Auxiliary power start system and photovoltaic device

Abstract

The application discloses an auxiliary power supply starting system and a photovoltaic device. The system comprises a starting circuit arranged between a positive electrode of an input power supply and a power supply port, a shunt circuit, a voltage dividing circuit and a starting capacitor arranged between the power supply port and a negative electrode of the input power supply. The shunt circuit comprises a shunt resistor and a reference voltage comparison device. The voltage dividing circuit is provided with a plurality of voltage dividing resistors connected in series. Adjacent voltage dividing resistors are provided with voltage dividing nodes. The controlled end of the reference voltage comparison device is connected with the voltage dividing nodes. When the reference voltage comparison device is cut off, the charging current of the starting capacitor is a first current. When the reference voltage comparison device is turned on, the charging current of the starting capacitor is a second current. The application can make the starting capacitor charge at a slow speed with the second current smaller than the first current after fast charging at the first current, so as to ensure the restart charging time and avoid the problem of repeated transient restart of a chip.

Description

Technical Field

[0001] This application relates to the field of photovoltaic equipment technology, and in particular to an auxiliary power start-up system and photovoltaic equipment. Background Technology

[0002] In the field of photovoltaic inverter auxiliary power supply, traditional auxiliary power supply startup systems can generally obtain a large charging current by setting the resistance value of the charging resistor, so that the charging current can quickly charge the charging capacitor, thereby achieving rapid chip startup. However, when the auxiliary power supply triggers abnormal protection and needs to restart, the charging capacitor will be quickly charged to the startup threshold by the large charging current during the previous startup, which will cause the chip to repeatedly restart momentarily. This will cause the components in the auxiliary power supply startup system to be damaged due to heat accumulation, thus affecting the stability and service life of the auxiliary power supply startup system. Utility Model Content

[0003] This application provides an auxiliary power start-up system and a photovoltaic device to solve the problem of repeated instantaneous restarts of the chip caused by the charging capacitor rapidly reaching the start-up threshold due to excessive charging current during restart in traditional systems.

[0004] This application provides the following solution:

[0005] According to a first aspect, this application provides an auxiliary power supply startup system, including: an input power supply, a startup circuit, a shunt circuit, a voltage divider circuit, a startup capacitor, and a power supply port. The startup circuit is disposed between the positive terminal of the input power supply and the power supply port. The shunt circuit, the voltage divider circuit, and the startup capacitor are all disposed between the power supply port and the negative terminal of the input power supply. The shunt circuit includes a shunt resistor and a reference voltage comparator. The voltage divider circuit has multiple voltage divider resistors connected in series, and a voltage divider node is disposed between adjacent voltage divider resistors. The controlled terminal of the reference voltage comparator is connected to the voltage divider node.

[0006] When the reference voltage comparator is turned off, the voltage divider circuit is connected in parallel with the start-up capacitor, and the charging current of the start-up capacitor is the first current;

[0007] When the reference voltage comparator is turned on, the shunt resistor and the voltage divider circuit are both connected in parallel with the start-up capacitor, and the charging current of the start-up capacitor is the second current;

[0008] Wherein, the second current is less than the first current.

[0009] As an alternative, the reference voltage comparator includes a voltage reference source, the reference terminal of which is connected to the voltage divider node as a controlled terminal, the cathode of which is connected to the shunt resistor, the anode of which is connected to the negative terminal of the input power supply, and the negative terminal of the input power supply is grounded.

[0010] When the voltage divider between the reference electrode and the anode of the voltage reference source is greater than the reference voltage of the voltage reference source, the cathode and anode of the voltage reference source are turned on.

[0011] When the voltage divider voltage between the reference electrode and the anode of the voltage reference source is less than the reference voltage of the voltage reference source, the cathode and anode of the voltage reference source are cut off.

[0012] As an optional embodiment, the startup circuit includes a first drive switch and a startup resistor. The input terminal of the first drive switch is connected to the positive terminal of the input power supply, the output terminal of the first drive switch is connected to the power supply port through the startup resistor, and the controlled terminal of the first drive switch is connected to the signal terminal of the power chip.

[0013] When the first drive switch is closed, the start-up circuit is turned on;

[0014] When the first drive switch is turned off, the start-up circuit is cut off.

[0015] As an optional embodiment, the shunt circuit further includes a second drive switch, the input terminal of which is connected to the power supply port, the output terminal of which is connected to the shunt resistor, and the controlled terminal of which is connected to the signal terminal of the power chip.

