Low-cost circuit capable of effectively prolonging service life of super capacitor

Abstract

The utility model provides a low-cost circuit capable of effectively prolonging the service life of a super capacitor. The circuit comprises an MCU, and a super capacitor charging control circuit, a super capacitor discharging control circuit, a super capacitor voltage detection circuit and a super capacitor power supply circuit which are connected with the MCU. Two control signal output ends of the MCU are respectively connected with the super capacitor through a super capacitor charging control circuit and a super capacitor discharging control circuit; the detection signal end of the super capacitor is connected with the detection signal input end of the MCU through the super capacitor voltage detection circuit; and the super capacitor is connected with the super capacitor power supply circuit. According to the utility model, the voltage of the super-capacitor can be adjusted at different working temperatures of the electric energy meter, and the risk of failure of the super-capacitor is reduced; the utility model has the characteristics of simple realization, low cost and high reliability.

Description

Technical Field

[0001] The utility model relates to the field of applying electric energy meters with supercapacitor functions, and is particularly suitable for occasions where electric energy meters have high requirements for supercapacitor life acceleration tests. Background Art

[0002] Many electricity meters on the market today require supercapacitor functionality. These requirements not only require the supercapacitor to operate within the normal operating temperature range and maintain the MCU's clock for a specified period of time when the meter lacks an alternative power source, but also impose stringent requirements on the meter's accelerated lifespan testing. Some require 1000 hours of operation in an environment with a high temperature of 85°C and a humidity of 85% RH, while others require even higher requirements of 1000 hours of operation in an environment with a high temperature of 85°C and a humidity of 95% RH. After the test, the supercapacitor must still be able to maintain the MCU's operation for a specified period of time.

[0003] However, the higher the voltage of the supercapacitor, the more likely it is to fail in a high-temperature environment. The failure is mostly caused by supercapacitor leakage. In addition, the leakage of the supercapacitor has conductive properties, which can easily cause a short circuit between lines on the PCB, resulting in failure of the electricity meter and failure of the accelerated life test.

[0004] To address this issue, some products on the market use potting to significantly reduce the voltage of supercapacitors to address the issue of supercapacitor failure at high temperatures. However, this voltage reduction requires increasing the supercapacitor capacity to maintain MCU operation for a short period of time, which increases costs. Utility Model Content

[0005] This utility model addresses the problem of supercapacitors being prone to failure during accelerated lifespan and proposes a low-cost circuit that effectively extends the lifespan of supercapacitors. This utility model enables an electric energy meter to regulate the supercapacitor voltage at different temperatures, thereby resolving the problem of supercapacitor failure.

[0006] The technical solution of the utility model is:

[0007] The utility model provides a circuit that is low-cost and effectively improves the life of a supercapacitor, which includes an MCU and a temperature sensor connected to the MCU, a supercapacitor charging control circuit, a supercapacitor discharging control circuit, a supercapacitor voltage detection circuit, and a supercapacitor power supply circuit;

[0008] The two control signal output terminals of the MCU are connected to the supercapacitor through the supercapacitor charging control circuit and the supercapacitor discharging control circuit respectively;

[0009] The detection signal end of the supercapacitor is connected to the detection signal input end of the MCU through the supercapacitor voltage detection circuit; the output end of the temperature sensor is connected to the temperature signal input end of the MCU;

[0010] The supercapacitor is connected to a supercapacitor power supply circuit.

[0011] Furthermore, the supercapacitor charging control circuit includes resistors R1, R2, R3, R4, R5, R6, R7, NPN transistors Q1, Q2 and supercapacitor E1. The input end of the supercapacitor charging control circuit is connected to the charging power supply provided by the electric energy meter, which is recorded as DC_IN. The charging power supply DC_IN is connected to one end of the resistor R1 and one end of the resistor R3. The other end of the resistor R1 is connected to the collector of the transistor Q1 through the resistor R2. The emitter of the transistor Q1 is connected to the positive electrode of the supercapacitor E1. The connection point Marked as VCAP, the negative electrode of the supercapacitor E1 is grounded, the other end of the resistor R3 is connected to the base of the transistor Q1, the emitter of the transistor Q2 and one end of the resistor R4, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, the connection point between the resistors R5 and R6 is connected to the supercapacitor charging control signal VCAP-Charge of the MCU, the other end of the resistor R6 is grounded, and the other end of the resistor R4 is grounded through the resistor R7.

