Sustainable charging and discharging power supply circuit

Abstract

The utility model discloses a power supply circuit capable of continuously charging and discharging, which belongs to the technical field of power management and comprises a rectification filter circuit, a DC / DC (direct current / direct current) converter, an energy storage capacitor, an overcurrent protection circuit, an overvoltage protection circuit, a control circuit I and a control circuit II, the output end of the DC / DC converter is divided into two paths, the first path of output supplies power to external equipment through a first power supply end OUT1, the second path of output charges the battery BAT through the overcurrent protection circuit and the control circuit, the energy storage capacitor is connected between the output end of the DC / DC converter and the ground in parallel, and the energy storage capacitor is used for supplying power to the equipment in a conversion gap between mains supply energy supply and battery energy supply. And uninterrupted power supply of equipment is ensured. Compared with the prior art, the circuit has the functions of current-limiting protection, overvoltage protection and the like, can achieve the effect that equipment can continue to work after power failure, is simple in structure, and is very suitable for uninterruptible power supply of low-power equipment.

Description

Technical Field

[0001] The utility model belongs to the technical field of power management, and particularly relates to a power supply circuit capable of sustainable charging and discharging. Background Art

[0002] With the continuous development of power technology, the scale of the power grid is getting larger and the complexity is increasing. The functions of electronic products are becoming increasingly diverse and are used more frequently, which is closely related to our daily life. In order to ensure the stability of the power system and electronic products, a backup power supply method is required to prevent mistakes or losses caused by power outages or power failures of equipment products.

[0003] A backup power supply device is a device that can automatically and quickly switch the backup power supply to work or switch the user to the backup power supply when the working power supply fails and disconnects, so that the product is powered off.

[0004] Most of the existing backup power supply devices in the prior art are for high-power electrical equipment and are mostly equipped with large-capacity backup batteries, which have the disadvantages of long charging time, slow charging speed, and large volume. In addition, the overall circuit lacks functions such as current limiting protection, overvoltage protection, and timely temperature monitoring. There is a risk of power outage for a very short time before the backup power supply is successfully switched during a power outage.

[0005] How to design a power supply circuit capable of sustainable charging and discharging to solve the above technical problems has long troubled the technicians in this field. Summary of the Utility Model

[0006] In view of the above technical problems, the utility model provides a power supply circuit capable of sustainable charging and discharging. The circuit has functions such as current limiting protection and overvoltage protection, and can enable the equipment to continue working after a power outage. The circuit structure is simple and is very suitable for the uninterrupted power supply of low-power equipment.

[0007] The utility model solves the above problems by the following technical means:

[0008] A power supply circuit capable of sustainable charging and discharging, characterized in that it includes a rectifier filter circuit, a DC / DC converter, an energy storage capacitor, an overcurrent protection circuit, an overvoltage protection circuit, a control circuit one and a control circuit two, wherein: the mains power is connected to the input end of the DC / DC converter through the rectifier filter circuit, and the output end of the DC / DC converter is divided into two paths: the first path output supplies power to external devices through the first power supply terminal, and the second path output charges the battery through the overcurrent protection circuit and the control circuit one; the overvoltage protection circuit is connected in parallel between the output ends of the DC / DC converter; the battery supplies power to external devices through the second power supply terminal only under the condition of no mains power through the control of the control circuit two; the energy storage capacitor is connected in parallel between the output end of the DC / DC converter and the ground, and the energy storage capacitor is used to supply power to the device during the conversion gap between mains power supply and battery power supply.

[0009] Preferably, the rectifier filter circuit converts the 220V AC voltage into 311V DC voltage through four rectifier diodes and a filter capacitor circuit.

[0010] Preferably, the DC / DC converter adopts a BUCK isolation step-down topology structure to isolate and convert the 311V DC voltage into 12V DC voltage.

[0011] Preferably, the overcurrent protection circuit includes a first triode, a third mos tube, a first resistor and a second resistor, and the control circuit one includes a third resistor, a fourth resistor and a second triode, wherein: the positive output terminal of the DC / DC converter charges the battery through the first resistor and the third mos tube in sequence; the base and emitter of the first triode are connected in parallel at both ends of the first resistor, and the collector of the first triode is connected to the gate of the third mos tube; both ends of the second resistor are connected between the source and the gate of the third mos tube; the gate of the third mos tube is connected to the negative output terminal of the DC / DC converter through the third resistor and the second triode; the base of the second triode is connected to the control signal 1 through the fourth resistor.