[0016] When the first drive switch is closed, the second drive switch is closed, and the reference voltage comparator is turned on, the shunt circuit is turned on;

[0017] The shunt circuit is turned off when the first drive switch is open, or the second drive switch is open, or the reference voltage comparator is turned off.

[0018] As an alternative, both the first driving switch and the second driving switch include a transistor, wherein the collector of the transistor is the input terminal of the driving switch, the emitter of the transistor is the output terminal of the driving switch, the base of the transistor is the controlled terminal of the driving switch, and an on-resistance is provided between the collector and the base of the transistor.

[0019] As an optional embodiment, the startup circuit further includes a first diode, the cathode of which is connected to the controlled terminal of the first drive switch, and the anode of which is connected to the power supply port.

[0020] The shunt circuit further includes a second diode, the cathode of which is connected to the controlled terminal of the second drive switch, and the anode of which is connected to the end of the shunt resistor near the reference voltage comparator.

[0021] As an alternative, a current-limiting resistor and a third diode are further provided between the input terminal of the first drive switch and the positive terminal of the input power supply. One end of the current-limiting resistor is connected to the positive terminal of the input power supply, the other end of the current-limiting resistor is connected to the cathode of the third diode, and the anode of the third diode is connected to the first drive switch.

[0022] As an alternative, a first switching circuit is provided between the controlled terminal of the first driving switch and the signal terminal of the power chip, and a second switching circuit is provided between the controlled terminal of the second driving switch and the signal terminal of the power chip.

[0023] Both the first and second switching circuits include an input resistor, a grounding resistor, and a voltage switch. The controlled terminal of the voltage switch is connected to the signal terminal of the power chip through the input resistor. The grounding resistor is provided between the controlled terminal and the output terminal of the voltage switch. The output terminal of the voltage switch is grounded. The input terminal of the voltage switch is connected to the controlled terminal of the drive switch.

[0024] As an alternative, a fourth diode is provided between the power supply port and the negative terminal of the input power supply, with the cathode of the fourth diode connected to the power supply port and the anode of the fourth diode connected to the negative terminal of the input power supply.

[0025] According to a second aspect, a photovoltaic device is provided, including an auxiliary power start-up system as described in the first aspect above.

[0026] The auxiliary power supply startup system and photovoltaic equipment provided in this application embodiment, by setting up a startup circuit, a shunt circuit, a voltage divider circuit, and a reference voltage comparator, can quickly charge the startup capacitor using a first current provided by the startup circuit when the reference voltage comparator is off, thus meeting the chip's rapid startup requirements. When the voltage of the startup capacitor reaches a preset value, causing the reference voltage comparator to conduct, the shunt resistor is connected in parallel with the voltage divider circuit and the startup capacitor, allowing the startup capacitor to be slowly charged with a second current less than the first current. It can be understood that since the charging time during chip restart includes the extended charging time during the above-mentioned slow charging process, the above-mentioned slow charging process can effectively guarantee the restart charging time, thereby avoiding the problem of repeated instantaneous chip restarts caused by excessive charging current during restart in traditional systems, which leads to the charging capacitor quickly reaching the startup threshold. This reduces heat accumulation damage to auxiliary power components, thereby improving the stability and service life of the auxiliary power supply startup system.

[0027] Of course, any product implementing this application does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 Electrical connection diagram of the auxiliary power start-up system provided in the embodiments of this application;

[0030] Figure 2 Another electrical connection diagram for the drive switch in the auxiliary power start-up system provided in the embodiments of this application;

[0031] Figure 3 Another electrical connection diagram for the auxiliary power start-up system provided in the embodiments of this application, showing the installation of protective components;

[0032] Figure 4 Another electrical connection diagram for the voltage switch in the auxiliary power start-up system provided in the embodiments of this application;

[0033] Figure 5 The voltage timing diagram at the power supply port in the auxiliary power supply startup system provided in the embodiments of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0035] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0036] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0037] In the field of photovoltaic inverter auxiliary power supply, traditional auxiliary power supply startup systems can generally obtain a large charging current by setting the resistance value of the charging resistor, so that the charging current can quickly charge the charging capacitor, thereby achieving rapid chip startup. However, when the auxiliary power supply triggers abnormal protection and needs to restart, the charging capacitor will be quickly charged to the startup threshold by the large charging current during the previous startup, which will cause the chip to repeatedly restart momentarily. This will cause the components in the auxiliary power supply startup system to be damaged due to heat accumulation, thus affecting the stability and service life of the auxiliary power supply startup system.

