Hair dryer

Abstract

The invention provides an air blower. The air blower comprises a control circuit and a main control chip connected with the control circuit. The control circuit comprises a power supply voltage detection circuit and a voltage conversion circuit, and the power supply voltage detection circuit can detect power supply voltage output by the power supply, process the power supply voltage and then output corresponding detection voltage to the main control chip. The main control chip can control the voltage conversion circuit to perform voltage-multiplying rectification on the power supply voltage when the detected voltage is greater than a first preset value so as to output the power supply voltage after voltage-multiplying rectification to supply power to the motor. The main control chip can also control the voltage conversion circuit to carry out bridge rectification on the power supply voltage when the detection voltage is smaller than or equal to a first preset value so as to output the power supply voltage after bridge rectification to supply power to the motor. The hair dryer can solve the problem that in the prior art, a hair dryer has potential safety hazards, the hair dryer can be directly connected with the mains supply for use in different regions in the world, and the user experience is improved.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and particularly to a hair dryer. Background Art

[0002] There are usually two working voltages for hair dryers. One is the high voltage of 133V - 264V, and the other is the low voltage of 80V - 132V. When traveling, if one is not familiar with the local voltage, there will be potential safety hazards when using a single-voltage hair dryer. For example, if the hair dryer is a product with a voltage of 110V and is used on a 220V voltage, it will cause the hair dryer to burn out or pose more serious safety hazards. Summary of the Invention

[0003] In view of the above, it is necessary to provide a hair dryer that can solve the problem of potential safety hazards in existing hair dryers. The hair dryer of this application can be directly connected to the mains power in different regions of the world, improving the user experience.

[0004] In a first aspect of this application, a hair dryer is provided for connection to a power supply. The hair dryer of this application includes a control circuit and a main control chip connected to the control circuit. The control circuit includes a supply voltage detection circuit and a voltage conversion circuit. The supply voltage detection circuit can detect the supply voltage output by the power supply and can process the supply voltage and output a corresponding detection voltage to the main control chip. When the detection voltage is greater than a first preset value, the main control chip can control the voltage conversion circuit to perform voltage doubling rectification on the supply voltage to output the supply voltage after voltage doubling rectification to supply power to the motor. When the detection voltage is less than or equal to the first preset value, the main control chip can also control the voltage conversion circuit to perform bridge rectification on the supply voltage to output the supply voltage after bridge rectification to supply power to the motor.

[0005] This application can solve the problem of potential safety hazards in existing hair dryers. The hair dryer of this application can detect the voltage range of the supply voltage through the control circuit and perform bridge rectification or voltage doubling rectification on the supply voltage according to different supply voltage ranges, so as to output a supply voltage within the working voltage range of the motor. Therefore, the hair dryer of this application can adapt to different mains power and can be directly connected to the mains power in different countries or regions of the world, improving the user experience.

[0006] As an alternative implementation, the power supply voltage detection circuit includes a first rectifier bridge, a programmable precision voltage reference, and a first optocoupler. The first optocoupler includes a first light-emitting unit and a first photosensitive unit. The first input terminal and the second input terminal of the first rectifier bridge are respectively connected to the first output terminal and the second output terminal of the power supply. The first output terminal of the first rectifier bridge is connected to the first terminal of the programmable precision voltage reference. The second terminal of the programmable precision voltage reference is connected to the cathode of the first light-emitting unit. The adjustment terminal of the programmable precision voltage reference is connected to the second output terminal of the first rectifier bridge. The second output terminal of the first rectifier bridge is connected to the anode of the first light-emitting unit. The emitter of the first photosensitive unit is grounded, and the collector of the first photosensitive unit outputs the detected voltage after filtering and rectification to the first signal pin of the main control chip.

[0007] As an alternative implementation, the voltage conversion circuit includes a second rectifier bridge, a first thyristor, a second optocoupler, a first capacitor, and a second capacitor. The second optocoupler includes a second light-emitting unit and a second switching unit.

[0008] The first input terminal and the second input terminal of the second rectifier bridge are respectively connected to the first output terminal and the second output terminal of the power supply. The first output terminal of the second rectifier bridge is grounded through the first capacitor and the second capacitor. The second output terminal of the second rectifier bridge is grounded. The first terminal of the first thyristor is connected to the node between the first capacitor and the second capacitor. The second terminal of the first thyristor is connected to the second input terminal of the second rectifier bridge. The third terminal of the first thyristor is connected to the second terminal of the second switching unit. The first terminal of the second switching unit is connected to the first terminal of the first thyristor. The anode of the second light-emitting unit is connected to a first power supply. The cathode of the second light-emitting unit is connected to the first signal pin of the main control chip. The node between the second output terminal of the second rectifier bridge and the first capacitor outputs a second voltage to supply power to the motor.

[0009] As an alternative implementation, the main control chip is further configured to control the first thyristor to conduct when the detected voltage is greater than the first preset value.

[0010] As an alternative implementation, the main control chip is further configured to control the first thyristor to turn off when the detected voltage is less than or equal to the first preset value.

[0011] As an alternative implementation, the control circuit further includes a heating wire control circuit, and the heating wire control circuit includes a first heating wire, a second heating wire, a third heating wire, a third optocoupler, a fourth optocoupler, a second thyristor, and a third thyristor; wherein, the third optocoupler includes a third light-emitting unit and a third switching unit, and the fourth optocoupler includes a fourth light-emitting unit and a fourth switching unit; a first end of the first heating wire is connected to a first end of the second heating wire and a first output terminal of the power supply, a second end of the first heating wire is connected to a second end of the second heating wire, a first end of the third heating wire, and a first end of the second thyristor, and a second end of the third heating wire is connected to a first end of the third thyristor; the first end of the second thyristor is further connected to a second end of the third switching unit, a second end of the second thyristor is connected to a first end of the third switching unit, the second end of the second thyristor is further connected to a second output terminal of the power supply, and a cathode of the third light-emitting unit is connected to a second signal pin of the main control chip; the first end of the third thyristor is connected to a second end of the fourth switching unit, a second end of the third thyristor is connected to a first end of the fourth switching unit, the second end of the third thyristor is further connected to a second output terminal of the power supply, an anode of the fourth light-emitting unit is further connected to a cathode of the fourth light-emitting unit, and the cathode of the fourth light-emitting unit is connected to a third signal pin of the main control chip.

