Adaptive control circuit for alternating-current variable voltage

Abstract

The utility model discloses a self-adaptive control circuit for alternating-current variable voltage. The self-adaptive control circuit comprises a voltage conversion circuit, a voltage detection circuit, a rectification circuit, a power supply circuit, a control chip and a heating control circuit, the first input end of the voltage conversion circuit is connected with an alternating-current phase line, and the second input end is connected with an alternating-current zero line and the first and second connecting ends of the heating control circuit; a first conversion output end of the voltage conversion circuit is connected with a detection input end of the voltage detection circuit and a power supply input end of the power supply circuit, and a second conversion output end of the voltage conversion circuit is grounded; the detection output end of the voltage detection circuit is connected with the sixth pin of the control chip. According to the self-adaptive control circuit, the AC voltage is detected through the voltage detection circuit, and the unidirectional silicon controlled rectifier of the rectification circuit and the bidirectional silicon controlled rectifier of the heating control circuit are controlled through the control chip, so that the blower can be matched with AC commercial power of various specifications for use.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to an adaptive control circuit for alternating current variable voltage. Background Art

[0002] At present, hair dryers in the industry are usually only suitable for a certain voltage and frequency, such as 220V / 50Hz or 120V / 60Hz AC. However, there are certain differences in the voltage and frequency of the mains electricity in different countries or regions. The mains electricity specifications in some countries may be 220V / 60Hz or 110V / 60Hz. If the user takes the hair dryer to use in areas with different mains electricity specifications, a power adapter plug must be prepared. If the voltage is too high or too low, the hair dryer may be damaged. Therefore, the control circuit for the hair dryer in the prior art method has the problem of being unable to adapt to various specifications of AC mains electricity. Utility Model Content

[0003] The embodiment of the utility model provides an adaptive control circuit for AC variable voltage, aiming to solve the problem that the control circuit for hair dryers in the prior art methods cannot adapt to AC mains of various specifications.

[0004] The embodiment of the utility model provides an adaptive control circuit for AC variable voltage, wherein the adaptive control circuit includes a voltage conversion circuit, a voltage detection circuit, a rectifier circuit, a power supply circuit, a control chip and a heating control circuit;

[0005] The first input end of the voltage conversion circuit is connected to the AC phase line, and the second input end is connected to the AC neutral line and the first connection end and the second connection end of the heating control circuit;

[0006] The first conversion output terminal of the voltage conversion circuit is connected to the detection input terminal of the voltage detection circuit and the power supply input terminal of the power supply circuit, and the second conversion output terminal of the voltage conversion circuit is grounded;

[0007] The detection output end of the voltage detection circuit is connected to the sixth pin of the control chip;

[0008] The voltage-stabilizing output terminal of the power supply circuit is connected to the voltage-stabilizing input terminal of the heating control circuit; the first power supply terminal of the heating control circuit is connected to the first input terminal of the voltage conversion circuit, the second power supply terminal of the heating control circuit is connected to the second input terminal of the voltage conversion circuit, and the first control terminal, the second control terminal and the third control terminal of the heating control circuit are respectively connected to the seventh pin, the eighth pin and the ninth pin of the control chip;

[0009] The rectifier circuit includes a unidirectional thyristor, a fifth photocoupler, a third resistor, a seventeenth resistor and an eighteenth resistor;

[0010] The voltage conversion circuit includes a voltage transformer, a bridge rectifier, a first polarity capacitor and a third polarity capacitor; the two ends of the primary side of the voltage transformer are respectively connected to the AC neutral line and the fourth connection end of the bridge rectifier; the two ends of the secondary side of the voltage transformer are respectively connected to the first input end of the voltage conversion circuit and the third connection end of the bridge rectifier; the first connection end of the bridge rectifier is connected to the positive electrode of the first polarity capacitor, and the connection point serves as the first conversion output end of the voltage conversion circuit; the second connection end of the bridge rectifier is connected to the negative electrode of the third polarity capacitor, and the connection point serves as the second conversion output end of the voltage conversion circuit; the negative electrode of the first polarity capacitor is connected to the positive electrode of the third polarity capacitor, and the connection point is connected to the second connection end of the unidirectional thyristor and one end of the third resistor;

[0011] The third connection end of the bridge rectifier is also connected to the first connection end of the unidirectional thyristor; the control connection end of the unidirectional thyristor is connected to one end of the eighteenth resistor; the other end of the third resistor is connected to the fourth connection end of the fifth photocoupler, the other end of the eighteenth resistor is connected to the third connection end of the fifth photocoupler, the second connection end of the fifth photocoupler is grounded, and the first connection end of the fifth photocoupler is connected in series with the seventeenth resistor and then connected to the second pin of the control chip.