[0012] Furthermore, the supercapacitor discharge control circuit includes resistors R11, R12, R13, R14 and a PNP transistor Q3. The output end of the supercapacitor discharge control circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to the emitter of the transistor Q3 through the resistors R11 and R12. The collector of the transistor Q3 is grounded. The base of the transistor Q3 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to one end of the resistor R14. The connection point of the resistors R13 and R14 is connected to the supercapacitor discharge control signal VCAP-Discharge of the MCU, and the other end of the resistor R14 is grounded.

[0013] Furthermore, the supercapacitor voltage detection circuit includes resistors R8, R9, R10 and capacitor C1. The input end of the supercapacitor voltage detection circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to one end of the resistor R8, and the other end of the resistor R8 is respectively connected to the resistors R9, R10 and one end of the capacitor C1. The other end of the resistor R10 and the other end of the capacitor C1 are grounded. The other end of the resistor R9 is connected to the analog signal input port of the MCU, marked as VCAP-ADC.

[0014] Furthermore, the supercapacitor power supply circuit includes a resistor R15, a capacitor C2 and a diode D1. The output end of the supercapacitor power supply circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point, the VCAP is connected to one end of the resistor R15, the other end of the resistor R15 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the capacitor C2 and the power supply VDD of the load, and the other end of the capacitor C2 is grounded.

[0015] Beneficial effects of the utility model:

[0016] The utility model adjusts the supercapacitor voltage within different operating temperatures of the electric energy meter, thereby extending the service life of the supercapacitor and reducing the risk of supercapacitor failure; there is no need to reduce the risk of failure at high temperature by derating the supercapacitor voltage or increasing the supercapacitor capacity.

[0017] The utility model has the characteristics of simple implementation, low cost and high reliability and has good application prospects.

[0018] Other features and advantages of the present invention will be described in detail in the subsequent detailed description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present invention.

[0020] Figure 1 The circuit principle block diagram of the utility model is shown, which is low-cost and effectively improves the life of the supercapacitor.

[0021] Figure 2 A supercapacitor charging control circuit diagram according to an embodiment of the present utility model is shown.

[0022] Figure 3 FIG2 is a diagram showing a supercapacitor discharge control circuit according to an embodiment of the present invention.

[0023] Figure 4 FIG2 is a circuit diagram showing a supercapacitor voltage detection circuit according to an embodiment of the present invention.

[0024] Figure 5 1 is a diagram showing a supercapacitor power supply circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein.

[0026] Example 1

[0027] Figure 1 The circuit principle block diagram of the utility model is shown, which is low-cost and effectively improves the life of the supercapacitor.

[0028] like Figure 1 As shown, the utility model provides a circuit that is low-cost and effectively improves the life of a supercapacitor, which includes an MCU and a temperature sensor connected to the MCU, a supercapacitor charging control circuit, a supercapacitor discharging control circuit, a supercapacitor voltage detection circuit, and a supercapacitor power supply circuit;

[0029] The two control signal output terminals of the MCU are connected to the supercapacitor through the supercapacitor charging control circuit and the supercapacitor discharging control circuit respectively;

[0030] The detection signal end of the supercapacitor is connected to the detection signal input end of the MCU through the supercapacitor voltage detection circuit; the output end of the temperature sensor is connected to the temperature signal input end of the MCU;

[0031] The supercapacitor is connected to a supercapacitor power supply circuit.

