Power supply output protection method and circuit and related medium and program product

Abstract

The embodiment of the application discloses a power output protection method and circuit, and related media and program products, a current detection resistor is arranged on a power output loop, a first input end and a second input end of a control chip are respectively connected to two ends of a control switch, a third input end and a fourth input end of the control chip are respectively connected to two ends of the current detection resistor, a first output end of the control chip is connected to a control end of a power supply, and a second output end of the control chip is connected to a control end of the control switch. The method comprises the following steps: a control chip detects a first voltage and a second voltage; the first voltage is a voltage difference between two ends of the control switch, and the second voltage is a voltage difference between two ends of the current detection resistor; the control chip controls an output voltage of the power supply and closing or opening of the control switch according to the first voltage and the second voltage, and when a single-point short circuit problem occurs in the power output protection circuit, the protection state can be entered in a targeted manner to meet the LPS certification requirement of the power supply.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to power output protection methods and circuits, as well as related media and software products. Background Technology

[0002] Currently, there are more and more power supply products with fast charging protocols on the market. In order to protect charging devices such as mobile phones, the output current and voltage delivered to the load are limited in accordance with the protocol, so that the power supply of the limited power source (LPS) will not cause electric shock or fire.

[0003] The current principle for limiting output current is: the output current is detected by the voltage difference across the output current sensing resistor, and the output power is controlled by the duty cycle of the primary PWM. For example... Figure 1 As shown, the AC-DC control chip directly detects the output current by checking the voltage difference across resistor Rs, and controls the output power through the primary PWM duty cycle. When resistor Rs is short-circuited, the AC-DC control chip detects significant power consumption in the main power circuit, but no output current is detected at the output terminal Rs. In this case, the AC-DC control chip enters a protection state, limiting the maximum output current by controlling the operation of the main power switching circuit. If resistor Rs is operating normally, the AC-DC control chip limits the maximum output current by controlling the current flowing through resistor Rs. However, indirectly determining whether there is a short circuit to control the output power through the primary PWM state requires configuration based on different output voltages and output power levels, making the control strategy complex. Summary of the Invention

[0004] This application provides a power output protection method and circuit. When a single-point short circuit occurs in the power output protection circuit, it can specifically enter the protection state to meet the power supply LPS certification requirements.

[0005] In a first aspect, embodiments of this application provide a power output protection method applied to a power output protection circuit. The power output protection circuit includes a power supply, a control switch, a current sensing resistor, a control chip, and an output port. The current sensing resistor is disposed in the power output circuit. The first input terminal and the second input terminal of the control chip are respectively connected to the two ends of the control switch. The third input terminal and the fourth input terminal of the control chip are respectively connected to the two ends of the current sensing resistor. The first output terminal of the control chip is connected to the control terminal of the power supply, and the second output terminal of the control chip is connected to the control terminal of the control switch.

[0006] The method includes:

[0007] The control chip detects a first voltage and a second voltage, where the first voltage is the voltage across the control switch and the second voltage is the voltage across the current sensing resistor.

[0008] The control chip controls the output voltage of the power supply and the closing or opening of the control switch based on the first voltage and the second voltage.

[0009] Secondly, this application provides a power output protection circuit, which includes a power supply, a control switch, a current sensing resistor, a control chip, and an output port. The current sensing resistor is disposed in the power output circuit. The first and second input terminals of the control chip are respectively connected to the two ends of the control switch. The third and fourth input terminals of the control chip are respectively connected to the two ends of the current sensing resistor. The first output terminal of the control chip is connected to the control terminal of the power supply, and the second output terminal of the control chip is connected to the control terminal of the control switch.

[0010] The control chip is used to detect a first voltage and a second voltage, wherein the first voltage is the voltage across the control switch and the second voltage is the voltage across the current sensing resistor.

[0011] The control chip is used to control the output voltage of the power supply and the closing or opening of the control switch according to the first voltage and the second voltage.

[0012] Thirdly, embodiments of this application provide an electronic device, which includes the power output protection circuit described in the second aspect.

[0013] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program for electronic data interchange, wherein the computer program causes a computer to perform some or all of the steps described in the method described in the first aspect above.

[0014] Fifthly, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, the computer program being operable to cause a computer to perform some or all of the steps described in the method described in the first aspect of embodiments of this application. The computer program product may be a software installation package.

