Power supply circuit and power supply system

Abstract

The utility model discloses a power supply circuit and a power supply system, the power supply circuit comprises an input end, an overvoltage protection branch circuit, an undervoltage protection branch circuit, a first switch branch circuit, a second switch branch circuit and an output end, the overvoltage protection branch circuit comprises a first controllable voltage stabilization source, and the undervoltage protection branch circuit comprises a second controllable voltage stabilization source. When the voltage of the input power supply is larger than the first voltage threshold value, the first controllable voltage-stabilizing source is switched on, and when the voltage of the input power supply is smaller than or equal to the first voltage threshold value, the first controllable voltage-stabilizing source is switched off. And when the first controllable voltage-stabilizing source is switched off, the second controllable voltage-stabilizing source, the first switch branch and the second switch branch are switched on in response to the fact that the voltage of the input power supply is larger than a second voltage threshold value, or the second controllable voltage-stabilizing source, the first switch branch and the second switch branch are switched off in response to the fact that the voltage of the input power supply is smaller than or equal to the second voltage threshold value. In this way, the precision of overvoltage protection and under-voltage protection can be improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of electronic circuit, in particular to a power supply circuit and a power supply system. BACKGROUND

[0002] In a power supply system (such as a photovoltaic charging system), overvoltage protection and undervoltage protection are key technologies to ensure the safe and stable operation of the system. At present, the common overvoltage protection and undervoltage protection usually adopts a voltage comparator and a relay to realize. However, for the above-mentioned scheme, it is easy to cause misoperation or protection failure due to voltage fluctuation, and the precision is poor. CONTENT OF THE UTILITY MODEL

[0003] Embodiments of the present application provide a power supply circuit and a power supply system, which can improve the precision of overvoltage protection and undervoltage protection.

[0004] In a first aspect, embodiments of this application provide a power supply circuit, including: an input terminal, an overvoltage protection branch, an undervoltage protection branch, a first switch branch, a second switch branch, and an output terminal. The overvoltage protection branch includes a first controllable voltage regulator, and the undervoltage protection branch includes a second controllable voltage regulator. The input terminal is configured to be connected to an input power supply. The output terminal is configured to be connected to a load to provide output power to the load. The overvoltage protection branch is connected to both the input terminal and a reference terminal of the second controllable voltage regulator. The overvoltage protection branch is configured to: in response to a voltage greater than a first voltage threshold, turn on the first controllable voltage regulator to pull the level of the reference terminal of the second controllable voltage regulator low; or, in response to a voltage less than or equal to the first voltage threshold, turn off the first controllable voltage regulator. The undervoltage protection branch is connected to the input terminal and is configured to: when the first controllable voltage regulator is turned off, respond to a voltage difference in the input power supply... When the voltage of the input power supply is greater than the second voltage threshold, the second controllable voltage source is turned on; or, in response to the voltage of the input power supply being less than or equal to the second voltage threshold, the second controllable voltage source is turned off, wherein the second voltage threshold is less than the first voltage threshold; the first switching branch is connected to the undervoltage protection branch and the second switching branch respectively, and the first switching branch is configured to: in response to the second controllable voltage source being turned on, the first switching branch is turned on to output a first level to the second switching branch, or, in response to the second controllable voltage source being turned off, the first switching branch is turned off to stop outputting the first level; the second switching branch is connected between the input terminal and the output terminal, and the second switching branch is configured to: in response to receiving the first level, the second switching branch is turned on to establish a connection between the input terminal and the output terminal, or, in response to not receiving the first level, the second switching branch is turned off to disconnect the connection between the input terminal and the output terminal.

[0005] In one or more embodiments, the overvoltage protection branch further includes a first voltage divider unit, which is connected to the input terminal and the first controllable voltage regulator respectively; the overvoltage protection branch is configured such that: the first voltage divider unit divides the voltage of the input power supply and outputs a first voltage to the first controllable voltage regulator; in response to the first voltage being greater than a third voltage threshold, the first controllable voltage regulator is turned on, or in response to the first voltage being less than or equal to the third voltage threshold, the first controllable voltage regulator is turned off, wherein when the input power supply is greater than the first voltage threshold, the first voltage is greater than the third voltage threshold.

