Switching power supply circuit with no-power-consumption current detection
By designing a current detection module in the switching power supply circuit, the combination of the field effect tube Q5, resistor R26 and diode D7 can realize the detection and limiting of the current, solving the problem of the field effect tube crashing and breaking down when the current exceeds the set threshold value. , improves product reliability and efficiency.
Patent Information
- Application Number
- CN202420223441.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-30
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-01-30
AI Technical Summary
Among the existing switching power supplies, the continuous overload capacity of the field effect tube is weak, which is prone to collapse and breakdown when the current exceeds the set threshold, making it difficult to effectively perform current detection and affecting product reliability.
A switching power supply circuit without power consumption current detection is designed, including a control module, a switching module, a current detection module, an input module and an output module. The current detection module realizes the detection and limiting of current through the combination of field effect transistor Q5, resistor R26 and diode D7.
This circuit can effectively detect and limit current, prevent the current from exceeding the set threshold, thereby improving product reliability and efficiency, and eliminating the additional power consumption problem caused by the large sampling resistance value and detection.
Smart Images
Figure CN222484555U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of current detection, in particular to a switching power supply circuit with power-free current detection. Background Art
[0002] With the rapid development of electronic technology, the power supply unit of electronic products has also undergone major changes. The traditional power frequency transformer has rapidly transformed into a switching power supply that is lighter, smaller, has a wider voltage adaptability range, and has a lower cost. Due to the increasingly higher performance requirements of switching power supplies, the switch modules of current switching power supplies usually use field effect transistors, which have a weak continuous overload capacity and will collapse and break down if the current exceeds its nominal limit. Therefore, it is very important to detect the current flowing through the field effect tube and limit the current that is not allowed to exceed the set threshold. It is a key factor in the overall product reliability. Utility Model Content
[0003] The utility model aims to provide a switching power supply circuit which can perform effective and reliable current and voltage detection.
[0004] To solve the above technical problems, a technical solution adopted in the present application is: to provide a switching power supply circuit with power-free current detection, wherein the switching power supply circuit includes a control module, a switch module, a current detection module, an input module and an output module.
[0005] The control module is connected to the switch module and the current detection module, the switch module is connected between the input module and the output module, and the current detection module is connected between the switch module and the output module.
[0006] The current detection module includes a field effect tube Q5, a resistor R26 and a diode D7, the drain of the field effect tube Q5 is connected between the switch module and the output module, the source of the field effect tube Q5 is grounded, the gate of the field effect tube Q5 is connected to the control module, one end of the resistor R26 is connected between the gate of the field effect tube Q5 and the control module, the other end of the resistor R26 is connected to the control module, the anode of the diode D7 is connected between the resistor R26 and the control module, and the cathode of the diode D7 is connected between the drain of the field effect tube Q5 and the switch module.
[0007] As a preferred solution, the current detection module further includes a diode D9, the anode of the diode D9 is connected between the resistor R26 and the control module, and the other end of the diode D9 is connected between the gate of the field effect transistor Q5 and the control module.
[0008] As a preferred solution, the current detection module further includes a resistor R22, one end of which is connected to the resistor R26 and the positive electrode of the diode D7, and the other end of which is connected to the control module and the positive electrode of the diode D9.
[0009] As a preferred solution, the control module includes a main control chip IC1 and a driver chip IC2, the driver chip IC2 is connected to the main control chip IC1, and the gate of the field effect transistor Q5 is connected to the driver chip IC2.
[0010] As a preferred embodiment, the switching power supply circuit further includes a level conversion module, which includes a resistor R36 and a resistor R39, one end of the resistor R36 is connected between the resistor R22 and the main control chip IC1, one end of the resistor R39 is connected between the resistor R36 and the main control chip IC1, and the other end of the resistor R39 is grounded.
[0011] As a preferred solution, the level conversion module also includes a capacitor C29 and a diode D10, the cathode of the diode D10 is connected to the power supply end, the anode of the diode D10 is connected to the main control chip IC1, resistor R36 and resistor R39, one end of the capacitor C29 is connected to the anode of the diode D10, and the other end of the capacitor C29 is grounded.
[0012] As a preferred solution, the switch module includes a field effect transistor Q1, the gate of the field effect transistor Q1 is connected to the driving chip IC2, the drain of the field effect transistor Q1 is connected to the input module, and the source of the field effect transistor Q2 is connected to the output module and the drain of the field effect transistor Q5.
