Power-on protection circuit, switching power supply and electric equipment

Abstract

The utility model provides a power-on protection circuit, a switching power supply and electric equipment. The power-on protection circuit comprises a power supply load; the first voltage division circuit is formed by connecting a first activation resistor R6 and a second activation resistor R7 in series, the first activation resistor R6 is connected with the power supply input positive electrode end, the second activation resistor R7 is connected with the power supply input negative electrode end, and the first activation resistor R6 is connected with a power supply load in parallel; the activation control module comprises a first control switch, the first control switch is connected with the second activation resistor R7 in parallel, and the activation control module controls the connection state of the second activation resistor R7 by controlling the first control switch to be switched on or switched off. The power-on protection circuit provided by the utility model solves the technical problem that the switching power supply and the electrolytic capacitor are easy to break down because the switching power supply is arranged for a long time in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of protection circuit technology, specifically to a power-on protection circuit, a switching power supply, and electrical equipment. Background Technology

[0002] If a switching power supply is left unused for an extended period, the electrolyte in its electrolytic capacitors will solidify, causing a decline in capacitor performance. Therefore, electrolytic capacitors in a switching power supply that has been stored for a long time need to be activated before reuse. However, directly connecting the electrolytic capacitors to their rated voltage during activation can easily lead to a short circuit, damaging the power supply and reducing its lifespan.

[0003] Therefore, existing technologies need further development. Utility Model Content

[0004] The purpose of this utility model is to overcome the above-mentioned technical deficiencies and provide a power protection circuit, a switching power supply and electrical equipment to solve the technical problem that switching power supplies and electrolytic capacitors are prone to failure due to prolonged storage in related technologies.

[0005] To achieve the above technical objectives, the present invention adopts the following technical solution: A power protection circuit is provided, comprising: a power supply load; a first voltage divider circuit, wherein the first voltage divider circuit is composed of a first activation resistor R6 and a second activation resistor R7 connected in series, the first activation resistor R6 being connected to the positive terminal of the power supply input, the second activation resistor R7 being connected to the negative terminal of the power supply input, and the first activation resistor R6 being connected in parallel with the power supply load; and an activation control module, comprising a first control switch, the first control switch being connected in parallel with the second activation resistor R7, the activation control module controlling the connection state of the second activation resistor R7 by controlling the first control switch to be on or off.

[0006] Furthermore, the activation control module includes a capacitor C1, with its first end connected to the positive terminal of the power supply input and its second end connected to the negative terminal of the power supply input; the base of the first control switch is connected to the second end of the capacitor C1, the collector of the first control switch is connected to the first activation resistor R6, and the emitter of the first control switch is connected to the negative terminal of the power supply input.

[0007] Furthermore, the activation control module includes a first control resistor R4 and a second control resistor R5. Both the first control resistor R4 and the second control resistor R5 are connected in series with the capacitor C1, and the connection node of the first control resistor R4 and the second control resistor R5 is connected to the capacitor C1.

[0008] Furthermore, the power-on protection circuit includes: a switch module, the input terminal of which is connected to the positive terminal of the power supply input, and the output terminal of which is connected to the first voltage divider circuit and the activation control module. The switch module includes an on state and an off state. A switch control module is connected to the control terminal of the switch module and is used to detect the power supply status of the power supply load. When a short circuit is detected in the power supply load, the switch module is controlled to disconnect.

[0009] Furthermore, the switching module includes a switching transistor Q2, the collector of which is connected to the positive terminal of the power supply input, the base of which serves as the control terminal and is connected to the switching control module, and the emitter of which is connected to the power supply load.

[0010] Furthermore, the switching module includes a switching module resistor R3, the first end of which is connected to the collector of the switching transistor Q2, and the second end of which is connected to the base of the switching transistor Q2.

[0011] Furthermore, the switching control module includes a switching control transistor Q1, the base of which is connected to a second voltage divider circuit, which provides a control voltage to the base of the switching control transistor Q1, the emitter of which is connected to the power supply load, and the collector of which is connected to the base of the switching transistor Q2.

[0012] Furthermore, the second voltage divider circuit is composed of a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 is connected to the positive terminal of the power supply input, and the second resistor R2 is connected to the negative terminal of the power supply input. The connection node of the first resistor R1 and the second resistor R2 is connected to the base of the switch control transistor Q1.

[0013] A switching power supply, comprising the aforementioned power-on protection circuit.

[0014] An electrical appliance includes the aforementioned power protection circuit.

[0015] Beneficial effects:

[0016] 1. The power-on protection circuit in this embodiment is applied to a switching power supply. By outputting a voltage lower than the rated voltage, the electrolytic capacitor is activated. Once activation is complete, the voltage is switched back to the rated voltage. This effectively activates electrolytic capacitors that have been stored for a long time. Using an output voltage lower than the rated voltage can prevent short-circuit faults in the electrolytic capacitors, avoid power supply losses, and improve the lifespan of the switching power supply. This solves the technical problem in related technologies where switching power supplies and electrolytic capacitors are prone to failure due to prolonged storage.

