Short circuit protection circuit, method, and related charging power supply and electronic equipment

Abstract

The present application discloses a short-circuit protection circuit, method, and related charging power supply and electronic equipment. The circuit includes a power supply, a control chip, a first resistor, a second resistor, and an output port. The power supply can output current in two channels. A mutual protection mechanism is established by the series relationship between the two resistors (the first resistor and the second resistor), which protects the entire circuit. When a component short-circuit occurs in the circuit, the output voltage of the power supply can be adjusted to meet the requirements of the LPS standard to prevent the output voltage of the power supply from being too high, causing the components to burn, thereby causing fire, etc., which is beneficial to ensuring charging safety in power supply usage scenarios.

Description

Technical Field

[0001] The present application relates to the field of electronic circuit technology, and in particular to a short-circuit protection circuit, method, and related charging power supply and electronic equipment. Background Art

[0002] With the rapid development of electronic products, more and more power supplies with fast charging protocols are now available on the market. To protect charging devices such as mobile phones, the protocol specifications are becoming increasingly stringent, and compliance with these specifications is a fundamental requirement for power supply products. Among these requirements, LPS (Limited Power Source) requirements are already defined in the IEC 60950-1 standard. These requirements can be used to define power supplies with relatively low maximum voltage, current, and capacitance.

[0003] At present, under normal circumstances, an output current detection resistor may be included in the circuit of a power supply product. Once the output current detection resistor is short-circuited, the traditional power supply does not take targeted protection action, or the power supply does not meet the LPS certification requirements, which may trigger a fire or electric shock. Summary of the Invention

[0004] The embodiments of the present application provide a short-circuit protection circuit, method, and related charging power supply and electronic equipment. By adjusting the output voltage of the power supply to meet the requirements of the LPS standard, the output voltage of the power supply can be adjusted to prevent the burning of components due to excessive output voltage of the power supply, thereby causing fire and other situations, which is beneficial to ensuring charging safety in power supply usage scenarios.

[0005] A first aspect of the embodiments of the present application provides a short circuit protection circuit,

[0006] The short circuit protection includes: a power supply, a control chip, a first resistor, a second resistor and an output port, wherein:

[0007] One end of the power supply is connected to the first port of the control chip, the other end of the power supply is connected to the input end of the first resistor and the second port of the control chip, the output end of the first resistor is connected to the third port of the control chip and the first port of the output port, the second resistor is connected between the power supply and the output port, the input end of the second resistor is connected to the fourth port of the control chip, the output end of the second resistor is connected to the fifth port of the control chip, and the second port of the output port is grounded;

[0008] The control chip is used to detect and obtain a first voltage across the first resistor and a second voltage across the second resistor;

[0009] The control chip is further used to determine the short circuit status of the first resistor and / or the second resistor based on the first voltage and the second voltage, and to adjust the output voltage of the power supply when the first resistor and / or the second resistor is short-circuited.

[0010] A second aspect of the present application provides a charging power supply, comprising the short-circuit protection circuit disclosed in the first aspect of the embodiment of the present application.

[0011] A third aspect of the present application provides an electronic device, comprising the charging power supply disclosed in the second aspect of the embodiment of the present application.

[0012] In an embodiment of the present application, the short-circuit protection circuit includes: a power supply, a control chip, a first resistor, a second resistor, and an output port, wherein one end of the power supply is connected to the first port of the control chip, the other end of the power supply is connected to the input end of the first resistor and the second port of the control chip, the output end of the first resistor is connected to the third port of the control chip and the first port of the output port, the input end of the second resistor is connected to the fourth port of the control chip and the second port of the output port, and the output end of the second resistor is connected to the fifth port of the control chip; the control chip is used to detect a first voltage across the first resistor and a second voltage across the second resistor; the control chip is also used to determine the short circuit of the first resistor and / or the second resistor based on the first voltage and the second voltage, and adjust the output voltage of the power supply when the first resistor and / or the second resistor is short-circuited. In this way, the power supply can output current in two ways, and a mutual protection mechanism is established by the series relationship between the two resistors (the first resistor and the second resistor), which plays a protective role for the entire circuit. When a component short circuit occurs in the circuit, the output voltage of the power supply can be adjusted to meet the requirements of the LPS standard to prevent the output voltage of the power supply from being too large and causing the component to burn, thereby causing a fire, etc., which is beneficial to ensure the charging safety of the power supply usage scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings involved in the embodiments of the present application or the background technology will be briefly introduced below.

