CN214626946U - Load switch circuit and electronic equipment - Google Patents
Load switch circuit and electronic equipment Download PDFInfo
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- CN214626946U CN214626946U CN202120349548.2U CN202120349548U CN214626946U CN 214626946 U CN214626946 U CN 214626946U CN 202120349548 U CN202120349548 U CN 202120349548U CN 214626946 U CN214626946 U CN 214626946U
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Abstract
The embodiment of the utility model discloses a load switch circuit and electronic equipment, the load switch circuit includes first switch module, second switch module and third switch module; the first switch module is connected with the input power supply at a first connection point, connected with the load at a second connection point, and used for being switched on when the voltage at two ends of the first switch module is greater than or equal to a first preset threshold value and being switched off when the voltage at two ends of the first switch module is less than the first preset threshold value; the second switch module is connected to the first connection point and the second connection point respectively, is connected to the third connection point with the first switch module, is used for conducting when the first switch module is disconnected and is disconnected when the first switch module is conducted, and the third switch module is connected with the second switch module, is connected with the second connection point and the ground respectively, is used for conducting when the second switch module is conducted and is disconnected when the second switch module is disconnected. By the mode, the load switch can be controlled by adopting a circuit structure, and the applicability is strong.
Description
Technical Field
The utility model relates to an electronic circuit technical field especially relates to a load switch circuit and electronic equipment.
Background
A load switch generally refers to an electronic relay that can be used to turn on and off a power rail in a system, and is usually a power-type electronic switch that connects a power source to a device (load) to be powered and provides a switch control based on a control signal to connect or disconnect the load to the power source, i.e., the load switch can be turned on or off (stopped) by controlling the on/off of the load switch through a logic level. Load switches offer many advantages to the system and integrate protection functions that are often difficult to implement with discrete components.
In the prior art, the load switch integrated chip is usually controlled by a unit to realize the function of the load switch. However, the load switch integrated chip has a certain limitation range for both the input voltage and the input current, and is poor in applicability.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a aim at providing a load switch circuit and electronic equipment, the utility model discloses can adopt circuit structure to realize stronger to load switch's control, the suitability.
To achieve the above object, in a first aspect, the present invention provides a load switch circuit for connecting with a load, the load switch circuit including:
the first switch module is connected with a first connecting point and the load at a second connecting point, and is used for being switched on when the voltage at two ends of the first switch module is greater than or equal to a first preset threshold value and being switched off when the voltage at two ends of the first switch module is smaller than the first preset threshold value, wherein the voltage at two ends of the first switch module is provided by the input power supply;
the second switch module is respectively connected to the first connection point and the second connection point, is also connected to a third connection point together with the first switch module, and is used for being switched on when the first switch module is switched off and being switched off when the first switch module is switched on;
and the third switch module is connected with the second switch module, is respectively connected with the second connection point and the ground, and is used for being switched on when the second switch module is switched on and being switched off when the second switch module is switched off.
In an alternative, the load switching circuit further includes a fourth switching module;
the input power supply is connected to the first connection point through the fourth switch module, and the fourth switch module is also connected to the third connection point;
the fourth switch module is used for being switched on when the voltage at two ends of the fourth switch module is larger than or equal to a second preset threshold value and being switched off when the voltage at two ends of the fourth switch module is smaller than the second preset threshold value, wherein the voltage at two ends of the fourth switch module is provided by the input power supply.
In an optional manner, the fourth switching module includes a first diode, a first resistor, a first zener diode, and a first switching tube;
the anode of the first diode is connected with the input power supply, the cathode of the first diode is respectively connected with one end of the first resistor, the first end of the first switch tube, the first switch module and the second switch module, the other end of the first resistor is respectively connected with the cathode of the first voltage stabilizing diode and the control end of the first switch tube, the anode of the first voltage stabilizing diode is grounded, and the second end of the first switch tube is respectively connected with the first switch module and the second switch module.
In an optional mode, the first switch module comprises a second switch tube and a first capacitor;
the control end of the second switch tube is connected to the third connection point, the first end of the second switch tube is connected to the first connection point, the second end of the third switch tube is connected to the second connection point, and two ends of the first capacitor are respectively connected with the first connection point and the third connection point.
