CN213637156U - Direct current power supply and charging circuit thereof - Google Patents

Direct current power supply and charging circuit thereof Download PDF

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CN213637156U
CN213637156U CN202022746418.0U CN202022746418U CN213637156U CN 213637156 U CN213637156 U CN 213637156U CN 202022746418 U CN202022746418 U CN 202022746418U CN 213637156 U CN213637156 U CN 213637156U
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resistor
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谭亮
李秋莲
曾云洪
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Abstract

The application relates to a direct-current power supply and a charging circuit thereof, wherein the direct-current power supply charging circuit comprises a first voltage division unit, a control unit, a switch unit, a second voltage division unit, an energy storage unit and a current division unit; the first voltage division unit is connected with the front-stage circuit, the energy storage unit is connected with the rear-stage circuit, and the second voltage division unit is connected with the energy storage unit; the control unit is connected with the first voltage division unit and the second voltage division unit and is also connected with the control end of the switch unit; the first end of the shunting unit is connected with the preceding stage circuit, the second end of the shunting unit is connected with the energy storage unit, the first end of the switch unit is connected with the first end of the shunting unit, and the second end of the switch unit is connected with the second end of the shunting unit. When the sampling voltage of the second voltage division unit is greater than that of the first voltage division unit, the control unit controls the switch unit to be closed, the shunt unit is short-circuited, the energy consumption of the shunt unit can be reduced, and the power conversion efficiency is improved.

Description

Direct current power supply and charging circuit thereof
Technical Field
The application relates to the technical field of automation, in particular to a direct-current power supply and a charging circuit thereof.
Background
For a load which needs to be powered by a direct current, a direct current power supply is generally required to provide working electric energy for the load. In the conventional direct-current power supply charging circuit, because the energy storage capacitor is equivalent to a short-circuit state at the moment of electrification, a large surge current can be generated, so that the current stress of each device in the charging circuit can be increased, the current stress of each device in a preceding stage circuit can be influenced, and the reliability of a direct-current power supply can be influenced. In order to limit the surge current, a resistor is usually connected to the main loop between the front-stage circuit and the energy storage capacitor, however, due to the resistor, extra loss is increased when the power supply operates stably, and the conversion efficiency of the power supply is reduced.
SUMMERY OF THE UTILITY MODEL
Therefore, it is necessary to provide a dc power supply and a charging circuit thereof to improve the power conversion efficiency of the dc power supply and the charging circuit thereof, aiming at the problem of low power conversion efficiency of the conventional dc power supply and charging circuit thereof.
In a first aspect of the present application, a dc power charging circuit is provided, which includes a first voltage dividing unit, a control unit, a switch unit, a second voltage dividing unit, an energy storage unit, and a current dividing unit;
the first voltage division unit is used for connecting a front-stage circuit, the energy storage unit is used for connecting a rear-stage circuit, and the second voltage division unit is connected with the energy storage unit; the control unit is connected with the first voltage division unit and the second voltage division unit and is also connected with the control end of the switch unit; the first end of the shunting unit is connected with the preceding stage circuit, the second end of the shunting unit is connected with the energy storage unit, the first end of the switch unit is connected with the first end of the shunting unit, and the second end of the switch unit is connected with the second end of the shunting unit; and the control unit controls the switch unit to be closed when the sampling voltage of the second voltage division unit is greater than the sampling voltage of the first voltage division unit.
In one embodiment, the first voltage dividing unit comprises a first voltage dividing resistor and a second voltage dividing resistor; the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series, a formed common end is connected with the control unit, the other end of the first voltage-dividing resistor is connected with a first end of the front-stage circuit, and the other end of the second voltage-dividing resistor is connected with a second end of the front-stage circuit.
In one embodiment, the second voltage dividing unit comprises a third voltage dividing resistor and a fourth voltage dividing resistor; the third voltage dividing resistor and the fourth voltage dividing resistor are connected in series, a common end formed by the third voltage dividing resistor and the fourth voltage dividing resistor is connected with the control unit, the other end of the third voltage dividing resistor is connected with the first end of the energy storage unit, and the other end of the fourth voltage dividing resistor is connected with the second end of the energy storage unit.
