Over-voltage and under-voltage detection circuit, power supply circuit and charging device

Abstract

The embodiment of the utility model discloses an overvoltage and undervoltage detection circuit, a power supply circuit and a charging device, the power supply circuit is provided with a DC bus, the overvoltage and undervoltage detection circuit comprises a first circuit, a second circuit, a third circuit and a controller, and the input end of the first circuit is connected with the DC bus; the input end of the second circuit is connected with the output end of the first circuit, and the controlled end of the second circuit is connected with the direct-current bus; the input end of the third circuit is connected with the output end of the first circuit, the controlled end of the third circuit is connected with the output end of the first circuit, and the output end of the second circuit and the output end of the third circuit are connected to the same detection output end; the receiving end of the controller is connected with the detection output end and used for controlling the DC bus to be powered off according to the state detection signal output by the detection output end. By sharing the first circuit, the circuit design of the overvoltage and undervoltage detection circuit can be simplified, the cost of the overvoltage and undervoltage detection circuit is reduced, and the overall cost of the charging device is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging, in particular to an over-voltage and under-voltage detection circuit, a power supply circuit and a charging device. BACKGROUND

[0002] In the field of switching power supply design and application, in order to protect the power supply device and external device from being damaged by voltage fluctuation, an over-voltage and under-voltage detection circuit is often arranged at the output end of the power supply. When the voltage fluctuates and the fluctuation exceeds the normal working range of the power supply and external device, the over-voltage and under-voltage detection circuit can detect the abnormal state and execute the protection logic sequence, thereby protecting the power supply and external device from being damaged.

[0003] In the related technical field, the design of the over-voltage and under-voltage detection circuit is relatively complex, resulting in a high production cost of the over-voltage and under-voltage detection circuit. INVENTION CONTENTS

[0004] The embodiments of the present application provide an over-voltage and under-voltage detection circuit, a power supply circuit and a charging device, aiming to make the second circuit and the third circuit share the first circuit, and thus simplify the whole over-voltage and under-voltage detection circuit to reduce the cost of the over-voltage and under-voltage detection circuit.

[0005] The embodiments of the present application provide an over-voltage and under-voltage detection circuit, which is applicable to a charging device. The charging device comprises a power supply circuit having a direct current bus. The over-voltage and under-voltage detection circuit comprises a first circuit, a second circuit, a third circuit and a controller. The input end of the first circuit is used to be connected with the direct current bus. The input end of the second circuit is connected with the output end of the first circuit, and the controlled end of the second circuit is used to be connected with the direct current bus. The first circuit and the second circuit are used to detect the under-voltage state of the direct current bus. The input end of the third circuit is connected with the output end of the first circuit, the controlled end of the third circuit is connected with the output end of the first circuit, and the output end of the second circuit and the output end of the third circuit are connected to the same detection output end. The first circuit and the third circuit are used to detect the over-voltage state of the direct current bus. The receiving end of the controller is connected with the detection output end, and is used to control the power-off of the direct current bus according to the state detection signal output by the detection output end.

[0006] Based on the above embodiments, since the input ends of the second circuit and the third circuit are connected with the output end of the first circuit, and the first circuit and the second circuit can detect the under-voltage state of the direct current bus and the first circuit and the third circuit can detect the over-voltage state of the direct current bus, the over-voltage and under-voltage detection of the direct current bus can be realized. Compared with arranging two circuits respectively to realize the over-voltage and under-voltage state detection, the circuit design of the over-voltage and under-voltage detection circuit can be simplified by sharing the first circuit, the cost of the over-voltage and under-voltage detection circuit is reduced, and the overall cost of the charging device is reduced.

[0007] And, in the embodiment of the present application, the output end of the second circuit and the output end of the third circuit are connected to the same detection output end, when transmitting signals to the receiving end of the controller, the number of occupied pins of the controller can be saved, so as to reduce the cost of the controller, and further reduce the cost of the over-voltage and under-voltage detection circuit, and reduce the cost of the charging device.

[0008] Further, the output end of the second circuit and the output end of the third circuit are connected to the same detection output end, so that the controller does not need to distinguish the over-voltage state detection signal and the under-voltage state detection signal, the control program in the controller can be simplified, and the detection efficiency of the over-voltage and under-voltage detection circuit is improved.