[0012] Preferably, the overvoltage protection circuit includes a voltage regulator tube, a thyristor, an eighth resistor and a ninth resistor, wherein: the voltage regulator tube, the eighth resistor, the light-emitting diode and the ninth resistor are connected in series in sequence and then the whole is connected in parallel between the output ends of the DC / DC converter; the positive and negative electrodes of the thyristor are connected in parallel between the output ends of the DC / DC converter, and the control end of the thyristor is connected between the eighth resistor and the light-emitting diode.

[0013] Preferably, the second control circuit includes a fourth MOS transistor, a fifth triode, a fifth resistor, a sixth resistor, and a seventh resistor, where: the positive electrode of the battery is connected to the second power supply terminal through the source and drain of the fourth MOS transistor; both ends of the fifth resistor are connected between the source and gate of the fourth MOS transistor; the gate of the fourth MOS transistor is connected to the negative electrode of the battery through the sixth resistor and the fifth triode; the base of the fifth triode is connected to the control signal 2 through the seventh resistor.

[0014] Preferably, it further includes a mains voltage monitoring circuit. The monitoring point of the mains voltage monitoring circuit is set between the connection circuit of the rectifier filter circuit and the DC / DC converter. The monitoring point of the mains voltage monitoring circuit transmits the signal to the control signal 4 on the other side of the optocoupler through the twelfth resistor and the optocoupler.

[0015] Preferably, it further includes a battery voltage monitoring circuit. The monitoring point of the battery voltage monitoring circuit is set at the positive electrode of the battery. The monitoring point of the battery voltage monitoring circuit transmits the signal to the control signal 3 through a voltage dividing circuit composed of a tenth resistor and an eleventh resistor.

[0016] The power supply circuit capable of sustainable charging and discharging of the present utility model has the following beneficial effects:

[0017] This circuit has functions such as current limiting protection and overvoltage protection, and can enable the device to continue working after a power outage. The circuit structure is simple and is very suitable for uninterrupted power supply of small power devices. Among them, the current limiting protection circuit utilizes the first triode and the third MOS transistor to automatically adjust to achieve the technical effect of constant current charging. The overvoltage protection circuit uses a thyristor to short-circuit the charging end of the circuit under the condition of overvoltage, driving the DC / DC converter to start the short-circuit protection action to complete the overvoltage protection work. In addition, due to the design of the energy storage capacitor, the energy storage capacitor can supply power to the device during the conversion gap between mains power supply and battery power supply, solving the technical problem of extremely short-time power outage before the successful switching of the backup power supply at the moment of power outage. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions of the present utility model, the drawings required for implementation will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 is the overall circuit schematic diagram of the present utility model;

[0020] Figure 2 is the structural schematic diagram of the overcurrent protection circuit and the first control circuit in the present utility model;

[0021] Figure 3 It is a schematic structural diagram of the overvoltage protection circuit in the present utility model;

[0022] Figure 4 It is a schematic structural diagram of the second control circuit in the present utility model;

[0023] Figure 5 It is a schematic structural diagram of the mains voltage monitoring circuit in the present utility model;

[0024] Figure 6 It is a schematic structural diagram of the battery voltage monitoring circuit in the present utility model. Specific embodiments

[0025] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "plurality" is two or more.

[0026] The present utility model will be described in detail below with reference to the drawings.

[0027] As Figures 1 to 6 shown, the sustainable charge-discharge power supply circuit converts the AC voltage into DC through rectification, then converts it into 12V DC voltage through a DC / DC converter, and then through the single-chip microcomputer for voltage detection and charge-discharge control management. Now, there are current-limiting protection and overvoltage protection functions during the battery charging process, and the function of enabling the device to continue working after a power outage can be realized.

[0028] Figure 1It specifically includes a rectifier filter circuit, a DC / DC converter, energy storage capacitors, an overcurrent protection circuit, an overvoltage protection circuit, control circuit 1 and control circuit 2. The mains power is connected to the input end of the DC / DC converter through the rectifier filter circuit. The output end of the DC / DC converter is divided into two paths: the first path output supplies power to external devices through the first power supply terminal OUT1, and the second path output charges the battery BAT through the overcurrent protection circuit and control circuit 1; the overvoltage protection circuit is connected in parallel between the output ends of the DC / DC converter; the battery BAT supplies power to external devices through the second power supply terminal OUT2 only under the condition of no mains power through the control of control circuit 2; the energy storage capacitors are connected in parallel between the output end of the DC / DC converter and the ground GND, and the energy storage capacitors are used to supply power to the device during the conversion gap between mains power supply and battery power supply.