In one embodiment, the shunt unit is a shunt resistor.
In one embodiment, the energy storage unit is a capacitor.
In one embodiment, the control unit is an operational amplifier, a first input terminal of the operational amplifier is connected to the first voltage division unit, a second input terminal of the operational amplifier is connected to the second voltage division unit, and an output terminal of the operational amplifier is connected to the switch unit.
In one embodiment, the switching unit is a MOS transistor.
In one embodiment, the voltage regulator further comprises a voltage regulation unit, and the voltage regulation unit is connected with the control end and the first end of the switch unit.
In one embodiment, the voltage stabilizing unit comprises a voltage stabilizing diode and a voltage stabilizing resistor, wherein the cathode of the voltage stabilizing diode is connected with the control end of the switch unit, and the anode of the voltage stabilizing diode is connected with the first end of the switch unit through the voltage stabilizing resistor.
In a second aspect of the present application, a dc power supply is provided, which includes a front stage circuit, a rear stage circuit, and the dc power supply charging circuit in any of the above embodiments.
According to the direct-current power supply charging circuit, the shunting unit is connected between the energy storage unit preceding stage circuits at the initial stage of circuit power-on, so that the surge current at the moment of power-on can be limited, and the current stress of a device is reduced. In the charging process, the sampling voltage of the first voltage division unit is determined by the output voltage of the front-stage circuit, and the sampling voltage of the second voltage division unit is increased along with the rise of the energy storage voltage of the energy storage unit. When the sampling voltage of the second voltage division unit is greater than that of the first voltage division unit, the control unit controls the switch unit to be closed, and at the moment, the shunt unit is short-circuited, so that the energy consumption of the shunt unit can be reduced, and the power conversion efficiency is improved.
Drawings
FIG. 1 is a block diagram of an embodiment of a DC power charging circuit;
FIG. 2 is a block diagram of a DC power charging circuit according to another embodiment;
fig. 3 is a schematic structural diagram of a dc power charging circuit according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. The first resistance and the second resistance are both resistances, but they are not the same resistance.
It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.
In order to improve the conversion efficiency of the power supply while suppressing the inrush current, two solutions are available. One is to connect a thermistor between the front-stage circuit and the energy-storage capacitor. In the initial stage of circuit power-on, because the thermistor has low temperature and high resistance, the surge current can be effectively limited; in the working process of the circuit, the temperature of the thermistor rises, the resistance value is reduced, and the energy consumption is reduced accordingly. However, in the dc power charging circuit, on one hand, after the resistance of the thermistor is reduced, a certain amount of energy also needs to be consumed, and the improvement effect on the power conversion efficiency is limited; on the other hand, since the temperature of the thermistor needs time to decrease, the direct-current power supply cannot be turned on immediately after being turned off, and the application scene of the direct-current power supply is limited.
The other is to add a switch tube in parallel with a resistor in the main loop and add a controller and a sampling circuit. The sampling circuit collects the energy storage or current of the energy storage capacitor, and the controller controls the switching tube according to the feedback signal of the sampling circuit: when the circuit is powered on, the switching tube is controlled to be disconnected, and surge current is limited; after the circuit operates stably, the switch tube is controlled to be closed, the resistor is short-circuited, and extra energy consumption is reduced. However, such a dc power charging circuit requires an additional controller and a sampling circuit, and is complex and costly.
Therefore, the direct-current power supply charging circuit has respective defects, and on the basis of the defects, the application provides the direct-current power supply charging circuit which does not need to be additionally provided with a controller and a sampling circuit, does not have the defect of a thermistor, and can achieve the effect of inhibiting surge current and simultaneously improving the conversion efficiency of a power supply.