[0014] Figure 1A This is a schematic structural diagram of a short-circuit protection circuit provided in an embodiment of the present application;

[0015] Figure 1B This is a schematic structural diagram of a short-circuit protection circuit provided in an embodiment of the present application;

[0016] Figure 1C This is a schematic structural diagram of a short-circuit protection circuit provided in an embodiment of the present application;

[0017] Figure 2This is a schematic diagram of the structure of a control chip provided in an embodiment of the present application;

[0018] Figure 3 This is a schematic structural diagram of a first ADC module and / or a second ADC module provided in an embodiment of the present application;

[0019] Figure 4A is a structural diagram of a second amplification module provided in an embodiment of the present application;

[0020] Figure 4B is a structural diagram of a first amplification module provided in an embodiment of the present application;

[0021] Figure 5 This is a schematic structural diagram of a short-circuit protection circuit provided in an embodiment of the present application;

[0022] Figure 6 This is a flow chart of a short-circuit protection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units, but may also include steps or units not listed, or may also include other steps or units inherent to the process, product, or apparatus.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] See also Figure 1A, is a schematic structural diagram of a short-circuit protection circuit provided in an embodiment of the present application. The short-circuit protection circuit may include: a power supply 100, a control chip 200, a first resistor R1, a second resistor R2 and an output port 300, wherein,

[0027] One end 101 of the power supply 100 is connected to the first port 201 of the control chip 200, the other end 102 of the power supply 100 is connected to the input end of the first resistor R1 and the second port 202 of the control chip 200, the output end of the first resistor R1 is connected to the third port 203 of the control chip 200 and the first port 301 of the output port 300, the second resistor R2 is connected between the power supply 100 and the output port 300, the input end of the second resistor R2 is connected to the fourth port 204 of the control chip 200, the output end of the second resistor R2 is connected to the fifth port 205 of the control chip 200, and the second port 302 of the output port 300 is grounded;

[0028] The control chip 200 is used to detect and obtain a first voltage across the first resistor R1 and a second voltage across the second resistor R2;

[0029] The control chip 200 is further used to determine the short circuit status of the first resistor R1 and / or the second resistor R2 based on the first voltage and the second voltage, and adjust the output voltage of the power supply 100 when the first resistor R1 and / or the second resistor R2 is short-circuited.

[0030] The power supply may include at least one of the following: an AC (alternating current) / DC (direct current) charger power supply, a DC / DC power supply, etc., which are not limited here.

[0031] Among them, the embodiments of the present application are not only applicable to flyback converters, but also to switching power supply topologies such as forward converters, BUCK circuits, BOOST circuits, and LLC resonant converters.

[0032] The control chip may include at least one of the following: an integrated circuit chip (IC) with a built-in MCU type such as IP2726, IP2723T, IP2712, or a system on chip (SOC), which is not limited here.

[0033] Among them, the resistance values ​​of the above-mentioned first resistor R1 and the second resistor R2 can be the same or different, which is not limited here; the above-mentioned first resistor R1 and / or second resistor R2 are output current detection resistors in the short-circuit protection circuit of this application, mainly used to detect the output current of current 100.

[0034] The second resistor R2 can be connected between the power supply 100 and the output port 300. That is, the second resistor R2 can be placed in the output circuit of the power supply 100. The specific connection relationship between the second resistor R2, the power supply 100, and the output port 300 is not limited. Figure 4A The connection relationship shown is only one of the embodiments of this application.

[0035] The output end of the second resistor R2 is grounded, and the other end of the power supply 100 is also grounded.

[0036] The first resistor R1 is connected to the first port 101 of the power supply 100 and can be used to detect the upper output current of the power supply 100 ; similarly, the second resistor R2 is connected to the second port 102 of the power supply 100 and can be used to detect the lower output current of the power supply 100 .

[0037] In a specific implementation, the output current at the upper end of the power supply 100 can be determined by detecting the voltage difference across the first resistor R1, i.e., the first voltage; the output current at the lower end of the power supply 100 can be determined by detecting the voltage difference across the second resistor R2, i.e., the second voltage.

[0038] The first resistor R1 and the second resistor R2 are connected in series.

[0039] Considering that the output current detection resistor (ie, the first resistor R1 and / or the second resistor R2 ) may generate system loss, the first resistor R1 and / or the second resistor R2 are generally selected to have a smaller resistance value to reduce the loss.

[0040] The voltage across the first resistor R1 and / or the second resistor R2 can be detected by the control chip, thereby obtaining a first current flowing through the first resistor R1 and / or a second current flowing through the second resistor R2.