[0015] Therefore, the power output protection method proposed in this application involves a control chip detecting a first voltage and a second voltage. The first voltage is the voltage difference across the control switch, and the second voltage is the voltage difference across the current detection resistor. The control chip controls the power output voltage and the closing or opening of the control switch based on the first and second voltages. When a single-point short circuit occurs in the power output protection circuit, it can specifically enter the protection state to meet the power supply LPS certification requirements. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a power output protection circuit in the prior art;

[0018] Figure 2 This is a schematic diagram of the structure of a power output protection circuit provided in an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of another power output protection circuit provided in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of another power output protection circuit provided in an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the structure of a control chip provided in an embodiment of this application;

[0022] Figure 6 This is a schematic diagram of the structure of a successive approximation register-type SAR analog-to-digital converter (ADC) provided in an embodiment of this application;

[0023] Figure 7 This is a schematic diagram of the structure of a first amplifier circuit provided in an embodiment of this application;

[0024] Figure 8 This is a schematic diagram of the structure of a second amplifier circuit provided in an embodiment of this application;

[0025] Figure 9 This is a schematic flowchart of a power output protection method provided in an embodiment of this application;

[0026] Figure 10 This is a schematic diagram of a process for determining a short circuit in a MOS transistor and / or a current sensing resistor, provided in an embodiment of this application. Detailed Implementation

[0027] To help those skilled in the art better understand the technical solutions of this application, the technical solutions in 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. Based on the description of the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, software, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units not listed, or other steps or units inherent to such processes, methods, products, or apparatus.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] The embodiments of this application are described below with reference to the accompanying drawings. In the drawings, the intersection of intersecting wires is indicated by dots, and the absence of dots indicates that the wires are not connected.

[0031] Please see Figure 2 , Figure 2 This is a schematic diagram of a power output protection circuit provided in an embodiment of this application. The power output protection circuit includes a power supply 100, a control switch 200, a current sensing resistor 300, a control chip 400, and an output port 500. The current sensing resistor 300 is disposed in the power output circuit. The first and second input terminals of the control chip 400 are respectively connected to the two ends of the control switch 200. The third and fourth input terminals of the control chip 400 are respectively connected to the two ends of the current sensing resistor 300. The first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0032] The power output circuit includes the output terminal of the power supply 100 being grounded in sequence through the control switch 200, the output port 500, and the current detection resistor 300.

[0033] Specifically, the first input terminal of the control chip 400 is connected to the input terminal of the control switch 200 and the output terminal of the power supply 100, the second input terminal of the control chip 400 is connected to the output terminal of the control switch 200 and the input terminal of the output port 500, the third input terminal of the control chip 400 is connected to one end of the current sensing resistor 300 and the output terminal of the output port 500, the fourth input terminal of the control chip 400 is connected to the other end of the current sensing resistor 300, the first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0034] For example, such as Figure 3 As shown, Figure 3 This is a schematic diagram of another power output protection circuit provided in an embodiment of this application. The power output protection circuit includes a power supply 100, a control switch 200, a current sensing resistor 300, a control chip 400, and an output port 500. The current sensing resistor 300 is disposed in the power output circuit. The first and second input terminals of the control chip 400 are respectively connected to the two ends of the control switch 200. The third and fourth input terminals of the control chip 400 are respectively connected to the two ends of the current sensing resistor 300. The first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0035] The power output circuit includes the output terminal of the power supply 100 being grounded sequentially through the current detection resistor 300, the control switch 200, and the output port 500.

[0036] Specifically, the first input terminal of the control chip 400 is connected to the input terminal of the control switch 200 and one end of the circuit detection resistor 300, the second input terminal of the control chip 400 is connected to the output terminal of the control switch 200 and the input terminal of the output port 500, the third input terminal of the control chip 400 is connected to the other end of the current detection resistor 300 and the output terminal of the power supply 100, the fourth input terminal of the control chip 400 is connected to one end of the current detection resistor 300 and the input terminal of the control switch 200, the first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0037] It is understood that the first input terminal and the fourth input terminal of the control chip 400 can be the same port. That is, the control chip 400 includes a first input terminal, a second input terminal, and a third input terminal. The first input terminal is connected to the input terminal of the control switch 200 and one end of the current sensing resistor 300, respectively. The second input terminal is connected to the output terminal of the control switch 200 and the input terminal of the output port 500, respectively. The third input terminal is connected to the output terminal of the power supply 100 and the other end of the current sensing resistor 300, respectively.

[0038] For example, such as Figure 4 As shown, Figure 4 This is a schematic diagram of another power output protection circuit provided in an embodiment of this application. The power output protection circuit includes a power supply 100, a control switch 200, a current sensing resistor 300, a control chip 400, and an output port 500. The current sensing resistor 300 is disposed in the power output circuit. The first and second input terminals of the control chip 400 are respectively connected to the two ends of the control switch 200. The third and fourth input terminals of the control chip 400 are respectively connected to the two ends of the current sensing resistor 300. The first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0039] The power output circuit includes the output terminal of the power supply 100 being grounded in sequence through the control switch 200, the current detection resistor 300, and the output port 500.