In an optional manner, the second switch module includes a first switch unit and a second switch unit;
the first switch unit is connected to the first connection point and the third connection point respectively, and is used for switching a switch state based on the input power supply so as to control a connection state between the input power supply and the second switch unit;
the second switch unit is connected to the first switch unit, the second connection point, and the third switch module, and the second switch unit is configured to switch a switch state based on a switch state of the first switch unit and a switch state of the first switch module to control a switch state of the third switch module.
In an optional mode, the first switch unit comprises a third switch tube and a second resistor;
the control end of the third switching tube and one end of the second resistor are both connected to the second connection point, the other end of the second resistor is grounded, the first end of the third switching tube is connected to the first connection point, and the second end of the third switching tube is connected with the second switching unit.
In an optional mode, the second switching unit includes a fourth switching tube and a third resistor;
the control end of the fourth switch tube is connected with one end of the third resistor, the other end of the third resistor is connected to the second connection point, the first end of the fourth switch tube is connected with the first switch unit, and the second end of the fourth switch tube is connected with the third switch module.
In an optional manner, the third switching module includes a fifth switching tube, a fourth resistor, and a fifth resistor;
the control end of the fifth switch tube is respectively connected with one end of the fourth resistor and one end of the fifth resistor, the other end of the fourth resistor is connected with the second switch module, the other end of the fifth resistor is grounded with the first end of the fifth switch tube, and the second end of the fifth switch tube is connected with the load.
In an optional manner, the third switch module further includes a sixth resistor, a seventh resistor, and a second capacitor;
one end of the sixth resistor is connected to the second connection point, the other end of the sixth resistor is connected to the load, two ends of the seventh resistor are respectively connected to the load and the ground, and the seventh resistor is connected to the second capacitor in parallel.
In a second aspect, the present invention provides an electronic device, comprising a load and a load switch circuit as described above;
the load switch circuit is respectively connected with the load and the input power supply, and the load switch circuit is used for controlling the on-off state of the load based on the input power supply.
The embodiment of the utility model provides a beneficial effect is: the utility model provides a load switch circuit, including first switch module, second switch module and third switch module, first switch module is connected in first tie point with the input power, and with the load connection in the second tie point, first switch module switches on when the voltage at first switch module both ends is greater than or equal to first predetermined threshold value, can make between input power and the load be the connected state, first switch module breaks off when the voltage at first switch module both ends is less than first predetermined threshold value, can make between input power and the load be the disconnected state, wherein, the voltage at first switch module both ends is provided by the input power; the second switch module is connected to the first connection point and the second connection point respectively, and is also connected to a third connection point with the first switch module, and the second switch module is switched on when the first switch module is switched off and is switched off when the first switch module is switched on; the third switch module is connected with the second switch module, and the third switch module is respectively connected with the second connection point and the ground, and the third switch module is turned on when the second switch module is turned on, so that the load and the ground can be in a connected state, and is turned off when the second switch module is turned off, so that the load and the ground can be in a disconnected state. Therefore, when the input power is normal voltage, firstly, when the power is just input, the voltage at two ends of the first switch module is smaller than a first preset threshold value, the first switch module is in an off state, the input power and the load are in an off state, at this time, as the input power is larger than zero and the first switch module is in the off state, the second switch module is in an on state, the third switch module is also in an on state, the load is grounded through the third switch module, and a signal received by the load is forcibly pulled down to be a low-level signal, so that the load stops working; then, when the voltage at the two ends of the first switch module is greater than or equal to a first preset threshold value, the first switch module is switched to be in a conducting state, namely, the input power supply and the load are in a connected state, the voltage of the second connection point is the voltage of the input power supply, at the moment, the second switch module is switched to be in a disconnected state, the third switch module is also in a disconnected state, the connection between the load and the ground is disconnected, the voltage of the second connection point is used for supplying power to the load, so that the load enters a working state, the process of controlling the on and off of the load can be realized through the above process, and components in the load switch circuit can be selected according to the actual use condition, so that the load switch circuit is suitable for different application scenes, namely, the applicability is strong.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.
