Startup and shutdown control circuit for dual-power-supply equipment

Abstract

The utility model provides an on-off control circuit for dual-power-supply equipment, and a power supply single member of the dual-power-supply equipment comprises an adapter and a battery, and comprises a first switching circuit, a third switching circuit and an adapter monitoring circuit, the first switching circuit is used for receiving an input voltage of the adapter, and the third switching circuit is used for receiving an input voltage of the battery and is connected to a power supply end of the dual-power-supply equipment; when the adapter is connected, the input channel of the battery is cut off, and the dual-power-supply equipment is powered by the adapter; when the adapter is not switched on and the battery is switched on, the input voltage of the battery is transmitted to the power supply end of the dual-power-supply equipment, the third switching circuit outputs a battery power supply detection signal to the dual-power-supply equipment, and the dual-power-supply equipment is powered by the battery; when the adapter is cut off, an interrupt signal is output to the dual-power-supply equipment; when receiving the interrupt signal, the dual-power-supply equipment obtains a battery power supply detection signal, and when it is judged that the battery is not connected according to the battery power supply detection signal, the dual-power-supply equipment sends out a protection action instruction.

Description

Technical Field

[0001] The present application mainly relates to the field of measuring equipment, and in particular to a power on / off control circuit for dual power supply equipment. Background Art

[0002] In the field of measuring equipment, portable electronic balances or other electronic devices generally include two power supply modes: power adapter and AA battery. For dual-power supply devices with power adapter and battery, the device itself must switch seamlessly between the two power supply modes without affecting the metering or measurement performance. At the same time, due to the requirements of the device itself, when the system is abnormally powered off, such as when there is no battery adapter power supply or the battery power cannot support the system, certain data or functions need special protection to prevent data loss or abnormalities. In embedded systems, the protection function trigger needs to obtain system power supply information to make a correct judgment.

[0003] In the battery-powered mode, in order to extend the working time of the device, multiple batteries are usually connected in series. As the battery continues to discharge, its voltage also changes. The working voltage of the power adapter may be between the maximum and minimum voltages of the battery. For electronic balances or other electronic measuring devices, the external adapter power supply may be 12V, 15V or other values, and there are also many voltages generated internally, such as 3.3V, 5V, 10V, etc., which are used to control the system and test and measurement units. In recent years, with the development of technology, the working voltage of the control system has become lower and lower, but the test and measurement unit still requires a higher voltage, such as the 10V voltage required by the balance. If the device has a larger LCD display unit, its backlight voltage requirement is also higher. Therefore, electronic measuring devices such as electronic balances have both high and low voltages. Traditionally, in order to extend the battery life, the conventional practice is to add a buck-boost circuit at the battery output end to adapt to the battery voltage as it discharges and the voltage continues to decrease, and the voltage required by the system can still be output stably. Figure 1 FIG. 1 shows a circuit block diagram of adding a buck-boost circuit. Figure 1 As shown, the AC power adapter 110 is connected to other units 140 of the electronic measuring device, and the battery 120 is connected to other units 140 of the electronic measuring device through the buck-boost circuit 130. From a system perspective, adding the buck-boost circuit 130 has the feature of a simple framework, but there are the following problems:

[0004] (1) As ordinary AA batteries discharge, their voltage range changes greatly, and the corresponding input voltage range of the buck-boost circuit becomes very wide. For example, the voltage range of 8 AA batteries can be between 5V and 16V. There are few power supply ICs on the market that can meet such a wide range, and if there are any, the price is also relatively high.

[0005] (2) In most cases, the low-voltage power consumption of electronic measuring equipment accounts for a relatively high proportion. If the use of a buck-boost circuit results in energy loss, the energy efficiency conversion of the entire system will be greatly reduced when the battery is continuously discharged.

[0006] (3) The buck-boost circuit increases the test complexity and needs to consider different working conditions such as the boost stage, buck-boost conversion point, and buck stage.

[0007] (4) The buck-boost circuit takes up a large amount of PCB space. Utility Model Content

[0008] The technical problems to be solved by the present application are the problem of data loss when a dual-power supply device is abnormally powered off, the problem of seamless switching between two power supplies, and the problems of unstable performance, high cost and large circuit area of ​​the boost circuit.

[0009] In order to solve the above technical problems, the present application provides a power on / off control circuit for a dual-power supply device, wherein the power supply unit of the dual-power supply device includes an adapter and a battery, including: a first switch circuit, a third switch circuit and an adapter monitoring circuit; wherein the first switch circuit is used to receive the input voltage of the adapter, the third switch circuit is used to receive the input voltage of the battery, and is connected to the power supply end of the dual-power supply device; the power on / off control circuit is configured as follows: when the adapter is connected, the first switch circuit is turned on, the third switch circuit is turned off, so that the input channel of the battery is cut off, and the dual-power supply device is powered by the adapter; when the adapter is not connected, the first switch circuit is turned off, and the third switch circuit is turned off. The third switch circuit is turned on, and when the battery is connected, the input voltage of the battery is transmitted to the power supply terminal of the dual-power supply device, and the third switch circuit outputs a battery power supply detection signal to the dual-power supply device, and the dual-power supply device is powered by the battery; the adapter monitoring circuit is used to monitor whether the adapter is connected, and the adapter monitoring circuit is configured to: when the adapter is disconnected, output an interrupt signal to the dual-power supply device; the dual-power supply device is configured to: when the adapter is disconnected, the dual-power supply device receives the interrupt signal, obtains the battery power supply detection signal, and when it is determined according to the battery power supply detection signal that the battery is not connected, the dual-power supply device issues a protection action instruction.

[0010] In an embodiment of the present application, the dual power supply device is further configured to: when the adapter and the battery are both not connected, and when the system operating voltage is lower than a preset value, the dual power supply device controls the dual power supply device to shut down.

[0011] In one embodiment of the present application, a second switch circuit is further included, connected between the first switch circuit and the third switch circuit; wherein the power on / off control circuit is further configured as follows: when the adapter is connected, the first switch circuit is turned on, and the second switch circuit and the third switch circuit are both turned off, so that the input channel of the battery is cut off, and the dual power supply device is powered by the adapter; when the adapter is not connected, the first switch circuit is turned off, and the second switch circuit and the third switch circuit are both turned on.