[0006] In one or more embodiments, the first voltage divider unit includes a first resistor and a second resistor; the first resistor and the second resistor are connected in series between the input terminal and ground, the connection point between the first resistor and the second resistor is connected to the reference terminal of the first controllable voltage regulator, the anode of the first controllable voltage regulator is grounded, and the cathode of the first controllable voltage regulator is connected to the reference terminal of the second controllable voltage regulator.

[0007] In one or more embodiments, the undervoltage protection branch further includes a second voltage divider unit, which is connected to the input terminal and the second controllable voltage regulator respectively; the undervoltage protection branch is configured such that: the second voltage divider unit divides the voltage of the input power supply and outputs a second voltage to the second controllable voltage regulator; when the first controllable voltage regulator is turned off, in response to the second voltage being greater than a fourth voltage threshold, the second controllable voltage regulator is turned on, or in response to the second voltage being less than or equal to the fourth voltage threshold, the second controllable voltage regulator is turned off, wherein when the input power supply is greater than the second voltage threshold, the second voltage is greater than the fourth voltage threshold.

[0008] In one or more embodiments, the second voltage divider unit includes a third resistor and a fourth resistor; the third resistor and the fourth resistor are connected in series between the input terminal and ground, and the connection point between the third resistor and the fourth resistor is connected to the reference terminal of the second controllable voltage regulator.

[0009] In one or more embodiments, the first switching branch includes a first switching unit and a second switching unit, the first switching unit being connected to the input power supply, the undervoltage protection branch, and the second switching unit, respectively, and the second switching unit being connected to the second switching branch; the first switching branch is configured to: in response to the second controllable voltage source being turned on, the first switching unit is turned on to establish a connection between the input power supply and the second switching unit, and the second switching unit is turned on to output a first level to the second switching branch; or, in response to the second controllable voltage source being turned off, the first switching unit is turned off to disconnect the connection between the input power supply and the second switching unit, and the second switching unit is turned off to stop outputting the first level.

[0010] In one or more embodiments, the first switching unit includes a fifth resistor, a sixth resistor, a first diode, and a first switching transistor; the fifth resistor is connected between the input terminal and the cathode of the second controllable voltage regulator, the cathode of the first diode is connected to the cathode of the second controllable voltage regulator, the anode of the first diode is connected to the first terminal of the first switching transistor through the sixth resistor, the second terminal of the first switching transistor is connected to the input terminal, and the third terminal of the first switching transistor is connected to the second switching unit.

[0011] In one or more embodiments, the second switching unit includes a seventh resistor, an eighth resistor, and a second switching transistor; the seventh resistor and the eighth resistor are connected in series between the first switching unit and ground, the connection point between the seventh resistor and the eighth resistor is connected to the first end of the second switching transistor, the second end of the second switching transistor is grounded, and the third end of the second switching transistor is connected to the second switching branch.

[0012] In one or more embodiments, the second switching branch includes a ninth resistor, a tenth resistor, a first Zener diode, and a third switching transistor; the ninth resistor and the tenth resistor are connected in series between the first switching branch and the input terminal; the connection point between the ninth resistor and the tenth resistor is connected to the first terminal of the third switching transistor; the anode of the first Zener diode is connected to the first terminal of the third switching transistor; the cathode of the first Zener diode is connected to the second terminal of the third switching transistor; and the third terminal of the third switching transistor is connected to the output terminal.

[0013] Secondly, embodiments of this application provide a power supply system, including a load and a power supply circuit as described above.