[0012] As an alternative implementation, the main control chip is further configured to control the second thyristor to conduct and control the third thyristor to turn off when the detected voltage is greater than the first preset value.

[0013] As an alternative implementation, the main control chip is further configured to control the second thyristor to turn off and control the third thyristor to conduct when the detected voltage is less than or equal to the first preset value.

[0014] As an alternative implementation, the hair dryer includes a housing, a copper foil is provided on an inner wall of the housing, and the control circuit further includes a touch control circuit, and the touch control circuit includes a touch control chip; an output pin of the touch control chip is connected to a touch control signal pin of the main control chip to output a touch control signal to the main control chip, a first signal pin of the touch control chip is grounded through a third capacitor, a second signal pin of the touch control chip is grounded through a fourth capacitor, and a detection signal pin of the touch control chip is connected to the copper foil through a spring.

[0015] As an alternative implementation, the main control chip is further configured to: when receiving the first touch signal output by the touch chip, control the hair dryer to enter the working state; when receiving the second touch signal output by the touch chip, control the hair dryer to enter the standby state; and after a preset time when the hair dryer is in the standby state, control the hair dryer to enter the shutdown state.

[0016] The hair dryer provided in this application can detect the voltage range of the power supply voltage through the control circuit, and perform bridge rectification or voltage doubling rectification on the power supply voltage according to different power supply voltage ranges, so as to output a power supply voltage that meets the working voltage range of the motor. Therefore, the hair dryer of this application can adapt to different mains power supplies and can be directly connected to the mains power in different countries or regions around the world, improving the user experience. Description of the Drawings

[0017] Figure 1 is a schematic diagram of a hair dryer provided by an embodiment of this application.

[0018] Figure 2 is another schematic diagram of a hair dryer provided by an embodiment of this application.

[0019] Figure 3 is a schematic diagram of a main control chip provided by an embodiment of this application.

[0020] Figure 4 is the circuit diagram of the power supply voltage detection circuit provided by an embodiment of this application.

[0021] Figure 5 is the circuit diagram of the voltage conversion circuit provided by an embodiment of this application.

[0022] Figure 6 is the circuit diagram of the heating wire control circuit provided by an embodiment of this application.

[0023] Figure 7 is the circuit diagram of the touch circuit provided by an embodiment of this application.

[0024] Description of the Main Component Symbols

[0025] Hair dryer 100

[0026] Power supply 200

[0027] Main control chip 10

[0028] Control circuit 20

[0029] Motor drive circuit 30

[0030] Motor 40

[0031] Power supply voltage detection circuit 21

[0032] Voltage conversion circuit 22

[0033] Safety regulation circuit 23

[0034] Step-down circuit 24

[0035] Touch control circuit 25

[0036] Heating wire control circuit 26

[0037] Negative ion control circuit 27

[0038] Peripheral module 28

[0039] Gate control circuit 32

[0040] Power output module 34

[0041] First rectifier bridge 210

[0042] Second rectifier bridge 220

[0043] First resistor to thirty-second resistor R1 - R32

[0044] First capacitor to eleventh capacitor C1 - C11

[0045] First optocoupler to fourth optocoupler U1 - U4

[0046] Touch control chip U5

[0047] First thyristor to third thyristor T1 - T3

[0048] First heating wire to third heating wire Rh1 - Rh3

[0049] Choke coil Q1

[0050] First diode to eighth diode D1 - D8

[0051] Safety regulation capacitor SC1

[0052] First thermistor NTC1

[0053] Second thermistor NTC2

[0054] Varistor VDR1

[0055] Temperature control switch K1

[0056] First fuse F1

[0057] Second fuse F2

[0058] Controlled precision voltage regulator ZD1

[0059] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific Embodiments

[0060] In the embodiments of the present application, terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. For example, the first application, the second application, etc. are used to distinguish different applications, rather than to describe a specific order of the applications. Features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0061] Currently, there are differences in the mains voltages of various countries and regions around the world. For example, the supply voltage output by the mains in Region A can be a high voltage of 220 - 240V, and the supply voltage output by the mains in Region B can be a low voltage of 100 - 130V. Existing hair dryers can only be applicable to the local mains voltage. When users travel, if they are not familiar with the local voltage, there will be potential safety hazards when using a single-voltage hair dryer. For example, if the hair dryer is a product with a 110V voltage and is used on a 220V voltage, it will cause the hair dryer to burn out or pose more serious safety hazards.

[0062] To address the above technical problems, the present application provides a hair dryer, which can solve the problems of potential safety hazards and inconvenient use existing in existing hair dryers. The hair dryer of the present application can be directly connected to the mains in different countries or regions around the world, improving the user experience.

[0063] Please refer to Figure 1 , Figure 1 which is a schematic diagram of a hair dryer 100 provided for an embodiment of the present application.

[0064] As Figure 1 shown, the hair dryer 100 in this embodiment is connected to a power supply 200, and the power supply 200 can be used to provide the supply voltage required for the normal operation of the hair dryer 100.

[0065] The power supply 200 can be the mains. That is, the supply voltage can be the grid voltage output by the mains. Among them, the supply voltages output by the mains in different countries or regions are also different. For example, the supply voltage output by the power supply 200 can be a high voltage of 133V - 264V or a low voltage of 80V - 132V.

[0066] The hair dryer 100 can include a main control chip 10, a control circuit 20, a motor drive circuit 30, and a motor 40. As an example, the main control chip 10 can be a Microcontroller Unit (MCU).

[0067] It can be understood that the power supply 200 is connected to the control circuit 20, and the control circuit 20 is connected to the main control chip 10. The control circuit 20 is also connected to the motor drive circuit 30. The power supply output terminal of the power supply 200 can be used to output a power supply voltage to the control circuit 20. The control circuit 20 can monitor the power supply voltage of the power supply 200 and output a corresponding detection voltage to the main control chip 10 according to the monitored power supply voltage.