[0040] Specifically, the first input terminal of the control chip 400 is connected to the input terminal of the control switch 200 and the output terminal of the power supply 100, the second input terminal of the control chip 400 is connected to the output terminal of the control switch 200 and one end of the current sensing resistor 300, the third input terminal of the control chip 400 is connected to one end of the current sensing resistor 300 and the output terminal of the control switch 200, the fourth input terminal of the control chip 400 is connected to the other end of the current sensing resistor 300 and the input terminal of the output port, the first output terminal of the control chip 400 is connected to the control terminal of the power supply 100, and the second output terminal of the control chip 400 is connected to the control terminal of the control switch 200.

[0041] It is understood that the second and third input terminals of the control chip 400 can be the same port. That is, the control chip 400 includes a first input terminal, a second input terminal, and a third input terminal. The first input terminal is connected to the output terminal of the power supply 100 and the input terminal of the control switch 200, respectively. The second input terminal is connected to the output terminal of the control switch 200 and one end of the current sensing resistor 300, respectively. The third input terminal is connected to the other end of the current sensing resistor 300 and the input terminal of the output port 500, respectively.

[0042] In this embodiment, the control chip 400 accurately detects the output current by detecting the voltage difference across the current sensing resistor 300, and also assists in detecting the output current by detecting the voltage difference across the control switch 200 (the MOS transistor has on-resistance). Since the control switch 200 and the current sensing resistor are the necessary paths in the current loop and are connected in series, the output current flowing through the control switch 200 is the same as the output current flowing through the current sensing resistor 300. When either the control switch 200 or the current sensing resistor 300 is short-circuited, a significant difference will occur between the current detected by the control chip 400 on the control switch 200 side and the current detected by the current sensing resistor 300 side. The control chip 400 can then use this as a condition to enter a short-circuit protection state, controlling the control switch 200 to open or close via an output control signal, and simultaneously adjusting the output voltage of the power supply 100 through voltage feedback to ensure that the output current and output voltage of the power supply meet the LPS specification requirements.

[0043] The control switch 200 is a MOS transistor, which can be an N-channel MOS transistor or a P-channel MOS transistor. The specific configuration can be determined according to the application scenario of the power output protection circuit. This application embodiment does not limit this.

[0044] It should be noted that the control switch 200 in this application can also be other components or switching circuits that can achieve the same function as a MOS transistor.

[0045] The control chip 400 can be a protocol integrated circuit (IC) of the type with built-in microcontroller unit (MCU) such as IP2726, IP2723T, or IP2712, or it can be other types of system on chip (SOC).

[0046] The power supply 100 may be an AC / DC power supply, a DC / DC power supply, a regulated power supply, a communication power supply, a module power supply, a frequency converter power supply, an inverter power supply, an AC regulated power supply, a DC regulated power supply, etc., and this application embodiment does not limit it.

[0047] The power output protection circuit proposed in this application is applicable to both AC / DC and DC / DC power supplies, which is more widely applicable than existing technologies that can only be used with low-power AC / DC power supplies. Furthermore, the power output protection circuit proposed in this application is applicable to flyback converters, as well as switching power supply topologies such as forward converters, BUCK circuits, BOOST circuits, and LLC resonant converters.

[0048] Optional, such as Figure 5 As shown, the control chip 400 includes a first amplifier circuit 401, a second amplifier circuit 402, a first analog-to-digital converter circuit 403, a second analog-to-digital converter circuit 404, and an output control circuit 405;

[0049] The first input terminal of the first amplifier circuit 401 is connected to the first input terminal of the control chip 400, the second input terminal of the first amplifier circuit 401 is connected to the second input terminal of the control chip 400, the output terminal of the first amplifier circuit 401 is connected to the input terminal of the first analog-to-digital converter circuit 403, and the output terminal of the first analog-to-digital converter circuit 403 is connected to the first input terminal of the output control circuit 405; the first input terminal of the second amplifier circuit 402 is connected to the third input terminal of the control chip 400, the second input terminal of the second amplifier circuit 402 is connected to the fourth input terminal of the control chip 400, the output terminal of the second amplifier circuit 402 is connected to the input terminal of the second analog-to-digital converter circuit 404, and the output terminal of the second analog-to-digital converter circuit 404 is connected to the second input terminal of the output control circuit 405; the first output terminal of the output control circuit 405 is connected to the first output terminal of the control chip 400, and the second output terminal of the output control circuit 405 is connected to the second output terminal of the control chip 400.

[0050] The first analog-to-digital converter circuit 403 is used to sample the output current flowing through the control switch 200, and the second analog-to-digital converter circuit 404 is used to sample the output current flowing through the current detection resistor 300.

[0051] Furthermore, the first analog-to-digital converter circuit 403 and the second analog-to-digital converter circuit 404 can be successive approximation register (SAR) analog-to-digital converters (ADCs). This SAR ADC is also known as a binary search ADC. Figure 6As shown, this SAR ADC includes a sample-and-hold circuit (S / H), an accumulator, a comparator, a successive approximation register (SAR), and a digital-to-analog converter (DAC). The SAR ADC uses a high-speed, high-precision comparator to compare the analog input signal with the output of the DAC after the previous analog-to-digital conversion, obtaining each bit from the most significant byte (MSB) to the least significant bit (LSB), thereby converting each sampled analog signal of the output current into a multi-bit digital signal.