In one embodiment, referring to fig. 1, a dc power charging circuit is provided, which includes a first voltage dividing unit 10, a control unit 20, a switch unit 30, a second voltage dividing unit 40, an energy storage unit 50, and a current dividing unit 60. The first voltage division unit 10 is used for connecting a front-stage circuit, the energy storage unit 50 is used for connecting a rear-stage circuit, and the second voltage division unit 40 is connected with the energy storage unit 50; the control unit 20 is connected with the first voltage division unit 10 and the second voltage division unit 40, and the control unit 20 is also connected with the control end of the switch unit 30; a first end of the shunting unit 60 is connected to the front-stage circuit, a second end of the shunting unit 60 is connected to the energy storage unit 50, a first end of the switching unit 30 is connected to the first end of the shunting unit 60, and a second end of the switching unit is connected to the second end of the shunting unit 60. The control unit 20 controls the switching unit 30 to be closed when the sampling voltage of the second voltage division unit 40 is greater than the sampling voltage of the first voltage division unit 10.
The first voltage dividing unit 10 and the second voltage dividing unit 40 include voltage dividers, voltage dividing resistors, and other devices that can implement a voltage dividing function. The control unit 20 includes a control chip, a voltage comparator, and the like that can control an output by voltage comparison. The switch unit 30 includes a relay or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS Transistor) or other switching device that can be turned on and off by changing an input. Further, the relay may be a voltage relay or a current relay. The shunt unit 60 includes a shunt, a shunt resistor, and the like, which can perform a shunt function. The energy storage unit 50 includes an energy storage capacitor, an energy storage battery, and other devices capable of realizing an energy storage function. In short, the embodiments of the present application do not limit the specific device configurations of the respective components.
Specifically, the shunting unit 60 may be disposed at any position between the front-stage circuit and the energy storage unit 50. When the circuit is powered on, the electric energy input by the preceding stage circuit reaches the energy storage unit 50 through the shunt unit 60, so that the surge current at the moment of power-on can be effectively limited. During the circuit operation, the control unit 20 samples the previous stage circuit and the energy storage unit 50 through the first voltage dividing unit 10 and the second voltage dividing unit 40, respectively. The sampling voltage of the first voltage division unit 10 is determined by the output voltage of the previous stage circuit, and the sampling voltage of the second voltage division unit 40 increases as the energy storage voltage of the energy storage unit 50 increases. When the sampling voltage of the second voltage division unit 40 is greater than the sampling voltage of the first voltage division unit 10, the control unit 20 controls the switch unit 30 to be closed, the voltage division unit 60 is short-circuited, the charging current reaches the energy storage unit 50 through the switch unit 30, and the energy storage unit 50 continues to be charged until the charging is completed.
In the direct-current power supply charging circuit, the shunt unit 60 is connected between the front-stage circuits of the energy storage unit 50 at the initial stage of circuit power-on, so that the surge current at the moment of power-on can be limited, the current stress of the device is reduced, and the reliability is improved. During the charging process, the sampling voltage of the first voltage division unit 10 is determined by the output voltage of the previous stage circuit, and the sampling voltage of the second voltage division unit 40 increases as the energy storage voltage of the energy storage unit 50 increases. When the sampling voltage of the second voltage division unit 50 is greater than the sampling voltage of the first voltage division unit 10, the control unit 20 controls the switch unit 30 to be closed, and at this time, the shunt unit 60 is short-circuited, so that the energy consumption of the shunt unit 60 can be reduced, and the power conversion efficiency can be improved.
In one embodiment, referring to fig. 2, the dc power charging circuit further includes a voltage regulator unit 70, and the voltage regulator unit 70 is connected to the control terminal and the first terminal of the switch unit 30.
The voltage stabilizing unit 70 includes a voltage stabilizer, a voltage stabilizing chip or a voltage stabilizing diode, and other devices capable of achieving a voltage stabilizing function. Specifically, the voltage stabilizing unit 70 is disposed between the control terminal and the first terminal of the switch unit 30, so as to keep the voltage difference between the control terminal and the first terminal of the switch unit 30 constant, which is beneficial to improving the stability of the dc power charging circuit.
