Protection circuit based on power supply driving chip, switching power supply and electric equipment

Abstract

The utility model discloses a protection circuit based on a power supply driving chip, a switching power supply and electric equipment. The protection circuit comprises a voltage sampling end used for being connected with a compensation pin of the power supply driving chip; the first connecting end is used for connecting a reference voltage source; the second connecting end is used for connecting a wave-by-wave current detection pin of the power supply driving chip; and the protection circuit is used for triggering the first connecting end to be coupled to the second connecting end under the condition that the voltage of the voltage sampling end exceeds a preset voltage threshold value, and pulling up the voltage of the wave-by-wave current detection pin so as to trigger the interior of the power supply driving chip to stop outputting the driving signal. In the embodiment of the invention, a simple circuit form is provided, overload protection and short-circuit protection of the power supply driving chip are realized, a peripheral protection circuit does not need to be frequently designed, the circuit design can be simplified, and the efficiency of the circuit design can be improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a protection circuit, switching power supply and electrical equipment based on a power driver chip. Background Technology

[0002] The UCx84x series power driver chips are commonly used fixed-frequency control driver chips in the field of switching power supplies. However, they do not integrate overload protection and short-circuit protection functions. This forces users to invest extra effort in designing external protection circuits when designing circuits, increasing the complexity and workload of the design. At the same time, multiple debugging is required. This process is not only time-consuming, but also prone to causing new problems due to improper debugging, which greatly hinders the improvement of circuit design efficiency, prolongs the product development cycle, and is not conducive to improving the efficiency of circuit design. Utility Model Content

[0003] This application provides a protection circuit, switching power supply, and electrical equipment based on a power driver chip, which can simplify circuit design and improve circuit design efficiency.

[0004] In a first aspect, embodiments of this application provide a protection circuit based on a power driver chip, comprising:

[0005] The voltage sampling terminal is used to connect to the compensation pin of the power driver chip;

[0006] The first connection terminal is used to connect to a reference voltage source;

[0007] The second connection terminal is used to connect to the wave-by-wave current detection pin of the power driver chip;

[0008] The protection circuit is used to trigger the first connection terminal to couple to the second connection terminal and pull up the voltage of the wave-by-wave current detection pin when the voltage at the voltage sampling terminal exceeds a preset voltage threshold, so as to trigger the power driver chip to stop outputting the drive signal.

[0009] In some embodiments, the protection circuit further includes a voltage regulator, a first switching transistor, and a second switching transistor. The control pin of the first switching transistor is connected to the voltage sampling terminal. The first switching pins of the first switching transistor and the second switching transistor are both coupled to the first connection terminal. The second switching pin of the first switching transistor is coupled to the reference terminal of the voltage regulator. The control pin of the second switching transistor is coupled to the ground reference terminal through the voltage regulator. The second switching pin of the second switching transistor is coupled to the second connection terminal.

[0010] In some embodiments, the control pin of the second switching transistor is connected to the negative terminal of the voltage regulator, and the positive terminal of the voltage regulator is connected to the ground reference terminal.

[0011] In some embodiments, the protection circuit further includes a first resistor and a second resistor connected in series, the second switch pin of the first switch transistor is connected to the ground reference terminal through the first resistor and the second resistor, and the connection point of the first resistor and the second resistor is connected to the reference terminal of the voltage regulator.

[0012] In some embodiments, the protection circuit further includes a third resistor and a fifth resistor, wherein the first switch pin of the second switch transistor is connected to the first connection terminal through the third resistor, and the second switch pin of the second switch transistor is connected to the second connection terminal through the fifth resistor.

[0013] In some embodiments, the protection circuit further includes a unidirectional diode, the second switch pin of the second switch transistor is connected to the positive terminal of the unidirectional diode, and the negative terminal of the unidirectional diode is connected to the second connection terminal through the fifth resistor.

[0014] In some embodiments, the first connection terminal is connected to the reference voltage pin of the power driver chip.

[0015] In some embodiments, the compensation pin is the COMP pin of the power driver chip, and the wave-by-wave current detection pin is the Isence pin of the power driver chip.

[0016] Secondly, embodiments of this application also provide a switching power supply, including a power driver chip and a protection circuit as described in the first aspect.

[0017] Thirdly, embodiments of this application also provide an electrical device, including a protection circuit as described in the first aspect or a switching power supply as described in the second aspect.

