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

Abstract

The invention 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] This application mainly relates to the field of measuring devices, and particularly to a power-on and power-off control circuit for dual-powered devices. Background Art

[0002] In the field of measuring devices, portable electronic balances or other electronic devices generally include two power supply modes: power adapter and AA battery. For dual-powered devices with a power adapter and battery power supply, the device itself needs to seamlessly switch 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, in the event of an abnormal power outage of the system, such as when there is no battery adapter power supply or the battery power cannot support the system, certain data or functions need to be specially protected to prevent data loss or abnormal occurrence. In an embedded system, the protection function trigger needs to obtain the system power supply information to make a correct judgment.

[0003] In the battery power supply mode, in order to extend the working time of the device, usually multiple batteries are connected in series. As the battery continuously discharges, its voltage also changes. The working voltage of the power adapter may be within the range of the maximum voltage and the minimum voltage of the battery. For an electronic balance or other electronic measuring devices, the external adapter power supply may be 12V, 15V or other values, and there are also multiple voltages generated inside, typically voltages such as 3.3V, 5V, 10V, etc., which are used to control the system and the test and measurement unit to work. 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 large-sized liquid crystal display unit, its backlight voltage requirement is also high. Therefore, in electronic measuring devices such as electronic balances, both high and low voltages exist inside at the same time. Traditionally, in order to extend the battery usage time, the conventional method is to add a buck-boost circuit at the battery output end to adapt to the battery voltage continuously decreasing as it discharges and still be able to stably output the voltage required by the system. Figure 1 A circuit block diagram of adding a buck-boost circuit is shown. As Figure 1 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 characteristic of a simple framework, but there are the following problems:

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

[0005] (2) In most cases, the low-voltage power consumption of electronic measurement devices accounts for a relatively high proportion. If a buck-boost circuit is used, it will bring energy consumption losses. Therefore, during continuous battery discharge, the energy efficiency conversion of the entire system will be greatly reduced.

[0006] (3) The buck-boost circuit increases the test complexity and different operating conditions such as the boost stage, buck-boost conversion point, and buck stage need to be considered.

[0007] (4) The buck-boost circuit occupies a relatively large PCB space. Summary of the Invention

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

[0009] To solve the above technical problems, this application provides a power-on and power-off control circuit for a dual-power supply device. The power supply units of the dual-power supply device include an adapter and a battery, and the circuit includes: a first switch circuit, a third switch circuit, and an adapter monitoring circuit. Among them, 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 power-on and power-off control circuit is configured as follows: when the adapter is connected, the first switch circuit conducts, the third switch circuit turns off, cutting off the input channel of the battery, and the dual-power supply device is powered by the adapter; when the adapter is not connected, the first switch circuit turns off, the third switch circuit conducts, 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 as follows: when the adapter is disconnected, an interrupt signal is output to the dual-power supply device; the dual-power supply device is configured as follows: when the adapter is disconnected and the dual-power supply device receives the interrupt signal, and when it is determined that the battery is not connected according to the battery power supply detection signal, the dual-power supply device issues a protection action instruction.

[0010] In an embodiment of this application, the dual-power supply device is further configured as follows: when neither the adapter nor the battery is 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 an embodiment of the present application, a second switch circuit is further included, which is connected between the first switch circuit and the third switch circuit; wherein, the power-on / off control circuit is further configured that: 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 as to cut off the input channel of the battery, 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 an embodiment of the present application, the first switch circuit includes a first switch tube, the second switch circuit includes a second switch tube, the third switch circuit includes a third switch tube, a first end of the first switch tube is connected to a control end of the second switch tube, and a first end of the second switch tube is connected to a control end of the third switch tube; a control end of the first switch tube is connected to an input voltage of the adapter, and the first switch circuit is configured that: when the adapter is connected, the first switch tube is turned on, and the second switch tube and the third switch tube are both turned off, so as to cut off the input channel of the battery, 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 both turned on; a control end of the second switch tube is connected to a first operating voltage of the dual-power supply device, and the second switch circuit is configured that: when the adapter is not connected, the first operating voltage is used to turn on the second switch tube; a control end of the third switch tube is connected to the first end of the second switch tube, a first end of the third switch tube is connected to an input voltage of the battery, and a second end of the third switch tube is connected to a power supply end of the dual-power supply device.

[0013] In an embodiment of the present application, the dual-power supply device is further configured that: when the battery is connected and the adapter is not connected, when the dual-power supply device has no operation after a preset duration, 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 and the third switch tube are both turned off, and the dual-power supply device shuts down.