[0009] The embodiment of the present application also provides a power supply circuit, which comprises a power supply, an output port, a direct current bus and an over-voltage and under-voltage detection circuit, the power supply is used for outputting direct current; the output port is used for connecting external equipment; the direct current bus is connected with the power supply and the output port; the over-voltage and under-voltage detection circuit is connected with the direct current bus; and a controller is connected with the power supply, and the controller is used for controlling the direct current bus to be powered off according to the state detection signal, so as to stop charging the power supply or stop the power supply from supplying power to the output port.

[0010] The embodiment of the present application also provides a charging device, which comprises a shell, a circuit board and a power supply circuit; the circuit board is arranged in the shell; and the power supply circuit is arranged on the circuit board.

[0011] Based on the over-voltage and under-voltage detection circuit of the present application, the input end of the second circuit and the input end of the third circuit are both connected with the output end of the first circuit, the first circuit and the second circuit can detect the under-voltage state of the direct current bus, and the first circuit and the third circuit can detect the over-voltage state of the direct current bus, so that the over-voltage and under-voltage detection of the direct current bus can be realized, compared with setting two circuits respectively to realize the over-voltage and under-voltage state detection, the circuit design of the over-voltage and under-voltage detection circuit can be simplified by sharing the first circuit, the cost of the over-voltage and under-voltage detection circuit is reduced, and the overall cost of the charging device is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0013] Figure 1 It is a structural schematic diagram of the charging device in one embodiment of the present application;

[0014] Figure 2 It is a frame structure schematic diagram of the power supply circuit in one embodiment of the present application;

[0015] Figure 3 A schematic diagram of a framework structure of a power supply circuit in another embodiment of the present application;

[0016] Figure 4 A schematic diagram of a framework structure of a power supply circuit in another embodiment of the present application;

[0017] Figure 5 A schematic diagram of a framework structure of a power supply circuit in another embodiment of the present application;

[0018] Figure 6 A schematic diagram of a framework structure of an over-voltage and under-voltage detection circuit in an embodiment of the present application;

[0019] Figure 7 A circuit diagram of an over-voltage and under-voltage detection circuit in an embodiment of the present application;

[0020] Figure 8 A circuit diagram of an over-voltage and under-voltage detection circuit in another embodiment of the present application.

[0021] BRIEF DESCRIPTION OF DRAWINGS 1, a charging device; 11, a housing; 12, a circuit board; 2, a power supply circuit; 21, a power supply; 211, a rectifier; 212, a battery; 22, an output port; 23, a DC bus; 231, a first bus; 232, a second bus; 233, a third bus; 3, an over-voltage and under-voltage detection circuit; 3A, a detection output terminal; 31, a first over-voltage and under-voltage detection circuit; 32, a second over-voltage and under-voltage detection circuit; 33, a third over-voltage and under-voltage detection circuit; 34, a first circuit; 35, a second circuit; 36, a third circuit; 37, a controller; 38, an isolation device; R1, a first resistor; R2, a second resistor; R3, a third resistor; R4, a fourth resistor; R5, a fifth resistor; D1, a first diode; D2, a second diode; D3, a third diode; C1, a first capacitor; Q1, a first switching element; Q2, a second switching element; ZD, a voltage stabilizing tube; U1, an optoelectronic coupler. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0023] Please refer to Figure 1 The embodiment of the present application provides a charging device 1, which comprises a housing 11, a circuit board 12 and a power supply circuit 2.

[0024] The shell 11 can support and protect the electronic components arranged in the shell 11. The shell 11 can be made of plastic or metal. Specifically, the shell 11 can be made of plastic, so that the shell 11 is insulated, thereby reducing the risk of electric shock for the user. In addition, the plastic material is light in weight, so that the shell 11 is light in weight, thereby reducing the overall weight of the charging device 1, facilitating the carrying and use of the charging device 1. Specifically, the shell 11 can be integrally injection molded, so that the shell 11 has high structural strength, thereby reducing the damage of the shell 11 and the other components in the shell 11, reducing the probability of damage of the other components, thereby prolonging the service life of the charging device 1.

[0025] The power supply circuit 2 can be formed on the circuit board 12 by an etching process, thereby improving the manufacturing efficiency of the power supply circuit 2 and reducing the manufacturing cost of the power supply circuit 2.

[0026] Please refer to Figure 2 In an embodiment, the power supply circuit 2 includes a power supply 21, an output port 22, and a DC bus 23. The power supply 21 is configured to output DC power. The output port 22 is configured to be connected to an external device. The output port 22 includes at least one of a USB-A interface, a Micro USB interface, a USB Type-C interface, or a Lightning interface. The external device includes, but is not limited to, a mobile phone, a tablet computer, and a smart watch. The DC bus 23 connects the output of the power supply 21 and the output port 22, so that the power supply 21 can supply power to the output port 22 through the DC bus 23, thereby enabling the output port 22 to supply power to the external device.