[0012] The embodiment of the utility model provides an adaptive control circuit for AC variable voltage, which includes a voltage conversion circuit, a voltage detection circuit, a rectifier circuit, a power supply circuit, a control chip and a heating control circuit; the first input end of the voltage conversion circuit is connected to the AC phase line, and the second input end is connected to the AC neutral line and the first connection end and the second connection end of the heating control circuit; the first conversion output end of the voltage conversion circuit is connected to the detection input end of the voltage detection circuit and the power supply input end of the power supply circuit, and the second conversion output end of the voltage conversion circuit is grounded; the detection output end of the voltage detection circuit is connected to the sixth pin of the control chip. The above-mentioned adaptive control circuit for AC variable voltage detects the AC voltage through the voltage detection circuit, and controls the unidirectional thyristor of the rectifier circuit and the bidirectional thyristor of the heating control circuit through the control chip, so that the hair dryer can be adapted for use with AC mains of various specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A partial circuit structure diagram of an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0015] Figure 2 A circuit structure diagram of a voltage detection circuit in an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0016] Figure 3 A circuit structure diagram of a key circuit in an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0017] Figure 4 A circuit structure diagram of a heating control circuit in an adaptive control circuit for an AC variable voltage provided by an embodiment of the utility model;

[0018] Figure 5 A circuit structure diagram of a zero-crossing detection circuit in an adaptive control circuit for an AC variable voltage provided by an embodiment of the utility model;

[0019] Figure 6 A circuit structure diagram of a gear position detection circuit in an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0020] Figure 7 A circuit structure diagram of a control chip in an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0021] Figure 8 A circuit structure diagram of a power supply circuit in an adaptive control circuit for AC variable voltage provided by an embodiment of the utility model;

[0022] Fig. 9 A circuit structure diagram of an indicator light circuit in an adaptive control circuit for AC variable voltage provided in an embodiment of the utility model.