[0068] When the detection voltage output by the control circuit 20 is greater than the first preset value, the main control chip 10 can determine that the power supply voltage output by the power supply 200 is within the low voltage range. The main control chip 10 outputs a first control signal to the control circuit 20. The control circuit 20 can perform voltage doubling rectification on the power supply voltage according to the first control signal and output the power supply voltage after voltage doubling rectification to the motor drive circuit 30. The motor drive circuit 30 performs an inversion process on the power supply voltage to provide a normal working voltage for the motor 40.

[0069] When the detection voltage output by the control circuit 20 is less than or equal to the first preset value, the main control chip 10 determines that the power supply voltage output by the power supply 200 is within the high voltage range. The main control chip 10 outputs a second control signal to the control circuit 20. The control circuit 20 can perform bridge rectification on the power supply voltage according to the second control signal and output the power supply voltage after bridge rectification to the motor drive circuit 30. The motor drive circuit 30 performs an inversion process on the power supply voltage to provide a normal working voltage for the motor 40.

[0070] The motor drive circuit 30 is connected between the main control chip 10 and the motor 40. The motor drive circuit 30 is used to receive the Pulse Width Modulation (PWM) signal output by the main control chip 10, process the PWM signal, and then drive the motor 40 to work.

[0071] Based on such a design, the hair dryer of the present application can automatically determine the power supply voltage range of the mains through the control circuit, and perform bridge rectification or voltage doubling rectification on the power supply voltage according to different power supply voltage ranges, so as to output a power supply voltage within the working voltage range of the motor. Therefore, the hair dryer of the present application can adapt to different mains and can be directly connected to the mains for use in different countries or regions around the world, improving the user experience.

[0072] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the hair dryer 100 provided for another embodiment of the present application.

[0073] As shown in Figure 2As shown, as an example, the control circuit 20 may include a power supply voltage detection circuit 21, a voltage conversion circuit 22, a safety standard circuit 23, a buck circuit 24, a touch control circuit 25, a heating wire control circuit 26, a negative ion control circuit 27, and a peripheral module 28. The safety standard circuit 21 is connected between the power supply 200 and the voltage conversion circuit 22, and the buck circuit 24 is connected between the voltage conversion circuit 22 and the main control chip 10. The power supply voltage detection circuit 21 is connected between the output terminal of the safety standard circuit 23 and the main control chip 10. The voltage conversion circuit 22 is also connected to the main control chip 10. The main control chip 10 may also be connected to the touch control circuit 25, the heating wire control circuit 26, the negative ion control circuit 27, and the peripheral module 28.

[0074] The power supply voltage detection circuit 21 and the voltage conversion circuit 22 may receive the power supply voltage output by the power supply 200 through the safety standard circuit 23. The safety standard circuit 23 can prevent problems such as product burning or damage due to the excessive power supply voltage output by the power supply 200.

[0075] The main control chip 10 may control the voltage conversion circuit 22 according to the voltage range of the power supply voltage output by the power supply 200. The voltage conversion circuit 22 is used to provide a working voltage for the motor 40.

[0076] In a specific implementation process, the power supply voltage detection circuit 21 detects the power supply voltage output by the power supply 200, and outputs a corresponding detection voltage to the main control chip 10 according to the detected power supply voltage. The main control chip 10 judges the voltage range of the power supply voltage output by the power supply 200 according to the detection voltage.

[0077] For example, if the detection voltage is greater than the first preset value, the main control chip 10 may judge that the power supply voltage output by the power supply 200 is in the low voltage range, and the main control chip 10 outputs a first control signal to the voltage conversion circuit 22 to make the voltage conversion circuit 22 work in the voltage doubler rectification mode. If the detection voltage is less than or equal to the first preset value, the main control chip 10 may judge that the power supply voltage output by the power supply 200 is in the high voltage range, and the main control chip 10 outputs a second control signal to the voltage conversion circuit 22 to make the voltage conversion circuit 22 work in the bridge rectification mode.

[0078] It can be understood that the buck circuit 24 is used to convert the output voltage of the voltage conversion circuit 22 into a preset voltage, where the preset voltage may supply power to the input / output (IO) interface of the main control chip 10. As an example, the preset voltage may be a 5V DC voltage.

[0079] The main control chip 10 can also control the heating wire control circuit 26 to generate heat according to the voltage range of the supply voltage of the power supply 200. The negative ion control circuit 27 can receive the signal of the main control chip 10 and control a negative ion generator (not shown in the figure) according to the received signal. The peripheral module 28 serves as the human-computer interaction interface of the hair dryer 100. For example, the peripheral module 28 can include an indicator light, a switch button, a mode switching key, etc.

[0080] The motor drive circuit 30 includes a gate control circuit 32 and a power output module 34. The gate control circuit 32 is connected between the main control chip 10 and the power output module 34. The gate control circuit 32 is used to receive the PWM signal output by the main control chip 10, increase the driving ability of the PWM signal, and drive the power device in the power output module 34. That is, the power output module can perform an inversion process on the supply voltage output by the voltage conversion circuit 22 and provide a working voltage for the motor 40.

[0081] The main control chip 10 of the present application can integrate an 8051 core and a motor control engine to achieve field-oriented control (FOC) of the motor 40.

[0082] The main control chip 10 can collect the phase current of the motor 40, calculate the speed and position of the motor 40 based on the collected phase current of the motor 40, and thus can output a three-phase sine wave to drive the motor 40, accurately control the magnitude and direction of the magnetic field, so that the motor torque is stable, the noise is small, and the efficiency is high.

[0083] Please refer to Figure 3 , Figure 3 which is a schematic diagram of the main control chip 10 provided by an embodiment of the present application.

[0084] In this embodiment, the main control chip 10 includes a voltage detection pin AC_Det, a first signal pin Low_EN, a second signal pin Heat1, a third signal pin Heat2, and a touch signal pin Touch.

[0085] Among them, the voltage detection pin AC_Det is connected to the power supply voltage detection circuit to receive the detection voltage output by the power supply voltage detection circuit 21. The first signal pin Low_EN is connected to the voltage conversion circuit 22 to output a control signal to the voltage conversion circuit 22. Both the second signal pin Heat1 and the third signal pin Heat2 are connected to the heating wire control circuit 26 to output a control signal to the heating wire control circuit 26. The touch signal pin Touch is connected to the touch circuit 25 to receive the touch signal output by the touch circuit 25.