[0029] It should be noted that the AC 220V voltage is converted into a 311V DC voltage through the rectifier filter circuit, and then converted into a 12V DC voltage through the DC / DC converter. After the energy storage capacitors C1 and C2 are connected in parallel, one path OUT1 directly supplies power to the power supply device, and the other path conducts charge management on the battery BAT through overcurrent protection, overvoltage protection, voltage monitoring, and control circuits. When a power outage occurs, control circuit 2 starts discharging the battery to supply power to the electrical equipment.

[0030] In this embodiment, the rectifier filter circuit converts the 220V AC voltage into a 311V DC voltage through four rectifier diodes and a filter capacitor circuit, rectifies the sine wave into a half-sine wave through diode rectification, and outputs a smooth DC voltage after filtering through a diode. The DC / DC converter adopts a BUCK isolation step-down topology structure to isolate and convert the 311V DC voltage into a 12V DC voltage. Specifically, the DC / DC converter isolates and converts the 311V DC voltage into a 12V voltage to supply power to the device and charge the battery. Capacitors C1 and C2 are energy storage capacitors. When the mains power is cut off, control circuit 2 detects the absence of mains power. Before turning on OUT2 to supply power to the device, capacitors C1 and C2 briefly supply power to the device to achieve a seamless connection between mains power and backup power.

[0031] In the figure, the overcurrent protection circuit includes a first triode Q1, a third MOS transistor Q3, a first resistor R1, and a second resistor R2. The first control circuit includes a third resistor R3, a fourth resistor R4, and a second triode Q2, where: the positive output terminal of the DC / DC converter charges the battery BAT through the first resistor R1 and the third MOS transistor Q3 in sequence; the base b and the emitter e of the first triode Q1 are connected in parallel across both ends of the first resistor R1, and the collector c of the first triode Q1 is connected to the gate g of the third MOS transistor Q3; both ends of the second resistor R2 are connected between the source s and the gate g of the third MOS transistor Q3; the gate g of the third MOS transistor Q3 is connected to the negative output terminal of the DC / DC converter through the third resistor R3 and the second triode Q2; the base b of the second triode Q2 is connected to the control signal 1 through the fourth resistor R4.

[0032] It should be noted that the overcurrent protection is for the protection of the current magnitude during battery charging when there is mains power. When charging the battery, the current passes through the resistor R1 and the MOS transistor Q3. When the charging current increases, the voltage drop across the resistor R1 becomes larger, causing the voltage across the be terminals of the triode Q1 to increase. When the be terminal voltage of the triode reaches the turn-on voltage (generally 0.4V can reach turn-on), the ce terminal of the triode Q1 conducts, shorting the Vgs of the MOS transistor Q3, and the MOS transistor Q3 turns off, stopping the battery charging. At this time, no current passes through the resistor R1, there is no voltage drop across R1, the ce terminal of the triode Q1 does not conduct, the Vgs of the MOS transistor Q3 is 12V, the MOS transistor Q3 conducts, and starts charging the battery. When the current becomes large again, it turns off again, and so on in a cycle, which can achieve a constant current effect and play a role in current limiting protection.

[0033] It should be noted that when the control signal 1 is the switch control for charging the battery by the single-chip microcomputer. When the single-chip microcomputer monitors that the charging voltage has reached the full charge voltage of the battery, the control signal 1 of the single-chip microcomputer is at a low level, the triode Q2 turns off, and since the Vgs of the MOS transistor Q3 = 0V, the MOS transistor Q3 does not conduct, stopping the battery charging. When the single-chip microcomputer monitors that the charging voltage has reached 50% or less of the battery voltage, the control signal 1 of the single-chip microcomputer is at a high level, the triode Q2 conducts, the Vgs of the MOS transistor Q3 = 12V, the MOS transistor Q3 conducts and starts charging the battery.

[0034] In the figure, the overvoltage protection circuit includes a zener diode D3, a thyristor Q6, an eighth resistor R8, and a ninth resistor R9, where: the zener diode D3, the eighth resistor R8, the light-emitting diode D4, and the ninth resistor R9 are connected in series in sequence and then the whole is connected in parallel across the output terminals of the DC / DC converter; the positive and negative electrodes of the thyristor Q6 are connected in parallel across the output terminals of the DC / DC converter, and the control terminal of the thyristor Q6 is connected between the eighth resistor R8 and the light-emitting diode D4.