[0018] The protection circuit, switching power supply, and electrical equipment based on the power driver chip in this application embodiment have at least the following beneficial effects: Utilizing the characteristic that the voltage output of the compensation pin of the power driver chip can reflect the output load of the power driver chip, the voltage output of the compensation pin is sampled. When the power driver chip experiences output overload or output short circuit, the voltage output of the compensation pin increases. If the voltage at the voltage sampling terminal exceeds a preset voltage threshold, it triggers the first connection terminal to couple to the second connection terminal, causing the reference voltage source to couple to the wave-by-wave current detection pin. Since the reference voltage source pulls up the voltage of the wave-by-wave current detection pin, the wave-by-wave current limiting function of the power driver chip is triggered, and the internal drive signal output of the power driver chip is automatically shut off. This provides a simple circuit form that achieves overload and short-circuit protection for the power driver chip, eliminating the need for frequent design of external protection circuits, simplifying circuit design, and improving circuit design efficiency.

[0019] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the description and the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the framework of a protection circuit based on a power driver chip provided in an embodiment of this application;

[0021] Figure 2 This is a circuit diagram of a protection circuit based on a power driver chip provided in one embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various implementations. Simultaneously, the steps or actions described in the method description can be rearranged or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0023] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0025] The UCx84x series power driver chips are commonly used fixed-frequency control driver chips in the field of switching power supplies. However, they do not integrate overload protection and short-circuit protection functions. This forces users to invest extra effort in designing external protection circuits when designing circuits, increasing the complexity and workload of the design. At the same time, multiple debugging is required. This process is not only time-consuming, but also prone to causing new problems due to improper debugging, which greatly hinders the improvement of circuit design efficiency, prolongs the product development cycle, and is not conducive to improving the efficiency of circuit design.

[0026] Based on this, embodiments of this application provide a protection circuit, switching power supply, and electrical equipment based on a power driver chip. Utilizing the characteristic that the voltage output from the compensation pin of the power driver chip can reflect the output load of the power driver chip, the voltage output from the compensation pin is sampled. When the power driver chip experiences output overload or output short circuit, the voltage output from the compensation pin increases. If the voltage at the voltage sampling terminal exceeds a preset voltage threshold, it triggers the coupling of the first connection terminal to the second connection terminal, causing a reference voltage source to couple to the wave-by-wave current detection pin. Since the reference voltage source pulls up the voltage of the wave-by-wave current detection pin, the wave-by-wave current limiting function of the power driver chip is triggered, and the internal drive signal output of the power driver chip is automatically shut off. This provides a simple circuit configuration that achieves overload and short-circuit protection for the power driver chip, eliminating the need for frequent design of external protection circuits, simplifying circuit design, and improving circuit design efficiency.

[0027] The following description, with reference to the accompanying drawings, illustrates the protection circuit based on the power driver chip, the switching power supply, and the electrical equipment:

[0028] Reference Figure 1 As shown, Figure 1 This is a schematic diagram of the framework of a protection circuit based on a power driver chip provided in one embodiment of this application.

[0029] In some embodiments, the protection circuit based on the power driver chip includes a voltage sampling terminal, a first connection terminal, and a second connection terminal. The structure of the protection circuit of the power driver chip is described in detail below.

[0030] Reference Figure 2 As shown, Figure 2 This is a circuit diagram of a protection circuit based on a power driver chip provided in one embodiment of this application.

[0031] It is understood that the power driver chip U1 in this application embodiment can be a UCx84x chip, or other driver chips that do not integrate overload and short circuit protection functions. This application embodiment does not impose specific limitations.

[0032] Depend on Figure 2As can be seen, the power driver chip U1 includes, but is not limited to, the compensation pin COMP, the inverting input pin Vfb, the wave-by-wave current sensing pin Isense, the oscillator pin RT / CT, the reference voltage pin Vref, the power supply pin VCC, the output pin OUTPUT, and the ground pin GROUND. Specifically, in this embodiment, the compensation pin COMP is the error amplifier compensation pin COMP, and external compensation components can be connected to the compensation pin COMP to modify the error amplifier output. The inverting input pin Vfb is the inverting input pin Vfb of the internal error amplifier, used to control the voltage feedback loop of the power converter to achieve stability. The wave-by-wave current sensing pin Isense is connected to the current sensing resistor, and PWM (Pulse Width Modulation) can use this signal to terminate the conduction of the output pin OUTPUT switch. In addition, a voltage ramp can be applied to the wave-by-wave current sensing pin Isense to configure the operating device through voltage mode control. The oscillator pin RT / CT is the setpoint of the fixed-frequency oscillator. The reference voltage pin Vref is used to provide charging current to the oscillator timing capacitor through the timing resistor. The VCC power supply pin is used as the analog controller bias input to power the device. The OUTPUT output pin is the output of the on-chip driver stage, designed to directly drive the switching transistors. The GROUND ground pin can be used as either power ground or analog ground.