[0086] Please refer to Figure 4 , Figure 4Circuit diagram of the power supply voltage detection circuit 21 provided for an embodiment of the present application.

[0087] The power supply voltage detection circuit 21 includes a first rectifier bridge 210, a controllable precision voltage regulator ZD1, a first optocoupler U1, a first resistor to a tenth resistor R1 - R10, a fifth capacitor to a seventh capacitor C5 - C7, a tenth capacitor C10, and an eleventh capacitor C11. Among them, the first rectifier bridge 210 includes a first diode to a fourth diode D1 - D4. The first optocoupler U1 includes a first light emitting unit and a first photosensitive unit. The first photosensitive unit includes an emitter and a collector.

[0088] In this embodiment, the first input terminal and the second input terminal of the first rectifier bridge 210 are respectively connected to the first output terminal L and the second output terminal N of the power supply 200.

[0089] Specifically, the cathode of the first diode D1 is connected to the anode of the second diode D2. The cathode of the first diode D1 is also connected to the first output terminal L of the power supply 200 through the first resistor R1. The anode of the first diode D1 is connected to the anode of the fourth diode D4. The cathode of the second diode D2 is connected to the cathode of the third diode D3. The anode of the third diode D3 is connected to the cathode of the fourth diode D4. The anode of the third diode D3 is also connected to the second output terminal N of the power supply 200 through the second resistor R2. It can be understood that the node between the cathode of the first diode D1 and the anode of the second diode D2 can be used as the first input terminal of the first rectifier bridge 210. The node between the anode of the third diode D3 and the cathode of the fourth diode D4 can be used as the first input terminal of the first rectifier bridge 210.

[0090] The cathode of the second diode D2 is also connected to the first end of the third resistor R3. The second end of the third resistor R3 is connected to the anode of the first light-emitting unit through the fourth resistor R4. The second end of the third resistor R3 is also connected to the first end of the sixth capacitor C6, the first end of the seventh capacitor C7, and the first end of the fifth resistor R5. The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the adjustment terminal of the precision voltage regulator ZD1. The anode of the fourth diode D4 is also connected to the second end of the sixth capacitor C6, the second end of the seventh capacitor C7, the second end of the sixth resistor R6, and the first end of the precision voltage regulator ZD1. The second end of the precision voltage regulator ZD1 is connected to the cathode of the first light-emitting unit. The second end of the precision voltage regulator ZD1 is also connected to the adjustment terminal of the precision voltage regulator ZD1 through the tenth capacitor C10 and the seventh resistor R7. The second end of the precision voltage regulator ZD1 is also connected to the anode of the first light-emitting unit through the eighth resistor R8. The first output terminal of the first rectifier bridge 210 is connected to the first end of the precision voltage regulator ZD1. The adjustment terminal of the precision voltage regulator ZD1 is also connected to the second output terminal of the first rectifier bridge 210 through the fifth resistor R5 and the third resistor R3. It can be understood that the node between the anode of the first diode D1 and the anode of the fourth diode D4 can be used as the first output terminal of the first rectifier bridge 210, and the node between the cathode of the second diode D2 and the cathode of the third diode D3 can be used as the second output terminal of the first rectifier bridge 210.

[0091] The collector of the first photosensitive unit is connected to the first power supply V1 through the ninth resistor R9. The collector of the first photosensitive unit is also connected to the voltage detection pin AC_Det of the main control chip 10 through the tenth resistor R10. The collector of the first photosensitive unit is also connected to the first end of the eleventh capacitor C11. The second end of the eleventh capacitor C11 is grounded. The second end of the eleventh capacitor C11 is also connected to the emitter of the first photosensitive unit. The second end of the eleventh capacitor C11 is also connected to the voltage detection pin AC_Det of the main control chip 10 through the fifth capacitor C5. In other words, the node P1 between the tenth resistor R10 and the fifth capacitor C5 can be connected to the voltage detection pin AC_Det of the main control chip 10 to output a detection voltage to the main control chip 10.

[0092] In this embodiment, the supply voltage of the power supply 200 is rectified by the first rectifier bridge 210, and then divided and filtered by the first resistor R1, the second resistor R2, the third resistor R3, the fifth resistor R5, the sixth resistor R6, the sixth capacitor C6 and the seventh capacitor C7. After being regulated by the controllable precision voltage regulator ZD1, it is electrically isolated by the first optocoupler U1, and then the detection voltage can be output to the voltage detection pin AC_Det of the main control chip 10. For example, when the supply voltage of the power supply 200 increases within the range of 80V to 132V, the detection voltage output at the node P1 decreases between 4.5V and 2.5V. When the supply voltage of the power supply 200 increases within the range of 132V to 264V, the detection voltage output at the node P1 decreases between 2.5V and 0V. In other words, when the voltage detection pin AC_Det of the main control chip 10 detects that the detection voltage is greater than 2.5V, the main control chip 10 determines that the supply voltage of the power supply 200 is within the low voltage range, and thus outputs the first control signal to the voltage conversion circuit 22. When the voltage detection pin AC_Det of the main control chip 10 detects that the detection voltage is less than or equal to 2.5V, the main control chip 10 determines that the supply voltage of the power supply 200 is within the high voltage range, and thus outputs the second control signal to the voltage conversion circuit 22.

[0093] Based on Figure 4 The power supply voltage detection circuit 21 shown in the embodiment has a simple circuit structure, low cost and strong anti-interference ability, enabling the main control chip 10 to quickly detect that the supply voltage of the power supply 200 is in the low voltage range (such as 88V to 132V) or the high voltage range (such as 176V to 264V), and is not affected by the backend load.

[0094] Please refer to Figure 5 , Figure 5 which is the circuit diagram of the voltage conversion circuit 22 and the safety regulation circuit 23 provided by an embodiment of the present application.