[0035] It should be noted that during the battery charging process, when the charging voltage is greater than the normal voltage, the diode D3 conducts, allowing a weak current to flow through the resistors R8 and R9, causing the thyristor Q6 to conduct, short-circuiting the battery charging terminal, and short-circuit protecting the DC / DC converter to achieve overvoltage protection and also protect the battery from being damaged by overvoltage.

[0036] In the figure, the control circuit two includes the fourth MOS transistor Q4, the fifth triode Q5, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, where: the positive electrode of the battery BAT is connected to the second power supply terminal OUT2 through the source s and the drain d of the fourth MOS transistor Q4; both ends of the fifth resistor R5 are connected between the source s and the gate g of the fourth MOS transistor Q4; the gate g of the fourth MOS transistor Q4 is connected to the negative electrode of the battery BAT through the sixth resistor R6 and the fifth triode Q5; the base b of the fifth triode Q5 is connected to the control signal 2 through the seventh resistor R7.

[0037] It should be noted that when the control signal 2 controls the battery discharge switch through the single-chip microcomputer. When the single-chip microcomputer detects the presence of commercial power, the control signal 1 of the single-chip microcomputer is at a low level, the triode Q2 is cut off, the Vgs of the MOS transistor Q3 is 0V, the MOS transistor Q3 does not conduct, and the battery stops discharging. When the single-chip microcomputer detects the absence of commercial power, the control signal 1 of the single-chip microcomputer is at a high level, the triode Q2 conducts, the Vgs of the MOS transistor Q3 is 12V, the MOS transistor Q3 conducts and starts discharging the battery.

[0038] In the figure, it also includes a commercial power voltage monitoring circuit. The monitoring point Vac of the commercial power voltage monitoring circuit is set between the connection circuit of the rectifier filter circuit and the DC / DC converter. The monitoring point Vac of the commercial power voltage monitoring circuit transmits the signal to the control signal 4 on the other side of the optocoupler U1 through the twelfth resistor R12 and the optocoupler U1.

[0039] It should be noted that the monitoring point Vac is the commercial power monitoring point. When there is commercial power, the light-emitting diode of the optocoupler U1 conducts, making the control signal 4 at a high level. The single-chip microcomputer monitors the high level as the presence of commercial power, and the battery discharge control signal 2 is at a low level, and the battery is prohibited from discharging. When there is no commercial power, the light-emitting diode of the optocoupler U1 does not conduct, making the control signal 4 at a low level. The single-chip microcomputer monitors the low level as the absence of commercial power, and the battery discharge control signal 2 is at a high level, and the battery starts discharging.

[0040] In the figure, it also includes a battery voltage monitoring circuit. The monitoring point BAT of the battery voltage monitoring circuit is set at the positive electrode of the battery BAT. The monitoring point BAT of the battery voltage monitoring circuit transmits the signal to the control signal 3 through a voltage dividing circuit composed of the tenth resistor R10 and the eleventh resistor R11.

[0041] It should be noted that the monitoring point BAT is the battery voltage monitoring point. When there is mains power, the control signal 3 collects the current battery voltage. If the battery voltage is lower than 50% of the normal voltage, it enters the charging stage. If the battery voltage is higher than 50% of the normal voltage, it does not charge and continues to be detected. When there is no mains power and the battery enters the discharge state, the control signal 3 collects the current battery voltage. If the battery voltage is not lower than 10% of the normal voltage, it continues to discharge. If the battery voltage is lower than 10% of the normal voltage, the discharge stops and the device powers off.

[0042] It should be further noted that the control signal 1, control signal 2, control signal 3, and control signal 4 are all connected to the single-chip microcomputer MSP430G2203. This single-chip microcomputer is an existing conventional model and only needs to have conventional IO ports, PWM ports, etc.