[0012] In one embodiment of the present application, the first switch circuit includes a first switch tube, the second switch circuit includes a second switch tube, and the third switch circuit includes a third switch tube. The first end of the first switch tube is connected to the control end of the second switch tube, and the first end of the second switch tube is connected to the control end of the third switch tube; the control end of the first switch tube is connected to the input voltage of the adapter, and the first switch circuit is configured as follows: when the adapter is connected, the first switch tube is turned on, and the second switch tube and the third switch tube are turned off, so that the input channel of the battery is cut off, and the dual power supply device is powered by the adapter; when the adapter is not connected, the first switch tube is turned off, and the second switch tube and the third switch tube are turned on; the control end of the second switch tube is connected to the first working voltage of the dual power supply device, and the second switch circuit is configured as follows: when the adapter is not connected, the first working voltage is used to turn on the second switch tube; the control end of the third switch tube is connected to the first end of the second switch tube, the first end of the third switch tube is connected to the input voltage of the battery, and the second end of the third switch tube is connected to the power supply end of the dual power supply device.

[0013] In one embodiment of the present application, the dual power supply device is further configured as follows: when the battery is connected and the adapter is not connected, and when the dual power supply device has not been operated for a preset period of time, the dual power supply device inputs a battery off signal to the control end of the first switch tube, so that the first switch tube is turned on, and the second switch tube is turned off, and the third switch tube is turned off, and the dual power supply device is shut down.

[0014] In one embodiment of the present application, the first switching circuit also includes a first voltage-dividing resistor and a second voltage-dividing resistor, wherein the first end of the first voltage-dividing resistor is connected to the input voltage of the adapter, the second end of the first voltage-dividing resistor is connected to the control end of the first switching tube, the first end of the second voltage-dividing resistor is connected to the control end of the first switching tube, and the second end of the second voltage-dividing resistor is grounded.

[0015] In one embodiment of the present application, the first switch circuit further includes a first diode, an anode of the first diode is connected to the input voltage of the adapter, and a cathode of the first diode is connected to the first end of the first voltage-dividing resistor.

[0016] In one embodiment of the present application, the second switching circuit also includes a third voltage-dividing resistor and a fourth voltage-dividing resistor, wherein a first end of the third voltage-dividing resistor is connected to the first operating voltage, a second end of the third voltage-dividing resistor is connected to a control end of the second switching tube, a first end of the fourth voltage-dividing resistor is connected to the control end of the second switching tube, and a second end of the fourth voltage-dividing resistor is grounded.

[0017] In one embodiment of the present application, the second switch circuit further includes a second diode, a cathode of the second diode is connected to the first operating voltage, and an anode of the second diode is connected to the first end of the third voltage-dividing resistor.

[0018] In one embodiment of the present application, the second switch circuit is further configured to: configure the sizes of the third voltage-dividing resistor and the fourth voltage-dividing resistor so that when the first switch tube is turned off, the control terminal voltage of the second switch tube is greater than the maximum on-state voltage of the second switch tube.

[0019] In one embodiment of the present application, the third switching circuit also includes a fifth voltage-dividing resistor and a sixth voltage-dividing resistor, wherein the first end of the fifth voltage-dividing resistor is connected to the first end of the second switching tube, the second end of the fifth voltage-dividing resistor is connected to the control end of the third switching tube, the first end of the sixth voltage-dividing resistor is connected to the control end of the third switching tube, and the second end of the sixth voltage-dividing resistor is connected to the input voltage of the battery and the first end of the third switching tube.

[0020] In one embodiment of the present application, the third switching circuit also includes a third diode, the anode of the third diode is connected to the input voltage of the battery, and the cathode of the third diode is connected to the second end of the sixth voltage-dividing resistor and the first end of the third switching tube.

[0021] In one embodiment of the present application, the third switching circuit further includes a fourth diode, the anode of the fourth diode is connected to the second end of the third switching tube, and the cathode of the fourth diode is connected to the power supply end of the dual power supply device.

[0022] In one embodiment of the present application, the third switching circuit also includes a control voltage clamping circuit, which includes a seventh voltage-dividing resistor, an eighth voltage-dividing resistor and a clamping diode, the first end of the seventh voltage-dividing resistor is connected to the second end of the third switching tube, the second end of the seventh voltage-dividing resistor is connected to the dual power supply device and is used to output the battery power supply detection signal, the first end of the eighth voltage-dividing resistor is connected to the second end of the seventh voltage-dividing resistor, the second end of the eighth voltage-dividing resistor is grounded, the positive pole of the clamping diode is grounded, and the negative pole of the clamping diode is connected to the second end of the seventh voltage-dividing resistor.

[0023] In one embodiment of the present application, the adapter monitoring circuit includes a reference voltage generating circuit and a comparator, wherein the reference voltage generating circuit is used to generate a reference voltage with a fixed value, the reference voltage is connected to a first input terminal of the comparator, the input voltage of the adapter is connected to a second input terminal of the comparator, and the output terminal of the comparator outputs the interrupt signal.

[0024] In one embodiment of the present application, the adapter monitoring circuit also includes a ninth voltage-dividing resistor and a tenth voltage-dividing resistor, the first end of the ninth voltage-dividing resistor is connected to the input voltage of the adapter, the second end of the ninth voltage-dividing resistor is connected to the second input terminal of the comparator, the first end of the tenth voltage-dividing resistor is connected to the second end of the ninth voltage-dividing resistor, and the second end of the tenth voltage-dividing resistor is grounded.

[0025] In one embodiment of the present application, the adapter monitoring circuit is further configured to: adjust the sizes of the ninth voltage-dividing resistor and the tenth voltage-dividing resistor to adjust the input voltage of the second input terminal of the comparator, thereby adjusting the length of time it takes for the input voltage of the adapter to drop to the time it takes for the dual power supply device to receive an interrupt signal when the adapter is unplugged.

[0026] In one embodiment of the present application, the adapter monitoring circuit also includes a load capacitor, which is connected between the second end of the ninth voltage-dividing resistor and ground. The adapter monitoring circuit is also configured to: adjust the size of the load capacitor to adjust the input voltage of the second input terminal of the comparator.

[0027] In one embodiment of the present application, the first switch circuit is further configured to: adjust the sizes of the ninth voltage-dividing resistor and the tenth voltage-dividing resistor so that when the dual power supply device receives the interrupt signal, the battery power supply detection signal is at a high level.