[0027] Further, in order to cut off the power output of the power supply 21 to the output port 22 when the DC bus 23 is in an under-voltage or over-voltage state, the power supply circuit 2 further includes an over-voltage and under-voltage detection circuit 3. The over-voltage and under-voltage detection circuit 3 is connected to the DC bus 23. When the over-voltage and under-voltage detection circuit 3 detects that the DC bus 23 is over-voltage or under-voltage, the over-voltage and under-voltage detection circuit 3 can control the DC bus 23 to be powered off, thereby protecting the power supply 21 and the external device, and reducing the probability of damage of the power supply 21 and the external device.

[0028] It can be understood that the voltage output by the power supply 21 has a preset voltage interval. When the voltage output by the power supply 21 is within the preset voltage interval, the DC bus 23 is in a normal state. When the output voltage of the power supply 21 is higher than the upper endpoint voltage of the preset voltage interval, the DC bus 23 is in an over-voltage state. When the output voltage of the power supply 21 is lower than the lower endpoint voltage of the preset voltage interval, the DC bus 23 is in an under-voltage state. It can be understood that the interval range of the preset voltage interval can be set according to the detection requirements of the over-voltage and under-voltage detection circuit 3. In the embodiments of the present application, no further limitation is made.

[0029] Please refer to Figure 3 Specifically, the power supply 21 can include a rectifier 211, the DC bus 23 is connected to the rectifier 211 and the output port 22, and the over-voltage and under-voltage detection circuit 3 is connected to the DC bus 23 and the rectifier 211. When the over-voltage and under-voltage detection circuit 3 detects over-voltage or under-voltage of the DC bus 23, the over-voltage and under-voltage detection circuit 3 controls the output end of the rectifier 211 to stop supplying power to the output port 22, thereby protecting the external device.

[0030] For example, the rectifier 211 can have a rectifier circuit (not shown in the figure), a filter circuit (not shown in the figure), and a voltage stabilizing circuit (not shown in the figure). The rectifier circuit is used to rectify alternating current into direct current, and the rectifier circuit includes but is not limited to a bridge rectifier circuit and a PWM (pulse width modulation) rectifier circuit. The filter circuit is used to filter the pulsating direct current output by the rectifier circuit, so that the waveform of the output direct current is smooth. The voltage stabilizing circuit is used to maintain the constant output voltage. In the embodiments of the present application, the specific form of the rectifier 211 is not limited.

[0031] Please refer to Figure 1 and Figure 4 It can be understood that the power supply 21 can include a battery 212, the DC bus 23 is connected to the output end of the battery 212 and the output port 22, and the over-voltage and under-voltage detection circuit 3 is connected to the DC bus 23 and the battery 212. When the over-voltage and under-voltage detection circuit 3 detects over-voltage of the DC bus 23, the over-voltage and under-voltage detection circuit 3 controls the output end of the battery 212 to stop supplying power to the output port 22, thereby protecting the external device; when the DC bus 23 is under-voltage, the output end of the battery 212 is controlled to stop supplying power to the output port 22 to prevent the battery 212 from over-discharging, thereby reducing the probability of damage to the battery 212, so that the battery 212 can have a longer service life, and thus the charging device 1 can have a longer service life.

[0032] Please refer to Figure 1 and Figure 5 It can be understood that the power supply 21 can include a rectifier 211 and a battery 212, the DC bus 23 includes a first bus 231, a second bus 232, and a third bus 233, and the power supply circuit 2 can include three over-voltage and under-voltage detection circuits 3, which are respectively a first over-voltage and under-voltage detection circuit 31, a second over-voltage and under-voltage detection circuit 32, and a third over-voltage and under-voltage detection circuit 33.

[0033] The first bus 231 connects the output of the rectifier 211 and the output port 22, the first over / under voltage detection circuit 31 is connected with the first bus 231, when the first over / under voltage detection circuit 31 detects over voltage or under voltage of the first bus 231, the first over / under voltage detection circuit 31 controls the output of the rectifier 211 to stop supplying power to the output port 22, thereby protecting the external device.