[0014] The beneficial effects of this application are as follows: The power supply circuit of this application embodiment includes an input terminal, an overvoltage protection branch, an undervoltage protection branch, a first switch branch, a second switch branch, and an output terminal. The overvoltage protection branch includes a first controllable voltage regulator, and the undervoltage protection branch includes a second controllable voltage regulator. When the voltage of the input power supply is greater than a first voltage threshold, an overvoltage occurs. The first controllable voltage regulator is turned on to pull the level of the reference terminal of the second controllable voltage regulator down to a low level. The second controllable voltage regulator is turned off, the first switch branch is turned off to stop outputting the first level, and the second switch branch is turned off to disconnect the connection between the input terminal and the output terminal, thereby achieving the overvoltage protection function. When the voltage of the input power supply is less than a second voltage threshold, an undervoltage occurs. Simultaneously, the voltage of the input power supply is necessarily less than the first voltage threshold. The first controllable voltage regulator is turned off, the second controllable voltage regulator is turned off, the first switch branch is turned off to stop outputting the first level, and the second switch branch is turned off to disconnect the connection between the input terminal and the output terminal, thereby achieving the undervoltage protection function. In summary, overvoltage protection and undervoltage protection functions are achieved. Furthermore, a first controllable voltage regulator and a second controllable voltage regulator are used to achieve this. Compared with the schemes using voltage comparators and relays in related technologies, the accuracy of this application is higher, thus achieving the effect of improving the accuracy of overvoltage protection and undervoltage protection. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0016] Figure 1 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 1 ;

[0017] Figure 2 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 2 ;

[0018] Figure 3 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 3 ;

[0019] Figure 4 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 4 ;

[0020] Figure 5 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 5 . Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0022] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0023] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0024] Please refer to Figure 1 , Figure 1 Schematic diagram of the power supply circuit provided in the embodiments of this application Figure 1 .like Figure 1 As shown, the power supply circuit 100 includes an input terminal VIN, an overvoltage protection branch 10, an undervoltage protection branch 20, a first switch branch 30, a second switch branch 40, and an output terminal VOUT. The overvoltage protection branch 10 includes a first controllable voltage regulator U1, and the undervoltage protection branch 20 includes a second controllable voltage regulator U2.

[0025] The input terminal VIN is configured to be connected to the input power supply 200. The output terminal VOUT is configured to be connected to the load 300 to provide output power to the load 300. The overvoltage protection branch 10 is connected to both the input terminal VIN and the reference terminal of the second controllable voltage regulator U2. The undervoltage protection branch 20 is connected to the input terminal VIN. The first switching branch 30 is connected to both the undervoltage protection branch 20 and the second switching branch 40. The second switching branch 40 is connected between the input terminal VIN and the output terminal VOUT.

[0026] The overvoltage protection branch 10 is configured such that, in response to the voltage of the input power supply 200 being greater than a first voltage threshold, the first controllable voltage source U1 is turned on to pull the level of the reference terminal of the second controllable voltage source U2 low; or, in response to the voltage of the input power supply 200 being less than or equal to the first voltage threshold, the first controllable voltage source U1 is turned off. The undervoltage protection branch 20 is configured such that, when the first controllable voltage source U1 is turned off, in response to the voltage of the input power supply 200 being greater than a second voltage threshold, the second controllable voltage source U2 is turned on; or, in response to the voltage of the input power supply 200 being less than or equal to the second voltage threshold, the second controllable voltage source U2 is turned off, wherein the second voltage threshold is less than the first voltage threshold. The first switch branch 30 is configured to: in response to the second controllable voltage source U2 being turned on, the first switch branch 30 is turned on to output a first level to the second switch branch 40; or, in response to the second controllable voltage source U2 being turned off, the first switch branch 30 is turned off to stop outputting the first level. The second switch branch 40 is configured to: in response to receiving the first level, the second switch branch 40 is turned on to establish a connection between the input terminal VIN and the output terminal VOUT; or, in response to not receiving the first level, the second switch branch 40 is turned off to disconnect the connection between the input terminal VIN and the output terminal VOUT.

[0027] In practical applications, if the voltage of the input power supply 200 is greater than the first voltage threshold, an overvoltage occurs. The first controllable voltage regulator U1 is turned on to pull the level of the reference terminal of the second controllable voltage regulator U2 down to a low level. The second controllable voltage regulator U2 is turned off, the first switch branch 30 is turned off to stop the output of the first level, and the second switch branch 40 is turned off to disconnect the connection between the input terminal VIN and the output terminal VOUT, thereby achieving the overvoltage protection function.