[0014] In an embodiment of the present application, the first switch circuit further includes a first voltage-dividing resistor and a second voltage-dividing resistor, wherein, a first end of the first voltage-dividing resistor is connected to the input voltage of the adapter, a second end of the first voltage-dividing resistor is connected to the control end of the first switch tube, a first end of the second voltage-dividing resistor is connected to the control end of the first switch tube, and a 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, the positive electrode of the first diode is connected to the input voltage of the adapter, and the negative electrode 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 switch circuit further 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.

[0017] In one embodiment of the present application, the second switch circuit further includes a second diode, the negative electrode of the second diode is connected to the first operating voltage, and the positive electrode 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 magnitudes of the third voltage dividing resistor and the fourth voltage dividing resistor such that when the first switching tube is turned off, the voltage at the control end of the second switching tube is greater than the maximum conduction voltage of the second switching tube.

[0019] In one embodiment of the present application, the third switch circuit further 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 switch circuit further includes a third diode, the positive electrode of the third diode is connected to the input voltage of the battery, and the negative electrode 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 switch circuit further includes a fourth diode, the positive electrode of the fourth diode is connected to the second end of the third switching tube, and the negative electrode of the fourth diode is connected to the power supply end of the dual-power supply device.

[0022] In an embodiment of the present application, the third switching circuit further includes a control voltage clamping circuit, and the control voltage clamping circuit 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 transistor, 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 electrode of the clamping diode is grounded, and the negative electrode of the clamping diode is connected to the second end of the seventh voltage dividing resistor.

[0023] In an embodiment of the present application, 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 the first input terminal of the comparator, the input voltage of the adapter is connected to the second input terminal of the comparator, and the output terminal of the comparator outputs the interrupt signal.

[0024] In an embodiment of the present application, the adapter monitoring circuit further 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 an embodiment of the present application, the adapter monitoring circuit is further configured to: adjust the magnitudes of the ninth voltage dividing resistor and the tenth voltage dividing resistor to adjust the level of the input voltage at the second input terminal of the comparator, so as to adjust the duration from when the input voltage of the adapter drops to when the dual power supply device receives the interrupt signal when the adapter is unplugged.

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

[0027] In an embodiment of the present application, the first switching circuit is further configured to: adjust the magnitudes 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 switch circuit is further configured to: adjust the magnitudes 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. 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 output the interruption signal.

[0029] According to the power-on and power-off control circuit of the present application, events of the adapter not being connected or unplugged can be detected in a timely manner, and the connection status of the battery can be judged in a timely manner. When the battery is also not connected, key data can be saved in a timely manner using the power-down time before the system operating voltage drops below the preset value, which can avoid data loss. In the scenario of only battery power supply, when the dual-power supply device does not work for a long time, the device can be automatically powered off. In the scenario of dual power supply by battery and adapter, 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 and power-off control circuit of the present application can also reduce the overall power consumption of the device, reduce energy consumption, and optimize the power consumption on the premise of ensuring the normal operation of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are provided to further understand the present application, and they are incorporated and constitute a part of the present application. The accompanying drawings show embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the accompanying drawings:

[0031] Figure 1 shows a circuit block diagram of a boost-buck circuit added;

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

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

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

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

[0036] Figures 6A - 6C shows a timing diagram when the adapter is unplugged in Scenario 2;

[0037] Figure 7 shows a timing diagram of switching to battery power supply when the adapter is unplugged in Scenario 3;

[0038] Figure 8A The power consumption of the dual-powered device when powered by the adapter is shown;

[0039] Figure 8B It is when using Figure 1 the buck-boost circuit shown that the power consumption of the dual-powered device when powered by the battery;

[0040] Figure 8C It is the power consumption of the dual-powered device when powered by the battery using the on / off control circuit of the present application. Detailed implementation manners

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0042] As shown in the present application, unless the context clearly indicates an exceptional situation, words such as "a", "an", "one" and / or "the" are not specifically singular and may also include plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0043] Unless specifically stated otherwise, the relative arrangements, numerical expressions and values of the components and steps described in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods and devices known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the said technologies, methods and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is merely for the convenience of distinguishing the corresponding components. Without additional declaration, these terms have no special meaning, and thus should not be construed as a limitation on the protection scope of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meaning implied by each term.

