CN110098661A - Power supply switch circuit and household electrical appliance - Google Patents

Abstract

The invention discloses a power switch circuit and a household appliance. The power switch circuit includes a battery output circuit, a battery switch circuit, an adapter detection circuit and an adapter output circuit; wherein, the battery output circuit is used for receiving an external control signal When the adapter is connected, power is supplied to the battery switch circuit; the adapter detection circuit is used to detect whether the adapter is connected, generate a first detection signal when the adapter is connected, and generate a second detection signal when the adapter is not connected signal; the battery switch circuit is used to turn off when the first detection signal is received, so that the battery stops supplying power to the load; it is turned on when receiving the second detection signal, so that the battery supplies power to the load; the The adapter output circuit is used to supply power to the load when the adapter is connected, thereby reducing the use frequency of the battery and improving the service life of the battery.

Description

Power switching circuits and household appliances

technical field

The invention relates to the technical field of battery charging, in particular to a power switching circuit and a household appliance.

Background technique

Among the current consumer electronic products, portable electronic products with batteries are more and more favored by consumers. When consumers use such products with batteries, they often have the following two usage scenarios: one is battery mode, that is, When the product is turned on, only the battery supplies power to the product, and the battery is only in the discharged state. The other is the adapter mode, that is, when the product is turned on, plug in the adapter to use, and the battery will be in the state of charging and discharging at the same time. In the above scenario, the battery will normally supply power to the back-end system while charging, which will result in the battery not being fully charged. The usage time will seriously affect the user experience of consumers.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a power switching circuit and a household appliance, aiming at solving the technical problem that the existing battery is discharged at the same time during charging, thereby affecting the service life of the battery.

In order to achieve the above object, the present invention provides a power switching circuit, the power switching circuit includes a battery output circuit, a battery switching circuit, an adapter detection circuit and an adapter output circuit; wherein

The battery output circuit is used to supply power to the battery switch circuit when receiving an external control signal;

The adapter detection circuit is configured to detect whether the adapter is connected, generate a first detection signal when the adapter is connected, and generate a second detection signal when the adapter is not connected;

The battery switch circuit is configured to turn off when the first detection signal is received, so that the battery stops supplying power to the load, wherein the load is a post-stage circuit; when the second detection signal is received, it leads to on, so that the battery supplies power to the load;

The adapter output circuit is used to supply power to the load when the adapter is connected.

Preferably, the battery output circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first triode and a first field effect transistor;

The first end of the first resistor is connected to the battery, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the first The collector of the triode is connected, the base electrode of the first triode is connected to the first end of the third resistor, the second end of the third resistor is grounded, and the first end of the fourth resistor is connected to a power supply connection, the second end of the fourth resistor is connected to the base of the first triode, and the emitter of the first triode is grounded;

The source of the first field effect transistor is connected to the battery, the gate of the first field effect transistor is connected to the first end of the second resistor, and the drain of the first field effect transistor is connected to the first end of the second resistor. load connection described above.

Preferably, the battery output circuit further includes a first capacitor and a second capacitor;

The first end of the first capacitor is connected to the battery, and the second end of the first capacitor is connected to the first end of the second resistor;

The first end of the second capacitor is connected to the power supply, and the second end of the second capacitor is grounded.

Preferably, the battery switch circuit includes a second field effect transistor, the drain of the second field effect transistor is connected to the output end of the battery output circuit, and the source of the second field effect transistor is connected to the adapter The detection circuit is connected, and the grid of the second field effect transistor is also connected with the adapter detection circuit.

Preferably, the battery switch circuit further includes a first anti-reverse diode;

The anode of the first anti-reverse diode is connected to the drain of the second field effect transistor, and the cathode of the first anti-reverse diode is connected to the adapter detection circuit.

