging time will vary with the change of the charging voltage; when the battery is connected to the RC circuit, the battery starts to charge the capacitor in the RC circuit. At this time, the storage capacity of the capacitor gradually reaches a saturated state from zero potential or low potential, so that the DC analysis of the RC circuit forms an open circuit without leakage current; the battery power detection method of the present invention uses the charging voltage to charge the capacitor. Look up the table to obtain the electric quantity of the storage battery of the charging voltage, wherein, the table lookup is to find out the different electric quantities of the storage battery corresponding to different charging times to charge the capacitor of the RC circuit.

In the discharge circuit of the capacitor, a grounding switch can be set at the terminal voltage of the capacitor, and the electric power can be released by using the open circuit (OFF) and closed circuit (ON) of the grounding switch, so that the electric capacity of the capacitor can be reduced from the saturated state to zero potential. This discharge action is mainly It is to prepare to recalculate the charging time of the capacitor, so that the capacitor can be charged from zero potential instead of the low potential of the capacitor, so as to avoid errors in calculating the charging time and affect the accuracy of power detection; when the capacitor discharge is completed , the battery charges the capacitor in the RC circuit again, and at the same time begins to count the charging time until the electric quantity of the capacitor reaches a preset potential, and the timer stops counting the charging time. After the charging time is calculated and the table is checked, the current state of the battery is obtained. power.

According to the above-mentioned power detection method, the present invention provides a battery power detection device, please refer to FIG. 4 , which shows the structure diagram of the battery power detection device of the present invention. In this embodiment of the present invention, the detection device at least includes: a resistor R, a capacitor C and a microprocessor 11, the connection method is shown in Figure 4, the voltage Vcc of the storage battery is provided to the microprocessor 11 The operating power and the capacitor charging in the RC circuit; when the microprocessor 11 obtains the operating power, its internal application program will start to work according to the content of its programming, and the microprocessor 11 sets the state of the detection pin.

In order to prevent leakage current from detecting battery power, and consume extra power of the battery. The invention utilizes the principle of DC charging and discharging of capacitors. When the capacitor is charged to saturation, the capacitor is regarded as an open circuit state, and the RC circuit does not generate leakage current. Since the input mode pin of the microprocessor 11 has a characteristic of high input impedance, it can be regarded as an open state of a ground switch. After the capacitor is fully charged, the terminal voltage Vc of the capacitor is almost equal to the voltage Vcc, and the terminal voltage of the capacitor presents a high level state to the detection pin of the microprocessor 11 . When the microprocessor 11 wants to detect the power of the storage battery, the application program is about to change the detection pin of the microprocessor 11 from the input state to the output state; when the detection pin is in the output state, the detection pin has a low input impedance It can be regarded as a closed-circuit state of a grounding switch. The terminal voltage of the capacitor uses the detection pin of the microprocessor 11 to release its power Vc. The purpose of the discharge is to ensure that the charging of the capacitor can start from zero potential every time. , and the discharge time of the capacitor refers to the state of continuous discharge from the saturation voltage of the capacitor terminal voltage Vc to zero potential. When the terminal voltage Vc of the capacitor presents zero potential to the detection pin, the application program of the microprocessor 11 immediately changes the detection pin from an output state to an input state again.

Please continue to refer to Fig. 4. After the detection pin of the aforementioned microprocessor 11 has completed the transition again, the detection pin is in the input state at this time. Since the discharge end of the capacitor has been closed, the voltage Vc is re-balanced by the RC circuit. The capacitor charges. When the detection pin of the microprocessor 11 turns over and the capacitor begins to charge, the microprocessor 11 starts the timer to record the charging time of the capacitor. The calculation of the charging time is to detect the capacitor terminal by the detection pin of the microprocessor 11. Level of voltage Vc: When the level of the detection pin changes from low level to high level, the charging time of the current battery voltage Vcc to the capacitor can be known, and the microprocessor 11 will use the charging time of this transition state The time matches the built-in power correspondence table in the program to find out the power level of the battery. Because the battery power detecting device of the present invention utilizes the microprocessor 11 to detect the transition of the pin, the microprocessor 11 only needs to provide a single detection pin to complete the work of continuously detecting the battery power.