[0038] To address the aforementioned issues, this application provides an auxiliary power start-up system and a photovoltaic device to resolve the problem of repeated instantaneous chip restarts caused by excessive charging current during restart in traditional systems, which leads to the charging capacitor rapidly reaching the start-up threshold.

[0039] refer to Figure 1 , Figure 1This is an electrical connection diagram of an auxiliary power supply startup system provided in an embodiment of this application. In some embodiments, this application provides an auxiliary power supply startup system, including: an input power supply, a startup circuit, a shunt circuit, a voltage divider circuit, a startup capacitor, and a power supply port. The startup circuit is disposed between the positive terminal of the input power supply and the power supply port. The shunt circuit, the voltage divider circuit, and the startup capacitor are all disposed between the power supply port and the negative terminal of the input power supply. The shunt circuit includes a shunt resistor and a reference voltage comparator. The voltage divider circuit has multiple voltage divider resistors connected in series, and a voltage divider node is disposed between adjacent voltage divider resistors. The controlled terminal of the reference voltage comparator is connected to the voltage divider node. When the reference voltage comparator is off, the voltage divider circuit is connected in parallel with the startup capacitor, and the charging current of the startup capacitor is a first current. When the reference voltage comparator is on, the shunt resistor and the voltage divider circuit are both connected in parallel with the startup capacitor, and the charging current of the startup capacitor is a second current. The second current is less than the first current.

[0040] It is understood that the auxiliary power startup system provided in this application embodiment, by setting up a startup circuit, a shunt circuit, and a voltage divider circuit, uses the first current provided by the startup circuit to quickly charge the startup capacitor when the reference voltage comparator in the shunt circuit is turned off, thus meeting the chip's rapid startup requirements. When the voltage of the startup capacitor reaches a set value, causing the reference voltage comparator to conduct, the shunt resistor is connected in parallel with the voltage divider circuit and the startup capacitor, so that the startup capacitor is slowly charged with a second current less than the first current. It is understood that since the charging time during chip restart includes the extended charging time during the above-mentioned slow charging process, the above-mentioned slow charging process can effectively guarantee the restart charging time, thereby avoiding the problem of repeated instantaneous chip restarts caused by the charging capacitor quickly reaching the startup threshold due to excessive charging current during restart in traditional systems, reducing heat accumulation damage to auxiliary power components, and thus improving the stability and service life of the auxiliary power startup system.

[0041] Among them, such as Figure 1 As shown, the input power supply 110 provides the operating voltage for the system; it can be a DC power supply Vin or a rectified AC power supply. The startup circuit 120 serves as the main current path during the initial charging phase and can employ a combination of a startup resistor R3 and a switching device. The reference voltage comparator in the shunt circuit 130 monitors the voltage state of the voltage divider node. When this voltage reaches a set threshold, it changes its conduction state, causing the charging current to be shunt to the shunt resistor R7. The reference voltage comparator can be a voltage reference source U1 with a precise reference voltage, such as TL431. The voltage divider circuit 140 reflects the changes in the power supply port VCC voltage in real time through a voltage divider resistor network, such as... Figure 1The voltage divider resistors R4 and R5, and the position of the voltage divider node, determine the operating point of the reference voltage comparator. The starting capacitor C1, as an energy storage element, has a charging rate determined by the current flowing through it, or in other words, its charging speed is determined by the combined influence of different parallel branches.

[0042] It is worth noting that when the voltage of the starting capacitor C1 reaches the set value, the reference voltage comparator is turned on. This set value can be determined by the reference voltage of the reference voltage comparator, the resistance values ​​of multiple voltage divider resistors, the power supply port VCC, and the input voltage Vin. The reference voltage of the reference voltage comparator can be 2.5V.

[0043] Specifically, during the initial system startup, the low VCC voltage at the power supply port prevents the voltage at the voltage divider node from reaching the conduction threshold of the reference voltage comparator. At this time, the reference voltage comparator is off, and the voltage divider circuit 140 is connected in parallel with the startup capacitor C1. The current flowing from the positive terminal of the input power supply 110 into the startup circuit 120, after exiting the startup circuit 120, flows through the voltage divider circuit 140, forming the first current charging the startup capacitor C1. When the VCC voltage at the power supply port rises to a point where the voltage at the voltage divider node exceeds the reference voltage of the reference voltage comparator, the reference voltage comparator conducts, causing the shunt resistor R7 to be connected in parallel to the circuit. That is, the shunt resistor R7 is connected in parallel across the voltage divider circuit 140. The current flowing out of the startup circuit 120 flows through both the voltage divider circuit 140 and the shunt resistor R7, forming the second current charging the startup capacitor C1. This second current is less than the first current, thus achieving the current switching process, ensuring rapid charging in the initial stage, and preventing repeated restarts caused by voltage overshoot.