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

[0046] Figure 2 is an exemplary block diagram of the power-on / off control circuit of an embodiment of this application. Refer to 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 in is a dual-power supply device 201, which has a processor 202 and a power supply terminal 203. Among them, the processor 202 can be a CPU, MCU, etc., and the power supply terminal 203 can be a pin of a certain 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 an installation part for installing 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 installation circuit to supply power to the dual-power supply device 201. It can be understood that at the same moment, only one of the adapter 261 and the battery 262 is required to supply power. In the embodiment of this application, the battery 262 can be a series connection of multiple AA batteries, for example, 8 sections, and the range of the input voltage BAT_IN is 6V - 13V.

[0047] As Figure 2As shown in the figure, 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 power-on and power-off control circuit is configured such that 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, cutting off the input channel of the battery 262, 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, as Figure 2 shown. The adapter monitoring circuit 240 is used to monitor whether the adapter 261 is connected. The adapter monitoring circuit 240 is configured such that when the adapter 262 is disconnected, it outputs an interrupt signal ADAPT_Down to the dual-power supply device 201. In some embodiments, the interrupt signal ADAPT_Down is input to the processor 202, as Figure 2 shown. The dual-power supply device 201 is configured such that when the adapter 261 is disconnected and the dual-power supply device 201 receives the interrupt signal ADAPT_Down, it obtains the battery power supply detection signal BAT_ON. When it is determined that the battery is not connected based on 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 performing data saving, saving critical data, clearing the cache, etc.

[0049] It should be noted that referring to Figure 2 , the adapter 261 is connected to the power supply pin of the dual-power supply device 201 through other circuits, such as the line L1, to provide power to the dual-power supply device 201 when the adapter 261 is connected.

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

[0051] In some embodiments, the dual-power supply device 201 is further configured to: when neither the adapter 261 nor the battery 262 is 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] Generally, the voltage range of the adapter 261 is 12V, 15V, etc. In this specification, 12V is taken as an example for illustration, and it is not used to limit its range. The system operating voltage refers to the operating voltage of the processor 202 in the dual-power supply device 201, which is usually relatively low, such as 3.3V, and is converted from the voltage provided by the adapter 261 or the battery 262. When an event occurs that the adapter 261 is not connected or unplugged, according to Figure 2 the shown power-on and power-off control circuit, the event that the adapter 261 is not connected or unplugged can be detected in time, and the connection status of the battery 262 can be judged in time. If the battery 262 is also not connected, the critical data can be saved in time using the power-off time before the system operating voltage is lower than the preset value, which can avoid data loss. The preset value < 3.3V, for example, is 2.9V.

[0053] As Figure 2 shown, in some embodiments, the power-on and power-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. Among them, 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. 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 is a schematic circuit diagram of the power-on and power-off control circuit according to another embodiment of the present application. This embodiment is in Figure 2Based on the illustrated embodiments, the structures of each circuit are given more specifically. In this embodiment, the first switch circuit 210 includes a first switching transistor Q1, the second switch circuit 220 includes a second switching transistor Q2, and the third switch circuit 230 includes a third switching transistor Q3. The first end e12 of the first switching transistor Q1 is connected to the control end e21 of the second switching transistor Q2, and the first end e22 of the second switching transistor Q2 is connected to the control end e31 of the third switching transistor Q3. The control end e11 of the first switching transistor Q1 is connected to the input voltage ADAPT of the adapter 261. The first switch circuit 210 is configured such that when the adapter 261 is connected to the dual-power supply device 201, the first switching transistor Q1 is turned on, and the second switching transistor Q2 and the third switching transistor Q3 are turned off, cutting off the input channel of the battery 262, and the dual-power supply device 201 is powered by the adapter 261. When the adapter 261 is not connected, the first switching transistor Q1 is turned off, and the second switching transistor Q2 and the third switching transistor Q3 are turned on. The control end e21 of the second switching transistor Q2 is connected to the first operating voltage V1 of the dual-power supply device 201. In this embodiment, V1 = +5V. The first operating voltage V1 can be obtained by converting the voltage provided by the adapter 261 or the battery 262. The second switch circuit 220 is configured such that when the adapter 261 is not connected, the first operating voltage V1 is used to turn on the second switching transistor Q2. The third switch circuit 230 is used to receive the input voltage BAT_IN of the battery 262. The control end e31 of the third switching transistor Q3 is connected to the first end e22 of the second switching transistor Q2. The first end e32 of the third switching transistor Q3 is connected to the input voltage BAT_IN of the battery 262, and the second end e33 of the third switching transistor Q3 is connected to the power supply terminal 203 of the dual-power supply device 201. The power supply terminal 203 is denoted as POWER in Figure 2 which is represented as POWER.