[0043] During actual operation, when the mains power is normally supplied, the device is directly powered by the first power supply terminal OUT1, and the real-time detection of the mains power and battery voltage is carried out through the single-chip microcomputer. When the battery voltage is lower than 50%, the battery starts to be charged through the first control circuit, and the charging is turned off after being fully charged. When the mains power is cut off and no mains power is detected at the Vac point, the second control circuit turns on the battery discharge mode, and the device is powered by the second power supply terminal OUT2. During this discharge process, the battery voltage is monitored in real time. When the voltage is 10.5V, the discharge is turned off and the device stops working. When the mains power is normal, the power supply circuit starts to work, the device is powered by the first power supply terminal OUT1, and the battery starts to be charged and stops after being fully charged.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A power supply circuit capable of continuous charging and discharging, characterized in that: It includes a rectifier filter circuit, a DC / DC converter, an energy storage capacitor, an overcurrent protection circuit, an overvoltage protection circuit, a control circuit 1 and a control circuit 2, wherein: The mains is connected to the input of the DC / DC converter through a rectifier and filter circuit. The output of the DC / DC converter is divided into two paths: the first output is used to supply power to external devices through the first power supply terminal (OUT1), and the second output is used to charge the battery (BAT) through an overcurrent protection circuit and a control circuit. The overvoltage protection circuit is connected in parallel between the output terminals of the DC / DC converter; The battery (BAT) supplies power to the external device through the second power supply terminal (OUT2) only when there is no mains power under the control of the second control circuit; The energy storage capacitor is connected in parallel between the output end of the DC / DC converter and the ground (GND), and is used to supply power to the device during the conversion interval between the mains power supply and the battery power supply.

2. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: The rectification and filtering circuit converts the 220V AC voltage into a 311V DC voltage through four rectification diodes and a filtering capacitor circuit.

3. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: The DC / DC converter adopts a BUCK isolation step-down topology structure to isolate and convert a 311V DC voltage into a 12V DC voltage.

4. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: The overcurrent protection circuit comprises a first transistor (Q1), a third MOS transistor (Q3), a first resistor (R1) and a second resistor (R2); the control circuit 1 comprises a third resistor (R3), a fourth resistor (R4) and a second transistor (Q2), wherein: The positive output terminal of the DC / DC converter charges the battery (BAT) through the first resistor (R1) and the third MOS tube (Q3) in turn; The base (b) and emitter (e) of the first transistor (Q1) are connected in parallel to two ends of the first resistor (R1), and the collector (c) of the first transistor (Q1) is connected to the gate (g) of the third MOS transistor (Q3); Two ends of the second resistor (R2) are connected between the source (s) and the gate (g) of the third MOS tube (Q3); The gate (g) of the third MOS tube (Q3) is connected to the negative output terminal of the DC / DC converter through the third resistor (R3) and the second transistor (Q2); The base (b) of the second transistor (Q2) is connected to the control signal 1 via a fourth resistor (R4).

5. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: The overvoltage protection circuit comprises a voltage regulator (D3), a thyristor (Q6), an eighth resistor (R8) and a ninth resistor (R9), wherein: The voltage regulator tube (D3), the eighth resistor (R8), the light emitting diode (D4) and the ninth resistor (R9) are sequentially connected in series and then connected in parallel between the output ends of the DC / DC converter as a whole; The positive and negative electrodes of the thyristor (Q6) are connected in parallel between the output ends of the DC / DC converter, and the control end of the thyristor (Q6) is connected between the eighth resistor (R8) and the light-emitting diode (D4).

6. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: The control circuit 2 comprises a fourth MOS tube (Q4), a fifth triode (Q5), a fifth resistor (R5), a sixth resistor (R6) and a seventh resistor (R7), wherein: The positive electrode of the battery (BAT) is connected to the second power supply terminal (OUT2) through the source electrode (s) and the drain electrode (d) of the fourth MOS tube (Q4); Two ends of the fifth resistor (R5) are connected between the source (s) and the gate (g) of the fourth MOS tube (Q4); The gate (g) of the fourth MOS tube (Q4) is connected to the negative electrode of the battery (BAT) through the sixth resistor (R6) and the fifth transistor (Q5); The base (b) of the fifth transistor (Q5) is connected to the control signal 2 via a seventh resistor (R7).

7. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: It also includes a mains voltage monitoring circuit, wherein a monitoring point (Vac) of the mains voltage monitoring circuit is arranged between the rectifier filter circuit and the connection circuit of the DC / DC converter, and the monitoring point (Vac) of the mains voltage monitoring circuit transmits a signal to a control signal 4 on the other side of the optocoupler (U1) through a twelfth resistor (R12) and an optocoupler (U1).

8. The sustainable charge and discharge power supply circuit according to claim 1, characterized in that: It also includes a battery voltage monitoring circuit, wherein a monitoring point (BAT) of the battery voltage monitoring circuit is set at the positive electrode of the battery (BAT), and the monitoring point (BAT) of the battery voltage monitoring circuit transmits a signal to the control signal 3 through a voltage divider circuit composed of a tenth resistor (R10) and an eleventh resistor (R11).

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