[0095] The voltage conversion circuit 22 includes a second rectifier bridge 220, a first thyristor T1, a second optocoupler U2, a first capacitor C1, a second capacitor C2, an eighth capacitor C8, and eleventh to eighteenth resistors R11-R18. Among them, the second rectifier bridge 220 includes fifth to eighth diodes D5-D8. The second optocoupler U2 includes a second light emitting unit and a second switch unit.

[0096] It can be understood that the first input terminal and the second input terminal of the second rectifier bridge 220 can be electrically connected to the first output terminal L and the second output terminal N of the power supply 200 respectively.

[0097] In an alternative implementation, the first input terminal and the second input terminal of the second rectifier bridge 220 can be electrically connected to the first output terminal L and the second output terminal N of the power supply 200 through the safety circuit 23, respectively.

[0098] In a specific implementation process, the safety circuit 23 includes a first fuse F1, a first thermistor NTC1, a second thermistor NTC2, a varistor VDR1, a safety capacitor SC1, and a choke coil Q1. The first end of the first thermistor NTC1 is connected to the first output terminal L of the power supply 200 through the first fuse F1, and the second end of the first thermistor NTC1 is connected to the first end of the varistor VDR1, the first end of the safety capacitor SC1, and the first end of the choke coil Q1. The first end of the second thermistor NTC2 is connected to the second output terminal N of the power supply 200, and the second end of the second thermistor NTC2 is connected to the second end of the varistor VDR1, the second end of the safety capacitor SC1, and the second end of the choke coil Q1. The third end of the choke coil Q1 is connected to the cathode of the fifth diode D5 and the anode of the sixth diode D6, and the fourth end of the choke coil Q1 is connected to the cathode of the eighth diode D8 and the anode of the seventh diode D7. The anode of the fifth diode D5 is connected to the anode of the eighth diode D8, and the cathode of the sixth diode D6 is connected to the cathode of the seventh diode D7. The cathode of the sixth diode D6 is connected to the first end of the first capacitor C1 and the first end of the eleventh resistor R11. The second end of the first capacitor C1 is grounded through the second capacitor C2, and the second end of the eleventh resistor R11 is grounded through the twelfth resistor R12. The second end of the eleventh resistor R11 is also connected to the anode of the fifth diode D5 and the anode of the eighth diode D8 through the twelfth resistor R12. Among them, the node P2 between the cathode of the sixth diode D6 and the first capacitor C1 can output the second voltage V2. It can be understood that the node between the anode of the fifth diode D5 and the anode of the eighth diode D8 can be used as the first output terminal of the second rectifier bridge 220, and the node between the cathode of the sixth diode D6 and the cathode of the seventh diode D7 can be used as the second output terminal of the second rectifier bridge 220.

[0099] The first end of the first thyristor T1 is connected to the node between the first capacitor C1 and the first capacitor C2 and the node between the eleventh resistor R11 and the twelfth resistor R12. The second end of the first thyristor T1 is connected to the first end of the first thyristor T1 through the eighth capacitor C8 and the thirteenth resistor R13. The first end of the first thyristor T1 is also connected to the first end of the second switch unit through the fourteenth resistor R14 and the fifteenth resistor R15. The second end of the first thyristor T1 is also connected to the second end of the second switch unit through the sixteenth resistor R16. The third end of the first thyristor T1 is connected to the second end of the second switch unit.

[0100] The anode of the second light-emitting unit is connected to the first power supply V1. The anode of the second light-emitting unit is also connected to the cathode of the second light-emitting unit through the seventeenth resistor R17, and the cathode of the second light-emitting unit is also connected to the first signal pin Low_EN of the main control chip 10 through the eighteenth resistor R18.

[0101] It can be understood that the operating voltage range of the motor 40 in this embodiment is 176V to 264V. In order not to affect the service life and performance of the motor, the voltage provided by the power conversion circuit 22 to the motor 40 needs to be within a preset range.

[0102] In this embodiment, after the supply voltage of the power supply 200 passes through the safety circuit and the filtering and rectification of the second rectifier bridge 220, it is electrically isolated through the second optocoupler U2. The second optocoupler U2 can prevent the main control chip 10 from being damaged by high voltage. The main control chip 10 can control the state of the voltage conversion circuit 22 according to the detection voltage received by the voltage detection pin AC_Det.

[0103] For example, in a possible scenario, when the main control chip 10 detects that the supply voltage of the power supply 200 is between 133V and 264V, the first signal pin Low_EN of the main control chip 10 outputs a high-level control signal to turn off the first thyristor T1. The supply voltage output by the power supply 200 charges the first capacitor C1 and the second capacitor C2 through the second rectifier bridge 220. At this time, the voltage conversion circuit 22 operates in the full-bridge rectification mode, that is, the voltage conversion circuit 22 can perform full-bridge rectification on the supply voltage output by the power supply 200, so as to output the second voltage V2 to the motor 40 at the node P2. It can be understood that in the full-bridge rectification mode of the voltage conversion circuit 22, the second voltage V2 is times the supply voltage. In other words, the second voltage V2 is the voltage that can satisfy the normal operation of the motor 40.

[0104] In another possible scenario, when the main control chip 10 detects that the supply voltage of the power supply 200 is between 80V and 132V, the first signal pin Low_EN of the main control chip 10 outputs a low-level control signal to turn on the first thyristor T1. The first capacitor C1 is charged during the positive half-cycle of the supply voltage, and the second capacitor C2 is charged during the negative half-cycle of the supply voltage. At this time, the voltage conversion circuit 22 operates in the voltage-doubling rectification mode, that is, the voltage conversion circuit 22 can perform voltage-doubling rectification on the supply voltage output by the power supply 200, so as to output the second voltage V2 to the motor 40 at the node P2. It can be understood that in the voltage-doubling rectification mode of the voltage conversion circuit 22, the low voltage is multiplied to the operating voltage range of the motor, 176 to 264V, and the motor 40 can operate normally. For example, the second voltage V2 can be times the supply voltage.

