Protection circuit and unmanned aerial vehicle
By using a combination of protection switch tube, control switch tube, protection resistor and delay circuit in the protection circuit, the current limiting pre-charge of electronic equipment loads such as drones is achieved, solving the complex design and insufficient response speed in the prior art. The problem of simplifying the circuit structure and maintaining efficient overload protection.
Patent Information
- Application Number
- CN202420512585.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-15
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-03-15
AI Technical Summary
The existing protection circuit is designed in a complex manner when powered on, affects the response speed and increases the circuit area, making it difficult to effectively realize current limiting pre-charge of load in compact electronic devices such as drones.
The combination of protection switch tube, control switch tube, protection resistor and delay circuit is adopted. The delay circuit is used to delay conduction when the load is powered on. The load is first pre-charged by the protection resistor. After the charging is completed, the control switch is controlled. The tube conveys power without loss, simplifying the circuit structure and adding a small number of components.
It realizes current limiting pre-charge of the load when powered on, reduces the design difficulty, maintains the overload protection response speed of the protection circuit, and is suitable for electronic equipment such as compact drones.
Smart Images
Figure CN222191840U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of protection circuits, and in particular to a protection circuit and an unmanned aerial vehicle. Background Art
[0002] The protection circuit is used to cut off the power output to the load when it detects that the input power voltage is too high or too low to protect the load from being damaged by high voltage. It is a necessary circuit in various electronic devices. In some scenarios, the power demand of some loads is inconsistent with the input power supply. The input power needs to be processed by the buck-boost circuit inside or outside the load before being passed to the load. When these loads are powered on, a lower current needs to be input first to start the buck-boost circuit with current limiting charging. After the buck-boost function of the buck-boost circuit is started normally, the normal working current is input. In order to achieve the above functions, the existing designs all add peripheral circuits to the protection circuit, which is complex in design and will affect the response speed of the protection circuit. At the same time, it will also increase the circuit area, which is not conducive to compact electronic devices such as drones. To this end, it is necessary to design a protection circuit with a simple structure that can pre-charge the load with current limiting when powered on. Utility Model Content
[0003] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a protection circuit with a simple structure. Only a few components are needed to realize pre-charging of the load when power is turned on, and the overload protection response speed of the protection circuit will not be affected.
[0004] In order to solve the above problems, the technical solution adopted by the utility model is as follows: a protection circuit, comprising: a protection switch tube, the base of which is connected to the input power supply through a first voltage-dividing resistor, the base is grounded through a second voltage-dividing resistor, and the collector is connected to the input power supply; a control switch tube, the source and the drain are connected in series between the input power supply and the load, the gate is grounded, and the gate is connected to the emitter of the protection switch tube; a protection resistor is connected in parallel between the source and the drain of the control switch tube; a delay circuit is connected in parallel between the gate and the source of the control switch tube, and is used to delay the conduction of the control switch tube when the load is powered on.
[0005] Compared with the prior art, the beneficial effect of the utility model is that when powered on, the delay circuit delays the conduction of the control switch tube, and the power input will first be transmitted to the load through the protection resistor connected in parallel between the source and drain of the control switch tube, and the load is pre-charged with current limiting. After the load pre-charging is completed, the delay time of the delay circuit is also over, and the control switch tube is turned on. At this time, the conduction resistance of the control switch tube is much smaller than the protection resistor, and the protection resistor is equivalent to an open circuit. The input power can be delivered to the load without loss through the control switch tube. This protection circuit only needs to add two or three components on the original basis to realize the pre-charging function of the load when powered on. The circuit structure is simple, the design is easy, and it will not affect the overload protection response speed of the protection circuit.
[0006] In the above protection circuit, the emitter of the protection switch tube is grounded through the first resistor and the second resistor, and the gate of the control switch tube is grounded through the second resistor.
[0007] In the above protection circuit, the delay circuit is an RC delay circuit, including a delay capacitor and a delay resistor, and the delay capacitor and the delay resistor are connected in parallel between the gate and the source of the control switch tube.
[0008] In the above protection circuit, a voltage stabilizing diode is connected in parallel between the source and the gate of the control switch tube.
[0009] In the above protection circuit, the control switch tube is a PMOS tube.
[0010] A drone comprises the above-mentioned protection circuit.
[0011] In the above-mentioned drone, the drain of the control switch tube of the protection circuit is connected to the load through a buck-boost circuit.