[0032] In one example, if Figure 2 A supercapacitor charging control circuit diagram is shown. The supercapacitor charging control circuit includes resistors R1, R2, R3, R4, R5, R6, R7, NPN transistors Q1, Q2, and a supercapacitor E1. The input end of the supercapacitor charging control circuit is connected to a charging power supply provided by an electric energy meter, denoted as DC_IN. The charging power supply DC_IN is connected to one end of the resistor R1 and one end of the resistor R3. The other end of the resistor R1 is connected to the collector of the transistor Q1 through the resistor R2. The emitter of the transistor Q1 is connected to the positive electrode of the supercapacitor E1. The connection point is marked as VCAP, the negative electrode of the supercapacitor E1 is grounded, the other end of the resistor R3 is connected to the base of the transistor Q1, the emitter of the transistor Q2 and one end of the resistor R4, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, the connection point between the resistors R5 and R6 is connected to the supercapacitor charging control signal VCAP-Charge of the MCU, the other end of the resistor R6 is grounded, and the other end of the resistor R4 is grounded through the resistor R7.

[0033] When the charging control signal VCAP-Charge is at a low level, the VCAP-Charge signal is at a low level through the resistor R5 to the base of the transistor Q2, and the transistor Q2 is turned off. The base voltage of the transistor Q1 is divided by the supercapacitor power supply DC_IN through R3, resistor R4, and resistor R7, so that the transistor Q1 is turned on. The supercapacitor charging power supply DC-IN starts charging the supercapacitor E1 through the resistor R1, resistor R2, and transistor Q1.

[0034] When the charging control signal VCAP-Charge is at a high level, the VCAP-Charge signal passes through the current limiting resistor R5 to the base of the transistor Q2 and is at a high level. The transistor Q2 is turned on, and the base of the transistor Q1 is connected to the ground through the transistor Q2. The transistor Q1 is turned off, and the supercapacitor E1 stops charging.

[0035] Resistor R6 is used to prevent the MCU charging control signal VCAP-Charge from being disturbed and causing level changes. The maximum charging voltage of the supercapacitor is V capmax The base and emitter voltage drop of transistor Q1 is V Q1BE The saturation conduction voltage drop between the collector and emitter is V Q1CE Mark, super capacitor E1 voltage is V cap Mark, super capacitor power supply DC_IN voltage is V in Mark, the maximum charging voltage of the supercapacitor is calculated as V capmax＝ V in / (R3+R4+R7)*(R4+R7), the calculation formula of supercapacitor charging current is I Charge =(V in -V cap -V Q1CE ) / (R1+R2).

[0036] In one example, if Figure 3 A supercapacitor discharge control circuit diagram is shown. The supercapacitor discharge control circuit includes resistors R11, R12, R13, R14 and a PNP transistor Q3. The output end of the supercapacitor discharge control circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to the emitter of the transistor Q3 through the resistors R11 and R12. The collector of the transistor Q3 is grounded. The base of the transistor Q3 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to one end of the resistor R14. The connection point between the resistors R13 and R14 is connected to the supercapacitor discharge control signal VCAP-Discharge of the MCU. The other end of the resistor R14 is grounded.

[0037] When the discharge control signal VCAP-Discharge is at a high level, the VCAP-Discharge signal passes through the resistor R13 to the base of the transistor Q3 and becomes a high level, and the transistor Q3 is turned off, stopping discharging the supercapacitor E1.

[0038] The discharge control signal VCAP-Discharge is at a low level. The VCAP-Discharge signal passes through the resistor R13 to the base of the transistor Q3 and is at a low level. The transistor Q3 is turned on, and the supercapacitor E1 starts to discharge.

[0039] Resistor R14 is used to prevent the MCU charging control signal VCAP-Discharge from being disturbed and causing level changes. The saturation conduction voltage drop between the collector and emitter of transistor Q3 is represented by V Q3CE Mark, E1 discharge current is I Discharge =(V cap -V Q3CE ) / (R11+R12).

[0040] In one example, if Figure 4 A supercapacitor voltage detection circuit diagram is shown. The supercapacitor voltage detection circuit includes resistors R8, R9, R10 and a capacitor C1. The input end of the supercapacitor voltage detection circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to one end of the resistor R8, and the other end of the resistor R8 is respectively connected to the resistors R9, R10 and one end of the capacitor C1. The other end of the resistor R10 and the other end of the capacitor C1 are grounded. The other end of the resistor R9 is connected to the analog signal input port of the MCU, marked as VCAP-ADC.