Fig. 1 is a block diagram of an electronic device according to an embodiment of the present invention;
fig. 2 is a block diagram of a load switch circuit according to an embodiment of the present invention;
fig. 3 is a block diagram of a load switch circuit according to another embodiment of the present invention;
fig. 4 is a block diagram of a load switch circuit according to another embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a load switch circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a block diagram of an electronic device according to an embodiment of the present invention. As shown in fig. 1, the electronic device 1000 includes a load switch circuit 100 and a load 200. The load 200 may be a device or a circuit to be powered, and the like.
It is understood that, in the embodiments of the present invention, the electronic device refers to a consumer electronic product. Electronic devices include, but are not limited to: smart phones (such as Android phones and iOS phones that carry other operating systems), tablet computers, vehicle-mounted electronic products, and the like.
Specific types of electronic devices are listed above, but those skilled in the art will appreciate that embodiments of the present invention are not limited to the listed types, but may be applied to any other types of electronic devices.
The load switch circuit 100 is connected to the load 200 and the input power source 300, and the load switch circuit 100 can control whether the input power source 300 supplies power to the load 200, so as to control the working state of the load 200, i.e. control the load 200 to be in a normal working state or a stop working state.
As shown in fig. 2, the switching circuit 100 includes a first switching module 10, a second switching module 20, and a third switching module 30. The first switch module 10 and the input power source 300 are connected to a first connection point P1, and the first switch module 10 and the load are connected to a second connection point P2; the second switch module 20 is also connected to the first connection point P1 with the input power source 300 and the second connection point P2 with the load, respectively, and meanwhile, the second switch module 20 is also connected to the third connection point P3 with the first switch module; the third switching module 30 is connected to the second switching module 20, and the third switching module 30 is connected to the second connection point P2 and the ground GND, respectively.
Specifically, the input power supply 300 can provide a voltage input to both ends of the first switch module 10. When the voltage at the two ends of the first switch module 10 is greater than or equal to the first preset threshold, the first switch module 10 is switched to a connected state, at this time, the input power supply 300 is connected with the load 200, and the input power supply 300 is used as a power supply of the load 200, so that the load 200 enters a normal working state; when the voltage across the first switch module 10 is smaller than the first preset threshold, the switch is switched to the off state, the connection between the input power source 300 and the load 200 is disconnected, and the load 200 stops working.
The first preset threshold may be set according to an actual application of the first switch module 10, which is not limited herein. For example, when the first switch module 10 is a transistor, the first preset threshold may be set to a conducting voltage value of the transistor in order to switch states of the transistor.
The switching state of the second switching module 20 is determined by the switching states of the input power source 300 and the first switching module 20. If the input power 300 is 0, the switching state of the second switching module 20 is off; if the input power supply 300 is a normal input voltage, i.e. greater than 0, and the switching state of the first switch module 20 is an off state, the switching state of the second switch module 20 is a connected state; when the input voltage of the power supply 300 is a normal input voltage, i.e. greater than 0, and the switching state of the first switch module 10 is the on state, the switching state of the second switch module 20 is the off state.
In one embodiment, as shown in fig. 3, the second switch module 20 includes a first switch unit 21 and a second switch unit 22. The first switch unit 21 is connected to the first connection point P1 and the third connection point P3, and the second switch unit 22 is connected to the first switch unit 21, the second connection point P2 and the third switch module 30.
Specifically, the switching state of the first switching unit 21 is controlled by the input power source 300, and the switching state of the first switching unit 21 also controls the connection state between the input power source 300 and the second switching unit 22. When the input power supply 300 controls the switching state of the first switching unit 21 to be the connection state, the input power supply 300 and the second switching unit 22 are in the connection state; when the input power source 300 controls the switching state of the first switching unit 21 to be the off state, the input power source 300 and the second switching unit 22 are in the off state.
The switching state of the second switching unit 22 depends on the switching state of the first switching unit 21 and the switching state of the first switching module 10, and the switching state of the second switching unit 22 is used to control the switching state of the third switching module 30.