[0023] Figure symbols: 11, voltage conversion circuit; 12, rectifier circuit; U6, control chip; SCR1, unidirectional thyristor; U5, fifth photoelectric coupler; R3, third resistor; R17, seventeenth resistor; R18, eighteenth resistor; L2, voltage transformer; DB1, bridge rectifier; EC1, first polarity capacitor; EC3, third polarity capacitor; U11, eleventh photoelectric coupler; U12, twelfth photoelectric coupler; U13, thirteenth photoelectric coupler; HSCR1, first heating bidirectional thyristor; HSCR2, second heating bidirectional thyristor; HSCR3, third heating bidirectional thyristor; R63, first heating resistor; R62, second heating resistor; R60, sixtieth resistor; R58, fifty-eighth resistor; R59, fifty-ninth resistor; R61, sixty-first resistor; R67, sixty-seventh resistor; R63, sixty-third resistor; R64, sixty-fourth resistor; R65, sixty-fifth resistor; R66, sixty-sixth resistor; R22, twenty-second resistor; R25, twenty-fifth resistor; R26 , the twenty-sixth resistor; R29, the twenty-ninth resistor; C17, the seventeenth capacitor; F1, the fuse; ZNR1, thermistor; CX1, the isolation capacitor; TR1, the potentiometer; SW1, the control switch; R15, the fifteenth resistor; R1, the first resistor; U4, the fourth photocoupler; R10, the tenth resistor; R12, the twelfth resistor; C1, the first capacitor; R16, the sixteenth resistor; R11, the eleventh resistor; U3, the third photocoupler; R7, the seventh resistor; R13, the thirteenth resistor; C7, the seventh capacitor; R14, the fourteenth resistor; R9, the ninth resistor; C10, the tenth capacitor; S2, the switch button; U1, the first power supply conversion chip; U2, the second power supply conversion chip; D3, the third diode; D4, the fourth diode; D1, the first diode; C3, the third capacitor; L1, the first inductor; R4, the fourth resistor; R5, the fifth resistor; R6, the sixth resistor; R8, the eighth resistor; LED1, the first LED lamp; LED2, the second LED lamp; LED3, the third LED lamp. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the terms used in the utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in the utility model specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term “and / or” used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] See also Figures 1 to 9 As shown in the figure, the embodiment of the present application discloses an adaptive control circuit for AC variable voltage, which includes a voltage conversion circuit 11, a voltage detection circuit, a rectifier circuit 12, a power supply circuit, a control chip U6 and a heating control circuit; the first input end of the voltage conversion circuit 11 is connected to the AC phase line, and the second input end is connected to the AC neutral line and the first connection end and the second connection end of the heating control circuit; the first conversion output end of the voltage conversion circuit 11 is connected to the detection input end of the voltage detection circuit and the power supply input end of the power supply circuit, and the second conversion output end of the voltage conversion circuit 11 is connected to the detection input end of the voltage detection circuit and the power supply input end of the power supply circuit. The output end is grounded; the detection output end of the voltage detection circuit is connected to the sixth pin U6_6 of the control chip U6; the voltage stabilizing output end of the power supply circuit is connected to the voltage stabilizing input end of the heating control circuit; the first power supply end of the heating control circuit is connected to the first input end of the voltage conversion circuit 11, the second power supply end of the heating control circuit is connected to the second input end of the voltage conversion circuit 11, and the first control end, the second control end and the third control end of the heating control circuit are respectively connected to the seventh pin U6_7, the eighth pin U6_8 and the ninth pin U6_9 of the control chip U6.

[0029] Among them, Figure 1 As shown, the ACL terminal of the voltage conversion circuit 11 is connected to the AC phase line, and the CAN terminal is connected to the AC neutral line. The first input terminal of the voltage conversion circuit 11 is also the ACL1 terminal, and the second input terminal of the voltage conversion circuit 11 is also the CAN terminal; the first conversion output terminal of the voltage conversion circuit 11 is also the +HVDC terminal, and the second conversion output terminal of the voltage conversion circuit 11 is also the GND terminal.

[0030] like Figure 2 As shown, the detection output terminal of the voltage detection circuit is the V_DET terminal, and the detection output terminal of the voltage detection circuit outputs a voltage detection signal to the control chip U6. Among them, the specific structure of the control chip U6 is as follows Figure 7 shown.

[0031] Specifically, the rectifier circuit 12 includes a unidirectional thyristor SCR1, a fifth photocoupler U5, a third resistor R3, a seventeenth resistor R17 and an eighteenth resistor R18; the voltage conversion circuit 11 includes a voltage transformer L2, a bridge rectifier DB1, a first polarity capacitor EC1 and a third polarity capacitor EC3; the two ends of the primary side of the voltage transformer L2 are respectively connected to the AC neutral line and the fourth connection end of the bridge rectifier DB1; the two ends of the secondary side of the voltage transformer L2 are respectively connected to the first input end of the voltage conversion circuit 11 and the third connection end of the bridge rectifier DB1; the first connection end of the bridge rectifier DB1 is connected to the positive electrode of the first polarity capacitor EC1, and the connection point serves as the first conversion output end of the voltage conversion circuit 11; the second connection end of the bridge rectifier DB1 is connected to the negative electrode of the third polarity capacitor EC3, and the connection point as the second conversion output terminal of the voltage conversion circuit 11; the negative electrode of the first polarity capacitor EC1 is connected to the positive electrode of the third polarity capacitor EC3, and the connection point is connected to the second connection terminal of the unidirectional thyristor SCR1 and one end of the third resistor R3; the third connection terminal of the bridge rectifier DB1 is also connected to the first connection terminal of the unidirectional thyristor SCR1; the control connection terminal of the unidirectional thyristor SCR1 is connected to one end of the eighteenth resistor R18; the other end of the third resistor R3 is connected to the fourth connection terminal of the fifth photocoupler U5, the other end of the eighteenth resistor R18 is connected to the third connection terminal of the fifth photocoupler U5, the second connection terminal of the fifth photocoupler U5 is grounded, and the first connection terminal of the fifth photocoupler U5 is connected in series with the seventeenth resistor R17 and then connected to the second pin U6_2 of the control chip U6.