[0052] In this embodiment, considering that the current sensing resistor 300 will cause system losses, the resistance value of the current sensing resistor 300 is generally selected to reduce losses. Meanwhile, to improve the output current sampling accuracy, this application adds the first amplifier circuit 401 before the first digital-to-analog converter circuit 403 to amplify the sampling signal of the output current at the control switch 200; and adds the second amplifier circuit 402 before the second analog-to-digital converter circuit 404 to amplify the sampling signal of the output current at the current sensing resistor 300.

[0053] Optional, such as Figure 7 As shown, the first amplifier circuit 401 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first transistor Q1, and a first operational amplifier U1. One end of the first resistor R1 is connected to the first input terminal of the first amplifier circuit 401, and the other end of the first resistor R1 is connected to the non-inverting input terminal of the first operational amplifier U1 and one end of the third resistor R3. The other end of the third resistor R3 is connected to the collector of the first transistor Q1. The emitter of the first transistor Q1 is connected to one end of the second resistor R2 and the output terminal of the first amplifier circuit 401. The other end of the second resistor R2 is grounded. The base of the first transistor Q1 is connected to the output terminal of the first operational amplifier U1. One end of the fourth resistor R4 is connected to the second input terminal of the first amplifier circuit 401, and the other end of the fourth resistor R4 is connected to the inverting input terminal of the first operational amplifier U1.

[0054] Wherein, the voltages of the positive input terminal + and the negative input terminal - of the first operational amplifier U1 are the same, so the voltage difference across the first resistor R1 is equal to the voltage being sampled, and the current across the first resistor R1 is equal to the current across the second resistor R2. Therefore, the amplification factor of the current sampling signal is the ratio of the voltage across the second resistor R2 to the voltage across the first resistor R1, that is, the current sampling signal is amplified to R2 / R1.

[0055] In this embodiment, when the current sensing resistor 300 is connected in series with the control switch 200 in the stage before or after it, i.e. Figure 3 and Figure 4 As shown, the first amplifier circuit 401 and the second amplifier circuit 402 have the same circuit structure.

[0056] Optionally, when the current sensing resistor 300 is connected in series after the output port 500, that is, for Figure 2 ,like Figure 8 As shown, the second amplifier circuit 402 includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, and a second operational amplifier U2. One end of the fifth resistor R5 is connected to the second input terminal of the second amplifier circuit 402. The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and the inverting input terminal of the second operational amplifier U2. The other end of the sixth resistor R6 is connected to the emitter of the second transistor Q2. The base of the second transistor Q2 is connected to the output terminal of the second operational amplifier U2. The collector of the second transistor Q2 is connected to the collector of the third transistor Q3, the base of the third transistor Q3, and the base of the fourth transistor Q4. The emitter of the third transistor Q3 is connected to the emitter of the fourth transistor Q4 and the VCC terminal of the second operational amplifier U2. The collector of the fourth transistor Q4 is connected to one end of the seventh resistor R7 and the output terminal of the second amplifier circuit 402. The other end of the seventh resistor R7 is grounded. One end of the eighth resistor R8 is connected to the first input terminal of the second amplifier circuit 402, and the other end of the eighth resistor R8 is connected to the positive input terminal of the operational amplifier U2.

[0057] The third transistor Q3 and the fourth transistor Q4 can be either NPN or PNP transistors. The third transistor Q3 and the fourth transistor Q4 have the same base-emitter voltage and the same base drive voltage, thus forming a basic NPN current mirror circuit. This makes the current across the seventh resistor R7 equal to the current across the fifth resistor R5. Therefore, the amplification factor of the current sampling signal is the ratio of the voltage across the fifth resistor R5 to the voltage across the seventh resistor R7, i.e., the current sampling signal is amplified to R5 / R7.

[0058] In this embodiment, the output control circuit 405 determines whether the control switch 200 and / or the current sensing resistor 300 are short-circuited based on the difference between the output current flowing through the control switch 200 and the output current flowing through the current sensing resistor 300. When the difference between the output current flowing through the control switch 200 and the output current flowing through the current sensing resistor 300 is large, indicating a short circuit in the control switch 200 and / or the current sensing resistor 300, the output control circuit 405 enters a short-circuit protection state and outputs a control command to control the control switch 200 to close or open. For example, when the control switch 200 is an N-channel MOSFET, the output control circuit 405 outputs a low level to turn off the N-channel MOSFET, thereby turning off the control switch 200. Simultaneously, the output control circuit 405 outputs a control command to reduce the output voltage of the power supply 100 to a first voltage value, which is a preset output voltage that meets the LPS specification requirements.