Please refer to Figure 5, which shows the characteristic curve diagram of the corresponding table in the application program, and please refer to Figure 4 together. Due to the variety of battery types and materials, their discharge characteristics are also different, so the corresponding table built in the application must be tested for each type of battery to obtain the information required by the corresponding table; of course, the voltage of the battery Vcc will gradually decrease with use. When the voltage Vcc drops, the working power of the microprocessor 11 will also drop, and the high level of the detection pin of the microprocessor 11 will also drop with the working power of the microprocessor 11. , and change the voltage value of the high level of the detection pin.

Please continue to refer to Figure 5, the capacitor charging characteristic curve is represented by rectangular coordinates, where the ordinate is the terminal voltage Vc of the capacitor, and the abscissa is the capacitor charging time t; when the capacitor starts charging from zero potential each time, micro The timer in the processor 11 starts and starts to count the charging time of the capacitor. However, the high level of the detection pin of the microprocessor 11 will change with the change of the voltage Vcc, so the corresponding table must be found by using the characteristic curve diagram. Under different voltages such as Vcc1, Vcc2, Vccn, etc., detect the critical voltage V1 when the pin transitions from a low level to a high level, and use the capacitor charging characteristic curve to clearly find out that the battery is charging the capacitor under different voltages Vcc. The time T1, T2, . . . , Tn required for the detection pin of the processor 11 to transition from a low level to a high level.

When the capacitor charging voltage Vc reaches the transition threshold voltage V1 each time, the level of the detection pin of the microprocessor 11 will transition from a low level to a high level, and the timer in the microprocessor 11 will also record this charge. The time is sent to the corresponding table for comparison; through the way of looking up the table, the microprocessor 11 can obtain the remaining power of the storage battery at present, and display the power of the storage battery.

In a preferred embodiment of the present invention, the level is determined by using the detection pin of the microprocessor 11 to detect the terminal voltage Vc of the capacitor. In practice, the level of the detection pin of the microprocessor 11 will be further considered to confirm the level. There is a gray area, and when the terminal voltage Vc is in the gray area, the microprocessor 11 cannot determine its high/low level. In order to solve this problem, the present invention utilizes the characteristics of a Schmitt trigger circuit (Schmitt trigger) to distinguish High, in the range of the level. The Schmitt trigger circuit is a comparator with hysteresis characteristics, and adopts the method of positive feedback to increase the gain of the comparator. For its conversion characteristics, please refer to Figure 6, which shows the characteristic diagram of the Schmitt trigger circuit. In Fig. 6, H _min is the upper threshold (Upper threshold) or upper trigger voltage (UPPer trigger), and Lmax is the lower threshold (Lower threshold) or lower trigger (Lowertrigger) voltage.

Please continue to refer to Figure 6. When the capacitor terminal voltage Vc detected by the detection pin of the microprocessor is charged to the upper and lower threshold voltages of the Schmitt trigger circuit, the level is determined based on the previous level state, if the previous level is low level, then the detection pin is maintained at the low level, when the capacitor continues to charge until the terminal voltage Vc exceeds the H _min value, then the detection pin is confirmed to change from low level to high level .

According to a preferred embodiment of the present invention, a battery power detection method includes an RC loop formed by a battery, a resistor R, and a capacitor C and utilizes a microprocessor with pins that can be programmed to work. The method includes: Turn the pin of the microprocessor from the input mode to the output mode; the pin of the planned output mode outputs a low level, so that the capacitor of the RC circuit is discharged to zero potential through this pin; then the pin of the microprocessor is The pin transitions from output mode to input mode; and the microprocessor starts to calculate the time required for the pin to transition from low level to high level, that is, the charging time required for the capacitor of the RC circuit to charge from zero potential to high level, To obtain battery power.