[0055] In some embodiments, as Figure 2 shown, Q1 is a bipolar junction transistor, and Q2 and Q3 are both MOSFETs. Q1 is selected as a bipolar junction transistor, and its conduction range is narrower than that of a MOSFET. Thus, 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 and power-off control circuit of the present application can be applied to the following three scenarios:

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

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

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

[0060] As Figure 2 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 conducts, and the input voltage BAT_IN of the battery 262 is output to POWER, and the dual-power supply device 201 is powered on.

[0061] Combined with Figure 2 and Figure 3 shown, in some embodiments, the dual-power supply device 201 is further configured such that when the battery 262 is connected and the adapter 261 is not connected, that is, in Scenario 1, when the dual-power supply device 201 has no operation for a preset duration, the dual-power supply device 201 inputs a battery-off signal BAT_OFF to the control terminal e11 of the first switching transistor Q1. The battery-off signal BAT_OFF can be issued by the processor 202, so that the first switching transistor Q1 conducts, and the second switching transistor Q2 and the third switching transistor Q3 are turned off, and the dual-power supply device 201 shuts 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 switching transistor Q1 is greater than its conduction voltage. For example, the conduction voltage is 0.7V, and Q1 conducts. At this time, the voltage of the control terminal e21 of Q2 is lower than 0.7V, causing Q2 to turn off, and at the same time causing Q3 to turn off, and the dual-power supply device 201 shuts down.

[0062] More specifically, in some embodiments, as Figure 3 shown, the first switch circuit 210 further includes a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2. Among them, the first end of the first voltage-dividing resistor R1 ( Figure 3 the upper end shown in Figure 3 is connected to the input voltage ADAPT of the adapter 261, and the second end of the first voltage-dividing resistor R1 ( Figure 3 the lower end shown in Figure 3 is connected to the control terminal e11 of the first switching transistor Q1. The first end of the second voltage-dividing resistor R2 ( Figure 3 the upper end shown in Figure 3 is connected to the control terminal e11 of the first switching transistor Q1, and the second end of the second voltage-dividing resistor R2 ( Figure 3 the lower end shown in

[0063] is grounded (DGND). Further, the first switch circuit 210 further includes a first diode D1. The positive electrode of the first diode D1 is connected to the input voltage ADAPT of the adapter 261, and the negative electrode of the first diode D1 is connected to the first end of the first voltage-dividing resistor R1. The second switch circuit 220 further includes a third voltage-dividing resistor R3 and a fourth voltage-dividing resistor R4. Among them, the first end of the third voltage-dividing resistor R3 (Figure 3 The upper end shown in is connected to the first operating voltage V1, and the second end of the third voltage-dividing resistor R3 ( Figure 3 The lower end shown in is connected to the control end e21 of the second switching transistor Q2, and the first end of the fourth voltage-dividing resistor R4 ( Figure 3 The upper end shown in is connected to the control end e21 of the second switching transistor Q2, and the second end of the fourth voltage-dividing resistor R4 ( Figure 3 The lower end shown in is grounded to DGND. Further, the second switching circuit 220 further includes a second diode D2. The negative electrode of the second diode D2 is connected to the first operating voltage V1, and the positive electrode of the second diode D2 is connected to the first end of the third voltage-dividing resistor R3. According to these embodiments, the second switching circuit 220 is further configured to: configure the magnitudes of the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 such that when the first switching transistor Q1 is turned off, the control-end voltage of the second switching transistor Q2 is greater than the maximum conduction voltage of the second switching transistor Q2. Specifically, when the first switching transistor Q1 is turned off, V1 of +5V passes through the second diode D2, and the voltage division of R3 and R4 is the control-end voltage of Q2. Therefore, by adjusting the magnitudes of R3 and R4, the control-end voltage of Q2 can be made greater than 0.7V.