In one embodiment, referring to fig. 3, the first voltage dividing unit 10 includes a first voltage dividing resistor R1 and a second voltage dividing resistor R2; the first divider resistor R2 and the second divider resistor R2 are connected in series to form a common terminal connected to the control unit 20, the other end of the first divider resistor R1 is connected to the first terminal J1 of the previous stage circuit, and the other end of the second divider resistor R2 is connected to the second terminal J2 of the previous stage circuit.
Wherein, the first terminal J1 and the second terminal J2 of the front stage circuitThe pole type is not unique. When the first end J1 of the front-stage circuit is positive, the second end J2 is negative; correspondingly, when the first terminal J1 of the previous stage circuit is negative, the second terminal J2 is positive. Specifically, the first sampling voltage received by the control unit 20 is determined by the output voltage of the previous stage circuit and the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2. When the first terminal J1 of the previous stage circuit is positive, the sampling value V of the first sampling voltage1Comprises the following steps:
Figure BDA0002795568270000061
in the formula, R1Is the value of a first divider resistor R1, R2Is the resistance value, V, of the second divider resistor R2Preceding stage circuitIs the output voltage of the preceding stage circuit.
In the above embodiment, by selecting the first voltage dividing resistor R1 and the second voltage dividing resistor R2 with suitable resistances, the first sampling voltage V of the control unit 20 can be determined1And further determines the starting condition for opening and closing the switch unit 30.
In one embodiment, with continued reference to fig. 3, the second voltage dividing unit 40 includes a third voltage dividing resistor R3 and a fourth voltage dividing resistor R4; the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 are connected in series to form a common end connected with the control unit 20, the other end of the third voltage dividing resistor R3 is connected with the first end of the energy storage unit 50, and the other end of the fourth voltage dividing resistor R4 is connected with the second end of the energy storage unit 50.
The energy storage unit 50 is connected to the post-stage circuit, the first end of the energy storage unit 50 is connected to the first end J3 of the post-stage circuit, and the second end of the energy storage unit 50 is connected to the second end J4 of the post-stage circuit. The electrode types of the first terminal J3 and the second terminal J4 of the subsequent circuit correspond to the electrode types of the first terminal J1 and the second terminal J2 of the previous circuit. Specifically, the electrode type of the first terminal J3 of the subsequent circuit corresponds to the first terminal J1 of the previous circuit, and the electrode type of the second terminal J4 of the subsequent circuit corresponds to the second terminal J2 of the previous circuit. When the first terminal J1 of the front stage circuit is positive, the first terminal J3 of the rear stage circuit is positive, and the second terminal J4 is negativeA pole; correspondingly, when the first terminal J1 of the previous stage is negative, the first terminal J3 of the subsequent stage is negative, and the second terminal J4 is positive. Specifically, the second sampling voltage received by the control unit 20 is determined by the voltage of the energy storage unit 50 and the resistances of the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4. When the first terminal of the energy storage unit 50 is connected to the positive electrode of the subsequent circuit, the sampling value V of the second sampling voltage2Comprises the following steps:
Figure BDA0002795568270000062
in the formula, R3Is the value of the third divider resistor R3, R4Is the value of the fourth voltage dividing resistor R4, VEnergy storage unitIs the output voltage of the preceding stage circuit.
In the above embodiment, by selecting the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 with suitable resistances, the second sampling voltage V of the control unit 20 can be determined2It is advantageous to determine the starting condition of the opening and closing of the switch unit 30 and to adjust the closing time of the switch unit 30.
In one embodiment, with continued reference to fig. 3, the shunt unit 60 is a shunt resistor R5.