For further description, please refer to FIG. 3 , which shows the flow chart of the battery power detection of the present invention. In the detection method of battery power, the battery provides a voltage source Vcc, an RC loop formed by a resistor R and a capacitor C, and utilizes a microprocessor with a programmable working mode pin, which is connected to the charging of the capacitor C The terminals are connected to form a discharge circuit, and the method includes:

1. Detect pin F transition state 101:

The battery will provide a DC voltage source Vcc to provide the working power and charging power required by the microprocessor; when the microprocessor starts to work, its application program will pre-set the state of the microprocessor detection pin, at this time the detection The measuring pin is set to input mode (I/P), and at the same time the voltage source Vcc of the battery charges the capacitor to saturation; when the microprocessor wants to detect the battery power, the detecting pin of the microprocessor is set by the application program Input mode transitions to output mode (O/P);

2. Capacitor discharge 102:

After the detection pin of the microprocessor turns to the output mode, the output of the detection pin is set to a low level, the detection pin of the microprocessor forms a discharge circuit with the capacitor, and the capacitor is discharged by the detection pin of the microprocessor , until the terminal voltage of the capacitor is zero potential, the purpose of its discharge is to ensure that each charge of the capacitor can start from zero potential;

3. Detect foot re-transition 103:

When the capacitor is discharged to zero potential by the detection pin of the microprocessor, the detection pin of the microprocessor is changed from the output mode to the input mode through the setting of the application program; the detection pin is in a high impedance state in the input mode, Therefore, the capacitor starts to charge, and at the same time, the timer of the microprocessor is started to start counting, until the detection pin is confirmed to turn from a low level to a high level, and then the timing is stopped. the length of time required for the quasi-transition to be high; and

4. Check table 104:

The time recorded by the above-mentioned timer will cooperate with the table look-up method to obtain the power of the battery, and the power corresponding table is the actual data obtained through experiments; in fact, the microprocessor detection pin reaches the potential V1 and the capacitor to confirm the transition The charging time of each charge will vary with the battery voltage Vcc, so it is necessary to measure the power corresponding table in advance through the experiment; the microprocessor will compare the time recorded by the timer through the electric power corresponding table and then immediately Find the current charge of the battery.

The storage battery power detection device and method implemented according to the present invention will have many advantages and features, wherein the battery power detection method of the present invention can be applied to various types of battery power detection, and the charging time of the capacitor and the corresponding The setting of the table is calculated and compared to obtain the power of the battery.

The advantage of the storage battery power detection device of the present invention is that the principle of charging and discharging the capacitor through the RC circuit prevents the occurrence of leakage current and avoids the loss of battery power, and uses the charging time of the capacitor and the setting of the corresponding table to calculate and compare it. Obtain the power of the battery; at the same time, by detecting the transition of the pin, only a single detection pin can be used to complete the detection of the power level of the battery, effectively reducing the occupation of the microprocessor pin.

After describing the preferred embodiments of the present invention in detail, those skilled in the art can clearly understand that various changes and changes can be made without departing from the scope and spirit of the patent application, for example: the storage battery detection device Capacitors and resistors can also be added in parallel to improve the stability and accuracy of the detection device. Furthermore, the present invention is not limited to the embodiments described in the description.

Claims (18)