[0033] In some embodiments, the voltage sampling terminal is used to connect to the compensation pin COMP of the power driver chip U1, so that the voltage output by the compensation pin COMP can reflect the output load characteristics of the power driver chip U1. The voltage sampling terminal can sample the voltage output by the compensation pin COMP in real time. The first connection terminal is used to connect to a reference voltage source, and the second connection terminal is used to connect to the wave-by-wave current detection pin Isense of the power driver chip U1. Since the output voltage of the compensation pin COMP of the power driver chip U1 will increase under overload or short circuit conditions, this embodiment of the application sets a protection circuit to protect the compensation pin COMP. The output voltage is monitored in real time. Specifically, the protection circuit triggers the first connection terminal to couple to the second connection terminal when the voltage at the voltage sampling terminal exceeds a preset voltage threshold. At this time, the reference voltage source can couple to the wave-by-wave current detection pin Isense of the power driver chip U1, further raising the voltage of the wave-by-wave current detection pin Isense and triggering the power driver chip U1 to enable the wave-by-wave current limiting function. At this time, the power driver chip U1 stops outputting the drive signal, that is, it shuts down the drive output. This simplifies the circuit design while achieving overload protection and / or short circuit protection for the power driver chip U1, reducing circuit maintenance costs.

[0034] It is worth noting that if the voltage at the voltage sampling terminal exceeds the preset voltage threshold, it indicates that the voltage output by the compensation pin COMP of the power driver chip U1 is too high, which may indicate a short circuit or overload. The following is a detailed explanation of the output voltage of the compensation pin COMP of the power driver chip U1.

[0035] It should be noted that the preset voltage threshold in this application embodiment can be set according to the user's needs or the model of the circuit device, and this application embodiment does not impose any specific restrictions.

[0036] In some embodiments, the protection circuit further includes a voltage regulator U2, a first switching transistor Q1, and a second switching transistor Q2. The control pin of the first switching transistor Q1 is connected to the voltage sampling terminal. The first switching pin of the first switching transistor Q1 and the first switching pin of the second switching transistor Q2 are both coupled to the first connection terminal. The second switching pin of the first switching transistor Q1 is coupled to the reference terminal of the voltage regulator U2. The control pin of the second switching transistor Q2 is coupled to the ground reference terminal through the voltage regulator U2. The second switching pin of the second switching transistor Q2 is coupled to the second connection terminal.

[0037] It is understood that the voltage regulator U2 in this embodiment can be a voltage reference chip, an adjustable precision parallel voltage regulator U2, etc., and the first switch Q1 and the second switch Q2 can be transistors, field-effect transistors, insulated-gate bipolar transistors, etc. Specifically, the voltage regulator U2 in this embodiment is a TL431 voltage regulator U2, the first switch Q1 is an NPN transistor, and the second switch Q2 is a PNP transistor. Specifically, the first switch pin of the first switch Q1 is the collector of the NPN transistor, and the second switch pin is the emitter of the NPN transistor. The first switch pin of the second switch Q2 is the emitter of the PNP transistor, and the second switch pin of the second switch Q2 is the collector of the PNP transistor. That is, the collector of the first switch Q1 and the emitter of the second switch Q2 are both coupled to the first connection terminal. The emitter of the first switch Q1 is coupled to the reference terminal of the voltage regulator U2, and the collector of the second switch Q2 is coupled to the second connection terminal.

[0038] It is worth noting that the voltage regulator U2 in this embodiment of the application is provided with a reference voltage value. When the voltage flowing into the voltage regulator U2 is greater than the reference voltage value of the voltage regulator U2, the voltage regulator U2 is turned on and the second switch Q2 is connected to the reference ground, that is, the second switch Q2 is turned on; when the voltage flowing into the voltage regulator U2 is less than or equal to the reference voltage value of the voltage regulator U2, the voltage regulator U2 is turned off.