[0064] The third switching circuit 230 further includes a fifth voltage-dividing resistor R5 and a sixth voltage-dividing resistor R6. Among them, the first end of the fifth voltage-dividing resistor R5 ( Figure 3 The left end shown in is connected to the first end e22 of the second switching transistor Q2, and the second end of the fifth voltage-dividing resistor R5 ( Figure 3 The right end shown in is connected to the control end e31 of the third switching transistor Q3, and the first end of the sixth voltage-dividing resistor R6 ( Figure 3 The lower end shown in is connected to the control end e31 of the third switching transistor Q3, and the second end of the sixth voltage-dividing resistor R6 ( 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 switching transistor Q3. Further, the third switching circuit 230 further includes a third diode D3. The positive electrode of the third diode D3 is connected to the input voltage BAT_IN of the battery 262, and the negative electrode 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 switching transistor Q3. Further, the third switching circuit 230 further includes a fourth diode D4. The positive electrode of the fourth diode D4 is connected to the second end e33 of the third switching transistor Q3, and the negative electrode of the fourth diode D4 is connected to the power supply terminal 203 of the dual-power supply device 201. Further, the third switching circuit 230 further 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 is connected to the second end e33 of the third switching transistor Q3, and the second end of the seventh voltage-dividing resistor R7 ( Figure 3 The right end shown in 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 of the eighth voltage-dividing resistor R8 ( Figure 3 The upper end shown in is connected to the second end of the seventh voltage-dividing resistor R7. The second end of the eighth voltage-dividing resistor R8 ( Figure 3 The lower end shown in is grounded to DGND. The positive electrode of the clamping diode D5 is grounded to DGND, and the negative electrode of the clamping diode D5 is connected to the second end of the seventh voltage-dividing resistor R7. Combining 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. A suitable clamping diode D5 can be selected according to the requirements of the processor 202. 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 output battery power supply detection signal BAT_ON to the processor 202 can be limited below 3.3V by using a control voltage clamping circuit.

[0065] Figure 4 is a schematic structural diagram of a reference voltage generation circuit in an adapter monitoring circuit in a power-on / off control circuit according to an embodiment of the present application. Figure 5 is a schematic structural diagram of a comparator in an adapter monitoring circuit in a power-on / off control circuit according to an embodiment of the present application. Combining Figure 4 and Figure 5 , in some embodiments, the adapter monitoring circuit includes a reference voltage generation circuit U2 and a comparator U1. The reference voltage generation circuit U2 is used to generate a reference voltage REF with 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 the embodiment of the present application, REF is set to 2.5V. In other embodiments, REF can be set to other values according to the device requirements. Further, the adapter monitoring circuit further 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 is connected to the input voltage ADAPT of the adapter 261. The second end of the ninth voltage-dividing resistor R9 ( Figure 5 The right end shown in is connected to the second input terminal 5 of the comparator U1. The first end of the tenth voltage-dividing resistor R10 ( Figure 5 The upper end shown in is connected to the second end of the ninth voltage-dividing resistor R9. The second end of the tenth voltage-dividing resistor R10 ( Figure 5The lower end shown in the figure is grounded to DGND. The adapter monitoring circuit is also configured to: adjust the magnitudes of the ninth voltage-dividing resistor R9 and the tenth voltage-dividing resistor R10 to adjust the magnitude of the input voltage V2 at the second input terminal 5 of the comparator U1, thereby adjusting the duration during which the input voltage ADAPT of the adapter 261 drops to the dual-power supply device 201 receiving the interrupt signal ADAPT_Down when the adapter 261 is unplugged. Further, the adapter monitoring circuit further includes a load capacitor C2. The load capacitor C2 is connected between the second terminal of the ninth voltage-dividing resistor R9 and the ground DGND. The adapter monitoring circuit is also configured to: further adjust the magnitude of the load capacitor C2 to adjust the magnitude of the input voltage V2 at the second input terminal 5 of the comparator U1.

[0066] As Figure 5 shown, two voltage-dividing resistors are also connected to the output terminal 7 of the comparator U1. One of the voltage-dividing resistors is connected to the pull-up voltage V3. In this embodiment, V3 = +3.3V, which can be accessed by the system operating 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, the drop of the input voltage ADAPT requires a certain amount of time. The voltage after ADAPT passes through D1 and then is divided by R1 and R2 is the control terminal voltage of Q1. When the control terminal voltage of Q1 drops below 0.7V, Q1 turns off. At this time, since V1 (+5V) and V3 (+3.3V) in the circuit do not change, the voltage after V1 passes through D2 and then is divided by R3 and R4 is the control terminal voltage of Q2, and Q2 conducts. The control terminal voltage of Q3 is low, and Q3 turns off. However, since the battery 262 is not connected, when the dual-power supply device 201 receives the interrupt signal ADAPT_Down, as Figure 2 shown, it can be that the processor 202 receives the interrupt signal ADAPT_Down and at the same time detects that the battery power supply detection signal BAT_ON is low. At this time, the dual-power supply device 201 issues an instruction to save the key data. After a period of time, V3 is lower than 3.3V, and the dual-power supply device 201 shuts down.

[0068] Figures 6A - 6C shown is the timing diagram when the adapter is unplugged in scenario two, where the horizontal axis is time and the vertical axis is voltage. It should be noted that for the comparison of the timing, the voltage values to be compared are amplified or reduced, and the diagram does not represent the actual voltage values. As Figure 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 decline at time t3. The duration Δt1 between time t1 and time t2 is the duration for the input voltage ADAPT to drop until the dual-power supply device 201 receives the interrupt signal.