[0034] The second bus 232 connects the output of the rectifier 211 and the input of the battery 212, the second over / under voltage detection circuit 32 is connected with the second bus 232, when the second over / under voltage detection circuit 32 detects over voltage of the second bus 232, the second over / under voltage detection circuit 32 controls the output of the rectifier 211 to stop charging the battery 212, so as to prevent the battery 212 from overcharging, thereby reducing the probability of damage of the battery 212, so that the battery 212 can have a longer service life, and further the charging device 1 can have a longer service life.

[0035] The third bus 233 connects the output of the battery 212 and the output port 22, the third over / under voltage detection circuit 33 is connected with the third bus 233, when the over / under voltage detection circuit 3 detects over voltage of the DC bus 23, the over / under voltage detection circuit 3 controls the output of the battery 212 to stop supplying power to the output port 22, thereby protecting the external device; when the DC bus 23 is under voltage, the output of the battery 212 is controlled to stop supplying power to the output port 22, so as to prevent the battery 212 from over-discharging, thereby reducing the probability of damage of the battery 212, so that the battery 212 can have a longer service life, and further the charging device 1 can have a longer service life.

[0036] Please refer to Figure 1 , Figure 2 and Figure 6 In an embodiment, the over / under voltage detection circuit 3 comprises a first circuit 34, a second circuit 35, a third circuit 36 and a controller 37, the input of the first circuit 34 is used to be connected with the DC bus 23; the input of the second circuit 35 is connected with the output of the first circuit 34, the controlled end of the second circuit 35 is used to be connected with the DC bus 23; the first circuit 34 and the second circuit 35 are used to detect the under voltage state of the DC bus 23; the input of the third circuit 36 is connected with the output of the first circuit 34, the controlled end of the third circuit 36 is connected with the output of the first circuit 34, the output of the second circuit 35 and the output of the third circuit 36 are connected to the same detection output 3A; the first circuit 34 and the third circuit 36 are used to detect the over voltage state of the DC bus 23; the receiving end of the controller 37 is connected with the detection output 3A, and is used to control the DC bus 23 to be powered off according to the state detection signal output by the detection output 3A.

[0037] In the embodiment of the present application, since the input terminals of the second circuit 35 and the third circuit 36 are connected with the output terminal of the first circuit 34, and the first circuit 34 and the second circuit 35 can detect the under-voltage state of the DC bus 23, and the first circuit 34 and the third circuit 36 can detect the over-voltage state of the DC bus 23, thus the over-voltage and under-voltage detection of the DC bus 23 can be realized, compared with setting two circuits respectively to realize the over-voltage and under-voltage state detection, the present application can simplify the circuit design of the over-voltage and under-voltage detection circuit 3 as a whole, reduce the cost of the over-voltage and under-voltage detection circuit 3, so as to reduce the cost of the charging device 1 as a whole.

[0038] In addition, in the embodiment of the present application, the output terminal of the second circuit 35 and the output terminal of the third circuit 36 are connected to the same detection output terminal 3A, when transmitting signals with the receiving terminal of the controller 37, the number of pins of the controller 37 occupied can be saved, so as to reduce the cost of the controller 37, and further reduce the cost of the over-voltage and under-voltage detection circuit 3, so as to reduce the cost of the charging device 1.

[0039] Further, the output terminal of the second circuit 35 and the output terminal of the third circuit 36 are connected to the same detection output terminal 3A, so that the controller 37 does not need to distinguish the over-voltage state detection signal and the under-voltage state detection signal, the control program in the controller 37 can be simplified, so as to improve the detection efficiency of the over-voltage and under-voltage detection circuit 3.

[0040] Please refer to Figure 1 , Figure 2 and Figure 7 In an embodiment, the first circuit 34 comprises a first resistor R1, a second resistor R2, a first diode D1 and a first capacitor C1, the first terminal of the first resistor R1 is connected with the input terminal of the first circuit 34; the first terminal of the second resistor R2 is connected with the second terminal of the first resistor R1, and the second terminal of the second resistor R2 is grounded; the anode of the first diode D1 is connected with the second terminal of the first resistor R1; the first plate of the first capacitor C1 is connected with the cathode of the first diode D1, and the second plate of the first capacitor C1 is grounded.

[0041] The first resistor R1 and the second resistor R2 can be used to shunt and divide the voltage of the DC bus 23, so as to reduce the damage of the high voltage and high current of the DC bus 23 to the second circuit 35 and the third circuit 36, so that the second circuit 35 and the third circuit 36 can have a longer service life, and the overvoltage and undervoltage detection circuit 3 can have a longer service life, so that the charging device 1 can have a longer service life. It also ensures that the first detection circuit 34 and the second circuit 35, and the first detection circuit 34 and the third circuit 36 can output a state detection signal to the controller 37 when the DC bus 23 is in an overvoltage state or an undervoltage state, so that the controller 37 can power off the DC bus 23, thereby protecting the power supply 21 and external equipment.