[0028] In one embodiment of the present application, the first switching circuit is further configured to: adjust the size of the first voltage-dividing resistor and the second voltage-dividing resistor to adjust the voltage threshold for converting adapter power supply to battery power supply, wherein, when the adapter is unplugged and the input voltage of the adapter drops to the voltage threshold, the battery supplies power to the dual-power supply device, and at this time the comparator has not yet output the interrupt signal.

[0029] According to the power on / off control circuit of the present application, it is possible to promptly detect events in which the adapter is not connected or is unplugged, and promptly judge the connection status of the battery. If the battery is not connected, the power-off time is used to save key data in time when the system operating voltage is not lower than the preset value, thereby avoiding data loss. In a scenario where only the battery is powered, when the dual-powered device does not work for a long time, the device can be automatically shut down. In a scenario where both the battery and the adapter are powered, the two power supplies can be seamlessly switched, which will not affect the normal use of the device and will not affect the measurement or metering performance. The power on / off control circuit of the present application can also reduce the overall operating power consumption of the device, reduce energy consumption, and achieve power consumption optimization while ensuring the normal operation of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0031] Figure 1 A circuit block diagram of adding a buck-boost circuit is shown;

[0032] Figure 2 is an exemplary block diagram of a power on / off control circuit according to an embodiment of the present application;

[0033] Figure 3 is a circuit structure diagram of a power on / off control circuit according to another embodiment of the present application;

[0034] Figure 4 is a structural schematic diagram of a reference voltage generating circuit in an adapter monitoring circuit in a power on / off control circuit according to an embodiment of the present application;

[0035] Figure 5 is a schematic diagram of the structure of a comparator in an adapter monitoring circuit in a power on / off control circuit according to an embodiment of the present application;

[0036] Figure 6A-6C Shown is a timing diagram when the adapter is unplugged in scenario 2;

[0037] Figure 7 The following is a timing diagram showing the conversion to battery power supply when the adapter is unplugged in scenario three;

[0038] Fig. 8A Shown is the power consumption of a dual-powered device when powered by an adapter;

[0039] Figure 8B Is adopted Figure 1 The buck-boost circuit shown in the figure shows the power consumption of the dual-powered device when it is powered by a battery;

[0040] Figure 8C It is the power consumption of the dual power supply device when the power on / off control circuit of the present application is powered by batteries. DETAILED DESCRIPTION

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0042] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0043] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0044] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0045] The dual-power supply device of the present application refers to a device that has both adapter power supply and battery power supply functions, especially a measuring device with a measuring function, such as a portable electronic measuring device, such as an electronic balance.

[0046] Figure 2 is an exemplary block diagram of a power on / off control circuit according to an embodiment of the present application. Figure 2 As shown, the power on / off control circuit of this embodiment includes a first switch circuit 210 , a third switch circuit 230 and an adapter monitoring circuit 240 . Figure 2 Also shown is a dual power supply device 201, which has a processor 202 and a power supply terminal 203, wherein the processor 202 can be a CPU, MCU, etc., and the power supply terminal 203 can be a pin of a circuit in the dual power supply device 201. The power supply unit of the dual power supply device 201 includes an adapter 261 and a battery 262. It can be understood that the dual power supply device 201 includes an interface for connecting the adapter 261 and a mounting portion for mounting the battery 262. The input voltage ADAPT of the adapter 261 can be input into the dual power supply device 201 through the interface, and the input voltage BAT_IN of the battery 262 can also be connected to the dual power supply device 201 through the mounting circuit to provide power to the dual power supply device 201. It can be understood that at the same time, only one of the adapter 261 and the battery 262 needs to provide power. In an embodiment of the present application, the battery 262 can be a plurality of AA batteries connected in series, for example, 8, and the input voltage BAT_IN ranges from 6V to 13V.

[0047] like Figure 2As shown, the first switch circuit 210 is used to receive the input voltage ADAPT of the adapter 261, and the third switch circuit 230 is used to receive the input voltage BAT_IN of the battery 262, and is connected to the power supply terminal 203 of the dual power supply device 201. The switch control circuit is configured as follows: when the adapter 261 is connected to the dual power supply device 201, the first switch circuit 210 is turned on, and the third switch circuit 230 is turned off, so that the input channel of the battery 262 is cut off, and the dual power supply device 201 is powered by the adapter 261; when the adapter 261 is not connected, the first switch circuit 210 is turned off, and the third switch circuit 230 is turned on. When the battery 262 is connected, the input voltage BAT_IN of the battery 262 is transmitted to the power supply terminal 203 of the dual power supply device 201, and the third switch circuit 230 outputs a battery power supply detection signal BAT_ON to the dual power supply device 201, and the dual power supply device 201 is powered by the battery 262. In some embodiments, the battery power supply detection signal BAT_ON is input to the processor 202 for processing, such as Figure 2 The adapter monitoring circuit 240 is used to monitor whether the adapter 261 is connected. The adapter monitoring circuit 240 is configured to output an interrupt signal ADAPT_Down to the dual power supply device 201 when the adapter 262 is disconnected. In some embodiments, the interrupt signal ADAPT_Down is input to the processor 202, such as Figure 2 The dual power supply device 201 is configured as follows: when the adapter 261 is disconnected, the dual power supply device 201 receives the interrupt signal ADAPT_Down, obtains the battery power supply detection signal BAT_ON, and when it is determined that the battery is not connected according to the battery power supply detection signal BAT_ON, the dual power supply device 201 issues a protection action instruction.

[0048] In some embodiments, the protection action instructions include executing save data, save critical data, clear cache, etc.

[0049] Need explanation, reference Figure 2 The adapter 261 is connected to the power pin of the dual power supply device 201 through other circuits, such as line L1, so as to provide power to the dual power supply device 201 when the adapter 261 is turned on.

[0050] In some embodiments, a high level is used as a valid signal. When the adapter 261 is not connected and the battery 262 is connected, the battery power detection signal BAT_ON output by the third switch circuit 230 to the dual power supply device 201 is a high level, indicating that the battery 262 is connected, and the dual power supply device 201 is powered by the battery 262. When the battery 262 is not connected, the battery power detection signal BAT_ON output by the third switch circuit 230 to the dual power supply device 201 is a low level.

[0051] In some embodiments, the dual power supply device 201 is further configured to: when the adapter 261 and the battery 262 are both not connected, and when the system operating voltage is lower than a preset value, the dual power supply device 201 controls the dual power supply device 201 to shut down.