[0017] 2. By controlling the switch module to conduct, the first voltage divider circuit and the activation control module can be connected to the positive terminal of the power supply input; when a short circuit occurs in the power supply load, the switch control module controls the switch module to disconnect, triggering overcurrent protection to protect the components from damage, thereby protecting the power supply load and other downstream components.

[0018] 3. In the switching power supply of this embodiment, by adopting a power-on protection circuit with overcurrent protection and switchable voltage output value, the problems of switchable input voltage of electrolytic capacitors after long-term storage and protection against short-circuit faults in electrolytic capacitors can be effectively solved. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the power-on protection circuit used in an embodiment of this utility model.

[0020] The above figures include the following reference numerals:

[0021] 10. First voltage divider circuit; 20. Activation control module; 30. First control switch; 40. Switch module; 50. Switch control module; 60. Second voltage divider circuit. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0023] According to an embodiment of this utility model, a power-on protection circuit is provided. Please refer to [link / reference]. Figure 1 The system includes: a power supply load; a first voltage divider circuit 10, which is composed of a first activation resistor R6 and a second activation resistor R7 connected in series. The first activation resistor R6 is connected to the positive terminal of the power supply input, and the second activation resistor R7 is connected to the negative terminal of the power supply input. The first activation resistor R6 is connected in parallel with the power supply load; and an activation control module 20, which includes a first control switch 30 connected in parallel with the second activation resistor R7. The activation control module 20 controls the connection state of the second activation resistor R7 by controlling the first control switch 30 to be turned on or off.

[0024] By setting the first control switch 30, the connection state of the second activation resistor R7 can be controlled by turning the first control switch 30 on or off, thereby changing the voltage division value of R6 and thus changing the voltage value output to the power supply load. When the first control switch 30 is on, the second activation resistor R7 is short-circuited, and the rated voltage is output. When the first control switch 30 is off, the second activation resistor R7 and the first activation resistor R6 form a voltage divider circuit, and the output voltage is less than the rated voltage, so the output voltage lower than the rated voltage is output to the power supply load.

[0025] The power-on protection circuit in this embodiment is applied to a switching power supply. By outputting a voltage lower than the rated voltage, the electrolytic capacitor is activated. Once activation is complete, the voltage is switched back to the rated voltage. This effectively activates electrolytic capacitors that have been stored for a long time. Using an output voltage lower than the rated voltage can prevent short-circuit faults in the electrolytic capacitors, avoid power supply losses, and improve the lifespan of the switching power supply. This solves the technical problem in related technologies where switching power supplies and electrolytic capacitors are prone to failure due to prolonged storage.

[0026] It is understood that the electrical load in this embodiment includes, but is not limited to, electrolytic capacitors, and the power protection circuit in this embodiment can be connected to other power supply loads or electrical equipment.

[0027] In the power-on protection circuit of this embodiment, see... Figure 1 The activation control module 20 includes a capacitor C1. The first terminal of capacitor C1 is connected to the positive terminal of the power supply input, and the second terminal of capacitor C1 is connected to the negative terminal of the power supply input. The base of the first control switch 30 is connected to the second terminal of capacitor C1, the collector of the first control switch 30 is connected to the first activation resistor R6, and the emitter of the first control switch 30 is connected to the negative terminal of the power supply input. By setting capacitor C1, when the circuit is on, the circuit charges capacitor C1. During charging, the first activation resistor R6 and the second activation resistor R7 form an output voltage divider circuit, and the output voltage is the voltage divided by the first activation resistor R6. When charging is complete, the first control switch 30 is turned on, the second activation resistor R7 is short-circuited, and the rated voltage is output.

[0028] Preferably, the first control switch 30 is an NPN transistor.

[0029] In the power-on protection circuit of this embodiment, see... Figure 1The activation control module 20 includes a first control resistor R4 and a second control resistor R5. Both the first control resistor R4 and the second control resistor R5 are connected in series with the capacitor C1, and the connection node of the first control resistor R4 and the second control resistor R5 is connected to the capacitor C1. Specifically, by setting the first control resistor R4 and the second control resistor R5, a voltage divider circuit is formed to provide a voltage divider to the base of the first control switch 30. At the same time, the charging time constant t = R * C of the capacitor C1 is also determined by the first control resistor R4, the second control resistor R5, and the capacitor C1.