In one case, when the input power source 300 makes the switching state of the first switching unit 21 be the on state, that is, the input power source 300 is input to the second switching unit 22 through the first switching unit 21, and the operating state of the first switching module 10 is the off state, the switching state of the second switching unit 22 is the on state.
In another case, the input power 300 makes the switching state of the first switching unit 21 be the on state, the input power 300 is input to the second switching unit 22 through the first switching unit 21, and when the operating state of the first switching module 10 is the on state, the switching state of the second switching unit 22 is the off state.
In summary, when the input power 300 is a normal input voltage, the switching state of the first switching unit 21 is maintained to be a connected state.
If the switching state of the first switching module 10 is the off state, the switching state of the second switching unit 22 is the on state. In this case, corresponding to the embodiment described above: if the input power is a normal input voltage and the switching state of the first switch module 20 is an off state, the switching state of the second switch module 20 is an on state (at this time, the switching states of the first switch unit 21 and the second switch unit 22 are both on states).
If the switching state of the first switching module 10 is the on state, the switching state of the second switching unit 22 is the off state. In this case, corresponding to the embodiment described above: if the input power is a normal input voltage and the switching state of the first switch module 20 is an on state, the switching state of the second switch module 20 is an off state (at this time, the switching states of the first switch unit 21 are both an on state, and the switching state of the second switch unit 22 is an off state).
It can be understood that when the input power is 0, i.e., no voltage is input, the switching states of the first and second switching units 21 and 22 are both off states. In this case, the following embodiments are also applicable: if the input power is 0, the switching state of the second switching module 20 is an off state (at this time, the switching states of the first switching unit 21 and the second switching unit 22 are both off states).
It should be noted that, in the present embodiment, by setting the second switch module 20 as two switch units, it is possible to prevent the load from being damaged when an abnormality occurs in one of the switch units. For example, if one of the switch units is abnormal (possibly due to long usage time or aging), and the switch state thereof is erroneously switched to the on state, the switch state of the other switch unit is off, so that the second switch module 20 is also in the off state as a whole, and the subsequent load is protected.
Of course, in another embodiment, only the second switch module 20 may be provided as one switch unit for cost saving. However, in this case, if the switch unit is switched to the connected state by mistake due to an abnormality, the input power VCC may be connected to the load, which may damage the load and bring safety hazard to the human body due to sudden power-up of the load.
Referring to fig. 2 again, the switching state of the third switching module 30 is determined by the switching state of the second switching module 20, and the third switching module 30 is used for controlling the connection state between the load 200 and the ground GND. When the second switch module 20 is in the connected state, the third switch module 30 is also in the connected state, and the load 200 is connected to the ground GND through the third switch module 30, at this time, even if the input power 300 is connected to the load 200, the input voltage of the load 200 is forced to be pulled down by the ground GND, and the operation is stopped; when the second switch module 20 is in the off state, the third switch module 30 is also in the off state, and the load 200 is in the off state with respect to the ground GND.
In summary, when the load 200 is required to work, the input power source 300 controls the switching state of the first switch module 10 to be the connection state, at this time, the second switch module 20 and the third switch module 30 are both in the disconnection state, the load 200 is connected to the input power source 300 through the first switch module 20, the load 200 is powered on, and the load 200 enters the working state; when the load 200 is required to stop working (keeping the input power supply 300 unchanged), the switching state of the first switching module 10 is controlled to be an off state, at this time, the switching states of the second switching module 20 and the third switching module 30 are both in a connected state, the load 200 is grounded after passing through the third switching module 30, the input power supply of the load 200 is 0, and the load stops working.
Therefore, through the above manner, different types of components in the first switch module 10, the second switch module 20, and the third switch module 30 are selected, so that the load switch circuit 100 is applicable to various application scenarios, and has strong adaptability, where the on of the load refers to entering a working state, and the off of the load refers to stopping the load.