[0059] It is understandable that the specific method of the control command output by the output control circuit 405 is determined by the control method of the power supply, and the value of the first voltage is also set according to the safety requirements of the power supply, without any specific restrictions here.

[0060] As can be seen, the output power protection circuit provided in this application embodiment directly detects the output current flowing through the control switch 200 and the current detection resistor 300 through the control chip 400. Compared with the indirect output current estimation by monitoring the primary PWM change in the prior art, it is faster and more accurate. Moreover, the technical solution of mutual protection between the control switch 200 and the current detection resistor 300 adopted in this application has a wider protection range. Furthermore, it uses the original power supply components for detection and judgment, without the need to add an additional detection circuit, resulting in low cost and simple circuit.

[0061] Please see Figure 9 , Figure 9 This is a flowchart illustrating a power output protection method provided in an embodiment of this application, applicable to, for example... Figures 2-4 The power output protection circuit shown is an example. Figure 9 As shown, the method includes the following steps.

[0062] S910, the control chip detects a first voltage and a second voltage, the first voltage being the voltage across the control switch and the second voltage being the voltage across the current sensing resistor.

[0063] The control switch 200 is a MOS transistor.

[0064] In this embodiment, the control switch 200 and the current sensing resistor 300 are the necessary paths in the output current loop, and the MOS transistor and the current sensing resistor 300 are connected in series. Therefore, the output current through the MOS transistor and the current sensing resistor 300 is the same. Since the on-resistance of the MOS transistor and the resistance value of the current sensing resistor 300 are known, the output current flowing through the MOS transistor and the current sensing resistor 300 can be obtained by detecting the first voltage and the second voltage.

[0065] S920, the control chip controls the output voltage of the power supply and the closing or opening of the control switch according to the first voltage and the second voltage.

[0066] The first voltage reflects the magnitude of the output current flowing through the MOS transistor, and the second voltage reflects the output current flowing through the current sensing resistor 300. Since the output current flowing through the MOS transistor and the current sensing resistor 300 are the same, the output voltage of the power supply 100 and the opening or closing of the MOS transistor can be controlled according to the changes in the first and second voltages to ensure that the power supply 100 meets the LPS specification requirements.

[0067] Optionally, the control chip controls the output voltage of the power supply and the closing or opening of the control switch according to the first voltage and the second voltage, including: the control chip determines whether the MOS transistor and / or the current sensing resistor is short-circuited according to the first voltage and the second voltage; when the MOS transistor and / or the current sensing resistor is short-circuited, the control chip controls the control switch to be in a closed state or an open state for a first time period, and controls the power supply to output a first voltage value for the first time period.

[0068] When both the MOS transistor and the current sensing resistor 300 are in normal operation, the output current flowing through them is consistent. Therefore, the detected first and second voltages are within a preset range, and their ratio is also within the preset range. Consequently, when the first and second voltages change significantly, or when their ratio changes significantly, it indicates a short circuit in the MOS transistor and / or the current sensing resistor 300. In this case, the control chip needs to activate short-circuit protection, controlling the MOS transistor to open or close via an output control signal. Simultaneously, it adjusts the output voltage of the power supply 100 through voltage feedback to ensure that the output current and voltage meet the LPS specification requirements.

[0069] Optional, such as Figure 10 As shown, the control chip determines whether the MOS transistor and / or the current sensing resistor are short-circuited based on the first voltage and the second voltage, including:

[0070] S101. The output control circuit checks whether the MOS transistor is in the on state.

[0071] S102. If the MOS transistor is in the on state, the output control circuit determines whether the first ratio is less than the first preset value. The first ratio is the ratio of the first voltage to the second voltage.

[0072] S103. If the MOS transistor is in the off state, the output control circuit determines whether the first voltage is less than the second preset value.

[0073] S104. If the first ratio is less than the first preset value or the first voltage is less than the second preset value, the output control circuit starts the first timer.

[0074] S105, The output control circuit determines whether the value of the first timer is greater than or equal to the first value;

[0075] S106. If the value of the first timer is greater than or equal to the first value, the output control circuit determines that the MOS transistor is short-circuited; if the value of the first timer is less than the first value, the output control circuit initializes the first timer.

[0076] S107. If the first ratio is greater than or equal to the first preset value, the output control circuit determines whether the first ratio is greater than the third preset value.

[0077] S108. If the first ratio is greater than the third preset value, the output control circuit starts the second timer;

[0078] S109. The output control circuit determines whether the value of the second timer is greater than or equal to the first value;

[0079] S110. If the value of the second timer is greater than or equal to the first value, the output control circuit determines that the current detection resistor is short-circuited; if the value of the second timer is less than the first value, the output control circuit initializes the second timer.