Preferably, the adapter detection circuit includes a voltage divider circuit, a drive circuit and an adapter switch circuit;

The input end of the voltage divider circuit is connected to the adapter, the first output end of the voltage divider circuit is connected to the battery switch circuit, the second output end of the voltage divider circuit is connected to the control end of the drive circuit, The input end of the adaptor switch circuit is connected to the output end of the battery switch circuit, the output end of the adaptor switch circuit is connected to the load, and the drive end of the drive circuit is connected to the control end of the adaptor switch circuit.

Preferably, the voltage dividing circuit includes a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor;

The first end of the fifth resistor is connected to the adapter, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, and the second end of the sixth resistor is connected to the ground. The first end of the seventh resistor is connected to the adapter, the second end of the seventh resistor is connected to the first end of the eighth resistor, and the second end of the eighth resistor is grounded.

Preferably, the driving circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a second transistor and a third transistor;

The first end of the ninth resistor is connected to the battery switch circuit, the second end of the ninth resistor is connected to the collector of the second triode, and the base of the second triode is connected to the the second end of the seventh resistor is connected, and the emitter of the second triode is grounded;

The first end of the tenth resistor is connected to the collector of the second transistor, the second end of the tenth resistor is connected to the base of the third transistor, and the third transistor The emitter of the tube is grounded;

The first end of the eleventh resistor is connected to the battery switch circuit, and the second end of the eleventh resistor is connected to the first end of the twelfth resistor;

The first end of the twelfth resistor is connected to the control end of the adapter switch circuit, and the second end of the twelfth resistor is connected to the collector of the third triode;

The adapter switch circuit includes a third field effect transistor;

The gate of the third field effect transistor is connected to the first end of the twelfth resistor, the source of the third field effect transistor is connected to the first end of the eleventh resistor, and the third field effect transistor is connected to the first end of the eleventh resistor. The drain of the FET is connected to the load.

Preferably, the adapter output circuit includes an adapter port and a second diode;

The anode of the second diode is connected to the battery switch circuit, and the cathode of the second diode is connected to the adapter port.

In addition, in order to achieve the above object, the present invention also provides a household appliance, which includes the power switching circuit as described above.

The power switching circuit of the present invention includes a battery output circuit, a battery switch circuit, an adapter detection circuit and an adapter output circuit; wherein, the battery output circuit is used to supply power to the battery switch circuit when receiving an external control signal; The adapter detection circuit is used to detect whether the adapter is connected, a first detection signal is generated when the adapter is connected, and a second detection signal is generated when the adapter is not connected; the battery switch circuit is used to When the first detection signal is received, it is turned off, so that the battery stops supplying power to the load; when the second detection signal is received, it is turned on, so that the battery supplies power to the load; the adapter output circuit is used when the adapter is connected. , supply power to the load. When the adapter is connected, the load is powered through the adapter output circuit. When the adapter is not connected, the load is powered by the battery output circuit, so as to avoid the battery output circuit when the adapter is connected. The load is used to supply power, reducing the frequency of use of the battery and improving the service life of the battery.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

1 is a schematic structural diagram of a first embodiment of a power switching circuit of the present invention;

2 is a schematic structural diagram of a second embodiment of a power switching circuit of the present invention;

3 is a schematic structural diagram of a first simulation embodiment of a power switching circuit of the present invention;

4 is a schematic structural diagram of a second simulation embodiment of a power switching circuit of the present invention;

FIG. 5 is a schematic structural diagram of a third simulation embodiment of a power switching circuit of the present invention.

Description of reference numbers:

label name label name 100 Power switching circuit 200 household appliances 10 battery output circuit R1-R12 The first resistor to the twelfth resistor 20 battery switch circuit C1 and C2 first capacitor and second capacitor 30 Adapter Detection Circuit Q1 first triode 301 Voltage divider circuit Q4 and Q5 The second transistor and the third transistor 302 Drive circuit D1 and D2 The first anti-reverse diode and the second diode 303 Adapter switch circuit Q2 first field effect tube 40 Adapter output circuit Q3 second FET 60 load Q6 third field effect transistor

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indications are only used to explain a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for the purpose of description, and should not be construed as indicating or implying Its relative importance or implicitly indicates the number of technical features indicated. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection required by the present invention.