[0041] In one example, if Figure 5 A supercapacitor power supply circuit diagram is shown, which includes a resistor R15, a capacitor C2 and a diode D1. The output end of the supercapacitor power supply circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to one end of the resistor R15, the other end of the resistor R15 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the capacitor C2 and the power supply VDD of the load, and the other end of the capacitor C2 is grounded.

[0042] The diode D1 is used to prevent the supercapacitor from consuming energy from other power supplies of the energy meter when the supercapacitor charging power supply DC-IN is out of power.

[0043] When the circuit of the present invention is used in a specific application, the voltage of the supercapacitor is regulated according to the ambient temperature, including the following steps:

[0044] According to the working environment of the energy meter, multiple temperature ranges are set, and the voltage range of the supercapacitor is set corresponding to each temperature range, as shown in Table 1;

[0045] Table 1

[0046] temperature Super voltage / supercapacitor rated voltage*100% -40℃～10℃ 80％～100％ 10℃～50℃ 70％～80％ 50℃～70℃ 60％～70％ 70℃～85℃ 40％～60％

[0047] S1: When the charging power supply DC-IN provided by the energy meter is powered, the MCU reads the current temperature. When the temperature stabilizes, the MCU calculates the current supercapacitor voltage based on the output voltage of the supercapacitor voltage detection circuit received by the analog port VCAP-ADC.

[0048] The supercapacitor voltage is divided by resistors R8 and R10, filtered by resistor R9 and capacitor C1, and then fed to the MCU analog port VCAP-ADC. The voltage of the MCU analog port VCAP-ADC is represented by V AD The supercapacitor voltage is marked with V cap It is expressed as follows:

[0049]

[0050] S2: The MCU compares the supercapacitor voltage with the supercapacitor voltage range corresponding to the current temperature range.

[0051] S21: When the supercapacitor voltage is lower than the lower limit of the supercapacitor voltage range of the current temperature range, the MCU turns on the supercapacitor charging control circuit and turns off the supercapacitor discharging control circuit. Specifically:

[0052] The MCU's supercapacitor charging control signal VCAP-Charge is output at a low level, while the MCU's supercapacitor discharge control signal VCAP-Discharge is output at a high level;

[0053] The VCAP-Charge signal is at a low level. The VCAP-Charge signal passes through the resistor R5 to the base of the transistor Q2, which is at a low level. The transistor Q2 is cut off. The supercapacitor charging power supply DC_IN is divided by R3, R4, and R7, so that the transistor Q1 is turned on. The supercapacitor charging power supply DC-IN starts to charge the supercapacitor E1 through the resistors R1, R2, and transistor Q1.

[0054] The VCAP-Discharge signal is at a high level. The VCAP-Discharge signal passes through the resistor R13 to the base of the transistor Q3 and is at a high level. The transistor Q3 is cut off and stops discharging the supercapacitor E1.

[0055] S22: When the supercapacitor voltage is within the supercapacitor voltage range of the current temperature range, the MCU turns off the supercapacitor charging control circuit and the supercapacitor discharging control circuit; specifically:

[0056] The MCU's supercapacitor charging control signal VCAP-Charge is output at a high level, and the MCU's supercapacitor discharge control signal VCAP-Discharge is output at a high level;

[0057] The VCAP-Charge signal is high, and the VCAP-Charge signal passes through the resistor R5 to the base of the transistor Q2, which is high. The transistor Q2 is turned on, and the base of the transistor Q1 is connected to the ground through the transistor Q2. The transistor Q1 is cut off, and the charging of the supercapacitor E1 stops;

[0058] The VCAP-Discharge signal is at a high level. The VCAP-Discharge signal passes through the resistor R13 to the base of the transistor Q3 and is at a high level. The transistor Q3 is cut off and stops discharging the supercapacitor E1.