[0052] Usually, the voltage range of the adapter 261 is 12V, 15V, etc. This specification takes 12V as an example for explanation and is not intended to limit its scope. The system operating voltage refers to the operating voltage of the processor 202 in the dual power supply device 201, which is usually lower, such as 3.3V, and is converted from the voltage provided by the adapter 261 or the battery 262. When the adapter 261 is not connected or unplugged, according to Figure 2 The power on / off control circuit shown can timely detect the event that the adapter 261 is not connected or unplugged, and timely determine the connection status of the battery 262. If the battery 262 is not connected, the power-off time is used to save key data in time when the system operating voltage is not lower than the preset value, which can avoid data loss. The preset value is <3.3V, for example, 2.9V.

[0053] like Figure 2 As shown, in some embodiments, the power on / off control circuit further includes a second switch circuit 220, which is connected between the first switch circuit 210 and the third switch circuit 230, wherein when the adapter 261 is connected to the dual power supply device 201, the first switch circuit 210 is turned on, and the second switch circuit 220 and the third switch circuit 230 are both turned off, so that the input channel of the battery 262 is cut off, and the dual power supply device 201 is powered by the adapter 261; when the adapter 261 is not connected, the first switch circuit 210 is turned off, and the second switch circuit 220 and the third switch circuit 230 are both turned on, and when the battery 262 is connected, the input voltage BAT_IN of the battery 262 is transmitted to the power supply terminal 203 of the dual power supply device 201, and the third switch circuit 230 outputs a battery power supply detection signal BAT_ON to the dual power supply device 201, and the dual power supply device 201 is powered by the battery 262.

[0054] Figure 3 FIG. 1 is a schematic diagram of a circuit structure of a power on / off control circuit according to another embodiment of the present invention. Figure 2The structures of each circuit are given in more detail based on the illustrated embodiment. In this embodiment, the first switch circuit 210 includes a first switch tube Q1, the second switch circuit 220 includes a second switch tube Q2, the third switch circuit 230 includes a third switch tube Q3, the first end e12 of the first switch tube Q1 is connected to the control end e21 of the second switch tube Q2, the first end e22 of the second switch tube Q2 is connected to the control end e31 of the third switch tube Q3; the control end e11 of the first switch tube Q1 is connected to the input voltage ADAPT of the adapter 261, and the first switch circuit 210 is configured as follows: When the adapter 261 is connected to the dual power supply device 201, the first switch tube Q1 is turned on, and the second switch tube Q2 and the third switch tube Q3 are turned off, so that the input channel of the battery 262 is cut off, and the dual power supply device 201 is powered by the adapter 261; when the adapter 261 is not connected, the first switch tube Q1 is turned off, and the second switch tube Q2 and the third switch tube Q3 are turned on; the control end e21 of the second switch tube Q2 is connected to the first working voltage V1 of the dual power supply device 201. In this embodiment, V1 = +5V. The first working voltage V1 can be converted from the voltage provided by the adapter 261 or the battery 262. The second switch circuit 220 is configured as follows: when the adapter 261 is not connected, the first working voltage V1 is used to turn on the second switch tube Q2. The third switch circuit 230 is used to receive the input voltage BAT_IN of the battery 262, the control terminal e31 of the third switch tube Q3 is connected to the first terminal e22 of the second switch tube Q2, the first terminal e32 of the third switch tube Q3 is connected to the input voltage BAT_IN of the battery 262, and the second terminal e33 of the third switch tube Q3 is connected to the power terminal 203 of the dual power supply device 201. The power terminal 203 is connected to the power supply terminal 203 of the dual power supply device 201. Figure 2 Indicated as POWER.

[0055] In some embodiments, Figure 2 As shown, Q1 is a triode, and Q2 and Q3 are both MOSFETs. Q1 is a triode, and its conduction range is narrower than that of MOSFET. Therefore, the control end e21 of Q1 is the base, the first end e12 of Q1 is the collector, and the second end e13 of Q1 is the emitter; the control end e21 of Q2 is the gate, the first end e22 of Q2 is the source or drain, and the second end e23 of Q2 is the drain or source; the control end e31 of Q3 is the gate, the first end e32 of Q3 is the source or drain, and the second end e33 of Q2 is the drain or source.

[0056] The power on / off control circuit of the present application can be applied to the following three scenarios:

[0057] Scenario 1: The adapter 261 is not connected, but the battery 262 is connected;

[0058] Scenario 2: The adapter 261 is connected, but the battery 262 is not connected;

[0059] Scenario 3: Both the adapter 261 and the battery 262 are connected.

[0060] like Figure 2 As shown, in some embodiments, the third switch circuit 230 further includes a switch button S1, which is connected between the control terminal e31 of Q3 and the ground DGND. When the switch button S1 is pressed, Q3 is turned on, the input voltage BAT_IN of the battery 262 is output to POWER, and the dual power supply device 201 is turned on.

[0061] Combination Figure 2 and Figure 3 As shown, in some embodiments, the dual power supply device 201 is further configured as follows: when the battery 262 is connected and the adapter 261 is not connected, that is, in the scenario 1, when the dual power supply device 201 has no operation for a preset period of time, the dual power supply device 201 inputs a battery off signal BAT_OFF to the control terminal e11 of the first switch tube Q1, and the battery off signal BAT_OFF may be sent by the processor 202, so that the first switch tube Q1 is turned on, and the second switch tube Q2 is turned off, and the third switch tube Q3 is turned off, and the dual power supply device 201 is shut down. Specifically, when the dual power supply device 201 has no operation for a long time, the processor 202 sets the battery off signal BAT_OFF to high, at this time, the voltage of the control terminal e11 of the first switch tube Q1 is greater than its on-voltage, for example, the on-voltage is 0.7V, Q1 is turned on, and at this time, the voltage of the control terminal e21 of Q2 is lower than 0.7V, so that Q2 is turned off, and Q3 is turned off at the same time, and the dual power supply device 201 is shut down.