[0041] Among them, such as Figure 1AThe working principle of the short-circuit protection circuit shown is as follows: As shown in the figure, when the above circuit is operating normally, the relationship between the first resistor R1 and the second resistor R2 is a series relationship, and the current flowing between the first resistor R1 and the second resistor R2 is the same, that is, the first current is equal to the second current, that is, the current output by the first port 101 and the second port 102 of the above power supply 100 is the same; if any component between the first resistor R1 and the second resistor R2 is short-circuited, the first current corresponding to the first resistor R1 detected by the control chip 200 and the second current corresponding to the second resistor R2 will be different, and there may be a large difference. In this way, the control chip 200 can determine whether a component short circuit occurs in the circuit based on the first current corresponding to the first resistor R1 and the second current corresponding to the second resistor R2 to determine whether it is necessary to enter the short-circuit protection state. If the difference between the first current and the second current is large, the short-circuit protection state can be entered. Specifically, the output voltage of the power supply can be adjusted so that the output voltage of the power supply meets the LPS (Limited Power Source) specification requirements to achieve the purpose of protecting the entire circuit.

[0042] It can be seen that in the short-circuit protection circuit described in the embodiment of the present application, the power supply 100 can output current in two channels, and establish a mutual protection mechanism through the series relationship between two resistors (the first resistor R1 and the second resistor R2), which protects the entire circuit. When a component short-circuit occurs in the circuit, the output voltage of the power supply 100 can be adjusted to meet the requirements of the LPS standard to prevent the output voltage of the power supply 100 from being too high and causing the components to burn, thereby causing fire and other situations, which is beneficial to ensuring the charging safety of the power supply usage scenario.

[0043] In a possible example, the second resistor is connected between the power supply and the output port, including: the input end of the second resistor R2 is connected to the second port 302 of the output port 300, the output end of the second resistor R2 is connected to the second port 302 of the output port 300, and the output end of the second resistor R2 is grounded.

[0044] The connection relationship between the second resistor R2 and the power supply and the output port is as follows: Figure 1A shown.

[0045] In a possible example, the second resistor R2 is connected between the power supply 100 and the output port 300 , including: an input end of the second resistor R2 is connected to the first port 101 of the power supply 100 , and an output end of the second resistor R2 is connected to the input end of the first resistor R1 .

[0046] Among them, such as Figure 1BFIG. 1 is a schematic diagram of a short circuit protection circuit. In the diagram, the connection relationship between the second resistor R2 and the power supply 100 and the output port 300 is different from that between the second resistor R2 and the power supply 100 and the output port 300. Figure 1A The second resistor R2 and the first resistor R1 are connected in series.

[0047] In a possible example, the second resistor R2 is connected between the power supply 100 and the output port 300 , including: an input end of the second resistor R2 is connected to an output end of the first resistor R1 , and an output end of the second resistor R2 is connected to the first port 301 of the output port 300 .

[0048] Among them, such as Figure 1B FIG. 1 is a schematic diagram of a short circuit protection circuit. In the diagram, the connection relationship between the second resistor R2 and the power supply 100 and the output port 300 is different from that between the second resistor R2 and the power supply 100 and the output port 300. Figure 1A and Figure 1B The second resistor R2 and the first resistor R1 are connected in series.

[0049] For a possible example, see Figure 2 , Figure 2 : is a structural diagram of a control chip provided in an embodiment of the present application, the control chip includes: an output control module 210, a first ADC module 220, a second ADC module 230, a first amplification module 240 and a second amplification module 250, wherein:

[0050] The first port 211 of the output control module 210 is connected to the power supply, the second port 212 of the output control module 210 is connected to the first port 221 of the first ADC module 220, the second port 222 of the first ADC module 220 is connected to the first port 241 of the first amplification module 240, the second port 242 of the first amplification module 240 is connected to the second port 202 of the control chip 200, and the third port 243 of the first amplification module 240 is connected to the third port 203 of the control chip 200.

[0051] The specific number of the first ADC (analog / digital conversion) modules and / or the second ADC modules is not limited, that is, the number of the ADC modules is not limited in the embodiment of the present application.

[0052] In the embodiment of the present application, the specific number of the first amplification (amplification sampling) module and / or the second amplification module is not limited. The control chip may include 4, 5 or 6 amplification modules, etc., which is not limited here.

[0053] In an embodiment of the present application, in order to improve the output current sampling accuracy, the present application adds a first amplifier module 240 in the stage before the first ADC module 220 to amplify the sampling signal of the output current at the first resistor R1; and adds a second amplifier module 250 in the stage before the second ADC module 230 to amplify the sampling signal of the output current at the second resistor 300.

[0054] In a possible example, the third port 213 of the output control module 210 is connected to the first port 231 of the second ADC module 230, the second port 232 of the second ADC module 230 is connected to the first port 251 of the second amplification module 250, the second port 252 of the second amplification module 250 is connected to the fourth port 204 of the control chip 200, and the third port 253 of the second amplification module 250 is connected to the fifth port 205 of the control chip 200.