[0069] In this embodiment, REF = 2.5V, and the voltage V2 at the second input terminal 5 of U1 is V2 = ADAPT / (R9 + R10) * R10. By adjusting the magnitudes of R9 and R10, 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, as Figure 6B , that is, from time t1 to time t2, the elapsed time Δt1 = 5.65ms. Then ADAPT continues to decline, as Figure 6C , ADAPT drops from 7.5V to 3.3V, as Figure 6C , that is, from time t2 to time t3, the elapsed time Δt2 = 5.924ms, and the device uses this period to save key data.

[0070] By adjusting the magnitudes of R9 and R10 to set the level of V2, Δt1 and Δt2 can be changed. Δt1 is used to provide to the device so that it can detect the connection of the battery 262. When the voltage of the battery 262 is small, Δt1 correspondingly needs to be longer. According to the actual situation of the device, Δt1 can be minimized 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 figure shows the timing diagram of switching to battery power supply when the adapter is unplugged in Scenario 3. Among them, the horizontal axis is time and the vertical axis is voltage. It should be noted that in order to compare the timings, the voltage values to be compared are amplified or reduced, and the figure does not represent the real voltage values. As 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] Combined with Figure 3, in Scenario 3, 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 above 0.7V, Q1 conducts, the gate voltage of Q2 is 0, causing Q2 to turn off, the Vgs of Q3 is 0, causing Q3 to turn 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. This base voltage gradually decreases. When the base voltage of Q1 drops below 0.7V, Q1 turns off. At this time, V1 (+5V) and V3 (+3.3V) in the circuit do not change. V1 passes through D2, R3, and R4 to be the gate voltage of Q2. The gate voltage of Q2 is greater than the conduction voltage of Q2, causing Q2 to conduct. The source e33 voltage of Q3 is low, Q3 conducts, and the input voltage BAT_IN of the battery 262 is output to POWER. Combined Figure 5 , when ADAPT further drops and the interrupt signal ADAPT_Down is received, the device detects that BAT_ON is high. In these embodiments, considering the rise time of the input voltage BAT_IN of the battery 262, by adjusting the magnitudes 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 at a high level, indicating that the battery 262 is detected to be in an on state.

[0074] Reference Figure 3 , the base voltage Ve11 of Q1 = ADAPT / (R1 + R2) * R2. In some embodiments, the first switch circuit 210 is further configured to: adjust the magnitudes of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 to adjust the voltage threshold Vth for switching from adapter 261 power supply to battery 262 power supply. Wherein, when the adapter 261 is unplugged and the input voltage ADAPT of the adapter 261 drops to the voltage threshold Vth, 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 the input voltage ADAPT of the adapter 261 is 10V, to ensure the stability of this voltage, Vth can be set to 10.5V. Combined Figure 7 , when ADAPT drops from 12V to 10.5V, that is, from time t1 to time t4, taking Δt3 = 3.054ms, at this time V2 > 2.5V (REF), and the interrupt signal ADAPT_Down does not change and is not triggered. Therefore, in Figure 7 , ADAPT_Down is a straight line. Therefore, according to the power-on and power-off control circuit of the present application, seamless conversion from adapter power supply to battery power supply can be achieved in Scenario 3.

[0075] The power-on and power-off control circuit according to the present application can achieve the following functions:

[0076] (1) In Scenario 1, only battery power is supplied. When turning on the device through a mechanical button and the device does not work for a long time, it can automatically turn off.

[0077] (2) In Scenario 2, only adapter power is supplied. After the adapter loses power, the power-on and power-off control circuit of the present application will send an interrupt signal. When the device receives the interrupt signal, it will immediately perform corresponding actions, including saving important data, clearing the cache, etc. Depending on the application, the execution duration of these actions is several milliseconds or dozens of milliseconds, or longer. The power-on and power-off control circuit of the present application can obtain different action time margins by adjusting the resistors and capacitors in the adapter monitoring circuit.

[0078] (3) In Scenario 3, both battery and adapter power are supplied, and the two power supplies can be seamlessly switched, so as not to affect the normal use of the device and not affect the measurement or metering performance.

[0079] To illustrate the optimization of the power-on and power-off control circuit of the present application in terms of power consumption, the following is combined with the attached Figures 8A - 8C for illustration.