[0062] More specifically, in some embodiments, Figure 3 As shown, the first switch circuit 210 further includes a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2, wherein a first end ( Figure 3 The upper end shown in FIG. 1 is connected to the input voltage ADAPT of the adapter 261, and the second end ( Figure 3 The lower end shown in FIG. 1 is connected to the control end e11 of the first switch tube Q1, and the first end ( Figure 3 The upper end shown in FIG. 1 is connected to the control end e11 of the first switch tube Q1, and the second end ( Figure 3 Furthermore, the first switch circuit 210 further includes a first diode D1, an anode of the first diode D1 is connected to the input voltage ADAPT of the adapter 261, and a cathode of the first diode D1 is connected to the first end of the first voltage-dividing resistor R1.

[0063] The second switch circuit 220 further includes a third voltage-dividing resistor R3 and a fourth voltage-dividing resistor R4, wherein a first end ( Figure 3 The upper end shown in FIG. 1 is connected to the first working voltage V1, and the second end ( Figure 3 The lower end shown in FIG. 1 is connected to the control end e21 of the second switch tube Q2, and the first end ( Figure 3 The upper end shown in FIG. 1 is connected to the control end e21 of the second switch tube Q2, and the second end ( Figure 3 The lower end shown in (as shown in) is grounded DGND. Furthermore, the second switch circuit 220 also includes a second diode D2, the cathode of the second diode D2 is connected to the first operating voltage V1, and the anode of the second diode D2 is connected to the first end of the third voltage-dividing resistor R3. According to these embodiments, the second switch circuit 220 is also configured to: configure the sizes of the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 so that when the first switch tube Q1 is turned off, the control terminal voltage of the second switch tube Q2 is greater than the maximum on-voltage of the second switch tube Q2. Specifically, when the first switch tube Q1 is turned off, the +5V V1 passes through the second diode D2, and the divided voltage of R3 and R4 is the control terminal voltage of Q2, so by adjusting the sizes of R3 and R4, the control terminal voltage of Q2 can be made greater than 0.7V.

[0064] The third switch circuit 230 further includes a fifth voltage-dividing resistor R5 and a sixth voltage-dividing resistor R6, wherein a first end ( Figure 3 The left end shown in FIG. 1 is connected to the first end e22 of the second switch tube Q2, and the second end ( Figure 3 The right end shown in FIG. 1 is connected to the control end e31 of the third switch tube Q3, and the first end ( Figure 3 The lower end shown in FIG. 1 is connected to the control end e31 of the third switch tube Q3, and the second end ( Figure 3 The upper end shown in ( ) is connected to the input voltage BAT_IN of the battery 262 and the first end e32 of the third switch tube Q3. Further, the third switch circuit 230 also includes a third diode D3, the anode of the third diode D3 is connected to the input voltage BAT_IN of the battery 262, and the cathode of the third diode D3 is connected to the second end of the sixth voltage-dividing resistor R6 and the first end e32 of the third switch tube Q3. Further, the third switch circuit 230 also includes a fourth diode D4, the anode of the fourth diode D4 is connected to the second end e33 of the third switch tube Q3, and the cathode of the fourth diode D4 is connected to the power supply end 203 of the dual power supply device 201. Further, the third switch circuit 230 also includes a control voltage clamping circuit, the control voltage clamping circuit includes a seventh voltage-dividing resistor R7, an eighth voltage-dividing resistor R8 and a clamping diode D5, the first end of the seventh voltage-dividing resistor R7 ( Figure 3The left end shown in FIG. 1 is connected to the second end e33 of the third switch tube Q3, and the second end ( Figure 3 The right end shown in FIG. 1 is connected to the dual power supply device 201 and is used to output a battery power supply detection signal BAT_ON. The first end (right end) of the eighth voltage-dividing resistor R8 Figure 3 The upper end shown in FIG. 1 is connected to the second end of the seventh voltage-dividing resistor R7, and the second end of the eighth voltage-dividing resistor R8 ( Figure 3 The lower end shown in FIG. 1 is grounded DGND, the anode of the clamping diode D5 is grounded DGND, and the cathode of the clamping diode D5 is connected to the second end of the seventh voltage-dividing resistor R7. Figure 2 , the battery power supply detection signal BAT_ON is output to the processor 202, and the clamping diode D5 is used to protect the processor 202. According to the requirements of the processor 202, a suitable clamping diode D5 can be selected, for example, a clamping diode D5 with a clamping voltage of 3.3V is used. Since the battery power supply range is 6V-13V, and the operating voltage of the processor 202 is 3.3V, the battery power supply detection signal BAT_ON output to the processor 202 can be limited to below 3.3V by using a control voltage clamping circuit.

[0065] Figure 4 It is a structural schematic diagram of a reference voltage generating circuit in an adapter monitoring circuit in a power on / off control circuit according to an embodiment of the present application. Figure 5 FIG. 1 is a schematic diagram of the structure of a comparator in an adapter monitoring circuit in a power on / off control circuit according to an embodiment of the present application. Figure 4 and Figure 5 In some embodiments, the adapter monitoring circuit includes a reference voltage generating circuit U2 and a comparator U1. The reference voltage generating circuit U2 is used to generate a reference voltage REF having a fixed value. The reference voltage REF is connected to the first input terminal 6 of the comparator U1. The input voltage ADAPT of the adapter 261 is connected to the second input terminal 5 of the comparator U1. The output terminal 7 of the comparator U1 outputs an interrupt signal ADAPT_Down. In an embodiment of the present application, REF is set to 2.5V. In other embodiments, REF can be set to other values ​​according to device requirements. Furthermore, the adapter monitoring circuit also includes a ninth voltage-dividing resistor R9 and a tenth voltage-dividing resistor R10. The first end of the ninth voltage-dividing resistor R9 ( Figure 5 The left end shown in FIG. 1 is connected to the input voltage ADAPT of the adapter 261, and the second end ( Figure 5 The right end shown in FIG. 1 is connected to the second input terminal 5 of the comparator U1, and the first end of the tenth voltage resistor R10 ( Figure 5 The upper end shown in FIG. 1 is connected to the second end of the ninth voltage-dividing resistor R9, and the second end of the tenth voltage-dividing resistor R10 ( Figure 5The adapter monitoring circuit is further configured to: adjust the size of the ninth voltage-dividing resistor R9 and the tenth voltage-dividing resistor R10 to adjust the level of the input voltage V2 of the second input terminal 5 of the comparator U1, thereby adjusting the time length for the input voltage ADAPT of the adapter 261 to drop to the time length for the dual power supply device 201 to receive the interrupt signal ADAPT_Down when the adapter 261 is unplugged. Furthermore, the adapter monitoring circuit further includes a load capacitor C2, which is connected between the second end of the ninth voltage-dividing resistor R9 and the ground DGND. The adapter monitoring circuit is further configured to: further adjust the size of the load capacitor C2 to adjust the level of the input voltage V2 of the second input terminal 5 of the comparator U1.