[0080] When the power supply 100 starts to supply output current and voltage to the load, the control chip first initializes the output power protection circuit. Specifically, the control chip initializes the state of the SAR register in the first analog-to-digital converter circuit 403 and the second analog-to-digital converter circuit 404; at the same time, it obtains the resistance value of the current detection resistor 300 and the on-resistance of the MOS transistor, and restores the control switch to the recorded original state (open or closed).

[0081] In this embodiment, the voltage across the MOS transistor and the voltage across the current sensing resistor 300 can be used to determine whether a short circuit has occurred in the MOS transistor and / or the current sensing resistor 300. The criteria for determining a short circuit in the MOS transistor and / or the current sensing resistor 300 vary depending on the operating state of the MOS transistor. The criteria for determining a short circuit in the MOS transistor and / or the current sensing resistor 300 are shown in Table 1.

[0082] Table 1

[0083]

[0084] Specifically, when the MOS transistor is in the ON state, if the first ratio of the first voltage to the second voltage is less than a first preset value, and the duration of this ratio being less than the first preset value is greater than the first value, then the MOS transistor is determined to be short-circuited. When the MOS transistor is in the ON state, if the first ratio of the first voltage to the second voltage is greater than a third preset value, and the duration of this ratio being greater than the third preset value is greater than the first value, then the current sensing resistor 300 is determined to be short-circuited. When the MOS transistor is in the OFF state, if the first voltage is less than a second preset value, and the duration of this value is greater than the first value, then the MOS transistor is determined to be short-circuited; however, since no current flows through the current sensing resistor 300 at this time, it is impossible to detect whether the current sensing resistor 300 is short-circuited, and this determination must be made when the MOS transistor is in the ON state.

[0085] Furthermore, the first preset value can be The third preset value can be The second preset value can be V in *80%, the V in The output voltage of power supply 100, wherein R DS(ON)_min R is the minimum on-resistance of the MOS transistor. DS(ON)_max R is the maximum on-resistance of the MOS transistor. DS(ON)_min and the R DS(ON)_max Referring to the datasheet of the selected MOS transistor, the coefficients 80% and 120% are recommended values. However, these values ​​can be flexibly chosen based on the sampling precision. The first value can be 5ms, 10ms, 15ms, 20ms, etc., and the specific value can be set according to the actual application; no restrictions are imposed here.

[0086] Specifically, after the control chip is initialized, it determines whether the MOS transistor is in the on state. When the MOS transistor is in the on state, it determines whether the MOS transistor is short-circuited by sampling data, that is, based on the detected first voltage V. MOS Second voltage The criteria for determining whether a MOS transistor is short-circuited are as follows: If the above judgment criteria are met, i.e., the first ratio is less than the first preset value, then the MOS transistor is considered to have short-circuited. To detect the duration of the MOS transistor short circuit, the output control circuit 405 can start a first timer. When the value of the first timer is greater than or equal to the first value, it indicates that the power supply output protection circuit needs to enter the short-circuit protection state. The output control circuit 405 records the current state of the MOS transistor and simultaneously outputs a control command to control the MOS transistor to be in the off state, while controlling the power supply 100 output voltage to be adjusted to the first voltage value, such as 5V. If the value of the first timer is less than or equal to the first value, then the first timer is initialized, and the judgment on whether the first ratio is less than the first preset value continues.

[0087] Furthermore, if the first ratio is greater than or equal to the first preset value, the output control circuit 405 determines whether the current detection resistor 300 is short-circuited, based on the following criteria: If the above judgment criteria are met, i.e., the first ratio is greater than the third preset value, the second timer is started. If the value of the second timer is greater than or equal to the first value, it indicates that the current detection resistor 300 is short-circuited, and the power output protection circuit needs to enter the short-circuit protection state. The output control circuit 405 records the current state of the MOS transistor and outputs a control command to control the MOS transistor to be in the off state, while simultaneously controlling the output voltage of the power supply 100 to be adjusted to the first voltage value. If the value of the second timer is less than the first value, the second timer is initialized, and the judgment on whether the first ratio is greater than the third preset value continues.

[0088] Furthermore, if the MOS transistor is in the off state, the output control circuit 405 determines whether the MOS transistor is short-circuited, based on: V MOS <V in *80%. If the above judgment criteria are met, i.e., the first voltage is less than the second preset value, the output control circuit 405 starts the first timer. If the value of the first timer is greater than or equal to the first value, it indicates that the MOS transistor is short-circuited, and the power supply output protection circuit needs to enter the short-circuit protection state. The output control circuit 405 records the current state of the MOS transistor and simultaneously outputs a control command to control the MOS transistor to be in the off state and to control the output voltage of the power supply 100 to be adjusted to the first voltage value. If the value of the first timer is less than the first value, the first timer is initialized, and the judgment on whether the first voltage is greater than the first value continues.