[0059] S23: When the supercapacitor voltage is greater than the upper limit of the supercapacitor voltage range of the current temperature range, the MCU turns off the supercapacitor charging control circuit and turns on the supercapacitor discharging control circuit; specifically:

[0060] The MCU's supercapacitor charging control signal VCAP-Charge is output at a high level, while the MCU's supercapacitor discharge control signal VCAP-Discharge is output at a low level;

[0061] The VCAP-Charge signal is high, and the VCAP-Charge signal passes through the resistor R5 to the base of the transistor Q2, which is high. The transistor Q2 is turned on, and the base of the transistor Q1 is connected to the ground through the transistor Q2. The transistor Q1 is cut off, and the charging of the supercapacitor E1 stops;

[0062] The VCAP-Discharge signal is at a low level. The VCAP-Discharge signal passes through the resistor R13 to the base of the transistor Q3 and is at a low level. The transistor Q3 is turned on and starts to discharge the supercapacitor E1.

[0063] Return to the first step and continue testing.

[0064] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A low-cost circuit that effectively increases the life of supercapacitors, characterized by It includes an MCU and a temperature sensor connected to the MCU, a supercapacitor charging control circuit, a supercapacitor discharging control circuit, a supercapacitor voltage detection circuit and a supercapacitor power supply circuit; The two control signal output terminals of the MCU are connected to the supercapacitor through the supercapacitor charging control circuit and the supercapacitor discharging control circuit respectively; The detection signal end of the supercapacitor is connected to the detection signal input end of the MCU through the supercapacitor voltage detection circuit; the output end of the temperature sensor is connected to the temperature signal input end of the MCU; The supercapacitor is connected to a supercapacitor power supply circuit.

2. The circuit of claim 1 , wherein the circuit is low-cost and effectively improves the life of a supercapacitor, is characterized by: The supercapacitor charging control circuit includes resistors R1, R2, R3, R4, R5, R6, R7, NPN transistor Q1, NPN transistor Q2 and supercapacitor E1. The input end of the supercapacitor charging control circuit is connected to the charging power supply provided by the electric energy meter, which is recorded as DC_IN. The charging power supply DC_IN is connected to one end of the resistor R1 and one end of the resistor R3. The other end of the resistor R1 is connected to the collector of the transistor Q1 through the resistor R2. The emitter of the transistor Q1 is connected to the positive electrode of the supercapacitor E1. The connection point Marked as VCAP, the negative electrode of the supercapacitor E1 is grounded, the other end of the resistor R3 is connected to the base of the transistor Q1, the emitter of the transistor Q2 and one end of the resistor R4, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, the connection point between the resistors R5 and R6 is connected to the supercapacitor charging control signal VCAP-Charge of the MCU, the other end of the resistor R6 is grounded, and the other end of the resistor R4 is grounded through the resistor R7.

3. The circuit of claim 1 , wherein the circuit is low-cost and effectively improves the life of a supercapacitor, is characterized by: The supercapacitor discharge control circuit includes resistors R11, R12, R13, R14 and a PNP transistor Q3. The output end of the supercapacitor discharge control circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to the emitter of the transistor Q3 through the resistors R11 and R12. The collector of the transistor Q3 is grounded. The base of the transistor Q3 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to one end of the resistor R14. The connection point between the resistors R13 and R14 is connected to the supercapacitor discharge control signal VCAP-Discharge of the MCU. The other end of the resistor R14 is grounded.

4. The circuit of claim 1 , wherein the circuit is low-cost and effectively improves the life of a supercapacitor, is characterized by: The supercapacitor voltage detection circuit includes resistors R8, R9, R10 and capacitor C1. The input end of the supercapacitor voltage detection circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to one end of the resistor R8, and the other end of the resistor R8 is respectively connected to the resistors R9, R10 and one end of the capacitor C1. The other end of the resistor R10 and the other end of the capacitor C1 are grounded. The other end of the resistor R9 is connected to the analog signal input port of the MCU, marked as VCAP-ADC.

5. The circuit of claim 1 , which is low-cost and effectively improves the life of a supercapacitor, is characterized by: The supercapacitor power supply circuit includes a resistor R15, a capacitor C2 and a diode D1. The output end of the supercapacitor power supply circuit is connected to the positive electrode of the supercapacitor E1, namely the VCAP point. The VCAP is connected to one end of the resistor R15, the other end of the resistor R15 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the capacitor C2 and the power supply VDD of the load, and the other end of the capacitor C2 is grounded.

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