Further, after the on and off of the load 200 is implemented, some protection schemes may be applied to the load switch circuit 100 to complete the load switch circuit 100. For example, in one embodiment, as shown in fig. 4, the load switch circuit 100 further includes a fourth switch module 40, and the fourth switch module 40 is configured to implement overvoltage protection for the whole circuit.
Specifically, one end of the fourth switch module 40 is connected to the input power source 300, the other end of the fourth switch module 40 and the first switch module 10 are connected to the first connection point P1, and the fourth switch module 40 and the first switch module 10 are further connected to the third connection point.
The voltage across the fourth switch module 40 is also provided by the input power 300, i.e. the fourth switch module 40 can switch its switch state according to the input power 300 to control the switch states of the first switch module 10 and the second switch module 20 simultaneously.
When the input power supply 300 is a normal input voltage, that is, when the input power supply 300 does not exceed an overvoltage value (the overvoltage value is a maximum input voltage value that may cause an abnormal occurrence such as damage to the load 200), and the voltage across the fourth switch module 40 is smaller than a second preset threshold, the switch state of the fourth switch module 40 is an off state, and then the switch states of the first switch module 10 and the second switch module 20 are still performed as described in the above embodiment.
When the input power 300 exceeds the overvoltage value, the voltage across the fourth switch module 40 is greater than or equal to the second preset threshold, and the switch state of the fourth switch module 40 is switched to the on state, so that the switch states of the first switch module 10 and the second switch module 20 are both off states, and the connection between the load 200 and the input power 300 is disconnected, thereby protecting the load 200 and realizing the overvoltage protection function.
The second preset threshold is also set by the practical application of the fourth switch module 40, and is not limited herein.
In an embodiment, the first switch module includes a second switch tube and a first capacitor. The circuit configuration of the load switch circuit shown in fig. 5 will be described as an example. The second switch corresponds to the MOS transistor Q2, and the first capacitor corresponds to the first capacitor C1.
As shown in fig. 5, the first switch module 10 further includes a second zener diode DW2, a ninth resistor R9, and a fourth capacitor C4.
One end of the first capacitor C1 is connected to the cathode of the second zener diode DW2 and the source of the MOS transistor Q2, the other end of the first capacitor C1 and the anode of the second zener diode DW2 are both connected to the third connection point P3, the gate of the MOS transistor Q2 is connected to one end of the ninth resistor R9, the other end of the ninth resistor R9 and one end of the fourth capacitor C4 are both connected to the third connection point P3, and the other end of the fourth capacitor C4 is connected to the drain of the MOS transistor Q2 and the second connection point P2.
In an embodiment, the first switch unit includes a third switch tube and a second resistor, and the second switch unit includes a fourth switch tube and a third resistor. The circuit configuration of the load switch circuit shown in fig. 5 will be described as an example. The third switch tube corresponds to the MOS transistor Q3, the second resistor corresponds to the second resistor R2, the fourth switch tube corresponds to the triode Q4, and the third resistor corresponds to the third resistor R3.
Specifically, the gate of the MOS transistor Q3 and one end of the second resistor R2 are both connected to the third connection point P3, the source of the MOS transistor Q3 is connected to the first connection point P1, the other end of the second resistor R2 is grounded, and the drain of the MOS transistor Q1 is connected to the emitter of the transistor Q4. The base of the triode Q4 is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected to the second connection point P2, and the collector of the triode Q4 is connected with one end of the fourth resistor R4.
In an embodiment, the third switching module 30 includes a fifth switching tube, a fourth resistor and a fifth resistor.
In another embodiment, the third switching module 30 further includes a sixth resistor, a seventh resistor, and a second capacitor.
The circuit configuration of the load switch circuit shown in fig. 5 will be described as an example. The fifth switch tube corresponds to the triode Q5, the fourth resistor corresponds to the fourth resistor R4, the fifth resistor corresponds to the fifth resistor R5, the sixth resistor corresponds to the sixth resistor R6, the seventh resistor corresponds to the seventh resistor R7, and the second capacitor corresponds to the second capacitor C2.