[0044] It is worth noting that, compared with existing technologies, the traditional solution uses a fixed resistance value, which makes the charging current unadjustable. However, this solution uses the synergistic effect of the voltage divider circuit 140 and the reference voltage comparator to enable the startup capacitor C1 to be fast and slow charged in sequence, thereby ensuring the restart time and extending the service life of the auxiliary power supply system. Furthermore, the startup circuit 120 and the shunt circuit 130 are constant current circuits, which can make the startup time unaffected by the input voltage Vin, making it suitable for wide input voltage Vin scenarios.

[0045] In some embodiments, the startup circuit 120 may include a first constant current source, and the shunt circuit 130 may include a second constant current source. The first constant current source may replace the startup resistor R3, and the second constant current source may replace the shunt resistor R7. The current of the first constant current source in the startup circuit 120 is greater than the current of the second constant current source in the shunt circuit 130. It is understood that by using a constant current source to replace the corresponding resistor, the above-mentioned slow charging process can be achieved, effectively ensuring the restart charging time, while also making the startup time unaffected by the input voltage Vin, which is suitable for wide input voltage Vin scenarios.

[0046] In some embodiments, this application further proposes a reference voltage comparator including a voltage reference source U1. The reference terminal of the voltage reference source U1 is connected to a voltage divider node as a controlled terminal. The cathode of the voltage reference source U1 is connected to a shunt resistor R7. The anode of the voltage reference source U1 is connected to the negative terminal of the input power supply 110, and the negative terminal of the input power supply 110 is grounded. When the voltage divider voltage between the reference terminal and the anode of the voltage reference source U1 is greater than the reference voltage of the voltage reference source U1, the cathode and anode of the voltage reference source U1 are turned on. When the voltage divider voltage between the reference terminal and the anode of the voltage reference source U1 is less than the reference voltage of the voltage reference source U1, the cathode and anode of the voltage reference source U1 are turned off.

[0047] Among them, such as Figure 1 As shown, the voltage reference source U1 can be a semiconductor device with a stable reference voltage, specifically implemented using an integrated circuit such as TL431, used to trigger the conduction state when the voltage at the voltage divider node reaches a threshold. The reference terminal R can be the voltage sampling terminal of the voltage reference source U1, specifically obtained by connecting to the voltage divider node to obtain the divided voltage, used to monitor the change of the power supply port VCC voltage in real time. The conduction and cutoff states of the cathode C and anode A are determined by the difference between the divided voltage between the reference terminal and the anode and the reference voltage. When the divided voltage exceeds the reference voltage, a conduction loop is formed, causing the shunt resistor R7 to be connected to the circuit. That is, the TL431 identifies whether the charging capacitor voltage has reached the limit, and then switches the charging start mode.

[0048] Specifically, during the auxiliary power supply startup process, the voltage at the power supply port VCC forms a voltage divider node voltage through the voltage divider circuit 140. When the voltage divider node voltage is lower than the reference voltage, the voltage reference source U1 is in the off state. At this time, the voltage divider circuit 140 is connected in parallel with the startup capacitor C1, and the charging current is provided solely by the startup circuit 120. When the voltage divider node voltage rises above the reference voltage, the cathode and anode of the voltage reference source U1 conduct, causing the shunt resistor R7 to be connected in parallel to the circuit. The charging current is shunted by the shunt resistor R7, thereby reducing the charging speed of the startup capacitor C1. This allows the charging process of the charging capacitor to be divided into two parts: fast charging and slow charging. The fast charging part ensures the startup time, and the slow charging part ensures the restart time.

[0049] refer to Figure 2 , Figure 2Another electrical connection diagram for the drive switch in the auxiliary power start-up system provided in the embodiments of this application; in some embodiments, this application further proposes a start-up circuit 120 including a first drive switch Q1 and a start-up resistor R3. The input terminal of the first drive switch Q1 is connected to the positive terminal of the input power supply 110, the output terminal of the first drive switch Q1 is connected to the power supply port VCC through the start-up resistor R3, and the controlled terminal of the first drive switch Q1 is connected to the signal terminal SPS of the power chip; when the first drive switch Q1 is closed, the start-up circuit 120 is turned on; when the first drive switch Q1 is open, the start-up circuit 120 is turned off.