[0042] The first capacitor C1 can filter the voltage entering the second circuit 35 and the third circuit 36, so as to reduce the probability of false triggering of the second circuit 35 and the third circuit 36, thereby improving the detection stability of the overvoltage and undervoltage detection circuit 3.

[0043] Please refer to Figure 1 , Figure 2 and Figure 7 , in an embodiment, the second circuit 35 includes a first switching element Q1, the input end of the first switching element Q1 is connected with the input end of the second circuit 35, the controlled end of the first switching element Q1 is connected with the controlled end of the second circuit 35, and the output end of the first switching element Q1 is connected with the output end of the second circuit 35.

[0044] When the voltage of the power supply 21 is within a preset voltage interval, the voltage of the DC bus 23 is in a normal state, and the voltage stored between the first plate and the second plate of the first capacitor C1 is V C1 , the output voltage of the DC bus 23 is VIN, the voltage drop between the first diode D1 is V D1 , V C1 =(R2 / (R1+R2)*VIN)-V D1 , V C1 is less than VIN, so that the voltage of the input end of the first switching element Q1 is less than the voltage of the controlled end of the first switching element Q1, at this time, the first switching element Q1 is in an off state, and the third circuit 36 is also in an off state, at this time, the receiving end of the controller 37 has no signal input.

[0045] When the voltage output by the power supply 21 gradually decreases to a voltage lower than the lower end point voltage of the preset voltage range, the DC bus 23 is in an under-voltage state, the voltage at the controlled end of the first switching element Q1 is lower than the voltage at the input end of the first switching element Q1, and the conduction condition of the first switching element Q1 is met, so that the input end and the output end of the first switching element Q1 are conductive, thereby enabling the voltage and current of the DC bus 23 to enter the detection output end 3A through the conductive first switching element Q1, and the receiving end of the controller 37 receives the state detection signal output by the detection output end 3A, so that the controller 37 can control the output end of the power supply 21 to stop outputting.

[0046] Since the first diode D1 is in a reverse blocking state, the electric energy stored in the first capacitor C1 can be kept stable, so that the voltage at the input end of the first switching element Q1 is kept stable, thereby ensuring that the voltage at the controlled end of the first switching element Q1 is lower than the voltage at the input end when the DC bus 23 is in an under-voltage state, and thereby enabling the input end and the output end of the first switching element Q1 to be conductive, so that the receiving end of the controller 37 can receive the state detection signal output by the detection output end 3A.

[0047] It can be understood that the first switching element Q1 can be at least one of a PNP type triode (Positive-Negative-Positive Bipolar Junction Transistor) and a PMOS tube (Positive Channel Metal-Oxide-Semiconductor Field-Effect Transistor, PMOSFET).

[0048] Please refer to Figure 1 , Figure 2 and Figure 7 In the embodiment of the present application, the first switching element Q1 is a first PNP type triode, the input end of the first switching element Q1 is the emitter E of the first PNP type triode, the output end of the first switching element Q1 is the collector C of the first PNP type triode, and the controlled end of the first switching element Q1 is the base B of the first PNP type triode. As the voltage of the DC bus 23 decreases, the voltage at the base B of the first PNP type triode decreases, and when the voltage at the base B of the first PNP type triode is lower than the voltage at the emitter E of the first PNP type triode and the conduction condition of the first PNP type triode is met, the emitter E and the collector C of the first PNP type triode are conductive, thereby enabling the voltage and current of the DC bus 23 to enter the detection output end 3A through the conductive first PNP type triode, so that the receiving end of the controller 37 receives the state detection signal output by the detection output end 3A.

[0049] In other embodiments, the first switch element Q1 can also be equivalently replaced by a PMOS tube, which will not be described in detail here.

[0050] Please refer to Figure 1 , Figure 2 and Figure 7 , further, the second circuit 35 further comprises a third resistor R3, the first end of the third resistor R3 is connected with the first end of the first resistor R1, the second end of the third resistor R3 is connected with the controlled end of the first switch element Q1, the third resistor R3 is used for current limiting of the current entering the controlled end of the first switch element Q1, so as to prevent large current from entering the controlled end of the first switch element Q1, reduce the probability of damage of the first switch element Q1, and further can make the first switch element Q1 have a longer service life, so as to ensure that the first circuit 34 and the second circuit 35 can detect the undervoltage state of the DC bus 23, and reduce the probability of damage of the power supply 21 and external equipment.