[0032] Among them, after the control chip U6 obtains the voltage detection signal, the control chip U6 outputs the corresponding control signal to the first connection end of the fifth photocoupler U5 to control the rectification mode of the rectification circuit 12. The one-way thyristor SCR1 is in a non-conducting state by default (the hair dryer is not connected to the mains at this time). After connecting to the mains, the control chip U6 first determines whether the AC voltage of the voltage detection signal is between 90V and 135V. If the AC voltage of the voltage detection signal is lower than 90V, the control chip U6 sends a control signal and drives the one-way thyristor SCR1 through the fifth photocoupler U5 to conduct when the AC phase is 1°-180°; at this time, the rectification circuit 12 is changed to half-wave voltage doubling rectification. In the half-wave voltage doubling rectification mode, it is further determined whether the AC voltage of the voltage detection signal is still lower than 90V. If it is lower, a low voltage and undervoltage alarm message is issued and the hair dryer is not started. In the half-wave voltage doubler rectification mode, if the AC voltage is between 90-135V, the current mains voltage (input voltage of the AC phase line) is determined to be 110V or 120V, and the hair dryer is controlled to start normally. In the half-wave voltage doubler rectification mode, if the AC voltage is higher than 135V, the control chip U6 sends a control signal and drives the unidirectional thyristor SCR1 to disconnect through the fifth photocoupler U5. At this time, the rectification circuit 12 changes to full-wave rectification; at the same time, an overvoltage alarm message is issued, and the hair dryer is not started.

[0033] When the unidirectional thyristor SCR1 is in the non-conducting state, the rectifier circuit 12 is in full-wave rectification mode, and can determine whether the AC voltage is between 90-135V. If the AC voltage is lower than 90V, repeat the above steps; the rectifier circuit 12 is in full-wave rectification mode. If the AC voltage is between 90-135V, the AC voltage is determined to be 220V, and the hair dryer is controlled to start normally; the rectifier circuit 12 is in full-wave rectification mode. If the AC voltage is higher than 140V, an overvoltage alarm message is issued and the hair dryer is not started.

[0034] Through the above method, while ensuring the safety of the hair dryer, the rectification mode of the rectifier circuit 12 can be adaptively controlled according to the AC voltage through the control chip, so that the hair dryer can adaptively operate under the mains voltage of 110V, 120V or 220V, that is, the hair dryer can be adapted for use with various specifications of AC mains.