[0013] As a preferred solution, the control module further includes a transistor Q2 and a transistor Q3, the bases of the transistor Q2 and the transistor Q3 are connected to the driving chip IC2, and the emitters of the transistor Q2 and the transistor Q3 are connected to the gate of the field effect transistor Q1.
[0014] As a preferred solution, the control module also includes a transistor Q4 and a transistor Q7, the bases of the transistor Q4 and the transistor Q7 are connected to the driving chip IC2, and the emitters of the transistor Q4 and the transistor Q7 are connected to the gate of the field effect transistor Q5.
[0015] As a preferred solution, the switching power supply circuit further includes a voltage transformation module, and the voltage transformation module is connected between the switching module and the output module.
[0016] The utility model provides a switching power supply circuit with power-free current detection, and the switching power supply circuit includes a control module, a switch module, a current detection module, an input module and an output module. The control module connects the switch module and the current detection module, the switch module is connected between the input module and the output module, and the current detection module is connected between the switch module and the output module. The current detection module includes a field effect tube Q5, a resistor R26 and a diode D7, the drain of the field effect tube Q5 is connected between the switch module and the output module, the source of the field effect tube Q5 is grounded, the gate of the field effect tube Q5 is connected to the control module, one end of the resistor R26 is connected between the gate of the field effect tube Q5 and the control module, the other end of the resistor R26 is connected to the control module, the positive electrode of the diode D7 is connected between the resistor R26 and the control module, and the negative electrode of the diode D7 is connected between the drain of the field effect tube Q5 and the switch module. Among them, the input module is used to access the power supply, the output module is used to access the load, the switch module is connected between the input module and the output module, and the control module can control the on and off of the switch module, thereby controlling the on and off of the loop from the input module to the output module, and then controlling the power supply. When the power is supplied, the loop from the switch module to the output module is turned on, and the control module outputs a driving voltage to the gate of the field effect tube Q5 of the current detection module to turn it on. Since the drain and source of the field effect tube have an inherent characteristic of a specific on-resistance, the current passing through the drain and source of the field effect tube Q5 will generate a voltage drop corresponding to the current; at the same time, the driving voltage passes through the resistor R26, and forms a voltage divider with the diode D7 and the on-voltage of the field effect tube Q5. The control module measures the required current sampling level between the resistor R26 and the diode D7. The control module can judge whether the current voltage passing through the switch module exceeds the current voltage threshold of the switch module based on the measured current sampling level. If it exceeds, the loop between the switch module and the output module can be disconnected to achieve the purpose of protecting the circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the utility model will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0018] Figure 1 The utility model is a schematic diagram of the circuit principle of a switch module, a current detection module, a voltage conversion module and an output module of a switch power supply circuit according to an embodiment of the utility model.
[0019] Figure 2 The utility model is a schematic diagram of the circuit principle of a control module of a switching power supply circuit according to an embodiment of the present invention.
[0020] Figure 3 The utility model is a schematic diagram of the circuit principle of the input module of the switching power supply circuit of an embodiment of the utility model. DETAILED DESCRIPTION
[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments. Similar component numbers in the drawings represent similar components. Obviously, the embodiments to be described below are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0022] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.
[0023] It should also be understood that the terms used in this utility model embodiment specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model embodiments. As used in the utility model embodiment specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.
[0024] Please refer to Figure 1 , 2 3. The utility model provides a switching power supply circuit with power-saving current detection, and the switching power supply circuit includes a control module, a switch module, a current detection module, an input module and an output module.
[0025] The control module is connected to the switch module and the current detection module, the switch module is connected between the input module and the output module, and the current detection module is connected between the switch module and the output module.
[0026] The current detection module includes a field effect tube Q5, a resistor R26 and a diode D7, the drain of the field effect tube Q5 is connected between the switch module and the output module, the source of the field effect tube Q5 is grounded, the gate of the field effect tube Q5 is connected to the control module, one end of the resistor R26 is connected between the gate of the field effect tube Q5 and the control module, the other end of the resistor R26 is connected to the control module, the anode of the diode D7 is connected between the resistor R26 and the control module, and the cathode of the diode D7 is connected between the drain of the field effect tube Q5 and the switch module.