[0089] If the MOS transistor and / or current sensing resistor 300 are short-circuited, the power supply output protection circuit enters the short-circuit protection state and remains in the state for N clock cycles. That is, within the first time, the output control circuit 405 controls the MOS transistor to be in the off state and controls the output voltage of the power supply 100 to be adjusted to the first voltage value.

[0090] In this embodiment, the direct detection of dual output current is achieved by controlling the switch 200 and the current detection resistor 300. The two sets of current detection results are used as the basis for judgment to determine whether a single-point short circuit problem has occurred in the power output protection circuit, and enter the protection state accordingly to meet the power supply LPS certification requirements.

[0091] As can be seen, this application proposes a power output protection method in which a control chip detects a first voltage and a second voltage; the first voltage is the voltage difference across the control switch, and the second voltage is the voltage difference across the current detection resistor; the control chip controls the power output voltage and the closing or opening of the control switch according to the first voltage and the second voltage, and can enter a targeted protection state to meet the power supply LPS certification requirements when a single-point short circuit problem occurs in the power output protection circuit.

[0092] It should be understood that "at least one" in the embodiments of this application refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0093] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, "first information" and "second information" are only used to distinguish different information and do not indicate differences in the content, priority, sending order, or importance of these two types of information.

[0094] This application also provides an electronic device, which includes the above-described components. Figure 1 The power output protection circuit shown is shown.

[0095] This application also provides a computer storage medium storing a computer program for electronic data interchange, which causes a computer to perform some or all of the steps of any of the methods described in the above method embodiments.

[0096] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments. This computer program product can be a software installation package.

[0097] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0098] In the several embodiments provided in this application, it should be understood that the disclosed power output protection circuit can be implemented in other ways. For example, the power output protection circuit embodiments described above are merely illustrative, and the components in the above circuit can also be other components with the same function. Furthermore, the mutual couplings or direct couplings or communication connections shown or discussed can be indirect couplings or communication connections through some interfaces, circuits, or components, and can be electrical or other forms.

[0099] In addition, the circuits in the various embodiments of this application can be integrated into a single circuit board, or each circuit can exist as a separate entity, or two or more circuits can be integrated into a single circuit board.

[0100] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand this application and its core ideas. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A power output protection method, characterized in that, This invention relates to a power output protection circuit, comprising a power supply, a control switch, a current sensing resistor, a control chip, and an output port. The current sensing resistor is disposed in the power output circuit. The first and second input terminals of the control chip are respectively connected to the two ends of the control switch. The third and fourth input terminals of the control chip are respectively connected to the two ends of the current sensing resistor. The first output terminal of the control chip is connected to the control terminal of the power supply, and the second output terminal of the control chip is connected to the control terminal of the control switch. The first and fourth input terminals of the control chip may be the same or different ports. The method includes: The control chip detects a first voltage and a second voltage. The first voltage is the voltage across the control switch, and the second voltage is the voltage across the current sensing resistor. The control switch is a MOS transistor. The control chip controls the output voltage of the power supply and the closing or opening of the control switch according to the first voltage and the second voltage, including: determining whether the MOS transistor and / or the current sensing resistor is short-circuited according to the first voltage and the second voltage; when the MOS transistor and / or the current sensing resistor is short-circuited, controlling the control switch to be in a closed state or an open state for a first time period, and controlling the power supply to output a first voltage value for the first time period; The step of determining whether the MOS transistor and / or the current sensing resistor is short-circuited based on the first voltage and the second voltage includes: checking whether the MOS transistor is in the on state; and determining whether the current sensing resistor is short-circuited based on the result of checking whether the MOS transistor is in the on or off state, the first voltage, and the second voltage.

2. The method according to claim 1, characterized in that, The current sensing resistor is specifically installed in the power output circuit, including: The power output circuit includes the output terminal of the power supply being grounded in sequence through the control switch, the output port, and the current sensing resistor; or, The power output circuit includes the power supply output terminal connected to ground in sequence through the current sensing resistor, the control switch, and the output port; or, The power output circuit includes the power supply output terminal connected to ground in sequence through the control switch, the current sensing resistor, and the output port.

3. The method according to claim 1, characterized in that, The control chip includes a first amplifier circuit, a second amplifier circuit, a first analog-to-digital converter circuit, a second analog-to-digital converter circuit, and an output control circuit; The first input terminal of the first amplifier circuit is connected to the first input terminal of the control chip, the second input terminal of the first amplifier circuit is connected to the second input terminal of the control chip, the output terminal of the first amplifier circuit is connected to the input terminal of the first analog-to-digital converter circuit, and the output terminal of the first analog-to-digital converter circuit is connected to the first input terminal of the output control circuit. The first input terminal of the second amplifier circuit is connected to the third input terminal of the control chip, the second input terminal of the second amplifier circuit is connected to the fourth input terminal of the control chip, the output terminal of the second amplifier circuit is connected to the input terminal of the second analog-to-digital converter circuit, and the output terminal of the second analog-to-digital converter circuit is connected to the second input terminal of the output control circuit. The first output terminal of the output control circuit is connected to the first output terminal of the control chip, and the second output terminal of the output control circuit is connected to the second output terminal of the control chip.