[0055] Among them, the output control module is used to detect a first voltage across the first resistor R1 and a second voltage across the second resistor R2, and adjust the output voltage of the power supply 100. It is used to control the circuit so that when the first resistor R1 or the second resistor R2 is short-circuited, the entire circuit enters a short-circuit protection state, that is, the output voltage of the power supply 100 is adjusted to a preset voltage (for example, 5V), and within a preset period, the output state of the power supply 100 is monitored by a timer, and the maximum output current of the power supply is maintained at a preset current (for example, 500mA).

[0056] For a possible example, see Figure 3 , Figure 3 1 is a schematic structural diagram of a first ADC module and / or a second ADC module provided in an embodiment of the present application. The first ADC module and / or the second ADC module include: a comparator, a sample-and-hold circuit, a successive approximation register (SAR), and a digital-to-analog converter (DAC), wherein:

[0057] One end of the sample-and-hold circuit is connected to one end of the comparator, the other end of the comparator is connected to one end of the successive approximation register, the other end of the successive approximation register is connected to one end of the digital-to-analog converter, and the other end of the digital-to-analog converter is connected to the other end of the sample-and-hold circuit and one end of the comparator.

[0058] The first ADC module and / or the second ADC module may use a Successive Approximation Register (SAR) analog-to-digital converter (ADC), which is also called a binary search ADC.

[0059] The SAR ADC uses a high-speed, high-precision comparator to compare the analog input signal with the previous analog-to-digital conversion result after passing through the DAC, obtaining each bit from the most significant bit (MSB) to the least significant bit (LSB), thereby converting each sampled analog signal of the output current into a multi-bit digital signal.

[0060] In a possible example, the second amplification module 250 is different from the first amplification module 240 .

[0061] If the connection relationship between the second resistor R2, the power supply 100 and the output port 300 is as follows: Figure 1A As shown, the input end of the second resistor R2 is connected to the second port 302 of the output port 300, the output end of the second resistor R2 is connected to the second port 302 of the output port 300, and the output end of the second resistor R2 is grounded; then, in this case, the specific circuit of the above-mentioned second amplification module 250 is different from the specific circuit of the first amplification module 240.

[0062] In a possible example, the second amplification module 250 is the same as the first amplification module 240 .

[0063] If the connection relationship between the second resistor R2, the power supply 100 and the output port 300 is as follows: Figure 1B or Figure 1C As shown, the input end of the second resistor R2 is connected to the first port 101 of the power supply 100, and the output end of the second resistor R2 is connected to the input end of the first resistor R1, or the input end of the second resistor R2 is connected to the output end of the first resistor R1, and the output end of the second resistor R2 is connected to the first port 301 of the output port 300. In the above case, the specific circuit of the second amplifying module 250 is the same as the specific circuit of the first amplifying module 240.

[0064] For a possible example, see Figure 4A , Figure 4A: is a structural diagram of a second amplifying module provided in an embodiment of the present application. The second amplifying module 250 includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first amplifier U1, a first MOS transistor Q1, a second MOS transistor Q2 and a third MOS transistor Q3, wherein:

[0065] One end of the third resistor R3 is connected to the input end of the second resistor R2, and the third resistor R3 is connected to the positive input end of the first amplifier U1. The other end of the fourth resistor R4 is connected to the output end of the second resistor R2, and the fourth resistor R4 is connected to the negative input end of the first amplifier U1 and one end of the fifth resistor R5. The AVCC end of the first amplifier U1 is connected to the source of the first MOS transistor Q1 and the source of the second MOS transistor Q2. The gate of the first MOS transistor Q1 is connected to the gate of the second MOS transistor Q2 and the drain of the third MOS transistor Q3. The output end of the comparator U1 is connected to the gate of the third MOS transistor Q3. The source of the third MOS transistor Q3 is connected to the other end of the fifth resistor R5. The drain of the second MOS transistor Q2 is connected to one end of the sixth resistor R6 and the output end 222 of the second ADC module 220. The other end of the sixth resistor R6 is grounded.

[0066] The first MOS transistor and / or the second MOS transistor may also be a PNP type transistor.

[0067] The first MOS transistor and the second MOS transistor function to form a mirror current source circuit, so that the currents between the fifth resistor R5 and the sixth resistor R6 are equal. Therefore, the amplification factor of the current sampling signal in the circuit is the ratio of the voltage across the sixth resistor R6 to the voltage across the fifth resistor R5, that is, R6 / R5.