[0080] Figure 8A The power consumption of the dual-power supply device when powered by the adapter is shown, which generally includes 4 parts: (1) Power consumption P1, from the power supply terminal (Power) to the 3.3V working voltage (V3), with an efficiency η1; (2) Power consumption P2, from the power supply terminal to the 5V working voltage (V1), with an efficiency η2; (3) Power consumption P3, from the power supply terminal through an LDO (low dropout voltage regulator, rectifier) to 10V; (4) Power consumption P4, from the power supply terminal to the VLCD (display screen) after filtering. At this time, the overall power consumption of the device when powered by the adapter is:

[0081]

[0082] Figure 8B It is Figure 1 The power consumption of the dual-power supply device when powered by the battery when using the boost-buck circuit shown, which also includes 4 parts similar to the adapter. The difference is that there is a boost efficiency Ψ from the battery to the power supply terminal (Power). At this time, the overall power consumption of the device when powered by the battery is:

[0083]

[0084] Figure 8CIt is the power consumption of the dual-power supply device when the power-on and power-off control circuit of the present application is powered by a battery. Among them, the switch circuit of the present application is between the battery and the power supply terminal. The power consumptions P3 and P4 are both obtained after boosting the 5V voltage. At this time, the overall power consumption of the device when powered by the battery is:

[0085]

[0086] Comparing formula (2) and formula (3), assuming Pb < Pb'.

[0087] That is

[0088] Taking the usual values of ψ and η0 as 0.8 - 0.85, and the step-down efficiencies η1 and η2 as about 0.9, the result is:

[0089]

[0090] It can be obtained from formula (4) that the distribution ratio of the low voltage and the high voltage can determine the optimization scheme of the circuit power consumption. Generally, the power of the low voltage in the control system is greater than that of the high voltage. The power-on and power-off control circuit proposed in the present application can easily make formula (4) hold, thereby reducing the overall working power consumption of the device, reducing energy consumption, and realizing power optimization on the premise of ensuring the normal operation of the circuit. Since the power consumption ratio of the high voltage part is low, compared with Figure 1 the simple buck-boost circuit shown, the area of the power-on and power-off control circuit of the present application on the chip is also smaller, 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 to the present application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to the present application. Such modifications, improvements, and corrections are proposed in the present application, so such modifications, improvements, and corrections still belong to the spirit and scope of the exemplary embodiments of the present application.

[0092] At the same time, the present application uses specific terms to describe the embodiments of the present application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0093] Some aspects of the present application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above-mentioned hardware or software can all be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor can be one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or a combination thereof. In addition, aspects of the present application may be embodied as a computer product located in one or more computer-readable media, which includes computer-readable program codes. For example, the computer-readable media may include, but is not limited to, magnetic storage devices (such as hard disks, floppy disks, magnetic tapes...), optical discs (such as compact discs CD, digital versatile discs DVD...), smart cards, and flash memory devices (such as cards, sticks, key drives...).

[0094] Similarly, it should be noted that, in order to simplify the description of the present application and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the subject matter of the present application are more than those mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0095] In some embodiments, numbers are used to describe components and the quantity of attributes. It should be understood that such numbers used for the description of embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the stated number allows a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the present application are all approximate values, and such approximate values may change according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used to confirm the breadth of the scope in some embodiments of the present application are approximate values, in specific embodiments, such numerical settings are as precise as possible within the feasible range.

Claims

1. A power-on and power-off control circuit for a dual-powered device, the power supply unit of the dual-powered device comprising an adapter and a battery, characterized in that, Comprising: A first switch circuit, a third switch circuit, and an adapter monitoring circuit; wherein, The first switch circuit is configured to receive the input voltage of the adapter, and the third switch circuit is configured to receive the input voltage of the battery and is connected to the power supply terminal of the dual-power supply device; The power-on / off control circuit is configured such that when the adapter is connected, the first switch circuit is turned on, the third switch circuit is turned off, 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 configured to monitor whether the adapter is connected, and is configured such that when the adapter is disconnected, an interrupt signal is output to the dual-power supply device; The dual-power supply device is configured such that when the adapter is disconnected and the dual-power supply device receives the interrupt signal, and when it is determined that the battery is not connected according to the battery power supply detection signal, the dual-power supply device issues a protection action instruction.

2. The power-on / off control circuit according to claim 1, wherein The dual-power supply device is further configured such that when neither the adapter nor the battery is 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 further comprises a second switch circuit connected between the first switch circuit and the third switch circuit; wherein, The power-on / off control circuit is further configured such that when the adapter is connected, the first switch circuit is turned on, the second switch circuit and the third switch circuit are both turned off, 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, wherein, The first switch circuit includes a first switch tube, the second switch circuit includes a second switch tube, 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 such that 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, 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 operating voltage of the dual-power supply device, and the second switch circuit is configured such that when the adapter is not connected, the first operating voltage is used to turn on the second switch tube; The control terminal of the third switching transistor is connected to the first terminal of the second switching transistor. The first terminal of the third switching transistor is connected to the input voltage of the battery. The second terminal of the third switching transistor is connected to the power supply terminal of the dual-power supply device.