[0028] If the voltage of the input power supply 200 is less than the second voltage threshold, an undervoltage condition occurs. Simultaneously, since the second voltage threshold is less than the first voltage threshold, the voltage of the input power supply 200 must also be less than the first voltage threshold. The first controllable voltage regulator U1 is turned off, the second controllable voltage regulator U2 is turned off, and the first switch branch 30 is turned off to stop the output of the first level. The second switch branch 40 is turned off to disconnect the connection between the input terminal VIN and the output terminal VOUT, thus achieving the undervoltage protection function.

[0029] In summary, overvoltage and undervoltage protection functions are achieved, and this is accomplished by employing a first controllable voltage regulator U1 and a second controllable voltage regulator U2. Compared to related technologies that use voltage comparators and relays, this application achieves higher accuracy, thus improving the precision of overvoltage and undervoltage protection. Furthermore, the use of the first controllable voltage regulator U1 and the second controllable voltage regulator U2 also provides a faster response speed.

[0030] Furthermore, if the voltage of the input power supply 200 is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, then no overvoltage or undervoltage occurs. The first controllable voltage regulator U1 is turned off, the second controllable voltage regulator U2 is turned on, the first switching branch 30 is turned on to output the first level to the second switching branch 40, and the second switching branch 40 is turned on to establish the connection between the input terminal VIN and the output terminal VOUT, so that the input power supply 200 can normally supply power to the load 300.

[0031] It is understood that the first voltage threshold and the second voltage threshold can be set according to the actual application scenario, and this application embodiment does not impose specific restrictions on this. It is sufficient that an overvoltage occurs when the voltage of the input power supply 200 is greater than the first voltage threshold, and an undervoltage occurs when the voltage of the input power supply 200 is less than the second voltage threshold.

[0032] In some embodiments, such as Figure 2 As shown, the overvoltage protection branch 10 also includes a first voltage divider unit 11, which is connected to the input terminal VIN and the first controllable voltage regulator U1 respectively.

[0033] The overvoltage protection branch 10 is configured such that: the first voltage divider unit 11 divides the voltage of the input power supply 200 and outputs a first voltage to the reference terminal of the first controllable voltage regulator U1; in response to the first voltage being greater than a third voltage threshold, the first controllable voltage regulator U1 is turned on, or in response to the first voltage being less than or equal to the third voltage threshold, the first controllable voltage regulator U1 is turned off, wherein when the input power supply 200 is greater than the first voltage threshold, the first voltage is greater than the third voltage threshold.

[0034] In this embodiment, by setting the first voltage divider unit 11, the voltage input to the reference terminal of the first controllable voltage regulator U1 is reduced, which helps to reduce the risk of the first controllable voltage regulator U1 being damaged.

[0035] In some embodiments, the first controllable voltage regulator U1 is configured as a controllable precision voltage regulator of model TL431, and the third voltage threshold can be set to 2.5V. When the first voltage is greater than 2.5V, the first controllable voltage regulator U1 is driven to conduct, that is, the anode and cathode of the first controllable voltage regulator U1 are connected; when the first voltage is less than or equal to 2.5V, the first controllable voltage regulator U1 remains off, that is, the anode and cathode of the first controllable voltage regulator U1 remain disconnected.

[0036] In some embodiments, such as Figure 3 As shown, the undervoltage protection branch 20 also includes a second voltage divider unit 21, which is connected to the input terminal VIN and the second controllable voltage regulator U2 respectively.

[0037] The undervoltage protection branch 20 is configured such that: the second voltage divider unit 21 divides the voltage of the input power supply 200 and outputs a second voltage to the second controllable voltage regulator U2; when the first controllable voltage regulator U1 is turned off, the second controllable voltage regulator U2 is turned on in response to the second voltage being greater than the fourth voltage threshold, or the second controllable voltage regulator U2 is turned off in response to the second voltage being less than or equal to the fourth voltage threshold, wherein when the input power supply 200 is greater than the second voltage threshold, the second voltage is greater than the fourth voltage threshold.