The present invention provides an embodiment of a power switching circuit 100 .

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram of a first embodiment of a power switching circuit 100 . In the embodiment of the present invention, the power switching circuit 100 includes: a battery output circuit 10, a battery switch circuit 20, an adapter detection circuit 30, and an adapter output circuit 40; wherein the battery output circuit 10 is used for receiving external control When the signal is received, supply power to the battery switch circuit 20;

The adapter detection circuit 30 is configured to detect whether the adapter is connected, generate a first detection signal when the adapter is connected, and generate a second detection signal when the adapter is not connected;

The battery switch circuit 20 is configured to turn off when the first detection signal is received, so that the battery stops supplying power to the load 60, wherein the load is a subsequent circuit; When the signal is detected, it is turned on, so that the battery supplies power to the load 60;

The adapter output circuit 40 is used to supply power to the load 60 when the adapter is connected.

In the technical solution provided by this embodiment, when the adapter is connected, the load 60 is powered by the adapter output circuit 40, and when the adapter is not connected, the load 60 is powered by the battery output circuit 10, so as to avoid the need for the adapter to be connected. The load 60 is still powered by the battery output circuit 10 to reduce the use frequency of the battery and achieve the purpose of improving the service life of the battery.

Referring to FIG. 2, FIG. 2 is a schematic structural diagram of a second embodiment of a power switching circuit 100', using two transistors, one MOS transistor, and six resistors to complete the power management work, which can effectively increase the use of batteries life,

The battery output circuit 10 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first transistor Q1 and a first field effect transistor Q2;

The first end of the first resistor R1 is connected to the battery, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the battery. The collector of the first transistor Q1 is connected, the base electrode of the first transistor Q1 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is grounded, and the The first end of the fourth resistor R4 is connected to the power supply, the second end of the fourth resistor R4 is connected to the base of the first triode Q1, and the emitter of the first triode Q1 is grounded;

The source of the first field effect transistor Q2 is connected to the battery, the gate of the first field effect transistor Q2 is connected to the first end of the second resistor R2, and the first field effect transistor Q2 The drain is connected to the load 60 .

Further, the battery output circuit 10 further includes a first capacitor C1 and a second capacitor C2;

The first end of the first capacitor C1 is connected to the battery, and the second end of the first capacitor C1 is connected to the first end of the second resistor R2;

The first end of the second capacitor C2 is connected to the power supply, and the second end of the second capacitor C2 is grounded.

Further, the battery switch circuit 20 includes a second field effect transistor Q3, the drain of the second field effect transistor Q3 is connected to the output end of the battery output circuit 10, and the source of the second field effect transistor Q3 The pole is connected to the adapter detection circuit 30 , and the gate of the second FET Q3 is also connected to the adapter detection circuit 30 .

Further, the battery switch circuit 20 further includes a first anti-reverse diode D1;

The anode of the first anti-reverse diode D1 is connected to the drain of the second field effect transistor Q3 , and the cathode of the first anti-reverse diode D1 is connected to the adapter detection circuit 30 .

In this embodiment, the power supply has two paths, which are the battery and the adapter respectively. There are three FETs on the working path of the battery and one Schottky diode on the path of the adapter. The specific working principle is as follows: when in battery mode, The microelectronics controls the first FET Q2 to be turned on; the adapter does not supply power, so that the second FET Q3 and the third FET Q6 are in the conducting state, then the battery supplies power to the back-end system, and the diode D1 prevents the current from the battery from flowing back to In the adapter; when the adapter is powered and the adapter voltage is greater than the battery voltage, the adapter supplies power to the back-end system through the diode D1; the third FET Q6 is controlled by two triodes, when the adapter is inserted, the third FET Q6 will will be cut off, the system is only powered by the adapter, and the battery is only charged at this time, which improves the charging efficiency and protects the battery.