[0030] Specifically, the first activation resistor R6 and the second activation resistor R7 form a voltage divider circuit. After the power-on protection circuit is powered on, the voltage output to the power supply load within the time controlled by the time constant t = R*C is provided by the first activation resistor R6 to activate the electrolytic capacitor. After the charging time constant t = R*C, the electrolytic capacitor is activated and capacitor C1 is fully charged. The voltage divider circuit composed of the first control resistor R4 and the second control resistor R5 sends an electrical signal to the base of the first control switch 30, triggering the first control switch 30 to conduct. The second activation resistor R7 is short-circuited, and the voltage divider circuit composed of the first activation resistor R6 and the second activation resistor R7 fails. Only the first activation resistor R6 provides the normal rated operating voltage.

[0031] In the power-on protection circuit of this embodiment, see... Figure 1 The power protection circuit includes: a switch module 40, the input terminal of which is connected to the positive terminal of the power supply input, and the output terminal of which is connected to the first voltage divider circuit 10 and the activation control module 20. The switch module 40 includes an on state and an off state; and a switch control module 50, which is connected to the control terminal of the switch module 40 and is used to detect the power supply status of the power supply load. When a short circuit is detected in the power supply load, the switch module 40 is controlled to disconnect.

[0032] With the above settings, by controlling the switch module 40 to be turned on, the first voltage divider circuit 10 and the activation control module 20 can be connected to the positive terminal of the power supply input; when the power supply load is short-circuited, the switch control module 50 controls the switch module 40 to be turned off, triggering overcurrent protection to protect the components from damage, thereby protecting the power supply load and other downstream components.

[0033] With the above settings, if a short circuit occurs in the electrolytic capacitor during the operation of the switching power supply, the overcurrent protection will be triggered, and the switching module 40 will be disconnected.

[0034] In the power-on protection circuit of this embodiment, see... Figure 1The switching module 40 includes a switching transistor Q2. The collector of the switching transistor Q2 is connected to the positive terminal of the power supply input, the base of the switching transistor Q2 is connected to the switching control module 50 as a control terminal, and the emitter of the switching transistor Q2 is connected to the power supply load. By setting the switching transistor Q2, when the circuit is powered on normally, the emitter junction of the switching transistor Q2 receives a forward voltage and conducts, thereby causing the circuit to start charging capacitor C1.

[0035] Preferably, the switching transistor Q2 is an NPN transistor.

[0036] In the power-on protection circuit of this embodiment, see... Figure 1 The switching module 40 includes a switching module resistor R3. The first end of the switching module resistor R3 is connected to the collector of the switching transistor Q2, and the second end of the switching module resistor R3 is connected to the base of the switching transistor Q2. With this configuration, the switching module resistor R3 is connected between the base and collector of the switching transistor Q2, providing the emitter junction forward voltage for the switching transistor Q2 when it is turned on, during normal circuit operation.

[0037] In the power-on protection circuit of this embodiment, see... Figure 1 The switching control module 50 includes a switching control transistor Q1. The base of the switching control transistor Q1 is connected to a second voltage divider circuit 60, which provides a control voltage to the base of the switching control transistor Q1. The emitter of the switching control transistor Q1 is connected to the power supply load, and the collector of the switching control transistor Q1 is connected to the base of the switching transistor Q2. With this configuration, the emitters of both the switching control transistors Q1 and Q2 are connected to the positive output terminal, providing a short-circuit loop between the base and emitter of the switching transistor Q2 when overcurrent protection is triggered. When a short circuit occurs, the emitter voltages of both the switching control transistors Q1 and Q2 are 0.

[0038] Preferably, the switching control transistor Q1 is an NPN transistor.

[0039] In the power-on protection circuit of this embodiment, see... Figure 1 The second voltage divider circuit 60 is composed of a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 is connected to the positive terminal of the power supply input, and the second resistor R2 is connected to the negative terminal of the power supply input. The connection node of the first resistor R1 and the second resistor R2 is connected to the base of the switch control transistor Q1.

[0040] Specifically, the first resistor R1 and the second resistor R2 form a voltage divider circuit to provide a control voltage for the base of the switch-controlled transistor Q1 to turn on or off. When the switching power supply is powered on normally, the circuit makes the base potential of the switch-controlled transistor Q1 lower than the emitter potential through the voltage division effect of the first resistor R1 and the second resistor R2. The emitter junction withstands the reverse voltage, and the switch-controlled transistor Q1 is turned off.

[0041] If a short circuit occurs in the power supply load during the operation of the switching power supply, the overcurrent protection is triggered. At this time, the emitter of the switching control transistor Q1 is equivalent to being connected to the negative terminal of the output, and the voltage value is 0. The switching control transistor Q1 is turned on. At this time, the base and emitter of the switching transistor Q2 are equivalent to a short circuit, and the switching transistor Q2 is in the cut-off state. The first voltage divider circuit 10 and the activation control module 20 are both cut off to protect the downstream components.