Specifically, the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the base of the transistor Q5, the other end of the fifth resistor R5, the emitter of the transistor Q5, one end of the seventh resistor R7, and one end of the third capacitor C3 are all grounded, the collector of the transistor Q5 is connected to the other end of the seventh resistor R7, the other end of the third capacitor C3, and one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the second connection point P2. The collector of the transistor Q5 is connected to the load 200 through the signal output terminal S1.
By further providing the sixth resistor R6, the seventh resistor R7, and the second capacitor C2, when the signal at the signal output terminal S1 changes from low level to high level, the voltage at the second connection point P2 charges the second capacitor C2 through the sixth resistor R6; conversely, when the signal at the signal output terminal S1 changes from a high level to a low level, the second capacitor C2 may discharge through the seventh resistor R7. Since the charging and discharging of the capacitor requires a certain time, it can play a role of buffering to prevent the load connected to the signal output terminal S1 from being damaged by the sudden voltage signal. Meanwhile, by setting the capacitance of the second capacitor C2 accordingly, the charging and discharging time of the second capacitor C2 can be controlled, so as to control the switching time between the high and low levels output by the signal output terminal S1 to be suitable for different loads (the requirements of different loads on the switching time between the high and low levels may be different).
In an embodiment, the fourth switching module includes a first diode, a first resistor, a first zener diode, and a first switching tube. The circuit configuration of the load switch circuit shown in fig. 5 will be described as an example. The first diode corresponds to the first diode D1, the first resistor corresponds to the first resistor R1, the first zener diode corresponds to the first zener diode DW1, and the first light-emitting diode corresponds to the triode Q1.
As shown in fig. 5, the fourth switch module 40 further includes an eighth resistor R8 and a third capacitor C3.
Specifically, the input power VCC is connected to one end of an eighth resistor R8 and an anode of a first diode D1, respectively, the other end of the eighth resistor R8 is connected to the ground GND through a third capacitor C3, a cathode of the first diode D1 is connected to one end of a first resistor R1, an emitter of a transistor Q1, and a first connection point P1, the other end of the first resistor R1 is connected to a base of a transistor Q1 and a cathode of a first zener diode DW1, an anode of the first zener diode DW1 is connected to the ground, and a collector of the transistor Q1 is connected to a third connection point P3.
The first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the fifth switch tube can be selected from one of a triode, an MOS tube and an IGBT switch tube. The first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the fifth switch tube may be the same or different, for example, the first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the fifth switch tube all use triodes.
Taking the example that the first switch tube is selected from a triode, at this time, the base of the triode is the control end of the first switch tube, the emitter of the triode is the first end of the first switch tube, and the collector of the triode is the second end of the first switch tube.
Taking the second switch tube as an example, the gate of the MOS tube is the control end of the second switch tube, the source of the MOS tube is the first end of the second switch tube, and the drain of the MOS tube is the second end of the second switch tube.
In practical applications, it can be seen from the above that, when the overvoltage protection occurs, the switching state of the fourth switching module 40 needs to be switched to the on state. At this time, the transistor Q1 is turned on, and the input power VCC passes through the first diode D1, the emitter and base of the transistor Q1, and the second zener diode DW1 to the ground GND, which forms a loop. The overvoltage values in this circuit can be obtained as: vovp ═ VD1+VBE+VDW1Wherein V isD1Is the voltage value, V, across the first diode D1BEIs the voltage value between the base and emitter of the transistor Q1, VDW1Is the regulated voltage value across the first regulator diode DW 1.
Therefore, when the voltage value of the input power VCC exceeds Vovp, the transistor Q1 is turned on, and the first capacitor C1 discharges through the transistor Q1, so that the voltage across the first capacitor C1 has substantially no voltage difference, i.e., no voltage difference exists between the gate and the source of the MOS transistor Q2 and the MOS transistor Q3, and the MOS transistor Q2 and the MOS transistor Q3 are both turned off. Thereby triggering overvoltage protection and disconnecting the input power VCC from the signal output terminal S1, i.e., from the load 200, thereby protecting the load 200 from damage.