[0066] like Figure 5 As shown, two voltage-dividing resistors are connected to the output terminal 7 of the comparator U1, one of which is connected to the pull-up voltage V3. In this embodiment, V3 = +3.3 V, which can be connected by the system working voltage.

[0067] In scenario two, the adapter 261 is connected, and the battery 262 is not connected. When the adapter 261 is unplugged, due to the effect of the capacitor, it takes a certain amount of time for the input voltage ADAPT to drop. The voltage after ADAPT passes through D1 and then through the voltage division of R1 and R2 is the control terminal voltage of Q1. When the control terminal voltage of Q1 drops below 0.7V, Q1 is turned off. At this time, since V1 (+5V) and V3 (+3.3V) in the circuit have not changed, V1 passes through D2 and then through the voltage division of R3 and R4 is the control terminal voltage of Q2. Q2 is turned on, the control terminal voltage of Q3 is low, and Q3 is turned off. However, since the battery 262 is not connected, when the dual power supply device 201 receives the interrupt signal ADAPT_Down, such as Figure 2 As shown, the processor 202 may receive the interrupt signal ADAPT_Down and detect that the battery power detection signal BAT_ON is low. At this time, the dual power supply device 201 issues an instruction to save key data. After a period of time, V3 is lower than 3.3V, and the dual power supply device 201 shuts down.

[0068] Figure 6A-6C The following is a timing diagram of the adapter being unplugged in scenario 2, where the horizontal axis is time and the vertical axis is voltage. It should be noted that in order to compare the timing, the voltage values ​​to be compared are enlarged or reduced, and the diagram does not represent the actual voltage values. Fig. 6A, which shows the input voltage ADAPT of the adapter 261, the interrupt signal ADAPT_Down and the system operating voltage V3 (+3.3V). Among them, ADAPT starts to lose power at time t1, ADAPT_Down changes from 1 to 0 at time t2, and V3 starts to decrease at time t3. The time Δt1 from time t1 to time t2 is the time when the input voltage ADAPT drops to the time when the dual power supply device 201 receives the interrupt signal.

[0069] In this embodiment, REF = 2.5V, the voltage V2 of the second input terminal 5 of U1 = ADAPT / (R9+R10)*R10, and the values ​​of R9 and R10 are adjusted so that when ADAPT = 7.5V, V2 = 2.5V. When ADAPT < 7.5V, since V2 < 2.5V, the input ADAPT_Down of the comparator U1 = 0. When the adapter 261 is unplugged and powered off, ADAPT drops from 12V to 7.5V. Figure 6B , that is, from time t1 to time t2, it takes Δt1 = 5.65ms. Then ADAPT continues to decrease, such as Figure 6C , ADAPT drops from 7.5V to 3.3V, such as Figure 6C , that is, from time t2 to time t3, it takes Δt2 = 5.924ms, and the device is used to save key data during this time.

[0070] By adjusting the size of R9 and R10 to set the height of V2, Δt1 and Δt2 can be changed. Δt1 is provided to the device to detect the connection status of the battery 262. When the voltage of the battery 262 is small, Δt1 needs to be longer accordingly. According to the actual situation of the device, Δt1 can be shortened as much as possible and Δt2 can be increased to give the device enough time to save data. It should be noted that Δt1+Δt2 is a fixed value.

[0071] Figure 7 The following is a timing diagram of the conversion to battery power supply when the adapter is unplugged in scenario 3, where the horizontal axis is time and the vertical axis is voltage. It should be noted that in order to compare the timing, the voltage values ​​to be compared are enlarged or reduced, and the diagram does not represent the actual voltage value. Figure 7 , which shows the input voltage ADAPT of the adapter 261, the interrupt signal ADAPT_Down, the system operating voltage V3 (+3.3V) and the battery supply voltage Bat.

[0072] Combination Figure 3In scenario three, when the adapter 261 is turned on, ADAPT enters the first switch circuit 210 through D1, and then the voltage after voltage division by R1 and R2 is the base voltage of Q1. When the base voltage of Q1 rises to above 0.7V, Q1 is turned on, the gate voltage of Q2 is 0, making Q2 turned off, and the Vgs of Q3 is 0, making Q3 turned off, and the BAT_IN power input channel is cut off.

[0073] When the adapter 261 is unplugged, the ADAPT voltage passes through D1, R1 and R2 to obtain the base voltage of Q1. The base voltage gradually decreases. When the base voltage of Q1 drops below 0.7V, Q1 is turned off. At this time, V1 (+5V) and V3 (+3.3V) in the circuit have not changed. V1 passes through D2, R3 and R4 to become the gate voltage of Q2. The gate voltage of Q2 is greater than the turn-on voltage of Q2, making Q2 turn on. The source e33 voltage of Q3 is low, Q3 is turned on, and the input voltage BAT_IN of the battery 262 is output to POWER. Combined Figure 5 When ADAPT further decreases and the interrupt signal ADAPT_Down is received, the device detects that BAT_ON is high. In these embodiments, taking into account the rise time of the input voltage BAT_IN of the battery 262, by adjusting the size of the ninth voltage-dividing resistor R9 and the tenth voltage-dividing resistor R10, when the dual power supply device 201 receives the interrupt signal ADAPT_Down, the battery power supply detection signal BAT_ON is high, indicating that the battery 262 is detected to be connected.

[0074] refer to Figure 3 , Q1's base voltage Ve11=ADAPT / (R1+R2)*R2. In some embodiments, the first switch circuit 210 is further configured to: adjust the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 to adjust the voltage threshold Vth of the adapter 261 power supply switching to the battery 262 power supply. When the adapter 261 is unplugged, the adapter 261 input voltage ADAPT drops to the voltage threshold Vth, and the battery supplies power to the dual-power supply device 201. At this time, the comparator U1 has not yet output the interrupt signal ADAPT_Down. Assuming that the adapter 261 input voltage ADAPT is 10V, to ensure that the voltage is stable, Vth can be set to 10.5V. Figure 7 When ADAPT drops from 12V to 10.5V, that is, from time t1 to time t4, it takes Δt3 = 3.054ms. At this time, V2>2.5V(REF), and the interrupt signal ADAPT_Down does not change. Therefore, Figure 7 Therefore, according to the power on / off control circuit of the present application, in scenario three, a seamless transition from adapter power supply to battery power supply can be achieved.