[0068] For a possible example, see Figure 4B , Figure 4B : is a structural diagram of a first amplifying module 240 and / or a second amplifying module 250 provided in an embodiment of the present application. The first amplifying module 240 includes: a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a second amplifier U2, and a fourth MOS transistor Q4, wherein:

[0069] One end of the seventh resistor R7 is connected to the input end of the first resistor R1, the other end of the seventh resistor R7 is connected to the positive input end of the second amplifier U2 and one end of the ninth resistor R9, the other end of the ninth resistor R9 is connected to the drain of the fourth MOS transistor Q4, the gate of the fourth MOS transistor is connected to the output end of the second amplifier U2, the source of the fourth MOS transistor Q4 is connected to one end of the tenth resistor R10 and the output end of the first ADC module 220, and the other end of the tenth resistor R10 is grounded.

[0070] Among them, since the voltages at the positive input terminal + and the negative input terminal - of the second operational amplifier U2 are the same, the voltage difference across the seventh resistor R7 is equal to the sampled voltage, and the current across the seventh resistor R7 is equal to the current across the ninth resistor R9. Therefore, the amplification factor of the current sampling signal is the ratio of the voltage across the ninth resistor R9 to the voltage across the seventh resistor R7, that is, the current sampling signal is amplified to R9 / R7.

[0071] It should be noted that, in the embodiment of the present application, the first amplifying module and / or the second amplifying module may also be composed of other components, and their organizational structure is not limited here.

[0072] Optionally, when the connection relationship between the second resistor R2, the power supply 100 and the output port 300 is as follows: Figure 1A As shown, the specific circuit of the first amplifying module 240 is as follows Figure 4B As shown, the specific circuit of the second amplifying module 250 is as follows Figure 4A As shown, the second amplifying module 250 is different from the first amplifying module 240 .

[0073] Optionally, when the connection relationship between the second resistor R2, the power supply 100 and the output port 300 is as follows: Figure 1B When shown in FIG1C, the specific circuits of the first amplifying module 240 and / or the second amplifying module are as follows: Figure 4B As shown, the second amplifying module 250 is the same as the first amplifying module 240 .

[0074] In one possible example, the output control module includes: a register and a timer, wherein the timer is used to monitor the state of the output control module, and the register is used to reset the short-circuit protection state of the output control module when the first resistor and / or the second resistor is short-circuited.

[0075] When the first resistor R1 or the second resistor R2 is short-circuited in the circuit, the timer may be used to monitor the duration of the short-circuit of the first resistor R1 or the second resistor R2.

[0076] Among them, the above-mentioned register can reset the state of the entire circuit after the short circuit of the above-mentioned first resistor R1 and / or the second resistor R2 lasts for more than N clock cycles. That is, it can control the power supply to output at a normal voltage, release the short-circuit protection state, and restart monitoring whether the first resistor R1 and / or the second resistor R2 are short-circuited.

[0077] In one possible example, the output voltage of a power supply is regulated as follows:

[0078] The output voltage of the power supply is adjusted to a preset voltage, and within a preset period, the power supply is monitored by the timer, and the maximum output current of the power supply is maintained at the preset current.

[0079] The preset voltage can be user-defined or system-default, and is not limited here. This preset voltage can be set according to the LPS certification protocol. Generally speaking, LPS-compliant power supplies will not cause fire or electric shock because they have limited output current and voltage to the load. The following summarizes the specifications of power supplies certified as inherently power-limited (LPS) (VA = volts * amperes, Voc = open-circuit output voltage (no-load), a DC voltage of 30Vdc or less or a basic sinusoidal AC voltage of 30VACrms or less): maximum short-circuit current of 8A; maximum VA of 100; maximum marked output power rating of 5A * Voc; and maximum marked output current rating of 5A. In this embodiment of the present application, to ensure that the power supply meets LPS certification requirements, the preset voltage can be set to 5V (volts), and the preset current can be set to 500mA.

[0080] In a specific implementation, the control chip 200 can be used to control the output voltage of the power supply to be adjusted to 5V, and the OCP point of the power supply can be set to be adjusted to 500mA. In this way, the output current of the power supply can be limited to be lower than 500mA.

[0081] The purpose of adjusting the OCP point is to limit the current to achieve an overcurrent protection function. Specifically, when the current in the loop is higher than the current limit point, the power supply 100 will output a constant current at the set current limit value.

[0082] The preset period can be set by the user or by the system default, which is not limited here. The preset period can be N clock cycles, where N is a positive integer, and the power supply 100 is kept at an output current lower than 500 mA during the N clock cycles.

[0083] In a possible example, the short - circuit condition of the first resistor and / or the second resistor is determined as follows: Determine the product of the resistance ratio and the first coefficient to obtain a first comparison value; Determine the product of the resistance ratio and the second coefficient to obtain a second comparison value; If the voltage ratio is greater than the first comparison value, use the timer to determine the first duration during which the voltage ratio is greater than the first comparison value. If the first duration is greater than or equal to a first preset threshold, then determine that the second resistor is short - circuited; If the voltage ratio is less than the second comparison value, use the timer to determine the second duration during which the voltage ratio is less than the second comparison value. If the second duration is greater than or equal to a second preset threshold, then determine that the first resistor is short - circuited.