The shunt resistor R5 may be an adjustable resistor such as a thermistor or a varistor, or may be an unadjustable resistor with a constant resistance. In summary, the embodiment of the present application does not limit the specific type of shunt resistor R5. The resistance of the shunt resistor R5 is much smaller than that of any of the voltage dividing resistors. Specifically, the shunt resistor R5 may be disposed at any position between the pre-stage circuit and the energy storage unit 50. When the circuit is powered on, the electric energy input by the front stage circuit reaches the energy storage unit 50 through the shunt resistor R5, so that the surge current at the power-on moment can be effectively limited. For example, referring to fig. 3, the shunt resistor R5 may be disposed between the end J2 of the front-stage circuit and the energy storage unit 50. It is understood that J2 may be the positive output terminal of the previous stage circuit or the negative output terminal of the previous stage circuit.
In the above embodiment, the shunt unit 60 is the shunt resistor R5, and the circuit is simple, so that the surge current at the moment of power-on can be effectively reduced, and the cost of the dc power charging circuit can be reduced.
In one embodiment, continuing to refer to fig. 3, the energy storage unit 50 is a capacitor C1.
The two ends of the capacitor C1 are respectively connected to the first end J3 and the second end J4 of the post-stage circuit. It can be understood that the polarity of the first terminal J3 of the rear stage circuit is the same as the polarity of the first terminal J1 of the front stage circuit, and the polarity of the second terminal J4 of the rear stage circuit is the same as the polarity of the second terminal J2 of the front stage circuit. For example, when J1 is positive J2 is negative, J3 is positive J4 is negative.
Specifically, the capacitor C1 may be a super capacitor or a common capacitor. When the capacitor C1 is a super capacitor, the capacitor C1 may be an electric double layer capacitor or a faraday quasi-capacitor according to the energy storage mechanism. The electric double layer capacitor mainly generates stored energy by adsorbing pure electrostatic charges on the surface of an electrode. The faradaic capacitor is mainly generated by reversible redox reaction on the surface of active electrode materials (such as transition metal oxides and high molecular polymers) and near the surface, so that energy storage and conversion are realized. Next, the capacitor C1 may be an aqueous supercapacitor or an organic supercapacitor, depending on the type of electrolyte. In addition, the capacitor C1 may also be a symmetric supercapacitor or an asymmetric supercapacitor, depending on whether the types of active materials are the same. Finally, the capacitor C1 may be a solid electrolyte supercapacitor or a liquid electrolyte supercapacitor, depending on the state of the electrolyte. In summary, the embodiment of the present application does not limit the specific type of the capacitor C1.
In one embodiment, referring to fig. 3, the control unit 20 is an operational amplifier U1, a first input terminal of the operational amplifier U1 is connected to the first voltage divider 10, a second input terminal of the operational amplifier U1 is connected to the second voltage divider 40, and an output terminal of the operational amplifier U1 is connected to the switch unit 30.
The operational amplifier U1 may be a general-purpose operational amplifier (e.g., μ a741, LM358, and LM 324), a high-resistance operational amplifier (e.g., LF355, CA3130, and CA 3140), a low-temperature-drift operational amplifier (e.g., OP07, OP27, and AD508), a high-speed operational amplifier (e.g., LM318, μ a 715), a low-power operational amplifier (e.g., TL-022C, TL-060C), a high-voltage high-power operational amplifier (e.g., D41), and a programmable control type (e.g., PGA 103A). The embodiment of the present application does not limit the specific type of the operational amplifier.
Specifically, the sampling voltages of the first input terminal and the second input terminal of the operational amplifier U1 are determined by the voltage division values of the first voltage division unit 10 and the second voltage division unit 40, respectively. Specifically, according to the difference of the switch unit 30, one of the non-inverting input terminal and the inverting input terminal of the operational amplifier U1 is selected as the first input terminal, and the other is selected as the second input terminal. When the first input terminal is an in-phase input terminal, the second input terminal is an inverted input terminal, and correspondingly, when the first input terminal is an inverted input terminal, the second input terminal is an in-phase input terminal. Taking the inverting input terminal as the first input terminal and the non-inverting input terminal as the second input terminal as an example, in the initial power-on period of the circuit, the sampling voltage of the first input terminal is greater than the sampling voltage of the second input terminal, the operational amplifier U1 outputs the control signal to control the switch unit 30 to be turned off, the charging current charges the energy storage unit 50 through the shunting unit 60, and the voltage of the energy storage unit 50 rises. When the sampling voltage of the second input end of the operational amplifier U1 is greater than or equal to the sampling voltage of the first input end, the operational amplifier U1 outputs a control signal to control the switch unit 30 to be turned on, the shunt unit 60 is short-circuited, and the charging current charges the energy storage unit 50 through the switch unit 30 until the charging is completed.