Further, the adapter detection circuit 30 includes a voltage divider circuit 301, a drive circuit 302 and an adapter switch circuit 303;

The input end of the voltage divider circuit 301 is connected to the adapter, the first output end of the voltage divider circuit 301 is connected to the battery switch circuit 20 , and the second output end of the voltage divider circuit 301 is connected to the drive circuit 302 The input end of the adapter switch circuit 303 is connected to the output end of the battery switch circuit 20, the output end of the adapter switch circuit 303 is connected to the load 60, the drive end of the drive circuit 302 is connected to the The control terminal of the adapter switch circuit 303 is connected.

Further, the voltage dividing circuit 301 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8;

The first end of the fifth resistor R5 is connected to the adapter, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, and the second end of the sixth resistor R6 is grounded , the first end of the seventh resistor R7 is connected to the adapter, the second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8, and the second end of the eighth resistor R8 ground.

It should be noted that since the adapter is not inserted, the base of Q4 is at a low level, and the Vbe of Q4 is less than 0.7V, then Q4 is turned off; the battery voltage pulls up the base voltage of Q5 to the battery voltage through the voltage pull-up circuit 302, and Q5 If Vbe>0.7V, then Q5 is turned on, and the battery supplies power to the load 60 at the back end.

When the adapter is plugged in, the voltage of the adapter is lower than the voltage of the battery, the voltage of the adapter is divided by R5 and R6 so that the VGS voltage of Q3 is less than the turn-on voltage, then Q3 is turned off; the voltage of the adapter is divided by R7 and R8, when Q4 When the Vbe > 0.7V, Q4 is in the on state; since Q4 is turned on, then Q5 is turned off, then the gate voltage of Q6 is equal to the source voltage at this time, then Q6 is turned off.

Further, the driving circuit 302 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a second transistor Q4 and a third transistor Q5;

The first end of the ninth resistor R9 is connected to the battery switch circuit 20, the second end of the ninth resistor R9 is connected to the collector of the second transistor Q4, and the second transistor Q4 The base of Q4 is connected to the second end of the seventh resistor R7, and the emitter of the second transistor Q4 is grounded;

The first end of the tenth resistor R10 is connected to the collector of the second transistor Q4, the second end of the tenth resistor R10 is connected to the base of the third transistor Q5, and the The emitter of the third transistor Q5 is grounded;

The first end of the eleventh resistor R11 is connected to the battery switch circuit 20, and the second end of the eleventh resistor R11 is connected to the first end of the twelfth resistor R12;

The first end of the twelfth resistor R12 is connected to the control end of the adapter switch circuit 303, and the second end of the twelfth resistor R12 is connected to the collector of the third transistor Q5;

When the adapter is plugged in, the voltage of the adapter is lower than the voltage of the battery, the voltage of the adapter is divided by R5 and R6 so that the VGS voltage of Q3 is less than the turn-on voltage, then Q3 is turned off; the voltage of the adapter is divided by R7 and R8, when Q4 When the Vbe > 0.7V, Q4 is in the on state; since Q4 is turned on, then Q5 is turned off, then the gate voltage of Q6 is equal to the source voltage at this time, then Q6 is turned off.

The adapter switch circuit 303 includes a third field effect transistor Q6;

The gate of the third field effect transistor Q6 is connected to the first end of the twelfth resistor R12, the source of the third field effect transistor Q6 is connected to the first end of the eleventh resistor R11, The drain of the third field effect transistor Q6 is connected to the load 60 .

Further, the adapter output circuit 40 includes an adapter port and a second diode D2;

The anode of the second diode D2 is connected to the battery switch circuit 20, and the cathode of the second diode D2 is connected to the adapter port.

When the adapter is pulled out instantaneously, Q3 will be turned on, but due to the slow turn-on time of Q3, the current of the battery flows to the back end through D1, which can prevent the body diode of Q3 from being broken down instantaneously, and also prevent the moment when the adapter is pulled out. Machine power failure, sound interruption, restart and so on.