[0050] The first driving switch Q1 can be an electronic component that receives external signals at its controlled terminal to control the on / off state between the input and output terminals. Specifically, it can be implemented using transistors such as bipolar junction transistors (BJTs) or relay switching devices. Its function is to dynamically adjust the on / off state of the startup circuit 120 according to the control signal from the power supply chip. The startup resistor R3 can be a resistor connected in series between the output terminal of the first driving switch Q1 and the power supply port VCC. Specifically, it can be a carbon film resistor, metal film resistor, or wire-wound resistor. Its function is to limit the charging current of the input power supply 110 to the startup capacitor C1. The signal terminal of the power supply chip can be a pin in the power management chip used to output control logic signals. Specifically, it can be a general-purpose input / output interface or a dedicated control signal output terminal. Its function is to send a level signal to the controlled terminal of the first driving switch Q1 to drive the switch operation.

[0051] Specifically, when the input power supply 110 is powered on and the power chip needs to start the auxiliary power supply, the signal terminal can output a low-level signal (also known as an enable level) to close the first drive switch Q1. At this time, the positive terminal of the input power supply 110 supplies current to the power supply port VCC through the first drive switch Q1 and the start-up resistor R3. The start-up resistor R3 limits the magnitude of the charging current. After the power chip completes startup, the signal terminal outputs a high-level signal (also known as a disable level) to open the first drive switch Q1. At this time, the startup circuit 120 is cut off, and the input power supply 110 stops supplying power to the power supply port VCC. By opening the first drive switch Q1, the startup circuit 120 can be shut down after the power supply starts, thereby reducing circuit losses.

[0052] In some embodiments, this application further proposes that the shunt circuit 130 also includes a second drive switch Q2. The input terminal of the second drive switch Q2 is connected to the power supply port VCC, the output terminal is connected to the shunt resistor R7, and the controlled terminal is connected to the signal terminal of the power supply chip. When the first drive switch Q1 is closed, the second drive switch Q2 is closed, and the reference voltage comparator is turned on, the shunt circuit 130 is turned on. When the first drive switch Q1 is open, or the second drive switch Q2 is open, or the reference voltage comparator is turned off, the shunt circuit 130 is turned off.

[0053] The second drive switch Q2 can be an electronic component used to control the on / off state of the shunt circuit 130. Specifically, it can be implemented using transistors such as bipolar junction transistors (BJTs) or field-effect transistors (FETs). Its input terminal receives a voltage signal from the power supply port VCC, and its output terminal is connected to the shunt resistor R7. The controlled terminal receives control signals from the power supply chip to switch between on and off states. Specifically, when the power supply chip needs to start the auxiliary power supply, the signal terminal can simultaneously send a low-level signal to both the first drive switch Q1 and the second drive switch Q2. Both the first drive switch Q1 and the second drive switch Q2 are closed, and the positive terminal of the input power supply 110 supplies power to the power supply port VCC through the starting resistor R3. If the reference voltage comparator is in the on state, the shunt resistor R7 and the voltage divider circuit 140 form a parallel structure, and the charging current of the starting capacitor C1 is limited to a second current by the shunt resistor R7. After the power supply chip completes startup, the signal terminal can simultaneously send a high-level signal to both the first drive switch Q1 and the second drive switch Q2. At this time, the charging current path is disconnected from the shunt circuit 130 to reduce circuit losses.

[0054] In some embodiments, this application further proposes that both the first driving switch Q1 and the second driving switch Q2 include transistors. The collector of the transistor is the input terminal of the driving switch, the emitter of the transistor is the output terminal of the driving switch, and the base of the transistor is the controlled terminal of the driving switch. An on-resistance is provided between the collector and the base of the transistor. Furthermore, the transistor in this embodiment can be a bipolar transistor. The bipolar transistor can be a semiconductor device that controls the conduction or cutoff between the collector and emitter through the base current. Specifically, it can be an NPN or PNP type bipolar transistor, receiving a control signal at the base to switch the conduction state of the driving switch. The on-resistance can be a resistor connected between the collector and the base, specifically a fixed-value resistor or an adjustable resistor, used to limit the base current and stabilize the conduction state of the bipolar transistor.

[0055] like Figure 2 As shown, a first turn-on resistor R1 is provided between the collector and base of the first drive switch Q1, and a second turn-on resistor R6 is provided between the collector and base of the second drive switch Q2.