[0035] In a specific embodiment, Figure 4As shown, the heating control circuit includes an eleventh photocoupler U11, a twelfth photocoupler U12, a thirteenth photocoupler U13, a first heating bidirectional thyristor HSCR1, a second heating bidirectional thyristor HSCR2, a third heating bidirectional thyristor HSCR3, a first heating resistor R63 and a second heating resistor R62; the first connection end of the eleventh photocoupler U11 is grounded, the second connection end is connected to one end of the sixtieth resistor R60, and the other end of the sixtieth resistor R60 serves as the second control end of the heating control circuit; the third connection end of the eleventh photocoupler U11 is connected in series with the sixty-fourth resistor R64 and then connected to the first connection end of the second heating bidirectional thyristor HSCR2. end and the first connection end of the third heating bidirectional thyristor HSCR3; the fourth connection end of the eleventh photocoupler is connected in series with the sixty-third resistor R63 and then connected to the control connection end of the second heating bidirectional thyristor HSCR2; one end of the first heating resistor R63 and the second connection end of the third heating bidirectional thyristor HSCR3 are connected, and the connection point serves as the first power supply end of the heating control circuit; the other end of the first heating resistor R63 is connected to the second connection end of the second heating bidirectional thyristor HSCR2 and the first connection end of the first heating bidirectional thyristor HSCR1; one end of the second heating resistor R62 is connected to the first connection end of the third heating bidirectional thyristor HSCR3 end, the other end of the second heating resistor R62 is connected to the second connection end of the first heating bidirectional thyristor HSCR1 and one end of the fifty-ninth resistor R59, and the connection point serves as the second power supply end of the heating control circuit; a fifty-eighth resistor R58 is arranged in series between the fourth connection end of the twelfth photocoupler U12 and the control connection end of the first heating bidirectional thyristor HSCR1; the fifty-ninth resistor R59 is arranged in series between the third connection end of the twelfth photocoupler U12 and the second connection end of the first heating bidirectional thyristor HSCR1; a sixty-first resistor R is arranged in series between the first connection end of the twelfth photocoupler U12 and the voltage stabilizing input end of the heating control circuit. 61, the second connection end of the twelfth photocoupler U12 serves as the first control end of the heating control circuit; a sixty-fifth resistor R65 is connected in series between the third connection end of the thirteenth photocoupler U13 and the control connection end of the third heating bidirectional thyristor HSCR3, a sixty-sixth resistor R66 is connected in series between the fourth connection end of the thirteenth photocoupler U13 and the second connection end of the third heating bidirectional thyristor HSCR3, a sixty-seventh resistor R67 is connected in series between the first connection end of the thirteenth photocoupler U13 and the voltage stabilizing input end of the heating control circuit, and the second connection end of the thirteenth photocoupler U13 serves as the third control end of the heating control circuit.

[0036] Specifically, when the unidirectional thyristor SCR1 is in the non-conducting state by default, the rectifier circuit 12 is in the full-wave rectifier mode, and the control chip issues corresponding control instructions to control the first heating bidirectional thyristor HSCR1 and the third heating bidirectional thyristor HSCR3 to be disabled, and control the second heating bidirectional thyristor HSCR2 to be enabled, at which time the first heating resistor R63 and the second heating resistor R62 are connected in series. When the unidirectional thyristor SCR1 is in the conducting state at 1°-180°, the rectifier circuit 12 is in the half-wave voltage doubling rectifier mode, and the control chip issues corresponding control instructions to control the second heating bidirectional thyristor HSCR2 to be disabled, and control the first heating bidirectional thyristor HSCR1 and the third heating bidirectional thyristor HSCR3 to be enabled, and at this time the heating wires become connected in parallel.

[0037] When the unidirectional thyristor SCR1 is in the on state at 1°-180°, the rectifier circuit 12 is in the half-wave voltage doubler rectification mode, and the AC voltage is higher than 135V, the control chip sends a corresponding control instruction to control the unidirectional thyristor SCR1 to disconnect, and sends an overvoltage alarm message at the same time. At this time, the control chip also sends a control instruction to control the first heating bidirectional thyristor HSCR1, the second heating bidirectional thyristor HSCR2 and the third heating bidirectional thyristor HSCR3 to be disabled, and the heating wire does not work at this time to ensure the safety of the hair dryer.

[0038] Specifically, the voltage detection circuit includes a twenty-second resistor R22, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-ninth resistor R29 and a seventeenth capacitor C17; one end of the twenty-fifth resistor R25 is connected to one end of the twenty-sixth resistor R26 and one end of the twenty-ninth resistor R29, the twenty-second resistor R22 is arranged in series between the other end of the twenty-fifth resistor R25 and the detection input end of the voltage detection circuit, the other end of the twenty-ninth resistor R29 and one end of the seventeenth capacitor C17 are grounded, the other end of the seventeenth capacitor C17 is connected to the other end of the twenty-sixth resistor R26, and the connection point serves as the detection output end of the voltage detection circuit.

[0039] In order to accurately detect the voltage, a voltage detection circuit can be set to consist of a twenty-second resistor R22, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-ninth resistor R29 and a seventeenth capacitor C17. The specific circuit structure is as follows: Figure 2 shown.