In this embodiment, the problem of power path management of the dual power supply system can be solved at low cost, and discrete devices such as MOS transistors and diodes are used to control the power supply path to prevent the battery from premature aging due to cyclic charging, which effectively solves the problem. When the machine is plugged into the adapter, the battery can be fully charged. When the adapter is powered, suddenly unplugging the adapter can prevent the machine from shutting down, restarting, and making continuous sounds. Not only improves the user experience, but also prolongs the battery life cycle, without using additional power management chips, it also has a certain cost advantage.

It should be noted that the state of the circuit under different conditions is simulated by using Multisim to simulate. S1 is the adapter switch, S2 is the battery switch, S3 simulates the interface of the microprocessor, RL is the back-end load 60, and R14 is to prevent the reverse leakage current from D2 from affecting the control loop.

In experiment 1, as shown in Figure 3, when the adapter is not inserted, that is, when S2 and S3 are closed, and S1 is open, the output probe 1 of the circuit is 7.16V, and the voltage has a voltage drop of 0.24V through three MOS tubes, that is The output is the battery voltage. By simulating the machine without plugging in the adapter, only the battery supplies power to the back-end system. At this time, the battery voltage is 7.4V, and the output of the back-end system is 7.16V. At this time, Q4 is turned off, Q6 is turned on, and the PMOS tube is turned on. The Q6 is turned on and the battery powers the rear end through the Q6.

In experiment 2, as shown in Figure 4, when the adapter is inserted, that is, S1, S2, and S3 are all closed. At this time, the output of the circuit is the voltage of the adapter, which is 4.66V for probe 1 and 0.34V for D2. Turning on the voltage drop, it can be seen that when the adapter is inserted, that is, the S1 switch is closed, the network DC_IN1 voltage is the adapter voltage, and the voltage divided by R7 and R8 Q4 is turned on, so that Q5 is turned off, so that the VGS voltage of Q6 is equal to 0, because Q6 is a PMOS , then Q6 is in the cut-off state. At this time, the circuit of the battery is cut off, and only the adapter supplies power to the back-end system through D2. If there is no Q6, the battery voltage is higher than the adapter voltage at this time, the power supply of the system must be provided by the battery, and the battery is still discharging while being charged, which will verify the life of the battery.

In experiment 3, as shown in Figure 5, when in battery mode, S3 simulates the switch button, when S3 is turned on, Q2 is cut off, then the back-end system has no voltage, and the shutdown is realized; when in adapter mode, this The power supply is not controlled at any time, so in the adapter mode, the back-end system is always powered.

This embodiment provides a household appliance. The household appliance 200 includes the power switching circuit 100 as described above. The specific structure of the power switching circuit 100 refers to the above embodiments. All technical solutions, therefore at least have all the beneficial effects brought by the technical solutions of the above embodiments, and will not be repeated here.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields , are similarly included in the scope of patent protection of the present invention.

Claims (10)

1. a kind of power supply switch circuit, which is characterized in that the power supply switch circuit includes battery output circuit, cell switch electricity Road, adaptor detection circuit and adapter output circuit；Wherein

The battery output circuit, for being powered to the cell switch circuit when receiving external control signal；

Whether the adaptor detection circuit accesses for test adaptor, generates the first detection in adapter access Signal generates the second detection signal when the adapter does not access；

The cell switch circuit, for the shutdown when receiving the first detection signal, so that battery stops to load Power supply, wherein the load is late-class circuit；The conducting when receiving the second detection signal, so that battery is to described Load is powered；

The adapter output circuit, for being powered to the load in adapter access.