[0056] refer to Figure 3 , Figure 3Another electrical connection diagram for setting protective elements in the auxiliary power start-up system provided in the embodiments of this application; in some embodiments, this application further proposes that the start-up circuit 120 also includes a first diode Z2, the cathode of the first diode Z2 is connected to the controlled terminal of the first drive switch Q1, and the anode of the first diode Z2 is connected to the power supply port VCC; the shunt circuit 130 also includes a second diode Z4, the cathode of the second diode Z4 is connected to the controlled terminal of the second drive switch Q2, and the anode of the second diode Z4 is connected to the end of the shunt resistor R7 near the reference voltage comparator, that is, to the cathode C of the voltage reference source U1.

[0057] Specifically, the first diode Z2 can be a unidirectional conducting device with its cathode connected to the controlled terminal of the first driving switch Q1 and its anode connected to the power supply port VCC. It can be implemented using a fast recovery diode or a common rectifier diode, and is used to provide reverse current protection for the first driving switch Q1. Similarly, the second diode Z4 can be a unidirectional conducting device with its cathode connected to the controlled terminal of the second driving switch Q2 and its anode connected to the shunt resistor R7. It can be implemented using a Schottky diode or a common rectifier diode, and is used to provide reverse current protection for the second driving switch Q2.

[0058] In some embodiments, such as Figure 3 As shown, this application further proposes that a current-limiting resistor R2 and a third diode Z1 are provided between the input terminal of the first drive switch Q1 and the positive terminal of the input power supply 110. One end of the current-limiting resistor R2 is connected to the positive terminal of the input power supply 110, and the other end of the current-limiting resistor R2 is connected to the cathode of the third diode Z1. The anode of the third diode Z1 is connected to the first drive switch Q1.

[0059] The current-limiting resistor can be a resistive element used to limit the current transmitted from the input power supply 110 to the startup circuit 120. Specifically, it can be implemented using a carbon film resistor or a metal film resistor, and its resistance value can be determined according to the voltage of the input power supply 110 and the maximum allowable startup current. The third diode Z1 can be a semiconductor device with unidirectional conduction characteristics. A voltage threshold can be formed by the forward voltage drop of the third diode Z1. When the voltage of the input power supply 110 is lower than this forward voltage drop, the third diode Z1 is cut off, cutting off the startup circuit 120 and realizing low-voltage protection. This ensures that the system will not start when the input voltage Vin is lower than the set value, thereby avoiding insufficient load-carrying capacity of the auxiliary power supply and ensuring the stable operation of the auxiliary power supply.

[0060] refer to Figure 4 , Figure 4In the auxiliary power start-up system provided in the embodiments of this application, another electrical connection diagram of a voltage switch is provided; in some embodiments, this application further proposes that a first switching circuit is provided between the controlled terminal of the first drive switch Q1 and the signal terminal SPS of the power chip, and a second switching circuit is provided between the controlled terminal of the second drive switch Q2 and the signal terminal SPS of the power chip; both the first switching circuit and the second switching circuit include an input resistor, a grounding resistor and a voltage switch, the controlled terminal of the voltage switch is connected to the signal terminal of the power chip through the input resistor, a grounding resistor is provided between the controlled terminal and the output terminal of the voltage switch, the output terminal of the voltage switch is grounded, and the input terminal of the voltage switch is connected to the controlled terminal of the drive switch.

[0061] like Figure 4 As shown, the first switching circuit includes a first input resistor R10, a first grounding resistor R11, and a first voltage switch Q4. The controlled terminal of the first voltage switch Q4 is connected to the signal terminal SPS of the power supply chip through the first input resistor R10. A first grounding resistor R11 is provided between the controlled terminal and the output terminal of the first voltage switch Q4. The output terminal of the first voltage switch Q4 is grounded, and the input terminal of the first voltage switch Q4 is connected to the controlled terminal of the first drive switch Q1. The second switching circuit includes a second input resistor R8, a second grounding resistor R9, and a second voltage switch Q3. The controlled terminal of the second voltage switch Q3 is connected to the signal terminal SPS of the power supply chip through the second input resistor R8. A second grounding resistor R9 is provided between the controlled terminal and the output terminal of the second voltage switch Q3. The output terminal of the second voltage switch Q3 is grounded, and the input terminal of the second voltage switch Q3 is connected to the controlled terminal of the second drive switch Q2.

[0062] The input resistor can be a resistor connected between the signal terminal of the power chip and the controlled terminal of the voltage switch. Specifically, it can be implemented using a fixed-value surface-mount resistor to limit the current output from the signal terminal. The grounding resistor can be a resistor connected between the controlled terminal and the output terminal of the voltage switch. Specifically, it can be implemented using a voltage divider resistor or a pull-down resistor to stabilize the potential of the controlled terminal of the voltage switch. The voltage switch can be a device that controls the switching between the input and output terminals when the potential of the controlled terminal changes. Specifically, it can be implemented using a field-effect transistor or a transistor to adjust the conduction or cutoff of the drive switch according to the state of the signal terminal.