[0084] Among them, the above - mentioned first coefficient and / or second coefficient can be set by the user themselves or be the system default, which is not limited here; The value range of the first coefficient can also be preset as [a, b], and the value range of the second coefficient can be preset as [c, d]; The above two ranges can be the same or different. Among them, the first coefficient or the second coefficient can be taken from the above ranges respectively; Specifically, it is not limited here; The first coefficient can also be different from the second coefficient, and both can be preset according to the specific sampling accuracy. For example, the first coefficient can be preset as 120%, and the second coefficient can be preset as 80%.

[0085] Among them, the above - mentioned first preset threshold and second preset threshold can be set by the user themselves or be the system default. For example, they can be 5ms, 10ms, 15ms, 20ms, etc. The specific values can be set according to the actual application situation and are not limited here.

[0086] In specific implementation, determine the voltage of the first resistor R1 as V , ,

[0087] , R1 , R2 , R1 , R2 , R1 ,

[0088] , R2 ,

[0089] , ,determine the voltage of the second resistor R2 as V R2 ;If V R1 / V R2 > R1 / R2×120%, and the first duration is greater than or equal to the first preset threshold (for example, 10ms), then it can be determined that the second resistor R2 is short - circuited; If V R1 / V R2 < R1 / R2×80%, and the second duration is greater than or equal to the second preset threshold (for example, 10ms), then determine that the first resistor R1 is short - circuited.

[0087] In a possible example, the output voltage of the power supply is adjusted as follows:

[0088] If it is determined that the first resistor R1 is short - circuited, then adjust the output voltage of the power supply 100;

[0089] If it is determined that the second resistor R2 is short-circuited, the output voltage of the power supply 100 is adjusted.

[0090] Regardless of whether the first resistor or the second resistor is short-circuited, the output voltage of the power supply 100 can be adjusted to a preset voltage (for example, 5V), and within a preset period, the output status of the power supply 100 is monitored by a timer, and the maximum output current of the power supply is maintained at a preset current (for example, 500mA); in this way, the short-circuit protection state is entered.

[0091] In a possible example, when the first resistor and / or the second resistor is short-circuited, the state of the output control module is reset in the following manner:

[0092] After maintaining the maximum output current of the power supply at the preset current for the preset period, the short-circuit protection state of the output control module is reset through the register.

[0093] In the embodiment of the present application, the above-mentioned preset period can be set by the user or by the system default, which is not limited here.

[0094] Among them, after maintaining the above-mentioned short-circuit protection state for a preset period, that is, maintaining the maximum output current of the power supply at the preset current for a preset period, the short-circuit protection state of the above-mentioned output control module can be reset through the register, that is, the first voltage across the first resistor R1 and the second voltage across the second resistor R2 can be detected again, and the short-circuit condition of the first resistor and / or the second resistor can be determined through the first voltage and the second voltage, and when the first resistor and / or the second resistor is short-circuited, the output voltage of the power supply is adjusted, and so on, over and over again, cyclically protecting the entire circuit.

[0095] See also Figure 5 , Figure 5 : is a schematic diagram of a short-circuit protection circuit provided in an embodiment of the present application. The short-circuit protection circuit includes: a power supply 100, a control chip 200, a first resistor R1, a second resistor R2 and an output port 300, wherein:

[0096] One end 101 of the power supply 100 is connected to the first port 201 of the control chip 200, the other end 102 of the power supply 100 is connected to the input end of the first resistor R1 and the second port 202 of the control chip 200, the output end of the first resistor R1 is connected to the third port 203 of the control chip 200 and the first port 301 of the output port 300, the second resistor R2 is connected between the power supply 100 and the output port 300, the input end of the second resistor R2 is connected to the fourth port 204 of the control chip 200, the output end of the second resistor R2 is connected to the fifth port 205 of the control chip 200, and the second port 302 of the output port 300 is grounded;

[0097] The control chip 200 is used to detect and obtain a first voltage across the first resistor R1 and a second voltage across the second resistor R2;

[0098] The control chip 200 is further used to determine the short circuit status of the first resistor R1 and / or the second resistor R2 based on the first voltage and the second voltage, and adjust the output voltage of the power supply 100 when the first resistor R1 and / or the second resistor R2 is short-circuited.

[0099] The control chip includes an output control module 210 , a first ADC module 220 , a second ADC module 230 , a first amplification module 240 and a second amplification module 250 .

[0100] Among them, such as Figure 5 As shown, the connection relationship between the second resistor R2, the power supply 100 and the output port 300 is as follows: Figure 1A shown.