2. power supply switch circuit as described in claim 1, which is characterized in that the battery output circuit include first resistor, Second resistance, 3rd resistor, the 4th resistance, the first triode and the first field-effect tube；

The first end of the first resistor is connect with the battery, and the of the second end of the first resistor and the second resistance One end connection, the second end of the second resistance are connect with the collector of first triode, the first triode base electricity Pole is connect with the first end of the 3rd resistor, the second end of 3rd resistor ground connection, the first end of the 4th resistance with Power supply connection, the second end of the 4th resistance are connect with first transistor base, the emitter of first triode Ground connection；

The source electrode of first field-effect tube is connect with the battery, the grid of first field-effect tube and the second resistance First end connection, the drain electrode of first field-effect tube and the load connection.

3. power supply switch circuit as claimed in claim 2, which is characterized in that the battery output circuit further includes first capacitor And second capacitor；

The first end of the first capacitor is connect with the battery, and the of the second end of the first capacitor and the second resistance One end connection；

The first end of second capacitor is connect with the power supply, the second end ground connection of second capacitor.

4. power supply switch circuit as claimed any one in claims 1 to 3, which is characterized in that the cell switch circuit packet The second field-effect tube is included, the drain electrode of second field-effect tube is connect with the output end of the battery output circuit, and described second The source electrode of field-effect tube is connect with the adaptor detection circuit, and the grid of second field-effect tube is also examined with the adapter Slowdown monitoring circuit connection.

5. power supply switch circuit as claimed in claim 4, which is characterized in that the cell switch circuit further includes the first counnter attack Diode；

The anode of the first counnter attack diode is connect with the drain electrode of second field-effect tube, the first counnter attack diode Cathode is connect with the adaptor detection circuit.

6. power supply switch circuit as claimed in claim 5, which is characterized in that the adaptor detection circuit includes partial pressure electricity Road, driving circuit and adapter switch circuit；

The input terminal of the bleeder circuit is connect with adapter, the first output end of the bleeder circuit and cell switch electricity Road connection, the second output terminal of the bleeder circuit are connect with the control terminal of the driving circuit, the adapter switch circuit Input terminal connect with the output end of the cell switch circuit, the output end of the adapter switch circuit and load connect, The driving end of the driving circuit is connect with the control terminal of the adapter switch circuit.

7. power supply switch circuit as claimed in claim 6, which is characterized in that the bleeder circuit includes the 5th resistance, the 6th Resistance, the 7th resistance and the 8th resistance；

The first end of 5th resistance is connect with the adapter, second end and the 6th resistance of the 5th resistance First end connection, the second end ground connection of the 6th resistance, the first end of the 7th resistance is connect with the adapter, described The second end of 7th resistance is connect with the first end of the 8th resistance, the second end ground connection of the 8th resistance.

8. power supply switch circuit as claimed in claim 7, which is characterized in that the driving circuit includes the 9th resistance, the tenth Resistance, eleventh resistor, twelfth resistor, the second triode and third transistor；

The first end and the cell switch circuit connection of 9th resistance, the second end and described second of the 9th resistance The collector of triode connects, and the base stage of second triode is connect with the second end of the 7th resistance, and the described 2nd 3 The emitter of pole pipe is grounded；

The first end of tenth resistance is connect with the collector of second triode, the second end of the tenth resistance and institute State the base stage connection of third transistor, the emitter ground connection of the third transistor；

The first end of the eleventh resistor and the cell switch circuit connection, the second end of the eleventh resistor with it is described The first end of twelfth resistor connects；

The first end of the twelfth resistor is connect with the control terminal of the adapter switch circuit, and the of the twelfth resistor Two ends are connect with the collector of the third transistor；

The adapter switch circuit includes third field-effect tube；

The grid of the third field-effect tube is connect with the first end of the twelfth resistor, the source electrode of the third field-effect tube It is connect with the first end of the eleventh resistor, the drain electrode and load of the third field-effect tube connect.

9. power supply switch circuit as claimed in claim 8, which is characterized in that the adapter output circuit includes adapter end Mouth and the second diode；

The anode of second diode and the cell switch circuit connection, the cathode of second diode are adapted to described The connection of device port.

10. a kind of household electrical appliance, which is characterized in that the household electrical appliance include electricity as claimed in any one of claims 1 to 9 Source switching circuit.