[0075] According to the power on / off control circuit of the present application, the following functions can be realized:

[0076] (1) In the following scenario, the device is powered only by batteries and is turned on by a mechanical button. If the device is not used for a long time, it can automatically shut down.

[0077] (2) In scenario 2, only the adapter is powered. After the adapter loses power, the power on / off control circuit of the present application will send an interrupt signal. When the device receives the interrupt signal, it will immediately take corresponding actions, including saving important data, clearing cache, etc. Depending on the application, the execution time of these actions is several ms or dozens of ms, or even longer. The power on / off control circuit of the present application can obtain different action time margins by adjusting the resistance and capacitance in the adapter monitoring circuit.

[0078] (3) In scenario three, the battery and adapter are dual powered, and the two power sources can be switched seamlessly, which will not affect the normal use of the device and will not affect the measurement or metering performance.

[0079] In order to illustrate the optimization of power consumption of the power on / off control circuit of the present application, the following is combined with the attached Figures 8A-8C Provide explanation.

[0080] Fig. 8A The figure shows the power consumption of the dual-power device when powered by an adapter, which roughly includes four parts: (1) Power consumption P1, from the power supply end (Power) to the 3.3V operating voltage (V3), efficiency η1; (2) Power consumption P2, from the power supply end to the 5V operating voltage (V1), efficiency η2; (3) Power consumption P3, from the power supply end to 10V through the LDO (low dropout voltage regulator, rectifier); (4) Power consumption P4, from the power supply end to VLCD (display) after filtering. At this time, the power consumption of the whole machine when powered by the adapter is:

[0081]

[0082] Figure 8B Is adopted Figure 1 The buck-boost circuit shown is the power consumption of the dual-powered device when powered by a battery. It also includes four parts similar to the adapter. The difference is that there is a boost efficiency Ψ from the battery to the power supply end (Power). At this time, the power consumption of the whole device when powered by a battery is:

[0083]

[0084] Figure 8CIt is the power consumption of the dual power supply device when the power switch control circuit of the present application is powered by a battery, wherein the switch circuit of the present application is between the battery and the power supply terminal, and the power consumption P3 and the power consumption P4 are obtained by boosting the 5V voltage. At this time, the power consumption of the whole device when powered by the battery is:

[0085]

[0086] Comparing equation (2) and equation (3), assuming that Pb <Pb',

[0087] Right now

[0088] The values ​​of ψ and η0 are usually 0.8-0.85, and the voltage reduction efficiency η1 and η2 are usually around 0.9. The result is:

[0089]

[0090] From formula (4), it can be seen that the distribution ratio of low voltage and high voltage can determine the optimization scheme of circuit power consumption. In general control systems, the power of low voltage is greater than that of high voltage. The power on / off control circuit proposed in this application can easily make formula (4) valid, thereby reducing the overall working power consumption of the equipment and reducing energy consumption. Under the premise of ensuring the normal operation of the circuit, the power consumption is optimized. Since the power consumption of the high voltage part accounts for a low proportion, compared with Figure 1 As shown in the simple buck-boost circuit, the power on / off control circuit of the present application occupies a smaller chip area, and the range of chip selection is wider, which is beneficial to cost control.

[0091] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

Claims

1. A power on / off control circuit for a dual power supply device, wherein the power supply unit of the dual power supply device comprises an adapter and a battery, characterized in that: include: A first switch circuit, a third switch circuit and an adapter monitoring circuit; wherein, The first switch circuit is used to receive the input voltage of the adapter, and the third switch circuit is used to receive the input voltage of the battery and is connected to the power supply terminal of the dual power supply device; The switch control circuit is configured as follows: when the adapter is connected, the first switch circuit is turned on, the third switch circuit is turned off, so that the input channel of the battery is cut off, and the dual power supply device is powered by the adapter; when the adapter is not connected, the first switch circuit is turned off, the third switch circuit is turned on, and when the battery is connected, the input voltage of the battery is transmitted to the power supply terminal of the dual power supply device, and the third switch circuit outputs a battery power supply detection signal to the dual power supply device, and the dual power supply device is powered by the battery; The adapter monitoring circuit is used to monitor whether the adapter is connected, and the adapter monitoring circuit is configured to: when the adapter is disconnected, output an interrupt signal to the dual power supply device; The dual power supply device is configured to: when the adapter is disconnected, the dual power supply device receives the interrupt signal, obtains the battery power supply detection signal, and when it is determined according to the battery power supply detection signal that the battery is not connected, the dual power supply device issues a protection action instruction.

2. The power on / off control circuit according to claim 1, characterized in that: The dual power supply device is further configured to: when the adapter and the battery are both not connected, and when the system operating voltage is lower than a preset value, the dual power supply device controls the dual power supply device to shut down.

3. The power on / off control circuit according to claim 1, characterized in that: It also includes a second switch circuit connected between the first switch circuit and the third switch circuit; wherein, The power on / off control circuit is also configured as follows: when the adapter is connected, the first switch circuit is turned on, and the second switch circuit and the third switch circuit are both turned off, so that the input channel of the battery is cut off, and the dual power supply device is powered by the adapter; when the adapter is not connected, the first switch circuit is turned off, and the second switch circuit and the third switch circuit are both turned on.

4. The power on / off control circuit according to claim 3, characterized in that: The first switch circuit includes a first switch tube, the second switch circuit includes a second switch tube, and the third switch circuit includes a third switch tube, the first end of the first switch tube is connected to the control end of the second switch tube, and the first end of the second switch tube is connected to the control end of the third switch tube; The control end of the first switch tube is connected to the input voltage of the adapter, and the first switch circuit is configured as follows: when the adapter is connected, the first switch tube is turned on, and the second switch tube and the third switch tube are turned off, so that the input channel of the battery is cut off, and the dual power supply device is powered by the adapter; when the adapter is not connected, the first switch tube is turned off, and the second switch tube and the third switch tube are turned on; The control end of the second switch tube is connected to the first working voltage of the dual power supply device, and the second switch circuit is configured as follows: when the adapter is not turned on, the first working voltage is used to turn on the second switch tube; The control end of the third switch tube is connected to the first end of the second switch tube, the first end of the third switch tube is connected to the input voltage of the battery, and the second end of the third switch tube is connected to the power supply end of the dual power supply device.