[0101] It can be seen that in the short-circuit protection circuit described in the embodiment of the present application, the power supply 100 can output current in two channels, and establish a mutual protection mechanism through the series relationship between the two resistors (the first resistor R1 and the second resistor R2), which protects the entire circuit. When a component short-circuit occurs in the circuit, the output control module 210 in the control chip 200 can adjust the output voltage of the power supply 100 to meet the requirements of the LPS standard to prevent the output voltage of the power supply 100 from being too high, causing the components to burn, thereby causing fire, etc., which is beneficial to ensuring the charging safety of the power supply usage scenario.

[0102] See also Figure 6 , is a flow chart of a short circuit protection method provided in an embodiment of the present application. As shown in the figure, the short circuit protection method is applied to Figure 1A 、 Figure 1B 、 Figure 1C and Figure 5The short-circuit protection circuit shown includes: a power supply, a control chip, a first resistor, a second resistor, and an output port, wherein one end of the power supply is connected to the first port of the control chip, the other end of the power supply is connected to the input end of the first resistor and the second port of the control chip, the output end of the first resistor is connected to the third port and the output port of the control chip, the input end of the second resistor is connected to the fourth port and the output port of the control chip, and the output end of the second resistor is connected to the fifth port of the control chip; the method includes:

[0103] S601: Detecting, by the control chip, a first voltage across the first resistor and a second voltage across the second resistor;

[0104] S602: Determine, by the control chip, a short-circuit condition of the first resistor and / or the second resistor based on the first voltage and the second voltage, and adjust the output voltage of the power supply when the first resistor and / or the second resistor is short-circuited.

[0105] It can be seen that the short-circuit protection method described in the embodiment of the present application can establish a mutual protection mechanism through the series relationship between two resistors (a first resistor and a second resistor), thereby protecting the entire circuit. When a component short-circuit occurs in the circuit, the output voltage of the power supply can be adjusted through the output control module in the control chip to meet the requirements of the LPS standard to prevent the output voltage of the power supply from being too high, causing the components to burn, thereby causing fires, etc., which is beneficial to ensuring the charging safety of the power supply usage scenario.

[0106] In one possible example, determining the short-circuit condition of the first resistor and / or the second resistor may include the following steps: determining a voltage ratio between the first voltage and the second voltage; determining a resistance ratio between the first resistor and the second resistor; obtaining a first coefficient and a second coefficient, wherein the first coefficient and / or the second coefficient are used to constrain the resistance ratio; determining the short-circuit condition of the first resistor and / or the second resistor based on the voltage ratio, the resistance ratio, the first coefficient and the second coefficient.

[0107] In one possible example, the control chip includes: an output control module, and the output control module includes: a timer; determining the short-circuit condition of the first resistor and / or the second resistor based on the voltage ratio, the resistance ratio, the first coefficient and the second coefficient may include the following steps: determining the product of the resistance ratio and the first coefficient to obtain a first comparison value; determining the product of the resistance ratio and the second coefficient to obtain a second comparison value; if the voltage ratio is greater than the first comparison value, determining the first duration of the voltage ratio greater than the first comparison value through the timer, and if the first duration is greater than or equal to a first preset threshold, determining that the second resistor is short-circuited; if the voltage ratio is less than the second comparison value, determining the second duration of the voltage ratio less than the second comparison value through the timer, and if the second duration is greater than or equal to a second preset threshold, determining that the first resistor is short-circuited.

[0108] In a possible example, adjusting the output voltage of the power supply may include the following steps: if it is determined that the first resistor is short-circuited, adjusting the output voltage of the power supply; if it is determined that the second resistor is short-circuited, adjusting the output voltage of the power supply.

[0109] In a possible example, the adjusting the output voltage of the power supply may include the following steps: adjusting the output voltage of the power supply to a preset voltage, and maintaining the maximum output current of the power supply to a preset current through the timer within a preset period.

[0110] In a possible example, the output control module further includes: a register; the method may further include the following steps: maintaining the maximum output current of the power supply at the preset current for the preset period, and resetting the short-circuit protection state of the output control module through the register.

[0111] It should be noted that the implementation method of the above steps is the same as the specific steps in the above short-circuit protection circuit, and will not be repeated here.

[0112] The present embodiment provides a charging power supply including the short-circuit protection circuit provided in any of the above-mentioned embodiments. The short-circuit protection circuit in the charging power supply is the same as the short-circuit protection circuit described in any of the above-mentioned embodiments and will not be described again here.

[0113] The present application provides an electronic device including a charging power supply.