[0063] Specifically, when the power chip outputs a high-level signal (also known as a disable level), the input resistor transfers current to the controlled terminal of the voltage switch. At this time, the potential of the controlled terminal of the voltage switch rises, making the input and output terminals of the voltage switch conductive. The controlled terminal of the drive switch is pulled low to ground potential, thus disconnecting the drive switch. When the signal outputs a low-level signal (also known as an enable level), the input resistor limits the current flow into the controlled terminal of the voltage switch. At this time, the ground resistor pulls the potential of the controlled terminal down to a low level, cutting off the connection between the input and output terminals of the voltage switch. The potential of the controlled terminal of the drive switch is determined by other circuitry, thus allowing the drive switch to conduct.

[0064] In some embodiments, such as Figure 4 As shown, this application further proposes that a fourth diode Z3 is provided between the power supply port VCC and the negative terminal of the input power supply 110. The cathode of the fourth diode Z3 is connected to the power supply port VCC, and the anode of the fourth diode Z3 is connected to the negative terminal of the input power supply 110.

[0065] Among them, the fourth diode Z3 can be a semiconductor device with unidirectional conduction characteristics. Specifically, it can be implemented by a silicon-based PN junction diode or a Schottky diode. Its cathode is connected to the high potential end and its anode is connected to the low potential end, which is used to realize overvoltage protection for the power supply chip connected to the power supply port VCC.

[0066] It is understood that, in the presence of multiple voltage divider resistors and multiple starting resistors, the resistance values ​​of each voltage divider resistor and starting resistor can be adjusted and set by those skilled in the art according to the range of input voltage in the actual situation.

[0067] refer to Figure 5 , Figure 5 The voltage timing diagram at the power supply port VCC in the auxiliary power supply startup system provided in the embodiments of this application; in some embodiments, Figure 5 Used to explain the principles of the system in this application, such as Figure 5 As shown, it is understandable that Figure 5The vertical axis represents voltage, and the horizontal axis represents time. Vcc is the chip's stable operating voltage, Vcc_on is the chip's startup threshold voltage, Vcc_set is the slow charging trigger voltage (which can also be understood as the set value reached by the voltage of the startup capacitor C1 in the above embodiment), Vcc_off is the chip's shutdown threshold voltage, and T0 is the initial moment of system power-on, at which time the chip's signal terminal SPS outputs an enable level signal. In the initial stage (T0-T1), the reference voltage comparator is off, and the startup capacitor C1 charges rapidly with the first current. The voltage at the power supply port VCC rises rapidly from Vcc_off to Vcc_set; this is the fast charging stage. When the voltage reaches Vcc_set (at time T1), the reference voltage comparator is turned on, the shunt resistor R7 is connected, and the charging current switches to the second current, and the voltage enters a slow charging phase. The chip's steady-state period (T1-T2) is the slow charging phase; T2-T3 is the chip's preparation for startup; T3-T4 is the chip's startup phase, with the voltage dropping to the operating voltage Vcc at time T4; during the T4-T5 phase, the chip operates stably, and the chip's SPS terminal outputs a disabled level signal to cut off the drive switch and avoid circuit losses; if the power supply triggers abnormal protection (the voltage drops to Vcc_off at time T5), the chip shuts down and stops working, and the chip's SPS terminal outputs an enabled level signal again to turn on the drive switch, preparing for the chip to restart; the chip restart process (T5-T6) must include the same slow charging phase (T1-T2), and its charging time is extended (T5-T6>T1-T2), thus completely avoiding the component heat accumulation damage caused by instantaneous restart in traditional solutions.

[0068] This application further proposes a photovoltaic device that may include: the auxiliary power start-up system of the first aspect described above, which enables the start-up capacitor to be charged slowly with a second current less than the first current after being charged quickly with a first current, so as to ensure the restart charging time and avoid the problem of repeated instantaneous restart of the chip. Therefore, it will not be described in detail here.

[0069] In the embodiments provided in this application, it should be understood that the disclosed system can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces or units, and may be electrical, mechanical, or other forms.