[0038] In this embodiment, by setting the second voltage divider unit 21, the voltage input to the reference terminal of the second controllable voltage regulator U2 is reduced, which helps to reduce the risk of damage to the second controllable voltage regulator U2.

[0039] In some embodiments, the second controllable voltage regulator U2 is configured as a controllable precision voltage regulator of model TL431, and the fourth voltage threshold can be set to 2.5V. When the second voltage is greater than 2.5V, the second controllable voltage regulator U2 is driven to conduct, that is, the anode and cathode of the second controllable voltage regulator U2 are connected; when the second voltage is less than or equal to 2.5V, the second controllable voltage regulator U2 remains off, that is, the anode and cathode of the second controllable voltage regulator U2 remain disconnected.

[0040] In some embodiments, such as Figure 4 As shown, the first switch branch 30 includes a first switch unit 31 and a second switch unit 32. The first switch unit 31 is connected to the input power supply 200, the undervoltage protection branch 20 and the second switch unit 32 respectively. The second switch unit 32 is connected to the second switch branch 40.

[0041] The first switching branch 30 is configured to: in response to the second controllable voltage source U2 being turned on, the first switching unit 31 is turned on to establish a connection between the input power supply 200 and the second switching unit 32, and the second switching unit 32 is turned on to output a first level to the second switching branch 40; or, in response to the second controllable voltage source U2 being turned off, the first switching unit 31 is turned off to disconnect the connection between the input power supply 200 and the second switching unit 32, and the second switching unit 32 is turned off to stop outputting the first level.

[0042] Specifically, if the voltage of the input power supply 200 is greater than the first voltage threshold, an overvoltage occurs. The first controllable voltage regulator U1 is turned on to pull the level of the reference terminal of the second controllable voltage regulator U2 down to a low level. The second controllable voltage regulator U2 is turned off, the first switching unit 31 is turned off, the second switching unit 32 is turned off to stop the output of the first level, and the second switching branch 40 is turned off to disconnect the connection between the input terminal VIN and the output terminal VOUT, thereby achieving the overvoltage protection function.

[0043] If the voltage of the input power supply 200 is less than the second voltage threshold, an undervoltage condition occurs. Simultaneously, since the second voltage threshold is less than the first voltage threshold, the voltage of the input power supply 200 must also be less than the first voltage threshold. The first controllable voltage regulator U1 is turned off, the second controllable voltage regulator U2 is turned off, the first switching unit 31 is turned off, and the second switching unit 32 is turned off to stop the output of the first voltage level. The second switching branch 40 is turned off to disconnect the connection between the input terminal VIN and the output terminal VOUT, thus achieving the undervoltage protection function.

[0044] If the voltage of the input power supply 200 is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, then no overvoltage or undervoltage has occurred. The first controllable voltage regulator U1 is turned off, the second controllable voltage regulator U2 is turned on, the first switching unit 31 and the second switching unit 32 are turned on, so as to output the first level to the second switching branch 40. The second switching branch 40 is turned on to establish the connection between the input terminal VIN and the output terminal VOUT, so that the input power supply 200 can normally supply power to the load 300.

[0045] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the circuit structure of the power supply circuit provided in an embodiment of this application. Figure 5 As shown, the first voltage divider unit 11 includes a first resistor R1 and a second resistor R2.

[0046] In this configuration, the first resistor R1 and the second resistor R2 are connected in series between the input terminal VIN and ground GND. The connection point between the first resistor R1 and the second resistor R2 (i.e., the first connection point N1) is connected to the reference terminal of the first controllable voltage source U1. The anode of the first controllable voltage source U1 is grounded to GND. The cathode of the first controllable voltage source U1 is connected to the reference terminal of the second controllable voltage source U2 and is connected to the second connection point N2.

[0047] In some embodiments, the second voltage divider unit 21 includes a third resistor R3 and a fourth resistor R4.

[0048] Among them, the third resistor R3 and the fourth resistor R4 are connected in series between the input terminal VIN and ground GND, and the connection point between the third resistor R3 and the fourth resistor R4 (i.e. the second connection point N2) is connected to the reference terminal of the second controllable voltage regulator U2.