[0051] Please refer to Figure 1 and Figure 7 , in an embodiment, the second circuit 35 further comprises a second diode D2, the positive electrode of the second diode D2 is connected with the output end of the first switch element Q1, and the negative electrode of the second diode D2 is connected with the output end of the second circuit 35. When the third circuit 36 is turned on, the second diode D2 is used for reverse blocking, so as to prevent large current and large voltage from entering the output end of the first switch element Q1, so as to reduce the probability of damage of the first switch element Q1, so that the second circuit 35 can have a longer service life.

[0052] Please refer to Figure 1 , Figure 2 and Figure 7 , in an embodiment, the third circuit 36 comprises a fourth resistor R4, a Zener tube ZD and a second switch element Q2, the first end of the fourth resistor R4 is connected with the controlled end of the third circuit 36; the negative electrode of the Zener tube ZD is connected with the second end of the fourth resistor R4, and the positive electrode of the Zener tube ZD is grounded; the input end of the second switch element Q2 is connected with the input end of the third circuit 36, the output end of the second switch element Q2 is connected with the output end of the third circuit 36, and the controlled end of the second switch element Q2 is connected with the negative electrode of the Zener tube ZD.

[0053] When the voltage of the power supply 21 is in the preset voltage interval, the voltage of the DC bus 23 is in the normal state, the voltage stored between the first and second plates of the first capacitor C1 is V C1 , the output voltage of the DC bus 23 is VIN, the voltage drop between the two ends of the first diode D1 is V D1 , and V C1 =(R2 / (R1+R2)*VIN)-V D1at this time the voltage V stored in the first capacitor C1 C1 The voltage difference between the input end of the second switch element Q2 and the controlled end of the second switch element Q2 is equal to the voltage drop across the fourth resistor R4, so that the second switch element Q2 is in the off state, and the second circuit 35 is also in the off state, at this time the receiving end of the controller 37 has no signal input.

[0054] When the voltage output by the power supply 21 gradually rises, and the voltage of the DC bus 23 is higher than the upper end point voltage of the preset voltage interval, the DC bus 23 is in an overvoltage state, so that the voltage at the first end of the fourth resistor R4 gradually rises, so that the voltage at the second end of the fourth resistor R4 gradually rises, so that the voltage stabilizes at the breakdown voltage of the Zener diode ZD, at this time the voltage at the input end of the second switch element Q2 is higher than the voltage at the controlled end of the second switch element Q2, and the second switch element Q2 is in the on state, so that the input end and the output end of the second switch element Q2 are in the on state, so that the voltage and current of the DC bus 23 can enter the detection output end 3A through the on second switch element Q2, and the receiving end of the controller 37 receives the state detection signal of the detection output end 3A, and then the controller 37 controls the output end of the power supply 21 to stop outputting.

[0055] It can be understood that the second switch element Q2 can be at least one of a PNP type triode and a PMOS tube.

[0056] Please refer to Figure 1 , Figure 2 and Figure 7 In the embodiment of the present application, the second switch element Q2 is a second PNP type triode, the input end of the second switch element Q2 is the emitter E of the second PNP type triode, the output end of the second switch element Q2 is the collector C of the second PNP type triode, and the controlled end of the second switch element Q2 is the base B of the second PNP type triode. As the voltage of the DC bus 23 rises, the voltage at the base B of the second PNP type triode rises, and the voltage at the emitter E of the second PNP type triode stabilizes at the breakdown voltage of the Zener diode ZD, when the voltage at the base B of the second PNP type triode is less than the voltage at the emitter E of the second PNP type triode, and the second PNP type triode is in the on state, the emitter E and the collector C of the second PNP type triode are in the on state, so that the voltage and current of the DC bus 23 can enter the detection output end 3A through the on second PNP type triode, so that the receiving end of the controller 37 receives the state detection signal of the detection output end 3A.

[0057] In other embodiments, the second switch element Q2 can also be replaced by a PMOS tube, which will not be described in detail here.

[0058] It can be understood that the low-power charging device 1, for example, the 5V1A and 5V2A charging device 1, the first end of the fourth resistor R4 and the input end of the second switch element Q2 can be directly connected with the DC bus 23, and the overvoltage detection purpose can be achieved by using the third circuit 36 alone. In the embodiment of the present application, this will not be described in detail.