[0039] In some embodiments, the control pin of the second switch Q2 is connected to the negative terminal of the voltage regulator U2, and the positive terminal of the voltage regulator U2 is connected to the ground reference terminal, thereby providing a stable reference voltage within a certain range and a stable bias voltage, ensuring the accuracy and stability of the signal.

[0040] In some embodiments, the protection circuit further includes a first resistor R1 and a second resistor R2 connected in series. The second switch pin of the first switch Q1 is connected to the ground reference terminal through the first resistor R1 and the second resistor R2. The connection point of the first resistor R1 and the second resistor R2 is connected to the reference terminal of the voltage regulator U2, thereby forming a voltage divider through the first resistor R1 and the second resistor R2, further ensuring that the voltage of the switch is within a suitable range. At the same time, the first resistor R1 and the second resistor R2 can also achieve current limiting protection for the protection circuit.

[0041] It is understood that the first resistor R1 and the second resistor R2 in the embodiments of this application can be set according to the user's needs, and the embodiments of this application do not impose specific limitations.

[0042] In some embodiments, the protection circuit further includes a first capacitor C1, which is connected in parallel with a second resistor R2. The first capacitor C1 is used to filter the circuit, thereby effectively removing high-frequency noise and ripple in the power supply, filtering out high-frequency interference signals in the power supply, and making the output voltage smoother.

[0043] In some embodiments, the protection circuit further includes a third resistor R3 and a fifth resistor R5. The first switch pin of the second switch transistor Q2 is connected to the first connection terminal through the third resistor R3, and the second switch pin of the second switch transistor Q2 is connected to the second connection terminal through the fifth resistor R5. Thus, a voltage divider is formed by the third resistor R3 and the fifth resistor R5 to prevent excessive current from passing through the transistor while raising the voltage to a preset range.

[0044] In some embodiments, the protection circuit further includes a fourth resistor R4, one end of which is connected between the third resistor R3 and the first switching pin of the second switching transistor Q2, and the other end is connected between the control pin of the second switching transistor Q2 and the voltage regulator U2, thereby achieving current limiting protection for the second switching transistor Q2.

[0045] In some embodiments, the protection circuit further includes a unidirectional diode D1, the second switch pin of the second switch Q2 is connected to the positive terminal of the unidirectional diode D1, and the negative terminal of the unidirectional diode D1 is connected to the second connection terminal through the fifth resistor R5, thereby stabilizing the voltage in the circuit and improving voltage stability.

[0046] In some embodiments, the first connection terminal is connected to the reference voltage pin of the power driver chip U1, thereby providing a stable reference voltage, ensuring accurate measurement of analog signals, and enhancing circuit stability.

[0047] Specifically, when the voltage at the voltage sampling terminal exceeds the preset voltage threshold, the output voltage of the compensation pin COMP of the power driver chip U1 is constant. The voltage output by the compensation pin COMP is sent to the control pin and the second switch pin of the first switch Q1 through the first connection terminal. After being divided by the first resistor R1 and the second resistor R2, it flows into the voltage regulator U2. At this time, the voltage flowing into the voltage regulator U2 is greater than the reference voltage value of the voltage regulator U2, driving the second switch Q2 to conduct. The reference voltage output by the power driver chip U1 is sent to the wave-by-wave current detection pin Isense of the power driver chip U1 through the third resistor R3, the first switch pin and the second switch pin of the second switch Q2, the unidirectional diode D1, and the fifth resistor R5, raising its voltage value above its protection threshold. This pulls up the voltage of the wave-by-wave current detection pin Isense, thereby triggering the wave-by-wave current limiting function of the power driver chip U1. The power driver chip U1 automatically shuts off the output of the drive signal, and the output of the power driver chip U1 is low, realizing overload protection and / or short-circuit protection for the power driver chip U1.

[0048] It should be noted that the protection threshold in this application embodiment can be set according to the user's needs. For example, the protection threshold can be set to 0.8V, 1V, 1.5V, etc. The protection threshold in this application embodiment is 4V. This application embodiment does not impose specific restrictions on the setting of the protection threshold.

[0049] In some embodiments, the compensation pin COMP is the COMP pin of the power driver chip U1, allowing external compensation components to be connected to this pin to modify the error amplifier output. The wave-by-wave current sensing pin Isense is the Isense pin of the power driver chip U1, enabling voltage-mode control of the configured operating device.

[0050] In some embodiments, this application also provides a switching power supply, which includes a power driver chip U1 and a protection circuit as described above.