When no over-voltage protection occurs, i.e., the input power VCC is less than Vovp, the transistor Q1 is turned off. This is because the voltage input to the base of the transistor Q1 cannot turn on the transistor Q1 when the input power VCC is small.
When the input power VCC is just input, the gate of the transistor Q3 is connected to ground GND through the second resistor R2, and the source of the transistor Q3 inputs a voltage at the first connection point P1 (the voltage is approximately the voltage of the power VCC minus the voltage across the first diode D1), and the transistor Q3 is turned on. The first capacitor C1 is charged, the voltage across the first capacitor C1 is the voltage between the gate and the source of the MOS transistor Q2, and when the voltage across the first capacitor C1 is greater than vgs (th) of the MOS transistor Q2, the MOS transistor Q2 starts to turn on slowly. The voltage of the base of the transistor Q4 is the voltage of the second connection point P2, the voltage of the emitter of the transistor Q4 is the voltage of the first connection point P1, and at this time, because the MOS transistor Q2 is not fully turned on, the voltage of the first connection point P1 is greater than the voltage of the second connection point P2, that is, a large voltage difference exists between the emitter and the base of the transistor Q4, so that the transistor Q4 is turned on. Therefore, after the voltage of the first connection point P1 passes through the source and the drain of the MOS transistor Q2 and the emitter and the collector of the transistor Q4, the voltage is divided by the fourth resistor R4 and the fifth resistor R5 and then input to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, and the voltage difference between the emitter and the base of the transistor Q5 turns on the transistor Q5. At this time, the signal output terminal S1 is connected to the ground GND through the collector and the emitter of the transistor Q5, the signal output terminal S1 is forced to be pulled low, that is, no voltage is input to the load 200, and the load 200 stops operating.
When the conduction degree of the MOS transistor Q2 slowly deepens and reaches the miller plateau value, the MOS transistor Q2 is fully turned on. The miller platform in the MOS transistor is usually used as a mark that the MOS transistor is in an "amplification region", and at this time, the MOS transistor can be considered to be completely turned on. The voltage of the first connection point P1 and the voltage of the second connection point P2 are almost completely equal, i.e., there is no voltage difference between the base and the emitter of the transistor Q4, and the transistor Q4 is turned off. At this time, the base of transistor Q5 also loses input voltage and transistor Q5 turns off. The signal output terminal S1 is connected to the second connection point P2 through the sixth resistor R6, and the voltage of the second connection point P2 is the voltage of the first connection point P1, so the voltage at the signal output terminal S1 is the voltage division of the voltage of the first connection point P1 on the seventh resistor R7, and the voltage at the first connection point P1 is approximately the voltage of the power VCC minus the voltage across the first diode D1. At this time, the load 200 obtains the input voltage, and the load 200 enters a normal operation state.
When the input power VCC powers the load 200 through the load switch circuit 100, the load 200 is in a normal operating state; when the input power VCC cannot supply power to the load 200 through the load switch circuit 100, the load 200 loses power, and the load 200 stops working. When the input power VCC exceeds the overvoltage value, the input power 200 cannot supply power to the load 200 through the load switch circuit 100, and the load 200 stops operating. Thus, the load switch circuit 100 provided in this embodiment implements both the output enabling function, i.e., controlling the on and off of the load, and the overvoltage protection function. Moreover, the scheme is realized through a pure hardware circuit, so that the cost is low. Furthermore, in the load switch circuit 100, different components are selected, so that the load switch circuit is applicable to different types of loads 200, and has high applicability.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. A load switching circuit for connection to a load, the load switching circuit comprising:
the first switch module is connected with a first connecting point and the load at a second connecting point, and is used for being switched on when the voltage at two ends of the first switch module is greater than or equal to a first preset threshold value and being switched off when the voltage at two ends of the first switch module is smaller than the first preset threshold value, wherein the voltage at two ends of the first switch module is provided by the input power supply;
the second switch module is respectively connected to the first connection point and the second connection point, is also connected to a third connection point together with the first switch module, and is used for being switched on when the first switch module is switched off and being switched off when the first switch module is switched on;
and the third switch module is connected with the second switch module, is respectively connected with the second connection point and the ground, and is used for being switched on when the second switch module is switched on and being switched off when the second switch module is switched off.