In one embodiment, with continued reference to fig. 3, the switch unit 30 is a MOS transistor K1. The MOS transistor can be classified into two types, i.e., an "N-type" and a "P-type", which are also called an NMOS transistor and a PMOS transistor, according to the polarity of the working carrier. The embodiment of the present application does not limit the kind of the MOS transistor. For ease of understanding, the following description will take NMOS transistors as an example.
Specifically, the first input terminal of the operational amplifier U1 is an inverting input terminal, and the second terminal is a non-inverting input terminal. The output end of the operational amplifier U1 is connected with the grid G of the NMOS tube K1; the source S of the NMOS transistor is connected with the preceding stage circuit, and the drain D of the NMOS transistor K1 is connected with the energy storage unit 50. In the initial stage of circuit power-on, the sampling voltage of the inverting input end of the operational amplifier U1 is greater than the sampling voltage of the non-inverting input end, a low level is output, the NMOS tube K1 is controlled to be disconnected, the charging current charges the energy storage unit 50 through the shunt unit 60, and the voltage of the energy storage unit 50 rises. The sampling voltage of the non-inverting input end of the operational amplifier U1 increases with the rising of the voltage of the energy storage unit 50, when the sampling voltage of the non-inverting input end is greater than or equal to the sampling voltage of the inverting input end, the operational amplifier U1 outputs a high level to control the NMOS transistor K1 to be turned on, the shunt unit 60 is short-circuited, and the charging current charges the energy storage unit 50 through the NMOS transistor K1 until the charging is completed.
In one embodiment, with continued reference to fig. 3, the voltage regulator unit 70 includes a voltage regulator diode D1 and a voltage regulator resistor R6, wherein a cathode of the voltage regulator diode D1 is connected to the control terminal of the switch unit 30, and an anode of the voltage regulator diode D1 is connected to the first terminal of the switch unit 30 through the voltage regulator resistor R6.
The zener diode D1 is a diode that is made by utilizing the reverse breakdown state of pn junction, and the current of the diode can change in a large range while the voltage is basically unchanged. Specifically, the forward characteristic of the volt-ampere characteristic curve of the zener diode is similar to that of a common diode, and the reverse characteristic is that when the reverse voltage is lower than the reverse breakdown voltage, the reverse resistance is large, and the reverse leakage current is extremely small. When the reverse voltage approaches the breakdown voltage, the reverse resistance suddenly drops to a small value, and at this time, although the current varies in a large range, the voltage across the diode is substantially stabilized around the breakdown voltage, thereby realizing the voltage stabilization function of the diode.
Specifically, the voltage stabilizing resistor R6 with a proper resistance value is selected to be connected with the voltage stabilizing diode D1 in series, so that the voltage stabilizing function can be realized, the current flowing through the voltage stabilizing diode D1 can be limited through the voltage stabilizing resistor R6, and the voltage stabilizing diode D1 is prevented from being damaged due to overlarge power consumption.
In one embodiment, with reference to fig. 3, the first terminal J1 of the front-stage circuit is positive, the second terminal J2 is negative, the first terminal J3 of the rear-stage circuit is positive, and the second terminal J4 is negative. The first voltage dividing unit 10 includes a first voltage dividing resistor R1 and a second voltage dividing resistor R2; the second voltage division unit 40 includes a third voltage division resistor R3 and a fourth voltage division resistor R4. The control unit 20 is an operational amplifier U1, the switch unit 30 is an NMOS transistor K1, the energy storage unit 50 is a capacitor C1, the shunt unit 60 is a shunt resistor R5, and the voltage regulator unit 70 includes a voltage regulator diode D1 and a voltage regulator resistor R6.