[0042] Specifically, the switch module 40 and the switch control module 50 constitute the overcurrent protection section of the first half of the circuit, while the first voltage divider circuit 10 and the activation control module 20 constitute the switchable voltage output circuit of the second half. When the power supply is working, it first outputs a voltage lower than the rated voltage to the load, and then switches back to the rated voltage output after a certain period of time. This period is determined by the resistance and capacitance values ​​of the first control resistor R4, the second control resistor R5, the first activation resistor R6, the second activation resistor R7, and the capacitor C1. If a short circuit occurs in the electrolytic capacitor, the overcurrent protection of the first half is triggered, protecting the subsequent components from damage. The power protection circuit of this embodiment is simple and practical, with low component cost and easy-to-replace and maintain circuit components.

[0043] In the switching power supply of this embodiment, the switching power supply includes the power-on protection circuit as described above.

[0044] In the switching power supply of this embodiment, by adopting a power-on protection circuit with overcurrent protection and switchable voltage output value, the problems of switchable input voltage of the electrolytic capacitor when the switching power supply is turned on after being left unused for a long time and protection after the electrolytic capacitor has a short circuit fault can be effectively solved.

[0045] In the electrical equipment of this embodiment, the electrical equipment includes the power protection circuit as described above.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0048] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0049] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0050] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A power-on protection circuit, characterized in that, include: Power supply load; The first voltage divider circuit (10) is composed of a first activation resistor R6 and a second activation resistor R7 connected in series. The first activation resistor R6 is connected to the positive terminal of the power supply input, and the second activation resistor R7 is connected to the negative terminal of the power supply input. The first activation resistor R6 is connected in parallel with the power supply load. An activation control module (20) is included, comprising a first control switch (30) connected in parallel with a second activation resistor R7. The activation control module (20) controls the connection state of the second activation resistor R7 by controlling the first control switch (30) to be turned on or off.

2. The power-on protection circuit according to claim 1, characterized in that, The activation control module (20) includes a capacitor C1, the first end of which is connected to the positive terminal of the power supply input, and the second end of which is connected to the negative terminal of the power supply input. The base of the first control switch (30) is connected to the second end of the capacitor C1, the collector of the first control switch (30) is connected to the first activation resistor R6, and the emitter of the first control switch (30) is connected to the negative terminal of the power supply input.

3. The power-on protection circuit according to claim 2, characterized in that, The activation control module (20) includes a first control resistor R4 and a second control resistor R5. Both the first control resistor R4 and the second control resistor R5 are connected in series with the capacitor C1, and the connection node of the first control resistor R4 and the second control resistor R5 is connected to the capacitor C1.

4. The power-on protection circuit according to claim 1, characterized in that, The power-on protection circuit includes: A switch module (40) is provided, wherein the input terminal of the switch module (40) is connected to the positive terminal of the power supply input, and the output terminal of the switch module (40) is connected to the first voltage divider circuit (10) and the activation control module (20). The switch module (40) includes an on state and an off state. A switch control module (50) is connected to the control terminal of the switch module (40) and is used to detect the power supply status of the power supply load. When a short circuit is detected in the power supply load, the switch module (40) is controlled to disconnect.

5. The power-on protection circuit according to claim 4, characterized in that, The switching module (40) includes a switching transistor Q2. The collector of the switching transistor Q2 is connected to the positive terminal of the power supply input. The base of the switching transistor Q2 is connected to the switching control module (50) as a control terminal. The emitter of the switching transistor Q2 is connected to the power supply load.

6. The power-on protection circuit according to claim 5, characterized in that, The switching module (40) includes a switching module resistor R3, the first end of which is connected to the collector of the switching transistor Q2, and the second end of which is connected to the base of the switching transistor Q2.

7. The power-on protection circuit according to claim 5, characterized in that, The switch control module (50) includes a switch control transistor Q1. The base of the switch control transistor Q1 is connected to a second voltage divider circuit (60). The second voltage divider circuit (60) is used to provide a control voltage to the base of the switch control transistor Q1. The emitter of the switch control transistor Q1 is connected to the power supply load. The collector of the switch control transistor Q1 is connected to the base of the switch transistor Q2.

8. The power-on protection circuit according to claim 7, characterized in that, The second voltage divider circuit (60) is composed of a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 is connected to the positive terminal of the power supply input, and the second resistor R2 is connected to the negative terminal of the power supply input. The connection node of the first resistor R1 and the second resistor R2 is connected to the base of the switch control transistor Q1.

9. A switching power supply, characterized in that, The switching power supply includes a power-on protection circuit as described in any one of claims 1 to 8.

10. An electrical appliance, characterized in that, The electrical equipment includes a power-on protection circuit as described in any one of claims 1 to 8.

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