[0027] The input module of the utility model is used to access the power supply, the output module is used to access the load, the switch module is connected between the input module and the output module, and the control module can control the on and off of the switch module, thereby controlling the on and off of the loop from the input module to the output module, and then controlling the power supply. When the power is supplied, the loop from the switch module to the output module is turned on, and the control module outputs a driving voltage to the gate of the field effect tube Q5 of the current detection module to turn it on. Since the drain and source of the field effect tube have an inherent characteristic of a specific on-resistance, the current passing through the drain and source of the field effect tube Q5 will generate a voltage drop corresponding to the current; at the same time, the driving voltage passes through the resistor R26, and forms a voltage division with the diode D7 and the on-voltage of the field effect tube Q5. The control module measures the required current sampling level between the resistor R26 and the diode D7. The control module can judge whether the current voltage passing through the switch module exceeds the current voltage threshold of the switch module according to the measured current sampling level. If it exceeds, the loop between the switch module and the output module can be disconnected to achieve the purpose of protecting the circuit.
[0028] It should be noted that the FET Q5 is an N-channel FET. Due to the characteristics of the FET, the FET has a drain-source conduction internal resistance "RDS(ON)". The current output by the input module passes through the drain and source of the FET Q5 and generates a voltage drop corresponding to the current. The voltage drop = the current flowing through the drain and source of the FET Q5 × the drain-source conduction internal resistance "RDS(ON)". In addition, the diode D7 also plays a role in preventing high-voltage backflow. When the FET Q5 is turned off, the drain of the FET Q5 forms a high voltage, which can prevent the high-voltage backflow from damaging the components in the current detection module loop.
[0029] Furthermore, the current detection module further includes a diode D9, the anode of the diode D9 is connected between the resistor R26 and the control module, and the other end of the diode D9 is connected between the gate of the field effect transistor Q5 and the control module. It can be understood that the diode D9 mainly plays a blanking role, so that the current output signal is blanked when the field effect transistor Q5 is turned off.
[0030] Furthermore, the current detection module further includes a resistor R22, one end of which is connected to the resistor R26 and the anode of the diode D7, and the other end of which is connected to the control module and the anode of the diode D9. It can be understood that the resistor R22 mainly plays a role in current limiting.
[0031] Furthermore, the control module includes a main control chip IC1 and a driving chip IC2, the driving chip IC2 is connected to the main control chip IC1, and the gate of the field effect transistor Q5 is connected to the driving chip IC2.
[0032] Specifically, the specification model of the main control chip IC1 is STM8S003, and the model of the driver chip IC2 is IRS2101S. Pin 13 of the main control chip IC1 is connected to pin 3 of the driver chip IC2, and pin 16 of the main control chip IC1 is connected to pin 2 of the driver chip IC2. The main control chip IC1 controls the square wave drive signal output to the driver chip IC2 according to the current and voltage signals obtained by feedback, so that the driver chip IC2 controls the switch module, thereby realizing the control of the on-off of the switch power supply circuit loop.
[0033] Furthermore, the switching power supply circuit also includes a level conversion module, which includes a resistor R36 and a resistor R39, one end of the resistor R36 is connected between the resistor R22 and the main control chip IC1, one end of the resistor R39 is connected between the resistor R36 and the main control chip IC1, and the other end of the resistor R39 is grounded.
[0034] It can be understood that the current and voltage signals transmitted by the current detection module are divided by the resistors R36 and R39 and then fed back by the pin 11 of the main control chip IC1.
[0035] Furthermore, the level conversion module also includes a capacitor C29 and a diode D10, the cathode of the diode D10 is connected to the power supply end, the anode of the diode D10 is connected to the main control chip IC1, the resistor R36 and the resistor R39, one end of the capacitor C29 is connected to the anode of the diode D10, and the other end of the capacitor C29 is grounded.
[0036] Understandably, capacitor C29 can filter out high-frequency interference signals and improve the accuracy of detection. Among them, diode D10 mainly plays a clamping role to prevent overcurrent and overvoltage from damaging the connecting pins or ports of the main control chip IC1, thereby improving the safety and stability of the circuit.
[0037] Furthermore, the switch module includes a field effect transistor Q1, a gate of the field effect transistor Q1 is connected to the driving chip IC2, a drain of the field effect transistor Q1 is connected to the input module, and a source of the field effect transistor Q2 is connected to the output module and the drain of the field effect transistor Q5.
[0038] It can be understood that the field effect transistor Q1 is an N-channel field effect transistor.
[0039] Further, the control module also includes a transistor Q2 and a transistor Q3, the bases of the transistor Q2 and the transistor Q3 are connected to the driver chip IC2, and the emitters of the transistor Q2 and the transistor Q3 are connected to the gate of the field effect transistor Q1. It can be understood that the transistor Q2 is an NPN transistor, and the transistor Q3 is a PNP transistor.