[0051] It is understood that since the switching power supply includes the power drive chip U1 and the protection circuit described above, the switching power supply can refer to the beneficial effects of any of the above embodiments, and the embodiments of this application do not impose specific limitations.

[0052] In some embodiments, this application also provides an electrical device, which includes the protection circuit described above or the switching power supply described above.

[0053] It is understood that since the electrical equipment includes the protection circuit as described above or the switching power supply as described above, the electrical equipment can refer to the beneficial effects of any of the above embodiments, and the embodiments of this application do not impose specific limitations.

[0054] The features disclosed in the various product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0055] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network nodes. Exemplarily, the division of units is merely a logical functional division; in actual implementation, there may be other division methods, such as multiple units or components being combined, integrated into another system, or some features being ignored or not executed. Furthermore, the coupling, direct coupling, or communication connection between the shown or discussed components may be through interfaces, indirect coupling, or communication connections between devices or units, and may be electrical, mechanical, or other forms. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0056] Those skilled in the art will understand that the systems disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as integrated circuits, such as application-specific integrated circuits (ASICs).

[0057] The above provides a detailed description of preferred embodiments of this application. However, the embodiments of this application are not limited to the above-described implementation methods. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the embodiments of this application. These equivalent modifications or substitutions are all included within the scope defined by the claims of the embodiments of this application. The device embodiments described above are merely illustrative. For example, the division of units is merely a logical functional division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection between the devices or units shown or discussed may be through some interfaces. The indirect coupling or communication connection between the devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate. Components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiment solution according to actual needs.

[0058] The above is a detailed description of the preferred embodiments of this application. However, this application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A protection circuit based on a power driver chip, characterized in that, include: The voltage sampling terminal is used to connect to the compensation pin of the power driver chip; The first connection terminal is used to connect to a reference voltage source; The second connection terminal is used to connect to the wave-by-wave current detection pin of the power driver chip; The protection circuit is used to trigger the first connection terminal to couple to the second connection terminal and pull up the voltage of the wave-by-wave current detection pin when the voltage at the voltage sampling terminal exceeds a preset voltage threshold, so as to trigger the power driver chip to stop outputting the drive signal.

2. The protection circuit according to claim 1, characterized in that, The protection circuit further includes a voltage regulator, a first switching transistor, and a second switching transistor. The control pin of the first switching transistor is connected to the voltage sampling terminal. The first switching pin of the first switching transistor and the first switching pin of the second switching transistor are both coupled to the first connection terminal. The second switching pin of the first switching transistor is coupled to the reference terminal of the voltage regulator. The control pin of the second switching transistor is coupled to the ground reference terminal through the voltage regulator. The second switching pin of the second switching transistor is coupled to the second connection terminal.

3. The protection circuit according to claim 2, characterized in that, The control pin of the second switching transistor is connected to the negative terminal of the voltage regulator, and the positive terminal of the voltage regulator is connected to the ground reference terminal.

4. The protection circuit according to claim 2, characterized in that, The protection circuit also includes a first resistor and a second resistor connected in series. The second switch pin of the first switch transistor is connected to the ground reference terminal through the first resistor and the second resistor. The connection point of the first resistor and the second resistor is connected to the reference terminal of the voltage regulator.

5. The protection circuit according to claim 2, characterized in that, The protection circuit further includes a third resistor and a fifth resistor. The first switch pin of the second switch transistor is connected to the first connection terminal through the third resistor, and the second switch pin of the second switch transistor is connected to the second connection terminal through the fifth resistor.

6. The protection circuit according to claim 5, characterized in that, The protection circuit also includes a unidirectional diode, the second switch pin of the second switch transistor is connected to the positive terminal of the unidirectional diode, and the negative terminal of the unidirectional diode is connected to the second connection terminal through the fifth resistor.

7. The protection circuit according to claim 1, characterized in that, The first connection terminal is connected to the reference voltage pin of the power driver chip.

8. The protection circuit according to claim 1, characterized in that, The compensation pin is the COMP pin of the power driver chip, and the wave-by-wave current detection pin is the Isence pin of the power driver chip.

9. A switching power supply, characterized in that, It includes a power driver chip and a protection circuit as described in any one of claims 1 to 8.

10. An electrical appliance, characterized in that, It includes the protection circuit as described in any one of claims 1 to 8 or the switching power supply as described in claim 9.

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