4. The method according to claim 3, characterized in that, The control chip determines whether the MOS transistor and / or the current sensing resistor are short-circuited based on the first voltage and the second voltage, including: The output control circuit checks whether the MOS transistor is in the on state; If the MOS transistor is in the on state, the output control circuit determines whether the first ratio is less than a first preset value, where the first ratio is the ratio of the first voltage to the second voltage. If the MOS transistor is in the off state, the output control circuit determines whether the first voltage is less than the second preset value; If the first ratio is less than the first preset value or the first voltage is less than the second preset value, the output control circuit starts the first timer. The output control circuit determines whether the value of the first timer is greater than or equal to the first value; If the value of the first timer is greater than or equal to the first value, the output control circuit determines that the MOS transistor is short-circuited; if the value of the first timer is less than the first value, the output control circuit initializes the first timer. If the first ratio is greater than or equal to the first preset value, the output control circuit determines whether the first ratio is greater than the third preset value; If the first ratio is greater than the third preset value, the output control circuit starts the second timer; The output control circuit determines whether the value of the second timer is greater than or equal to the first value; If the value of the second timer is greater than or equal to the first value, the output control circuit determines that the current detection resistor is short-circuited; if the value of the second timer is less than the first value, the output control circuit initializes the second timer.

5. The method according to claim 4 or 3, characterized in that, The first amplifier circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, and a first operational amplifier, wherein, One end of the first resistor is connected to the first input terminal of the first amplifier circuit, and the other end of the first resistor is connected to the non-inverting input terminal of the first operational amplifier and one end of the third resistor. The other end of the third resistor is connected to the collector of the first transistor. The emitter of the first transistor is connected to one end of the second resistor and the output terminal of the first amplifier circuit. The other end of the second resistor is grounded. The base of the first transistor is connected to the output terminal of the first operational amplifier. One end of the fourth resistor is connected to the second input terminal of the first amplifier circuit, and the other end of the fourth resistor is connected to the inverting input terminal of the first operational amplifier.

6. The method according to claim 4 or 3, characterized in that, The second amplifier circuit includes: a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a second transistor, a third transistor, a fourth transistor, and a second operational amplifier, wherein, One end of the fifth resistor is connected to the second input terminal of the second amplifier circuit. The other end of the fifth resistor is connected to one end of the sixth resistor and the inverting input terminal of the second operational amplifier. The other end of the sixth resistor is connected to the emitter of the second transistor. The base of the second transistor is connected to the output terminal of the second operational amplifier. The collector of the second transistor is connected to the collector, base, and base of the third transistor and the fourth transistor. The emitter of the third transistor is connected to the emitter of the fourth transistor and the VCC terminal of the second operational amplifier. The collector of the fourth transistor is connected to one end of the seventh resistor and the output terminal of the second amplifier circuit. The other end of the seventh resistor is grounded. One end of the eighth resistor is connected to the first input terminal of the second amplifier circuit. The other end of the eighth resistor is connected to the non-inverting input terminal of the operational amplifier.

7. A power output protection circuit, characterized in that, The power output protection circuit includes a power supply, a control switch, a current sensing resistor, a control chip, and an output port. The current sensing resistor is set in the power output circuit. The first and second input terminals of the control chip are respectively connected to the two ends of the control switch. The third and fourth input terminals of the control chip are respectively connected to the two ends of the current sensing resistor. The first output terminal of the control chip is connected to the control terminal of the power supply, and the second output terminal of the control chip is connected to the control terminal of the control switch. The control chip is used to detect a first voltage and a second voltage, wherein the first voltage is the voltage across the control switch and the second voltage is the voltage across the current sensing resistor; the control switch is a MOS transistor. The control chip is used to control the output voltage of the power supply and the closing or opening of the control switch according to the first voltage and the second voltage, including: determining whether the MOS transistor and / or the current sensing resistor is short-circuited according to the first voltage and the second voltage; when the MOS transistor and / or the current sensing resistor is short-circuited, controlling the control switch to be in a closed state or an open state for a first time period, and controlling the power supply to output a first voltage value for the first time period; The step of determining whether the MOS transistor and / or the current sensing resistor is short-circuited based on the first voltage and the second voltage includes: checking whether the MOS transistor is in the on state; and determining whether the current sensing resistor is short-circuited based on the result of checking whether the MOS transistor is in the on or off state, the first voltage, and the second voltage.

8. An electronic device, characterized in that, The electronic device includes the power output protection circuit as described in claim 7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that causes a computer to perform the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, The computer program product contains a computer program that causes a computer to perform the method as described in any one of claims 1-6.

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