[0070] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the system and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An auxiliary power supply starting system, characterized in that, include: The system includes an input power supply, a startup circuit, a shunt circuit, a voltage divider circuit, a startup capacitor, and a power supply port. The startup circuit is located between the positive terminal of the input power supply and the power supply port. The shunt circuit, the voltage divider circuit, and the startup capacitor are all located between the power supply port and the negative terminal of the input power supply. The shunt circuit includes a shunt resistor and a reference voltage comparator. The voltage divider circuit has multiple voltage divider resistors connected in series, and a voltage divider node is provided between adjacent voltage divider resistors. The controlled terminal of the reference voltage comparator is connected to the voltage divider node. When the reference voltage comparator is turned off, the voltage divider circuit is connected in parallel with the start-up capacitor, and the charging current of the start-up capacitor is the first current; When the reference voltage comparator is turned on, the shunt resistor and the voltage divider circuit are both connected in parallel with the start-up capacitor, and the charging current of the start-up capacitor is the second current; Wherein, the second current is less than the first current.

2. The auxiliary power supply starting system according to claim 1, characterized in that, The reference voltage comparator includes a voltage reference source, the reference terminal of which is connected to the voltage divider node as a controlled terminal, the cathode of which is connected to the shunt resistor, the anode of which is connected to the negative terminal of the input power supply, and the negative terminal of the input power supply is grounded. When the voltage divider between the reference electrode and the anode of the voltage reference source is greater than the reference voltage of the voltage reference source, the cathode and anode of the voltage reference source are turned on. When the voltage divider between the reference electrode and the anode of the voltage reference source is less than the reference voltage of the voltage reference source, the cathode and anode of the voltage reference source are cut off.

3. The auxiliary power supply starting system according to claim 1, characterized in that, The startup circuit includes a first drive switch and a startup resistor. The input terminal of the first drive switch is connected to the positive terminal of the input power supply, the output terminal of the first drive switch is connected to the power supply port through the startup resistor, and the controlled terminal of the first drive switch is connected to the signal terminal of a power chip. When the first drive switch is closed, the start-up circuit is turned on; When the first drive switch is turned off, the start-up circuit is cut off.

4. The auxiliary power supply starting system according to claim 3, characterized in that, The shunt circuit further includes a second drive switch, the input terminal of which is connected to the power supply port, the output terminal of which is connected to the shunt resistor, and the controlled terminal of which is connected to the signal terminal of the power chip. When the first drive switch is closed, the second drive switch is closed, and the reference voltage comparator is turned on, the shunt circuit is turned on; The shunt circuit is turned off when the first drive switch is open, or the second drive switch is open, or the reference voltage comparator is turned off.

5. The auxiliary power supply starting system according to claim 4, characterized in that, Both the first driving switch and the second driving switch include a transistor. The collector of the transistor is the input terminal of the driving switch, the emitter of the transistor is the output terminal of the driving switch, and the base of the transistor is the controlled terminal of the driving switch. An on-resistance is provided between the collector and the base of the transistor.

6. The auxiliary power start-up system according to claim 4, characterized in that, The startup circuit further includes a first diode, the cathode of which is connected to the controlled terminal of the first drive switch, and the anode of which is connected to the power supply port. The shunt circuit further includes a second diode, the cathode of which is connected to the controlled terminal of the second drive switch, and the anode of which is connected to the end of the shunt resistor near the reference voltage comparator.

7. The auxiliary power supply starting system according to claim 3, characterized in that, A current-limiting resistor and a third diode are also provided between the input terminal of the first drive switch and the positive terminal of the input power supply. One end of the current-limiting resistor is connected to the positive terminal of the input power supply, and the other end of the current-limiting resistor is connected to the cathode of the third diode. The anode of the third diode is connected to the first drive switch.

8. The auxiliary power supply starting system according to claim 4, characterized in that, A first switching circuit is provided between the controlled terminal of the first driving switch and the signal terminal of the power chip, and a second switching circuit is provided between the controlled terminal of the second driving switch and the signal terminal of the power chip. Both the first and second switching circuits include an input resistor, a grounding resistor, and a voltage switch. The controlled terminal of the voltage switch is connected to the signal terminal of the power chip through the input resistor. The grounding resistor is provided between the controlled terminal and the output terminal of the voltage switch. The output terminal of the voltage switch is grounded. The input terminal of the voltage switch is connected to the controlled terminal of the drive switch.

9. The auxiliary power supply starting system according to claim 1, characterized in that, A fourth diode is also provided between the power supply port and the negative terminal of the input power supply. The cathode of the fourth diode is connected to the power supply port, and the anode of the fourth diode is connected to the negative terminal of the input power supply.

10. A photovoltaic device, characterized in that, Includes the auxiliary power start-up system as described in any one of claims 1 to 9.

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