2. The load switch circuit of claim 1,
the load switching circuit further comprises a fourth switching module;
the input power supply is connected to the first connection point through the fourth switch module, and the fourth switch module is also connected to the third connection point;
the fourth switch module is used for being switched on when the voltage at two ends of the fourth switch module is larger than or equal to a second preset threshold value and being switched off when the voltage at two ends of the fourth switch module is smaller than the second preset threshold value, wherein the voltage at two ends of the fourth switch module is provided by the input power supply.
3. The load switch circuit of claim 2,
the fourth switch module comprises a first diode, a first resistor, a first voltage stabilizing diode and a first switch tube;
the anode of the first diode is connected with the input power supply, the cathode of the first diode is respectively connected with one end of the first resistor, the first end of the first switch tube, the first switch module and the second switch module, the other end of the first resistor is respectively connected with the cathode of the first voltage stabilizing diode and the control end of the first switch tube, the anode of the first voltage stabilizing diode is grounded, and the second end of the first switch tube is respectively connected with the first switch module and the second switch module.
4. The load switch circuit of claim 1,
the first switch module comprises a second switch tube and a first capacitor;
the control end of the second switch tube is connected to the third connection point, the first end of the second switch tube is connected to the first connection point, the second end of the third switch tube is connected to the second connection point, and two ends of the first capacitor are respectively connected with the first connection point and the third connection point.
5. The load switch circuit of claim 1,
the second switch module comprises a first switch unit and a second switch unit;
the first switch unit is connected to the first connection point and the third connection point respectively, and is used for switching a switch state based on the input power supply so as to control a connection state between the input power supply and the second switch unit;
the second switch unit is connected to the first switch unit, the second connection point, and the third switch module, and the second switch unit is configured to switch a switch state based on a switch state of the first switch unit and a switch state of the first switch module to control a switch state of the third switch module.
6. The load switch circuit of claim 5,
the first switch unit comprises a third switch tube and a second resistor;
the control end of the third switching tube and one end of the second resistor are both connected to the second connection point, the other end of the second resistor is grounded, the first end of the third switching tube is connected to the first connection point, and the second end of the third switching tube is connected with the second switching unit.
7. The load switch circuit of claim 5,
the second switch unit comprises a fourth switch tube and a third resistor;
the control end of the fourth switch tube is connected with one end of the third resistor, the other end of the third resistor is connected to the second connection point, the first end of the fourth switch tube is connected with the first switch unit, and the second end of the fourth switch tube is connected with the third switch module.
8. The load switch circuit of claim 1,
the third switch module comprises a fifth switch tube, a fourth resistor and a fifth resistor;
the control end of the fifth switch tube is respectively connected with one end of the fourth resistor and one end of the fifth resistor, the other end of the fourth resistor is connected with the second switch module, the other end of the fifth resistor is grounded with the first end of the fifth switch tube, and the second end of the fifth switch tube is connected with the load.
9. The load switch circuit of claim 8,
the third switch module further comprises a sixth resistor, a seventh resistor and a second capacitor;
one end of the sixth resistor is connected to the second connection point, the other end of the sixth resistor is connected to the load, two ends of the seventh resistor are respectively connected to the load and the ground, and the seventh resistor is connected to the second capacitor in parallel.
10. An electronic device comprising a load and the load switching circuit of any one of claims 1-9;
the load switch circuit is respectively connected with the load and the input power supply, and the load switch circuit is used for controlling the on-off state of the load based on the input power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120349548.2U CN214626946U (en) | 2021-02-07 | 2021-02-07 | Load switch circuit and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120349548.2U CN214626946U (en) | 2021-02-07 | 2021-02-07 | Load switch circuit and electronic equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214626946U true CN214626946U (en) | 2021-11-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120349548.2U Active CN214626946U (en) | 2021-02-07 | 2021-02-07 | Load switch circuit and electronic equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214626946U (en) |
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2021
- 2021-02-07 CN CN202120349548.2U patent/CN214626946U/en active Active
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