The first voltage-dividing resistor R2 and the second voltage-dividing resistor R2 are connected in series, a formed common end is connected with an inverting input end of the operational amplifier U1, the other end of the first voltage-dividing resistor R1 is connected with a first end J1 of the previous stage circuit, and the other end of the second voltage-dividing resistor R2 is connected with a second end J2 of the previous stage circuit. The third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 are connected in series, a formed common end is connected with a non-inverting input end of the operational amplifier U1, the other end of the third voltage dividing resistor R3 is connected with a first end of the capacitor C1, and the other end of the fourth voltage dividing resistor R4 is connected with a second end of the capacitor C1. The grid G of the NMOS tube K1 is connected with the output end of the operational amplifier U1; the source S of the NMOS transistor is connected with the second end J2 of the preceding stage circuit, and the drain D of the NMOS transistor K1 is connected with the second end of the capacitor C1. The cathode of the voltage stabilizing diode D1 is connected with the grid G of the NMOS tube K1, and the anode of the voltage stabilizing diode D1 is connected with the source S of the NMOS tube through a voltage stabilizing resistor R6. One end of the shunt resistor R5 is connected to the second terminal J2 of the preceding stage circuit, and the other end is connected to the second terminal of the capacitor C1. A first end of the capacitor C1 is connected with a first end J3 of the post-stage circuit, and a second end of the capacitor C1 is connected with a second end J4 of the post-stage circuit.
Sampled value V of sampled voltage at inverting input terminal of operational amplifier U11Comprises the following steps:
Figure BDA0002795568270000101
sampled value V of sampled voltage at non-inverting input end of operational amplifier U12Comprises the following steps:
Figure BDA0002795568270000102
at the initial stage of the power-on of the circuit,V1greater than V2When the output of the operational amplifier U1 is negative, the NMOS transistor K1 is turned off, the charging current charges the capacitor C1 through the shunt resistor R5, and the voltage of the capacitor C1 rises. The sampling voltage of the non-inverting input end of the operational amplifier U1 increases along with the rising of the voltage of the capacitor C1, when the sampling voltage of the non-inverting input end is larger than or equal to the sampling voltage of the inverting input end, the output of the operational amplifier U1 is a positive value, the NMOS tube K1 is controlled to be switched on, the shunt resistor R5 is short-circuited, and the charging current charges the capacitor C1 through the NMOS tube K1 until the charging is completed.
In the direct-current power supply charging circuit, at the initial stage of circuit electrification, the NMOS tube K1 is controlled to be disconnected through the operational amplifier U1, the charging current charges the capacitor C1 through the shunt resistor R5, the surge current at the moment of electrification can be effectively limited, the current stress of a device is reduced, and the reliability is improved. During the charging process, the sampling voltage at the non-inverting input terminal of the operational amplifier U1 increases as the energy storage voltage of the capacitor C1 increases. When the sampling voltage of the positive phase input end is greater than that of the negative phase input end, the NMOS tube K1 is controlled to be closed by the operational amplifier U1, at the moment, the shunt resistor R5 is short-circuited, no extra energy is consumed, the conversion efficiency of the power supply can be improved to a large extent, even if the circuit is turned on immediately after being turned off, the surge current limiting function is still achieved, and the application scene is flexible. Meanwhile, the voltage difference between the grid and the source of the NMOS tube K1 is kept constant through the voltage stabilizing diode D1 and the voltage stabilizing resistor R6, and the reliability of the circuit is improved. In addition, the direct-current power supply charging circuit does not need to be additionally provided with a controller and a sampling circuit, the effect of flexibly controlling the conduction time of the NMOS tube can be achieved only by reasonably designing the voltage dividing resistor, and the direct-current power supply charging circuit is simple in circuit and low in cost.