[0059] Please refer to Figure 6 In an embodiment, the third circuit 36 further includes a third diode D3, the positive electrode of the third diode D3 is connected with the output end of the second switch element Q2, and the negative electrode of the third diode D3 is connected with the output end of the third circuit 36. When the second circuit 35 is turned on, the third diode D3 can be used to prevent large current from entering the output end of the second switch element Q2, so as to reduce the probability of damage of the second switch element Q2, so that the third circuit 36 can have a longer service life.

[0060] Please refer to Figure 8 In an embodiment, the overvoltage and undervoltage detection circuit 3 further includes an isolation device 38, the input end of the isolation device 38 is connected with the detection output end 3A, and the output end of the isolation device 38 is connected with the receiving end of the controller. The isolation device 38 is used to realize the isolation between the DC bus 23 and the controller 37, so as to prevent large current and large voltage from directly entering the controller 37, reduce the probability of damage of the controller 37, so that the controller 37 can have a longer service life, and further so that the overvoltage and undervoltage detection circuit 3 can have a longer service life.

[0061] It can be understood that the isolation device 38 can include at least one of an optical coupling isolator, a magnetic coupling isolator, a capacitive isolator and a transformer isolator. In the embodiment of the present application, the specific form of the isolation device 38 is not limited.

[0062] Please refer to Figure 8 In an embodiment, the isolation device 38 can be an optical coupling isolator, and the optical coupling isolator includes a photoelectric coupler U1, the photoelectric coupler U1 includes a light-emitting element and a light-receiving element, the input end of the light-emitting element is connected with the input end of the isolation device 38, the output end of the light-emitting element is grounded, the input end of the light-receiving element is used to be connected with the DC bus 23 or used to be connected with a battery, in the embodiment of the present application, the power supply mode of the light-receiving element is not limited, and the output end of the light-receiving element is connected with the output end of the isolation device 38. When the second circuit 35 or the third circuit 36 is turned on, the detection output end 3A is turned on with the DC bus 23, so that the light-emitting element emits light, so that the light-receiving element is turned on, so that the controller 37 can receive a change signal corresponding to the state detection signal of the detection output end 3A.

[0063] The photoelectric coupler U1 is used to realize photoelectric isolation between the DC bus 23 and the controller 37, so as to prevent large current and large voltage from directly entering the controller 37, reduce the probability of damage of the controller 37, so that the controller 37 can have a longer service life, and thus the overvoltage and undervoltage detection circuit 3 can have a longer service life.

[0064] Please refer to Figure 2 and Figure 8 Further, in order to reduce the probability of damage of the light-emitting element, the overvoltage and undervoltage detection circuit 3 further comprises a fifth resistor R5, a first end of the fifth resistor R5 is connected with the detection output end 3A, and a second end of the fifth resistor R5 is connected with the input end of the light-emitting element, so as to reduce the probability of damage of the light-emitting element caused by large current and large voltage by current limiting and voltage dividing of the fifth resistor R5, so as to ensure that the state detection signal generated when the second circuit 35 or the third circuit 36 is turned on can be transmitted to the controller 37 through the photoelectric coupler U1, so as to improve the operation stability of the overvoltage and undervoltage detection circuit 3, and thus reliable protection can be provided for the power supply 21 and external equipment.

[0065] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components; in the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation of the present patent, any modification, equivalent replacement and improvement made within the spirit and principles of the present application should be included in the protection scope of the present application.

[0066] The above is only a preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement and improvement made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An over / under voltage detection circuit, characterized in that, Suitable for a charging device, the charging device including a power supply circuit having a DC bus, the over / under voltage detection circuit including: A first circuit, wherein the input terminal of the first circuit is used to connect to the DC bus; A second circuit is connected to the output of the first circuit, and the controlled terminal of the second circuit is connected to the DC bus; the first circuit and the second circuit are used to detect the undervoltage state of the DC bus. The third circuit has its input terminal connected to the output terminal of the first circuit, its controlled terminal connected to the output terminal of the first circuit, and its output terminal connected to the same detection output terminal as the output terminal of the second circuit. The first circuit and the third circuit are used to detect the overvoltage state of the DC bus. A controller, wherein the receiving end of the controller is connected to the detection output end, is used to control the DC bus to disconnect power according to the status detection signal output by the detection output end.