1. A storage battery electric quantity detection method, is to utilize the pin of a microprocessor to form the discharge circuit of the electric capacity C of an RC circuit, and this storage battery and aforementioned RC circuit form the charging circuit, and this detection method comprises: The aforementioned microprocessor sets the aforementioned pins as output mode, so that the aforementioned capacitor C discharges electricity in the discharge circuit until zero potential: The aforementioned microprocessor sets the front connection pin from the output mode to the input mode, and starts counting the time required for the voltage of the aforementioned capacitor C to reach a preset potential value; and The aforementioned microprocessor obtains the electric quantity of the aforementioned accumulator according to the aforementioned required time. 2. The battery power detection method according to claim 1, wherein the pins of the microprocessor are set to input mode before detection. 3. The battery power detection method according to claim 1, wherein the required time refers to the charging time for the battery to charge the RC loop to charge the capacitor C from zero potential to the preset potential value. 4. The battery power detection method as claimed in claim 1 or 3, wherein said microprocessor includes a corresponding table, which records the different electric quantities of said battery to charge the RC circuit, and charges the capacitor C from zero potential The time required to reach the aforementioned preset potential value. 5. The battery power detection method according to claim 4, wherein the microprocessor can check the corresponding power of the battery from the corresponding table according to the required time. 6 . The method for detecting battery power as claimed in claim 1 , wherein when the microprocessor sets the front connecting pin as an output mode, the potential output of the pin is a low level. 7 . 7. The battery power detection method according to claim 1, wherein said pin is set as an input mode and has a Schmitt trigger circuit. 8 . The battery power detection method according to claim 7 , wherein the preset potential value is the potential value when the output of the Schmitt trigger circuit is triggered to transition from a low level to a high level. 9 . 9. A storage battery power detection method, which is to use a programmable transition pin of a microprocessor to form a discharge circuit for the capacitor C of an RC circuit, and the storage battery forms a charging circuit for the aforementioned RC circuit, and the previous detection method includes : The aforementioned microprocessor sets the aforementioned pin as an output mode, so that the aforementioned capacitor C discharges electricity in the discharge circuit until it reaches zero potential; The aforementioned microprocessor sets the time required for the aforementioned pin to transition from the output mode to the input mode, and starts timing the connection pin from a low level to a high level; and The aforementioned microprocessor obtains the aforementioned battery white quantity according to the aforementioned required time. 10. The battery power detection method as claimed in claim 9, wherein said pin is set as an input mode and has a Schmitt trigger circuit. 11. The battery power detection method as claimed in claim 9, characterized in that the aforementioned required time means that the aforementioned battery charges the RC loop to charge the capacitor C from zero potential until the aforementioned pin transitions from a low level to a high level charging time. 12. The battery power detection method as claimed in claim 9 or 11, wherein said microprocessor comprises a corresponding table, and said corresponding table records the different electric quantities of said battery to charge the capacitor C of the RC circuit, and the capacitor C is changed from The time required from zero potential charging to the transition of the aforementioned pin from low level to high level. 13. The battery power detection method according to claim 12, wherein the microprocessor can check the corresponding power of the battery from the corresponding table according to the required time. 14. A storage battery power detection device, comprising: A storage battery: An RC circuit, the storage battery forms a charging circuit for the aforementioned RC circuit; and A microprocessor has a pin that can be programmed to turn the state. The aforementioned pin forms a discharge circuit for the capacitor C of the aforementioned RC loop. When the microprocessor detects the battery power, the aforementioned pin is set to an output mode to enable the The capacitor C discharges the electricity until it reaches zero potential, and then the aforementioned pin is set as an input mode to count the time required for the pin to transition from a low level to a high level, so as to obtain the power of the aforementioned battery. 15. The battery power detection device as claimed in claim 14, wherein said pin is set as an input mode and has a Schmitt trigger circuit. 16. The battery power detection method as claimed in claim 14, wherein said microprocessor includes a corresponding table, which records the different electric quantities of said battery to charge the capacitor C of the RC circuit, and changes the capacitor C from zero potential It is the time required for charging the aforementioned pin from a low value to a high level. 17. The battery power detection method according to claim 16, wherein the microprocessor can check the corresponding power of the battery from the corresponding table according to the required time. 18. A battery power detection method, using the battery to charge an RC loop to reflect the battery’s power from the charging time, the method comprising: forming a discharge circuit for the capacitor C in the RC loop until the capacitor C is discharged to zero electric potential; and Start to calculate the time required for the battery to charge the RC loop until the capacitor C is charged to a preset potential, so as to obtain the current power of the battery.

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