[0040] Further, the control module also includes a transistor Q4 and a transistor Q7, the bases of the transistor Q4 and the transistor Q7 are connected to the driving chip IC2, and the emitters of the transistor Q4 and the transistor Q7 are connected to the gate of the field effect transistor Q5. It can be understood that the transistor Q4 is an NPN transistor, and the transistor Q7 is a PNP transistor.
[0041] Furthermore, the switching power supply circuit also includes a transformer module, which is connected between the switch module and the output module. The transformer module can be a common transformer, which mainly transforms the voltage input from the input module and outputs it to the load through the output module after reaching the required current and voltage.
[0042] Compared with the circuit using a large sampling resistor for current detection, the switching power supply circuit provided by the utility model eliminates the problem of extra power consumption caused by the large resistance of the sampling resistor, so that the switching power supply has higher efficiency and can reduce the unnecessary heat in the circuit loop. In addition, the power / volume ratio of the switching power supply can be improved. The utility model can be applied to a switching power supply that is small in size, light in weight and has a high power requirement.
[0043] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0045] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0046] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0047] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.
[0049] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these modifications and variations.
[0050] The above is a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.
Claims
1. A switching power supply circuit with power-free current detection, characterized in that: The switching power supply circuit includes a control module, a switch module, a current detection module, an input module and an output module; The control module is connected to the switch module and the current detection module, the switch module is connected between the input module and the output module, and the current detection module is connected between the switch module and the output module; The current detection module includes a field effect tube Q5, a resistor R26 and a diode D7, the drain of the field effect tube Q5 is connected between the switch module and the output module, the source of the field effect tube Q5 is grounded, the gate of the field effect tube Q5 is connected to the control module, one end of the resistor R26 is connected between the gate of the field effect tube Q5 and the control module, the other end of the resistor R26 is connected to the control module, the anode of the diode D7 is connected between the resistor R26 and the control module, and the cathode of the diode D7 is connected between the drain of the field effect tube Q5 and the switch module.
2. The switching power supply circuit according to claim 1, characterized in that: The current detection module further includes a diode D9, an anode of the diode D9 is connected between the resistor R26 and the control module, and the other end of the diode D9 is connected between the gate of the field effect transistor Q5 and the control module.
3. The switching power supply circuit according to claim 2, characterized in that: The current detection module further includes a resistor R22 , one end of which is connected to the resistor R26 and the anode of the diode D7 , and the other end of which is connected to the control module and the anode of the diode D9 .
4. The switching power supply circuit according to claim 3, characterized in that: The control module includes a main control chip IC1 and a driver chip IC2. The driver chip IC2 is connected to the main control chip IC1. The gate of the field effect transistor Q5 is connected to the driver chip IC2.
5. The switching power supply circuit according to claim 4, characterized in that: The switching power supply circuit also includes a level conversion module, which includes a resistor R36 and a resistor R39, one end of the resistor R36 is connected between the resistor R22 and the main control chip IC1, one end of the resistor R39 is connected between the resistor R36 and the main control chip IC1, and the other end of the resistor R39 is grounded.
6. The switching power supply circuit according to claim 5, characterized in that: The level conversion module also includes a capacitor C29 and a diode D10, the cathode of the diode D10 is connected to the power supply end, the anode of the diode D10 is connected to the main control chip IC1, the resistor R36 and the resistor R39, one end of the capacitor C29 is connected to the anode of the diode D10, and the other end of the capacitor C29 is grounded.
7. The switching power supply circuit according to claim 4, characterized in that: The switch module includes a field effect transistor Q1, a gate of the field effect transistor Q1 is connected to the driving chip IC2, a drain of the field effect transistor Q1 is connected to the input module, and a source of the field effect transistor Q2 is connected to the output module and the drain of the field effect transistor Q5.
8. The switching power supply circuit according to claim 7, characterized in that: The control module further includes a transistor Q2 and a transistor Q3, the bases of the transistor Q2 and the transistor Q3 are connected to the driving chip IC2, and the emitters of the transistor Q2 and the transistor Q3 are connected to the gate of the field effect transistor Q1.
9. The switching power supply circuit according to claim 8, characterized in that: The control module further includes a transistor Q4 and a transistor Q7, the bases of the transistor Q4 and the transistor Q7 are connected to the driving chip IC2, and the emitters of the transistor Q4 and the transistor Q7 are connected to the gate of the field effect transistor Q5.
10. The switching power supply circuit according to claim 1, characterized in that: The switching power supply circuit further includes a voltage transformation module, and the voltage transformation module is connected between the switching module and the output module.