5. The power-on / off control circuit according to claim 4, wherein The dual-power supply device is further configured that when the battery is connected and the adapter is not connected, when the dual-power supply device has no operation for a preset duration, the dual-power supply device inputs a battery-off signal to the control terminal of the first switching transistor, so that the first switching transistor is turned on, and the second switching transistor and the third switching transistor are turned off, and the dual-power supply device shuts down.

6. The power-on / off control circuit according to claim 4, wherein The first switching circuit further includes a first voltage-dividing resistor and a second voltage-dividing resistor. Wherein, the first terminal of the first voltage-dividing resistor is connected to the input voltage of the adapter, the second terminal of the first voltage-dividing resistor is connected to the control terminal of the first switching transistor, the first terminal of the second voltage-dividing resistor is connected to the control terminal of the first switching transistor, and the second terminal of the second voltage-dividing resistor is grounded.

7. The power-on / off control circuit according to claim 6, wherein The first switching circuit further includes a first diode. The anode of the first diode is connected to the input voltage of the adapter, and the cathode of the first diode is connected to the first terminal of the first voltage-dividing resistor.

8. The power-on / off control circuit according to claim 4, wherein The second switching circuit further includes a third voltage-dividing resistor and a fourth voltage-dividing resistor. Wherein, the first terminal of the third voltage-dividing resistor is connected to the first operating voltage, the second terminal of the third voltage-dividing resistor is connected to the control terminal of the second switching transistor, the first terminal of the fourth voltage-dividing resistor is connected to the control terminal of the second switching transistor, and the second terminal of the fourth voltage-dividing resistor is grounded.

9. The power-on / off control circuit according to claim 8, wherein The second switching circuit further includes a second diode. The cathode of the second diode is connected to the first operating voltage, and the anode of the second diode is connected to the first terminal of the third voltage-dividing resistor.

10. The power-on / off control circuit according to claim 8, wherein The second switching circuit is further configured to configure the magnitudes of the third voltage-dividing resistor and the fourth voltage-dividing resistor such that when the first switching transistor is turned off, the voltage at the control terminal of the second switching transistor is greater than the maximum conduction voltage of the second switching transistor.

11. The power-on / off control circuit according to claim 4, wherein The third switching circuit further includes a fifth voltage-dividing resistor and a sixth voltage-dividing resistor. Wherein, the first terminal of the fifth voltage-dividing resistor is connected to the first terminal of the second switching transistor, the second terminal of the fifth voltage-dividing resistor is connected to the control terminal of the third switching transistor, the first terminal of the sixth voltage-dividing resistor is connected to the control terminal of the third switching transistor, and the second terminal of the sixth voltage-dividing resistor is connected to the input voltage of the battery and the first terminal of the third switching transistor.

12. The power-on / off control circuit according to claim 11, wherein The third switching circuit further 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 terminal of the sixth voltage-dividing resistor and the first terminal of the third switching transistor.

13. The power-on / off control circuit according to claim 12, wherein The third switching circuit further includes a fourth diode. The anode of the fourth diode is connected to the second terminal of the third switching transistor, and the cathode of the fourth diode is connected to the power supply terminal of the dual-power supply device.

14. The power-on / off control circuit according to claim 13, characterized in that, The third switching circuit further includes a control voltage clamping circuit, and the control voltage clamping circuit 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 transistor, 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 electrode of the clamping diode is grounded, and the negative electrode 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, wherein 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 the first input terminal of the comparator, the input voltage of the adapter is connected to the second input terminal of the comparator, and the output terminal of the comparator outputs the interruption signal.

16. The power-on / off control circuit according to claim 15, wherein, The adapter monitoring circuit further 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.

17. The power-on / off control circuit according to claim 16, characterized in that, The adapter monitoring circuit is further configured to: adjust the magnitudes of the ninth voltage dividing resistor and the tenth voltage dividing resistor to adjust the level of the input voltage at the second input terminal of the comparator, so as to adjust the duration from when the input voltage of the adapter drops to when the dual-power supply device receives the interruption signal when the adapter is unplugged.

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

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

20. The power-on / off control circuit according to claim 16, wherein The first switching circuit is further configured to: adjust the magnitudes 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, when 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 interruption signal.

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