[0105] It can be understood that, in order to ensure the working safety of the hair dryer 100, the voltage conversion circuit 22 can enter the full-bridge rectification mode first when the hair dryer 100 is started. When the voltage detection pin of the main control chip 10 detects a detection voltage between 4.5V and 2.5V, that is, when the detection voltage received by the voltage detection pin AC_Det is greater than the first preset value (that is, the main control chip 10 determines that the supply voltage is in the low voltage range), after delaying the first signal pin Low_EN by 500 ms, a control signal with a low level is output to the voltage conversion circuit 22 to enter the voltage-doubling rectification mode. Based on such a design, the present application can prevent the voltage conversion circuit 22 from entering the voltage-doubling rectification mode when the supply voltage is in the high voltage range, and avoid damaging the first capacitor C1, the second capacitor C2, and the subsequent load circuit.

[0106] In a possible scenario, due to the aging or abnormal conditions of the optocoupler or components in the hair dryer, there will be potential safety hazards in the hair dryer. For this reason, when the main control chip 10 of the present application detects that the detected voltage is greater than the second preset value (for example, 5V), a control signal with a high level is output to the voltage conversion circuit 22, so that the voltage conversion circuit 22 operates in the full-bridge rectification mode, thereby preventing the voltage conversion circuit 22 from entering the voltage-doubling rectification mode when the supply voltage is in the high voltage range under abnormal conditions and burning out the components.

[0107] Based on Figure 5 the embodiments shown, the voltage conversion circuit 22 can control the state of the first thyristor T2 according to the control signal output by the main control chip 10, and further enable the voltage conversion circuit 22 to perform voltage-doubling rectification or full-bridge rectification on the supply voltage output by the power supply 200. Therefore, when the supply voltage of the power supply 200 is in the low voltage range or the high voltage range, the voltage conversion circuit 22 of the present application can provide a normal working voltage for the motor 40, so that the motor can work normally, thereby ensuring the service life and performance of the motor.

[0108] In this embodiment, the second optocoupler U2 can be a zero-crossing optocoupler, and the first thyristor T1 can be a thyristor with high sensitivity. In addition, the present application can also suppress current triggering by using the eighth capacitor C8, the thirteenth resistor R13, and the seventeenth resistor R17, and can prevent the noise interference signal from causing misfiring of the first thyristor T1. Based on such a design, the hair dryer 100 of the present application has very high anti-interference and reliability, and can avoid potential safety hazards caused by manually switching the gear.

[0109] Please refer to Figure 6 , Figure 6 which is the circuit diagram of the heating wire control circuit 26 provided by an embodiment of the present application.

[0110] In this embodiment, the heating wire control circuit 26 includes a first heating wire Rh1, a second heating wire Rh2, a third heating wire Rh3, a third optocoupler U3, a fourth optocoupler U4, a second thyristor T2, a third thyristor T3, a temperature control switch K1, a second fuse F2, and a nineteenth resistor to a twenty-eighth resistor R19-R28. Among them, the third optocoupler U3 includes a third light-emitting unit and a third switching unit. The fourth optocoupler U4 includes a fourth light-emitting unit and a fourth switching unit.

[0111] The first end of the first heating wire Rh1 is connected to the first end of the second heating wire Rh2 and the first end of the temperature control switch K1. The second end of the temperature control switch K1 is connected to the first output terminal L of the power supply 200 through the second fuse F2. The second end of the first heating wire Rh1 is connected to the second end of the second heating wire Rh2, the first end of the third heating wire Rh3, and the first end of the second thyristor T2. The second end of the third heating wire Rh3 is connected to the first end of the third thyristor T3.

[0112] The first end of the second thyristor T2 is also connected to the second end of the third switching unit through the nineteenth resistor R19. The second end of the second thyristor T2 is connected to the first end of the third switching unit through the twentieth resistor R20 and the twenty-first resistor R21. The second end of the second thyristor T2 is also connected to the second output terminal N of the power supply 200. The third end of the second thyristor T2 is connected to the second end of the third switching unit. The anode of the third light-emitting unit is connected to the first power supply V1. The anode of the third light-emitting unit is also connected to the cathode of the third light-emitting unit through the twenty-second resistor R22. The cathode of the third light-emitting unit is also connected to the second signal pin Heat1 of the main control chip 10 through the twenty-third resistor R23. The third optocoupler U3 can be used to achieve electrical isolation and can be used to control the conduction or cut-off of the second thyristor T2.

[0113] The first end of the third thyristor T3 is also connected to the second end of the fourth switching unit through the twenty-fourth resistor R24. The second end of the third thyristor T3 is connected to the first end of the fourth switching unit through the twenty-fifth resistor R25 and the twenty-sixth resistor R26. The second end of the third thyristor T3 is also connected to the second output terminal N of the power supply 200. The third end of the third thyristor T3 is connected to the second end of the fourth switching unit. The anode of the fourth light-emitting unit is connected to the first power supply V1. The anode of the fourth light-emitting unit is also connected to the cathode of the fourth light-emitting unit through the twenty-seventh resistor R27. The cathode of the fourth light-emitting unit is also connected to the third signal pin Heat2 of the main control chip 10 through the twenty-eighth resistor R28. The fourth optocoupler U4 can be used to achieve electrical isolation and can be used to control the conduction or cut-off of the third thyristor T3.

[0114] In this embodiment, when the main control chip 10 detects that the supply voltage of the power supply 200 is within the high voltage range, the second signal pin Heat1 of the main control chip 10 outputs a control signal with a high level to turn off the second thyristor T2. The third signal pin Heat2 of the main control chip 10 outputs a control signal with a low level to turn on the fourth light-emitting unit, drive the fourth switching unit to conduct, and then turn on the third thyristor T3, so that all three heating wires (i.e., the first heating wire Rh1, the second heating wire Rh2, and the third heating wire Rh3) are energized and heated. When the main control chip 10 detects that the supply voltage of the power supply 200 is within the low voltage range, the second signal pin Heat1 of the main control chip 10 outputs a control signal with a low level to turn on the third light-emitting unit, drive the third switching unit to conduct, and then turn on the second thyristor T2. The third signal pin Heat2 of the main control chip 10 outputs a control signal with a high level to turn off the third thyristor T3, so that the first heating wire Rh1 and the second heating wire Rh2 are energized and heated.