[0049] In some embodiments, the first switching unit 31 includes a fifth resistor R5, a sixth resistor R6, a first diode D1, and a first switching transistor Q1.

[0050] The fifth resistor R5 is connected between the input terminal VIN and the cathode of the second controllable voltage regulator U2. The cathode of the first diode D1 is connected to the cathode of the second controllable voltage regulator U2. The anode of the first diode D1 is connected to the first terminal of the first switch Q1 through the sixth resistor R6. The second terminal of the first switch Q1 is connected to the input terminal VIN. The third terminal of the first switch Q1 is connected to the second switch unit 32.

[0051] In this embodiment, the first switching transistor Q1 is a PNP transistor. The base of the PNP transistor is the first terminal of the first switching transistor Q1, the emitter of the PNP transistor is the second terminal of the first switching transistor Q1, and the collector of the PNP transistor is the third terminal of the first switching transistor Q1.

[0052] In addition, the first switch Q1 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0053] In some embodiments, the second switching unit 32 includes a seventh resistor R7, an eighth resistor R8, and a second switching transistor Q2.

[0054] In this circuit, the seventh resistor R7 and the eighth resistor R8 are connected in series between the first switching unit 31 and ground GND. The connection point between the seventh resistor R7 and the eighth resistor R8 (i.e., the third connection point N3) is connected to the first terminal of the second switching transistor Q2. The second terminal of the second switching transistor Q2 is grounded to GND, and the third terminal of the second switching transistor Q2 is connected to the second switching branch 40. The seventh resistor R7 and the eighth resistor R8 are used for voltage division.

[0055] In this embodiment, the second switch Q2 is an NPN transistor. The base of the NPN transistor is the first terminal of the second switch Q2, the emitter of the NPN transistor is the second terminal of the second switch Q2, and the collector of the NPN transistor is the third terminal of the second switch Q2.

[0056] In addition, the second switch Q2 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0057] In some embodiments, the second switching branch 40 includes a ninth resistor R9, a tenth resistor R10, a first Zener diode Z1, and a third switching transistor Q3.

[0058] In this circuit, the ninth resistor R9 and the tenth resistor R10 are connected in series between the first switch branch 30 and the input terminal VIN. The connection point between the ninth resistor R9 and the tenth resistor R10 is connected to the first terminal of the third switch Q3. The anode of the first Zener diode Z1 is connected to the first terminal of the third switch Q3, and the cathode of the first Zener diode Z1 is connected to the second terminal of the third switch Q3. The third terminal of the third switch Q3 is connected to the output terminal VOUT. The ninth resistor R9 and the tenth resistor R10 are used for voltage division, and the first Zener diode Z1 is used to prevent the voltage between the first and second terminals of the third switch Q3 from becoming too high and damaging the third switch Q3.

[0059] In this embodiment, the third switch Q3 is a PMOS transistor. The gate of the PMOS transistor is the first terminal of the third switch Q3, the source of the PMOS transistor is the second terminal of the third switch Q3, and the drain of the PMOS transistor is the third terminal of the third switch Q3.

[0060] In addition, the third switch Q3 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0061] The following are Figure 5 The principle of the circuit structure shown will be explained.

[0062] If the voltage of the input power supply 200 is greater than the first voltage threshold, then the first voltage at the first connection point N1 will be greater than the third voltage threshold, resulting in an overvoltage. In this case, the first controllable voltage regulator U1 is turned on, and the reference terminal of the second controllable voltage regulator U2 is grounded to GND through the first controllable voltage regulator U1, which pulls the level of the reference terminal of the second controllable voltage regulator U2 low, and the second controllable voltage regulator U2 is turned off. The first switch Q1 is turned off, and the voltage at the third connection point N3 is zero, which stops the output of the first level to the second switch Q2, and the second switch Q2 is turned off. The third switch Q3 is also turned off, and the input terminal VIN and the output terminal VOUT are also disconnected, thus achieving the overvoltage protection function.