In a second aspect of the present application, a dc power supply is provided, which includes a front stage circuit, a rear stage circuit, and the dc power supply charging circuit in any of the above embodiments. For specific limitations of the dc power charging circuit, reference may be made to the above description, and details thereof are not repeated herein.
Specifically, the dc power supply may be a power supply socket, and includes a preceding stage circuit, a subsequent stage circuit, and a dc power supply charging circuit, where the preceding stage circuit is connected to the power supply interface of the previous stage, and the load is connected to the dc power supply through the subsequent stage circuit. The direct current power supply can also be a frequency converter and comprises a front-stage circuit, a rear-stage circuit and a direct current power supply charging circuit in any of the embodiments, wherein the front-stage circuit is connected with an external alternating current power supply, the rear-stage circuit is connected with a load, and the direct current power supply charging circuit is arranged on a direct current bus of the frequency converter. In short, the present embodiment does not limit the specific type and configuration of the dc power supply.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only show some embodiments of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A direct-current power supply charging circuit is characterized by comprising a first voltage division unit, a control unit, a switch unit, a second voltage division unit, an energy storage unit and a current division unit;
the first voltage division unit is used for connecting a front-stage circuit, the energy storage unit is used for connecting a rear-stage circuit, and the second voltage division unit is connected with the energy storage unit; the control unit is connected with the first voltage division unit and the second voltage division unit and is also connected with the control end of the switch unit; the first end of the shunting unit is connected with the preceding stage circuit, the second end of the shunting unit is connected with the energy storage unit, the first end of the switch unit is connected with the first end of the shunting unit, and the second end of the switch unit is connected with the second end of the shunting unit; and the control unit controls the switch unit to be closed when the sampling voltage of the second voltage division unit is greater than the sampling voltage of the first voltage division unit.
2. The dc power charging circuit of claim 1, wherein the first voltage dividing unit comprises a first voltage dividing resistor and a second voltage dividing resistor; the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series, a formed common end is connected with the control unit, the other end of the first voltage-dividing resistor is connected with a first end of the front-stage circuit, and the other end of the second voltage-dividing resistor is connected with a second end of the front-stage circuit.
3. The dc power charging circuit of claim 1, wherein the second voltage dividing unit comprises a third voltage dividing resistor and a fourth voltage dividing resistor; the third voltage dividing resistor and the fourth voltage dividing resistor are connected in series, a common end formed by the third voltage dividing resistor and the fourth voltage dividing resistor is connected with the control unit, the other end of the third voltage dividing resistor is connected with the first end of the energy storage unit, and the other end of the fourth voltage dividing resistor is connected with the second end of the energy storage unit.
4. The dc power charging circuit of claim 1, wherein the shunt unit is a shunt resistor.
5. The DC power charging circuit of claim 1, wherein the energy storage unit is a capacitor.
6. The DC power charging circuit of any one of claims 1 to 5, wherein the control unit is an operational amplifier, a first input terminal of the operational amplifier is connected to the first voltage dividing unit, a second input terminal of the operational amplifier is connected to the second voltage dividing unit, and an output terminal of the operational amplifier is connected to the switching unit.
7. The dc power charging circuit of claim 1, wherein the switching unit is a MOS transistor.
8. The dc power charging circuit of claim 1, further comprising a voltage regulator unit, the voltage regulator unit being coupled to the control terminal and the first terminal of the switching unit.
9. The DC power charging circuit of claim 8, wherein the voltage regulator unit comprises a voltage regulator diode and a voltage regulator resistor, a cathode of the voltage regulator diode is connected to the control terminal of the switch unit, and an anode of the voltage regulator diode is connected to the first terminal of the switch unit through the voltage regulator resistor.
10. A dc power supply comprising a front stage circuit, a rear stage circuit and a dc power supply charging circuit as claimed in any one of claims 1 to 9.
CN202022746418.0U 2020-11-24 2020-11-24 Direct current power supply and charging circuit thereof Active CN213637156U (en)

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Application Number Priority Date Filing Date Title
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