[0114] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A short circuit protection circuit, characterized in that: The short circuit protection is connected to the power supply, and the short circuit protection includes: a control chip, a first resistor, a second resistor and an output port, wherein, One end of the power supply is connected to the first port of the control chip, the other end of the power supply is connected to the input end of the first resistor and the second port of the control chip, the output end of the first resistor is connected to the third port of the control chip and the first port of the output port, the second resistor is connected between the power supply and the output port or the ground, the input end of the second resistor is connected to the fourth port of the control chip, the output end of the second resistor is connected to the fifth port of the control chip, and the second port of the output port is grounded; The control chip is used to detect and obtain a first voltage across the first resistor and a second voltage across the second resistor; The control chip is further used to determine the short circuit status of the first resistor and / or the second resistor based on the first voltage and the second voltage, and to adjust the output voltage of the power supply when the first resistor and / or the second resistor is short-circuited.

2. The circuit according to claim 1, wherein: The control chip includes: output control module, first ADC module, second ADC module, first amplification module and second amplification module, wherein: The first port of the output control module is connected to the power supply, the second port of the output control module is connected to the first port of the first ADC module, the second port of the first ADC module is connected to the first port of the first amplification module, the second port of the first amplification module is connected to the second port of the control chip, and the third port of the first amplification module is connected to the third port of the control chip.

3. The circuit according to claim 2, characterized in that The third port of the output control module is connected to the first port of the second ADC module, the second port of the second ADC module is connected to the first port of the second amplification module, the second port of the second amplification module is connected to the fourth port of the control chip, and the third port of the second amplification module is connected to the fifth port of the control chip; the power supply is: an AC / DC charger power supply or a DC / DC power supply.

4. The circuit according to claim 2 or 3, characterized in that The first ADC module and / or the second ADC module includes: a comparator, a sample-and-hold circuit, a successive approximation register and a digital-to-analog converter, wherein: One end of the sample-and-hold circuit is connected to one end of the comparator, the other end of the comparator is connected to one end of the successive approximation register, the other end of the successive approximation register is connected to one end of the digital-to-analog converter, and the other end of the digital-to-analog converter is connected to the other end of the sample-and-hold circuit and one end of the comparator.

5. The circuit according to claim 2 or 3, characterized in that The input end of the second resistor is connected to the second port of the output port, the output end of the second resistor is connected to the second port of the output port, and the output end of the second resistor is grounded; Alternatively, the input end of the second resistor is connected to the first port of the power supply, and the output end of the second resistor is connected to the input end of the first resistor; Alternatively, the input end of the second resistor is connected to the output end of the first resistor, and the output end of the second resistor is connected to the first port of the output port.

6. The circuit according to claim 5, characterized in that The second amplification module includes: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first amplifier, a first MOS transistor, a second MOS transistor and a third MOS transistor, wherein: One end of the third resistor is connected to the input end of the second resistor, the other end of the third resistor is connected to the positive input end of the first amplifier, the other end of the fourth resistor is connected to the output end of the second resistor, the fourth resistor is connected to the negative input end of the first amplifier and one end of the fifth resistor, the AVCC end of the first amplifier is connected to the source of the first MOS transistor and the source of the second MOS transistor, the gate of the first MOS transistor is connected to the gate of the second MOS transistor and the drain of the third MOS transistor, the drain of the first MOS transistor is connected to the drain of the third MOS transistor, the output end of the comparator is connected to the gate of the third MOS transistor, the source of the third MOS transistor is connected to the other end of the fifth resistor, the drain of the second MOS transistor is connected to one end of the sixth resistor and the output end of the second ADC module, and the other end of the sixth resistor is grounded.

7. The circuit according to claim 5, characterized in that The first amplifying module and / or the second amplifying module includes: a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a second amplifier, and a fourth MOS transistor, wherein: One end of the seventh resistor is connected to the input end of the first resistor, the other end of the seventh resistor is connected to the positive input end of the second amplifier and one end of the ninth resistor, the other end of the ninth resistor is connected to the drain of the fourth MOS transistor, the gate of the fourth MOS transistor is connected to the output end of the second amplifier, the source of the fourth MOS transistor is connected to one end of the tenth resistor and the output end of the first ADC, and the other end of the tenth resistor is grounded.

8. A short circuit protection method, characterized in that: The short-circuit protection method is applied to the short-circuit protection circuit according to any one of claims 1 to 7, and the method comprises: Detecting and obtaining a first voltage across the first resistor and a second voltage across the second resistor by the control chip; The control chip determines the short circuit status of the first resistor and / or the second resistor according to the first voltage and the second voltage, and adjusts the output voltage of the power supply when the first resistor and / or the second resistor is short-circuited.

9. A charging power supply, characterized in that: The charging power supply includes the short-circuit protection circuit according to any one of claims 1 to 8.

10. An electronic device, characterized in that: The electronic device comprises the charging power supply according to claim 9.

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