[0063] If the voltage of the input power supply 200 is less than the second voltage threshold, then the second voltage at the second connection point P2 is less than the fourth voltage threshold, resulting in undervoltage. Simultaneously, since the second voltage threshold is less than the first voltage threshold, the voltage of the input power supply 200 must be less than the first voltage threshold, meaning the first voltage at the first connection point P1 is less than the third voltage threshold. Both the first controllable voltage regulator U1 and the second controllable voltage regulator U2 are turned off. The first switch Q1 is turned off, and the voltage at the third connection point N3 is zero, corresponding to the cessation of the output of the first level (in this embodiment, the first level is high, meaning the level at the first terminal of the second switch Q2 is low, so the first terminal of the second switch Q2 does not receive a high level) to the second switch Q2, which is then turned off. The third switch Q3 is also turned off, and the input terminal VIN and the output terminal VOUT are also disconnected, thus achieving the undervoltage protection function.

[0064] In summary, overvoltage and undervoltage protection functions are achieved, and this is accomplished by employing a first controllable voltage regulator U1 and a second controllable voltage regulator U2. Compared to related technologies that use voltage comparators and relays, this application achieves higher accuracy, thus improving the precision of overvoltage and undervoltage protection. Furthermore, the use of the first controllable voltage regulator U1 and the second controllable voltage regulator U2 also provides a faster response speed.

[0065] Furthermore, if the voltage of the input power supply 200 is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, then no overvoltage or undervoltage occurs. On one hand, if the first voltage is less than or equal to the third voltage threshold, the first controllable voltage regulator U1 is turned off; on the other hand, if the second voltage is greater than or equal to the fourth voltage threshold, the second controllable voltage regulator U2 is turned on. Subsequently, the first switch Q1 is turned on, the seventh resistor R7 and the eighth resistor R8 divide the voltage of the input power supply 200, and the voltage at the third connection point N3 is input to the second switch Q2, which corresponds to the output of the first level to the second switch Q2, and the second switch Q2 is turned on. The tenth resistor R10 and the ninth resistor R9 divide the voltage of the input power supply 200 and drive the third switch Q3 to turn on, and the connection between the input terminal VIN and the output terminal VOUT is established, so that the input power supply 200 can normally supply power to the load 300.

[0066] This application also provides a power supply system. The power supply system includes a load and a power supply circuit 100 as described in any embodiment of this application.

[0067] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0068] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A power supply circuit, characterized by comprising: The application relates to a voltage protection circuit, comprising: an input terminal, an overvoltage protection branch, an undervoltage protection branch, a first switch branch, a second switch branch and an output terminal, wherein the overvoltage protection branch comprises a first controllable voltage source, and the undervoltage protection branch comprises a second controllable voltage source; the input terminal is configured to be connected with an input power supply; the output terminal is configured to be connected with a load to provide an output power supply for the load; the overvoltage protection branch is connected with the input terminal and the reference terminal of the second controllable voltage source respectively, and the overvoltage protection branch is configured to: in response to the voltage of the input power supply being greater than a first voltage threshold, the first controllable voltage source is turned on to pull the voltage level of the reference terminal of the second controllable voltage source to a low level, or in response to the voltage of the input power supply being less than or equal to the first voltage threshold, the first controllable voltage source is turned off; the undervoltage protection branch is connected with the input terminal, and the undervoltage protection branch is configured to: when the first controllable voltage source is turned off, in response to the voltage of the input power supply being greater than a second voltage threshold, the second controllable voltage source is turned on, or in response to the voltage of the input power supply being less than or equal to the second voltage threshold, the second controllable voltage source is turned off, wherein the second voltage threshold is less than the first voltage threshold; the first switch branch is connected with the undervoltage protection branch and the second switch branch respectively, and the first switch branch is configured to: in response to the second controllable voltage source being turned on, the first switch branch is turned on to output a first voltage level to the second switch branch, or in response to the second controllable voltage source being turned off, the first switch branch is turned off to stop outputting the first voltage level; the second switch branch is connected between the input terminal and the output terminal, and the second switch branch is configured to: in response to receiving the first voltage level, the second switch branch is turned on to establish a connection between the input terminal and the output terminal, or in response to not receiving the first voltage level, the second switch branch is turned off to disconnect the connection between the input terminal and the output terminal.