[0012] The above-mentioned UAV is characterized in that the buck-boost circuit includes a buck-boost converter chip and its peripheral circuits.
[0013] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The schematic diagram of the protection circuit of the embodiment of the utility model;
[0015] Figure 2 The schematic diagram of the load power supply circuit of the UAV according to the embodiment of the utility model. DETAILED DESCRIPTION
[0016] The embodiments of the present invention are described in detail below. Figure 1An embodiment of the utility model provides a protection circuit, including a protection switch tube Q9, a control switch tube Q8, a protection resistor R53 and a delay circuit. The base of the protection switch tube Q9 is connected to the input power supply through the first voltage-dividing resistor R58, and the base is also grounded through the second voltage-dividing resistor R64. The emitter of the protection switch tube Q9 is connected to the gate of the control switch tube Q8, and the collector is connected to the input power supply. The source and drain of the control switch tube Q8 are connected in series between the input power supply and the load, and the gate is grounded and connected to the emitter of the protection switch tube Q9. The protection resistor R53 is connected in parallel between the source and drain of the control switch tube Q8, and the delay circuit is connected in parallel between the gate and source of the control switch tube Q8. The delay circuit is used to make the voltage between the gate and source of the control switch tube Q8 reach the conduction threshold after a period of delay when the load is powered on, so that the control switch tube Q8 is delayed to turn on.
[0017] In the above protection circuit, the protection switch tube Q9 collects the voltage of the input power input through the first voltage-dividing resistor R58 and the second voltage-dividing resistor R64. During normal operation, the voltage value on the first voltage-dividing resistor R64 is lower than the voltage threshold required for the protection switch tube Q9 to be turned on, and the protection switch tube Q9 is turned off, so that the control switch tube Q8 can be turned on, and the electric energy input by the input power can be input to the load through the control switch tube Q8. When the voltage of the input power input increases, the voltage value on the second voltage-dividing resistor R64 increases. When the voltage value on the second voltage-dividing resistor R64 is higher than the voltage threshold required for the protection switch tube Q9 to be turned on, the protection switch tube Q9 is turned on, and the control switch tube Q8 is turned off, preventing the excessively high voltage of the input power input from flowing to the load, thereby realizing overvoltage protection for the load. When the load is powered on, due to the existence of the delay circuit, the voltage between the gate and the source of the control switch tube Q8 slowly climbs, so that the control switch tube Q8 is delayed for a period of time, and then turned on when the voltage between the gate and the source is stable and higher than its turn-on voltage threshold. At the moment when the load is powered on, since the control switch tube Q8 has not yet turned on, the current input by the input power supply will flow into the load through the protection resistor R53, and pre-charge the load's buck-boost circuit and other circuits that need to be started first. By setting the resistance value of the protection resistor R53, the current output to the load during the pre-charging stage can be limited to prevent the load from being damaged by large current. By setting the parameters of the delay circuit, the delay time of the control switch tube Q8 is adjusted so that the delay time is sufficient for the circuit that needs to be pre-charged in the load to be charged and started, and then the control switch tube Q8 is turned on. Since the on-resistance of the control switch tube Q8 is much smaller than the resistance value of the protection resistor R53, the protection resistor R53 can be regarded as an open circuit after the control switch tube Q8 is turned on, and the electric energy output by the input power supply can be transmitted to the load without loss through the control switch tube Q8.
[0018] The protection circuit of the embodiment of the utility model can realize the pre-charging function of the load when power is turned on by adding only one protection resistor and one delay circuit. Only a small number of components need to be added, which reduces the design difficulty and avoids adding more components to affect the overload protection response speed of the protection circuit. At the same time, the circuit occupies a small area and is suitable for compact electronic devices such as drones.
[0019] Reference Figure 1 The delay circuit generally adopts an RC delay circuit, including a capacitor C70 and a resistor R61, both of which are connected in parallel between the gate and the source of the control switch tube Q8. The delay time is adjusted by adjusting the parameters of the capacitor C70, and the resistance value of the resistor R61 is adjusted so that after the capacitor C70 is fully charged, the voltage divided across the resistor R61 can meet the voltage between the source and the gate required for the control switch tube Q8 to be turned on.