5. The power on / off control circuit according to claim 4, characterized in that: The dual power supply device is also configured as follows: when the battery is connected and the adapter is not connected, and when the dual power supply device has not been operated for a preset period of time, the dual power supply device inputs a battery off signal to the control end of the first switch tube, so that the first switch tube is turned on, and the second switch tube is turned off, and the third switch tube is turned off, and the dual power supply device is shut down.

6. The power on / off control circuit according to claim 4, characterized in that: The first switching circuit also includes a first voltage-dividing resistor and a second voltage-dividing resistor, wherein the first end of the first voltage-dividing resistor is connected to the input voltage of the adapter, the second end of the first voltage-dividing resistor is connected to the control end of the first switching tube, the first end of the second voltage-dividing resistor is connected to the control end of the first switching tube, and the second end of the second voltage-dividing resistor is grounded.

7. The power on / off control circuit according to claim 6, characterized in that: The first switch circuit further includes a first diode, an anode of the first diode is connected to the input voltage of the adapter, and a cathode of the first diode is connected to the first end of the first voltage-dividing resistor.

8. The power on / off control circuit according to claim 4, characterized in that: The second switching circuit also includes a third voltage-dividing resistor and a fourth voltage-dividing resistor, wherein the first end of the third voltage-dividing resistor is connected to the first operating voltage, the second end of the third voltage-dividing resistor is connected to the control end of the second switching tube, the first end of the fourth voltage-dividing resistor is connected to the control end of the second switching tube, and the second end of the fourth voltage-dividing resistor is grounded.

9. The power on / off control circuit according to claim 8, characterized in that: The second switch circuit further includes a second diode, a cathode of the second diode is connected to the first operating voltage, and an anode of the second diode is connected to the first end of the third voltage-dividing resistor.

10. The power on / off control circuit according to claim 8, characterized in that: The second switch circuit is further configured to: configure the sizes of the third voltage-dividing resistor and the fourth voltage-dividing resistor so that when the first switch tube is turned off, the control terminal voltage of the second switch tube is greater than the maximum on-voltage of the second switch tube.

11. The power on / off control circuit according to claim 4, characterized in that: The third switch circuit also includes a fifth voltage-dividing resistor and a sixth voltage-dividing resistor, wherein a first end of the fifth voltage-dividing resistor is connected to a first end of the second switch tube, a second end of the fifth voltage-dividing resistor is connected to a control end of the third switch tube, a first end of the sixth voltage-dividing resistor is connected to the control end of the third switch tube, and a second end of the sixth voltage-dividing resistor is connected to an input voltage of the battery and a first end of the third switch tube.

12. The power on / off control circuit according to claim 11, characterized in that: The third switch circuit also includes a third diode, the anode of the third diode is connected to the input voltage of the battery, and the cathode of the third diode is connected to the second end of the sixth voltage-dividing resistor and the first end of the third switch tube.

13. The power on / off control circuit according to claim 12, characterized in that: The third switch circuit further includes a fourth diode, the anode of the fourth diode is connected to the second end of the third switch tube, and the cathode of the fourth diode is connected to the power supply end of the dual power supply device.

14. The power on / off control circuit according to claim 13, characterized in that: The third switching circuit also includes a control voltage clamping circuit, which includes a seventh voltage-dividing resistor, an eighth voltage-dividing resistor and a clamping diode. The first end of the seventh voltage-dividing resistor is connected to the second end of the third switching tube, the second end of the seventh voltage-dividing resistor is connected to the dual power supply device and is used to output the battery power supply detection signal, the first end of the eighth voltage-dividing resistor is connected to the second end of the seventh voltage-dividing resistor, the second end of the eighth voltage-dividing resistor is grounded, the positive pole of the clamping diode is grounded, and the negative pole of the clamping diode is connected to the second end of the seventh voltage-dividing resistor.

15. The power on / off control circuit according to claim 6, characterized in that: The adapter monitoring circuit includes a reference voltage generating circuit and a comparator. The reference voltage generating circuit is used to generate a reference voltage with a fixed value. The reference voltage is connected to a first input terminal of the comparator. The input voltage of the adapter is connected to a second input terminal of the comparator. The output terminal of the comparator outputs the interrupt signal.

16. The power on / off control circuit according to claim 15, characterized in that: The adapter monitoring circuit also includes a ninth voltage-dividing resistor and a tenth voltage-dividing resistor, wherein a first end of the ninth voltage-dividing resistor is connected to the input voltage of the adapter, a second end of the ninth voltage-dividing resistor is connected to the second input terminal of the comparator, a first end of the tenth voltage-dividing resistor is connected to the second end of the ninth voltage-dividing resistor, and a second end of the tenth voltage-dividing resistor is grounded.

17. The power on / off control circuit according to claim 16, characterized in that: The adapter monitoring circuit is also configured to adjust the sizes of the ninth voltage-dividing resistor and the tenth voltage-dividing resistor to adjust the input voltage of the second input terminal of the comparator, thereby adjusting the length of time it takes for the input voltage of the adapter to drop to the time it takes for the dual power supply device to receive an interrupt signal when the adapter is unplugged.

18. The power on / off control circuit according to claim 17, characterized in that: The adapter monitoring circuit also includes a load capacitor connected between the second end of the ninth voltage-dividing resistor and ground. The adapter monitoring circuit is also configured to: adjust the size of the load capacitor to adjust the input voltage of the second input end of the comparator.

19. The power on / off control circuit according to claim 16, characterized in that: The first switch circuit is further configured to adjust the sizes of the ninth voltage-dividing resistor and the tenth voltage-dividing resistor so that when the dual power supply device receives the interrupt signal, the battery power supply detection signal is at a high level.

20. The power on / off control circuit according to claim 16, characterized in that: The first switching circuit is further configured to adjust the size of the first voltage-dividing resistor and the second voltage-dividing resistor to adjust the voltage threshold for switching from adapter power supply to battery power supply, wherein when the adapter is unplugged and the input voltage of the adapter drops to the voltage threshold, the battery supplies power to the dual-power supply device, and at this time the comparator has not yet output the interrupt signal.

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