2. The power supply circuit according to claim 1, characterized in that, The overvoltage protection branch further comprises a first voltage dividing unit, and the first voltage dividing unit is connected with the input terminal and the first controllable voltage source respectively; the overvoltage protection branch is configured to: the first voltage dividing unit divides the voltage of the input power supply and outputs a first voltage to the first controllable voltage source; in response to the first voltage being greater than a third voltage threshold, the first controllable voltage source is turned on, or in response to the first voltage being less than or equal to the third voltage threshold, the first controllable voltage source is turned off, wherein when the input power supply is greater than the first voltage threshold, the first voltage is greater than the third voltage threshold.

3. The power supply circuit of claim 2, wherein, The first voltage dividing unit comprises a first resistor and a second resistor; the first resistor and the second resistor are connected in series between the input terminal and the ground, a connection point between the first resistor and the second resistor is connected with the reference terminal of the first controllable voltage source, the anode of the first controllable voltage source is grounded, and the cathode of the first controllable voltage source is connected with the reference terminal of the second controllable voltage source.

4. The power supply circuit of claim 1, wherein, The under-voltage protection branch further comprises a second voltage dividing unit connected with the input end and the second controllable voltage source respectively; The under-voltage protection branch is configured to: The second voltage dividing unit divides the voltage of the input power supply and outputs a second voltage to the second controllable voltage source; When the first controllable voltage source is turned off, the second controllable voltage source is turned on in response to the second voltage being greater than a fourth voltage threshold, or the second controllable voltage source is turned off in response to the second voltage being less than or equal to the fourth voltage threshold, wherein the second voltage is greater than the fourth voltage threshold when the input power supply is greater than a second voltage threshold.

5. The power supply circuit of claim 4, wherein, The second voltage dividing unit comprises a third resistor and a fourth resistor; The third resistor and the fourth resistor are connected in series between the input end and the ground, and a connection point between the third resistor and the fourth resistor is connected with a reference end of the second controllable voltage source.

6. The power supply circuit of claim 1, wherein, The first switch branch comprises a first switch unit and a second switch unit, the first switch unit is connected with the input power supply, the under-voltage protection branch and the second switch unit respectively, and the second switch unit is connected with the second switch branch; The first switch branch is configured to: in response to the second controllable voltage source being turned on, the first switch unit is turned on to establish a connection between the input power supply and the second switch unit, and the second switch unit is turned on to output a first voltage level to the second switch branch, or in response to the second controllable voltage source being turned off, the first switch unit is turned off to disconnect the connection between the input power supply and the second switch unit, and the second switch unit is turned off to stop outputting the first voltage level.

7. The power supply circuit of claim 6, wherein, The first switch unit comprises a fifth resistor, a sixth resistor, a first diode and a first switch tube; The fifth resistor is connected between the input end and the cathode of the second controllable voltage source, the cathode of the first diode is connected with the cathode of the second controllable voltage source, the anode of the first diode is connected with the first end of the first switch tube through the sixth resistor, the second end of the first switch tube is connected with the input end, and the third end of the first switch tube is connected with the second switch unit.

8. The power supply circuit of claim 6, wherein, The second switch unit comprises a seventh resistor, an eighth resistor and a second switch tube; The seventh resistor and the eighth resistor are connected in series between the first switch unit and the ground, a connection point between the seventh resistor and the eighth resistor is connected with the first end of the second switch tube, the second end of the second switch tube is grounded, and the third end of the second switch tube is connected with the second switch branch.

9. The power supply circuit of claim 1, wherein, The second switch branch comprises a ninth resistor, a tenth resistor, a first voltage stabilizing diode and a third switch tube; The ninth resistor and the tenth resistor are connected in series between the first switch branch and the input end, a connection point between the ninth resistor and the tenth resistor is connected with the first end of the third switch tube, the anode of the first voltage stabilizing diode is connected with the first end of the third switch tube, the cathode of the first voltage stabilizing diode is connected with the second end of the third switch tube, and the third end of the third switch tube is connected with the output end.

10. A power supply system characterized by comprising: The power supply circuit according to any one of claims 1-9.

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