[0115] It can be understood that in a possible scenario, for example, if the supply voltage of the power supply 200 continuously rises from the low voltage range of 80V to 132V to the high voltage range, the main control chip 10 outputs a control signal with a high level through the second signal pin Heat1 and outputs a control signal with a low level through the third signal pin Heat2, so that the second thyristor T2 is turned off and the third thyristor T3 is turned on. If the supply voltage of the power supply 200 continuously drops from the high voltage range to the low voltage range of 80V to 132V, that is, when the voltage detection pin AC_Det of the main control chip 10 detects that the detected voltage is between 4.5V and 2.5V, after a delay of 500 ms, the second signal pin Heat1 outputs a control signal with a low level, and the third signal pin Heat2 outputs a control signal with a high level, so that the second thyristor T2 is turned on and the third thyristor T3 is turned off. Based on such a design, the embodiment of the present application can prevent misjudgment caused by an instantaneous drop or interference of the supply voltage of the power supply 200, resulting in the first heating wire Rh1 and the second heating wire Rh2 being turned on and burned out when the supply voltage is within the high voltage range.

[0116] Based on Figure 6 In the illustrated embodiment, the main control chip 10 can control the turn-off and turn-on of the second thyristor T2 and the third thyristor T3 according to the detected supply voltage to switch different heating wire groups to emit hot air at a stable temperature, realizing that the hair dryer is not affected by the supply voltage, can work normally within the maximum voltage fluctuation range, and has stable power performance. The hair dryer of the present application can be provided with a sensor (such as a glass bead thermal sensor) at the air outlet. The main control chip 10 can monitor the temperature at the air outlet in real time and implement intelligent constant temperature control through a constant temperature compensation algorithm to accurately control the temperature and avoid damage to the user's hair due to excessive temperature.

[0117] Please refer to Figure 7 , Figure 7 which is the circuit diagram of the touch circuit 25 provided for an embodiment of the present application.

[0118] The touch circuit 25 includes a touch chip U5, a third capacitor C3, a fourth capacitor C4, a ninth capacitor C9, and twenty-ninth to thirty-second resistors R29-R32.

[0119] In an optional implementation, the touch chip U5 is an XW01T chip.

[0120] The touch chip U5 includes a power supply pin VDD, a ground pin GND, an output pin OUT, a first signal pin S1, a second signal pin S2, and a detection signal pin KEY.

[0121] The power supply pin VDD of the touch chip U5 is connected to the first power supply V1 through the twenty-ninth resistor R29. The ground pin GND of the touch chip U5 is grounded. The ground pin GND of the touch chip U5 is also connected to the power supply pin VDD of the touch chip U5 through the ninth capacitor C9. The output pin OUT of the touch chip U5 is connected to the first power supply V1 through the thirtieth resistor R30. The output pin OUT of the touch chip U5 is also connected to the touch signal pin Touch of the main control chip 10 to output a touch signal to the main control chip 10. The first signal pin S1 of the touch chip U5 is grounded through the third capacitor C3. The second signal pin S2 of the touch chip U5 is grounded through the fourth capacitor C4. The detection signal pin KEY of the touch chip U5 is also connected to the pad (PAD) hole on the main board through the thirty-second resistor R32.

[0122] The hair dryer 100 may further include a housing (not shown in the figure). The main control chip 10, the control circuit 20, the motor drive circuit 30, and the motor 40 are all disposed inside the housing. It can be understood that the hair dryer of the present application may further include other components, which are not described herein again because they are not related to the inventive principle of the present application.

[0123] The hair dryer 100 of the present application has a touch function. When the user holds the hair dryer, the hair dryer automatically turns on. When the user puts down the hair dryer, the hair dryer automatically goes into standby.

[0124] In other embodiments, it may also automatically turn off after a preset standby time (such as 30 minutes).

[0125] In a specific implementation, a layer of copper foil (not shown in the figure) can be provided on the inner wall of the housing of the hair dryer 100, and the electrical connection between the copper foil and the touch chip U5 is achieved through a spring (not shown in the figure). Specifically, one end of the spring is welded to the pad hole of the main board, and the other end of the spring abuts against the copper foil on the inner wall of the housing, thereby realizing the touch function of the hair dryer 100. It can be understood that by reasonably setting the position of the copper foil on the inner wall of the hair dryer housing and the size of the copper foil, the present application can ensure that the effective touch of the palm can be accurately detected, thereby ensuring the sensitivity and stability of the product.

[0126] When the user holds the hair dryer, the total capacitance of the detection signal pin KEY of the touch chip U5 is more than 0.2 pF larger than the reference capacitance of the second signal pin S2 of the touch chip U5, and the touch signal output by the touch chip U5 changes from high level to low level. The main control chip 10 controls the hair dryer 100 to enter the working mode according to the touch signal of the low level.

[0127] When the hair dryer 100 is in the working mode and the hair dryer 100 is placed on the table, the touch signal output by the touch chip U5 changes from low level to high level. The main control chip 10 controls the hair dryer to enter the standby mode according to the touch signal of the high level, and enters the deep sleep after timing a preset time (such as 30 minutes). At this time, if the user picks up the hair dryer again, a normal startup operation needs to be performed, which can prevent children from accidentally touching and turning on the hair dryer when the user places the hair dryer on the table and forgets to unplug the power socket, improving the use safety.

[0128] It can be understood that the hair dryer 100 of the present application can adopt a T-shaped structure. Among them, the main board of the hair dryer 100 is arranged in the handle, and the power devices in the power output module and the second thyristor T2 and the third thyristor T3 are arranged in the main air duct with better heat dissipation conditions. Among them, the first rectifier bridge 210, the second rectifier bridge 220, and the first thyristor T1 arranged in the handle have a relatively high temperature during operation. The present application can provide a good heat dissipation environment for the devices in the handle through the negative pressure air duct.

[0129] Hair dryers are usually used in high-humidity scenarios such as bathrooms. Since moisture has high destructiveness to printed circuit boards (PCBs). For example, excessive moisture will reduce the insulation performance between conductors, and even corrode the conductors, thereby causing chemical reactions between metallic copper and water vapor and oxygen, resulting in situations such as verdigris, affecting the overall life of the machine. To solve the problems in the above scenarios, the present application can play the roles of waterproofing, moisture-proofing, and dust-proofing by coating the printed circuit board with three-proof UV glue, and also has advantages such as resistance to thermal shock, anti-aging, anti-corrosion, and vibration resistance, which can ensure the reliability and durability of the hair dryer in a high-humidity environment.