2. The over / under voltage detection circuit as described in claim 1, characterized in that, The second circuit includes a first switching element, and the third circuit includes a second switching element. When the bus voltage of the DC bus is outside the preset voltage range, the receiving end of the controller receives the status detection signal of the detection output end according to the conduction state of the first switching element or the second switching element. The controller is used to control the DC bus to disconnect from power according to the status detection signal, so as to stop charging the charging device or stop the charging device from supplying power to external devices.

3. The over / under voltage detection circuit as described in claim 1, characterized in that, The first circuit includes: A first resistor, the first end of which is connected to the input terminal of the first circuit; The second resistor has its first end connected to the second end of the first resistor, and its second end grounded. The first diode has its anode connected to the second terminal of the first resistor, and its cathode connected to the output terminal of the first circuit. The first capacitor has its first plate connected to the negative terminal of the first diode, and its second plate grounded.

4. The over / under voltage detection circuit as described in claim 3, characterized in that, The second circuit includes: A first switching element, the input terminal of which is connected to the input terminal of the second circuit, the controlled terminal of which is connected to the controlled terminal of the second circuit, and the output terminal of which is connected to the output terminal of the second circuit.

5. The over / under voltage detection circuit as described in claim 4, characterized in that, The second circuit also includes: The third resistor has its first end connected to the first end of the first resistor, and its second end connected to the controlled end of the first switching element.

6. The over / under voltage detection circuit as described in claim 4, characterized in that, The second circuit also includes: A second diode, the anode of which is connected to the output terminal of the first switching element, and the cathode of which is connected to the output terminal of the second circuit; and / or, The first switching element includes either a PNP transistor or a PMOS transistor.

7. The over / under voltage detection circuit as described in claim 3, characterized in that, The third circuit includes: A fourth resistor, the first end of which is connected to the controlled terminal of the third circuit; A Zener diode, the negative terminal of which is connected to the second terminal of the fourth resistor, and the positive terminal of which is grounded; The second switching element has its input terminal connected to the input terminal of the third circuit, its output terminal connected to the output terminal of the third circuit, and its controlled terminal connected to the negative terminal of the Zener diode.

8. The over / under voltage detection circuit as described in claim 7, characterized in that, The third circuit also includes: A third diode, wherein the anode of the third diode is connected to the output terminal of the second switching element, and the cathode of the third diode is connected to the output terminal of the third circuit; and / or, The second switching element includes either a PNP transistor or a PMOS transistor.

9. The over / under voltage detection circuit as described in any one of claims 1 to 8, characterized in that, Also includes: An isolation device is provided, wherein the input terminal of the isolation device is connected to the detection output terminal, and the output terminal of the isolation device is connected to the receiving terminal of the controller.

10. The over / under voltage detection circuit as described in claim 9, characterized in that, The isolation device includes: An optocoupler, comprising a light-emitting element and a photosensitive element, wherein the input terminal of the light-emitting element is connected to the input terminal of the isolation device, the output terminal of the light-emitting element is grounded, the input terminal of the photosensitive element is used to connect to the DC bus or to a battery, and the output terminal of the photosensitive element is connected to the receiving terminal of the controller.

11. The over / under voltage detection circuit as described in claim 10, characterized in that, The over / under voltage detection circuit also includes: The fifth resistor has its first end connected to the detection output terminal and its second end connected to the input terminal of the light-emitting element.

12. A power supply circuit, characterized in that, Suitable for charging devices, the power supply circuit includes: Power supply, used to output direct current; Output ports are used to connect external devices; A DC bus connects the power supply to the output port; The over / under voltage detection circuit as described in any one of claims 1 to 11 is connected to the DC bus, the controller is connected to the power supply, and the controller is used to control the DC bus to disconnect from the power supply according to the status detection signal, so as to stop charging the power supply or stop the power supply from supplying power to the output port.

13. The power supply circuit as described in claim 12, characterized in that, The power supply includes a rectifier, and the DC bus shown connects the output terminal of the rectifier to the output port. The controller is used to control the output terminal of the rectifier to stop supplying power to the output port according to the status detection signal; or... The power supply includes a battery, the DC bus connects the output terminal of the battery to the output port, and the controller is used to control the output terminal of the battery to stop supplying power to the output port according to the status detection signal; or... The power supply includes a rectifier and a battery. The DC bus connects the rectifier, the battery, and the output port. The controller is used to control the output of the rectifier to stop outputting and / or control the output of the battery to stop outputting based on the status detection signal.

14. A charging device, characterized in that, include: case; The circuit board is disposed within the housing; The power supply circuit as described in any one of claims 12 to 13 is disposed on the circuit board.

Images