[0020] Reference Figure 1 In this embodiment, since the delay circuit contains a capacitor C70 as an energy storage device, in order to quickly discharge the current in the capacitor C70 when the load is powered off, the emitter of the protection switch tube Q9 is grounded through the resistor R67 and the resistor R68, and the gate of the control switch tube Q8 is grounded through the resistor R68. When the load is powered off, the first voltage-dividing resistor R58, the second voltage-dividing resistor R64 and the resistor R68 form a discharge circuit of the capacitor C70. At this time, the voltage at the positive end of the second voltage-dividing resistor R64 is higher than the voltage at the negative end of the capacitor C70, that is, the base voltage of the protection switch tube Q9 is higher than the emitter voltage. By setting a specific resistance value, the protection switch tube Q9 can reach the conduction condition at this time, so that the protection switch tube Q9 and the resistor R67 form another discharge path of the capacitor C70, which accelerates the release of the energy stored in the capacitor C70.
[0021] Reference Figure 1 In order to protect the control switch tube Q8, a voltage stabilizing diode D27 is provided between the gate and source of the control switch tube Q8 to clamp the voltage between the gate and source of the control switch tube Q8 to prevent the control switch tube Q8 from being damaged by high voltage. The control switch tube Q8 is preferably a PMOS tube, which has extremely low conduction voltage loss, and can transmit the electric energy output by the input power supply to the load almost without loss.
[0022] The drone of the embodiment of the utility model includes the above-mentioned protection circuit, and supplies power to some specific loads through the above-mentioned protection circuit. Figure 2, the drain of the control switch tube Q8 is connected to the load through a buck-boost circuit. When the device is powered on, the switching power supply first transmits the electric energy to the buck-boost circuit through the protection resistor R53 to pre-charge the buck-boost circuit and start the buck-boost circuit. After the buck-boost circuit is started, the normal working electric energy is transmitted to the buck-boost circuit by controlling the switch tube Q8. The buck-boost circuit converts the transmitted electric energy into the electric energy specification required by the load after buck-boost processing, and transmits it to the load to avoid the situation that after power-on, the electric energy output by the switching power supply is directly transmitted to the load due to the failure of the buck-boost circuit to start, causing the load to be damaged by overvoltage or triggering the overvoltage protection of the load, resulting in power-on failure.
[0023] Reference Figure 2 , the buck-boost circuit includes a buck-boost converter chip U4 and its peripheral circuits. In this embodiment, the buck-boost converter chip U4 uses a BUCK chip of model SCT2650 to convert the 24V voltage input by the switching power supply into a 12V voltage, and connects to the load through a jumper connector J7. The peripheral circuit of the buck-boost converter chip needs to be designed according to the selected chip model. Its specific structure can be referred to the technical manual of the selected chip, and its structure is not described here. A light-emitting diode LED4 is provided at the output end of the buck-boost circuit to indicate the power supply status of the load.
[0024] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the present invention.
[0025] In the description of the present utility model, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0026] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0027] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.
Claims
1. A protection circuit, characterized in that: include: A protection switch tube, wherein the base is connected to the input power supply through a first voltage-dividing resistor, the base is grounded through a second voltage-dividing resistor, and the collector is connected to the input power supply; A control switch tube, wherein the source and the drain are connected in series between the input power supply and the load, the gate is grounded, and the gate is connected to the emitter of the protection switch tube; A protection resistor connected in parallel between the source and drain of the control switch tube; The delay circuit is connected in parallel between the gate and source of the control switch tube, and is used to delay the control switch tube from being turned on when the load is powered on.
2. The protection circuit according to claim 1, characterized in that: The emitter of the protection switch tube is grounded through a first resistor and a second resistor, and the gate of the control switch tube is grounded through the second resistor.
3. The protection circuit according to claim 1, characterized in that: The delay circuit is an RC delay circuit, including a delay capacitor and a delay resistor, and the delay capacitor and the delay resistor are connected in parallel between the gate and the source of the control switch tube.
4. The protection circuit according to claim 1, characterized in that: A voltage stabilizing diode is connected in parallel between the source and the gate of the control switch tube.
5. The protection circuit according to claim 1, characterized in that: The control switch tube is a PMOS tube.
6. A drone, characterized in that: The invention comprises a protection circuit according to any one of claims 1 to 5.
7. The drone according to claim 6, characterized in that: The drain of the control switch tube of the protection circuit is connected to the load through a buck-boost circuit.
8. The drone according to claim 7, characterized in that: The buck-boost circuit includes a buck-boost converter chip and its peripheral circuits.