[0130] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or basic characteristics of the present application. Therefore, as long as it is within the scope of the substantial spirit of the present application, the appropriate changes and variations made to the above embodiments should fall within the scope of protection required by the present application.

Claims

1. A hair dryer for connection to a power supply, characterized in that, The hair dryer includes a control circuit and a main control chip connected to the control circuit; The control circuit includes a power supply voltage detection circuit and a voltage conversion circuit. The power supply voltage detection circuit is used to detect the power supply voltage output by the power supply, and is used to process the power supply voltage and then output a corresponding detection voltage to the main control chip; The main control chip is used for: When the detection voltage is greater than a first preset value, controlling the voltage conversion circuit to perform voltage doubling and rectification on the power supply voltage, so as to output the power supply voltage after voltage doubling and rectification to supply power to the motor; When the detection voltage is less than or equal to the first preset value, controlling the voltage conversion circuit to perform bridge rectification on the power supply voltage, so as to output the power supply voltage after bridge rectification to supply power to the motor.

2. The hair dryer according to claim 1, characterized in that The power supply voltage detection circuit includes a first rectifier bridge, a controllable precision voltage regulator, and a first optocoupler. The first optocoupler includes a first light emitting unit and a first photosensitive unit; The first input terminal and the second input terminal of the first rectifier bridge are respectively connected to the first output terminal and the second output terminal of the power supply. The first output terminal of the first rectifier bridge is connected to the first terminal of the controllable precision voltage regulator. The second terminal of the controllable precision voltage regulator is connected to the cathode of the first light emitting unit. The adjustment terminal of the controllable precision voltage regulator is connected to the second output terminal of the first rectifier bridge. The second output terminal of the first rectifier bridge is connected to the anode of the first light emitting unit. The emitter of the first photosensitive unit is grounded, and the collector of the first photosensitive unit outputs the detection voltage to the voltage detection pin of the main control chip.

3. The hair dryer according to claim 1, characterized in that The voltage conversion circuit includes a second rectifier bridge, a first thyristor, a second optocoupler, a first capacitor and a second capacitor. The second optocoupler includes a second light emitting unit and a second switching unit; The first input terminal and the second input terminal of the second rectifier bridge are respectively connected to the first output terminal and the second output terminal of the power supply, The first output terminal of the second rectifier bridge is grounded through the first capacitor and the second capacitor. The second output terminal of the second rectifier bridge is grounded. The first terminal of the first thyristor is connected to the node between the first capacitor and the second capacitor. The second terminal of the first thyristor is connected to the second input terminal of the second rectifier bridge. The third terminal of the first thyristor is connected to the second terminal of the second switching unit. The first terminal of the second switching unit is connected to the first terminal of the first thyristor. The anode of the second light emitting unit is connected to a first power supply. The cathode of the second light emitting unit is connected to the first signal pin of the main control chip. The node between the second output terminal of the second rectifier bridge and the first capacitor outputs a second voltage to supply power to the motor.

4. The hair dryer according to claim 3, characterized in that The main control chip is further used to control the first thyristor to conduct when the detection voltage is greater than the first preset value.

5. The hair dryer according to claim 3 or 4, characterized in that The main control chip is further configured to control the first thyristor to turn off when the detected voltage is less than or equal to the first preset value.

6. The hair dryer according to claim 1, wherein the control circuit further includes a heating wire control circuit, and the heating wire control circuit includes a first heating wire, a second heating wire, a third heating wire, a third opto-coupler, a fourth opto-coupler, a second thyristor, and a third thyristor; wherein, the third opto-coupler includes a third light-emitting unit and a third switching unit, and the fourth opto-coupler includes a fourth light-emitting unit and a fourth switching unit; The first end of the first heating wire is connected to the first end of the second heating wire and the first output terminal of the power supply, and the second end of the first heating wire is connected to the second end of the second heating wire, the first end of the third heating wire, and the first end of the second thyristor, and the second end of the third heating wire is connected to the first end of the third thyristor; The first end of the second thyristor is further connected to the second end of the third switching unit, the second end of the second thyristor is connected to the first end of the third switching unit, the second end of the second thyristor is further connected to the second output terminal of the power supply, and the cathode of the third light-emitting unit is connected to the second signal pin of the main control chip; The first end of the third thyristor is connected to the second end of the fourth switching unit, the second end of the third thyristor is connected to the first end of the fourth switching unit, the second end of the third thyristor is further connected to the second output terminal of the power supply, the anode of the fourth light-emitting unit is further connected to the cathode of the fourth light-emitting unit, and the cathode of the fourth light-emitting unit is connected to the third signal pin of the main control chip.

7. The hair dryer according to claim 6, wherein the main control chip is further configured to control the second thyristor to turn on and control the third thyristor to turn off when the detected voltage is greater than the first preset value.

8. The hair dryer according to claim 6 or 7, wherein the main control chip is further configured to control the second thyristor to turn off and control the third thyristor to turn on when the detected voltage is less than or equal to the first preset value.

9. The hair dryer according to claim 1, wherein the hair dryer includes a housing, the inner wall of the housing is provided with a copper foil, and the control circuit further includes a touch control circuit, and the touch control circuit includes a touch control chip; The output pin of the touch control chip is connected to the touch control signal pin of the main control chip to output a touch control signal to the main control chip, the first signal pin of the touch control chip is grounded through a third capacitor, the second signal pin of the touch control chip is grounded through a fourth capacitor, and the detection signal pin of the touch control chip is connected to the copper foil through a spring.

10. The hair dryer according to claim 9, wherein the main control chip is further configured to: When receiving the first touch signal output by the touch chip, control the hair dryer to enter the working state. When receiving the second touch signal output by the touch chip, control the hair dryer to enter the standby state. After a preset time when the hair dryer is in the standby state, control the hair dryer to enter the shutdown state.

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