[0040] In a specific embodiment, Figure 1As shown, the voltage conversion circuit 11 also includes a fuse F1, which is arranged in series between the first input terminal of the voltage conversion circuit 11 and the AC phase line. Specifically, the voltage conversion circuit 11 also includes a thermistor ZNR1 and an isolation capacitor CX1, the thermistor ZNR1 is arranged in series between the first input terminal and the second input terminal of the voltage conversion circuit 11; the isolation capacitor CX1 is arranged in parallel at both ends of the thermistor ZNR1. The voltage conversion circuit 11 also includes a potentiometer TR1, which is arranged in series between the second connection terminal of the voltage transformer L2 and the second input terminal of the voltage conversion circuit 11.

[0041] In order to improve the safety of the adaptive control circuit, a fuse F1 may be connected in series between the first input terminal of the voltage conversion circuit 11 and the AC phase line, and the circuit is protected from overcurrent by the fuse F1. In order to further improve the safety of the adaptive control circuit, a thermistor ZNR1 and an isolation capacitor CX1 may be provided, and the isolation performance between the first input terminal and the second input terminal of the voltage conversion circuit 11 may be improved by the isolation capacitor CX1, and overheat protection may be performed by the thermistor ZNR1.

[0042] A potentiometer TR1 may also be provided in the voltage conversion circuit 11 to further improve the safety of the adaptive control circuit.

[0043] In a specific embodiment, Figure 1 As shown, the voltage conversion circuit 11 also includes a control switch SW1; the first connection end of the control switch SW1 is connected to the AC phase power, the second connection end of the control switch SW1 is connected to one end of the fuse F1; the third connection end of the control switch SW1 is connected to the gear detection circuit as a gear detection connection end; Figure 6As shown, the gear detection circuit includes a fifteenth resistor R15, a first resistor R1, a fourth photocoupler U4, a tenth resistor R10, a twelfth resistor R12 and a first capacitor C1; one end of the fifteenth resistor R15 is connected to the gear detection connection end, and the first resistor R1 is arranged in series between the other end of the fifteenth resistor R15 and the first connection end of the fourth photocoupler U4; the second connection end of the fourth photocoupler U4 is connected to the second input end of the voltage conversion circuit 11, the third connection end of the fourth photocoupler U4 is grounded, and the fourth connection end of the fourth photocoupler U4 is connected to one end of the twelfth resistor R12 and one end of the tenth resistor R10; the other end of the tenth resistor R10 is connected to one end of the first capacitor C1, and the connection point is connected to the thirteenth pin U6_13 of the control chip U6 as the gear signal output end; the other end of the first capacitor C1 is grounded; the other end of the twelfth resistor R12 is connected to the low-voltage power supply end.

[0044] The gear detection circuit can detect the current gear position of the hair dryer and output the detection signal to the control chip. Among them, the adaptive control circuit also includes an indicator light circuit, such as Fig. 9 As shown, the indicator light circuit specifically includes a fifth resistor R5, a sixth resistor R6, an eighth resistor R8, a first LED lamp LED1, a second LED lamp LED2 and a third LED lamp LED3, wherein one end of the fifth resistor, one end of the sixth resistor and one end of the seventh resistor are connected, and the connection point is connected to the low-voltage power supply end of the power supply circuit, the other end of the fifth resistor is connected to the positive electrode of the first LED lamp, the other end of the sixth resistor is connected to the positive electrode of the second LED lamp, the other end of the eighth resistor is connected to the positive electrode of the third LED lamp, the negative electrode of the first LED lamp is connected to the third pin U6_3 of the control chip U6, the negative electrode of the second LED lamp is connected to the fourth pin U6_4 of the control chip U6, and the negative electrode of the third LED lamp is connected to the fifth pin U6_5 of the control chip U6. Among them, the first LED lamp, the second LED lamp and the third LED lamp correspond to the three gears of high, medium and low respectively, and the control chip obtains the detection signal obtained by the gear detection circuit to detect the gear, and outputs the corresponding control instruction to control the corresponding LED lamp to be turned on (the other two LED lamps are turned off), so as to realize the control of the indicator light circuit by the control chip to display the corresponding gear information.

[0045] Specifically, Figure 5As shown, the adaptive control circuit also includes a zero-crossing detection circuit; the zero-crossing detection circuit includes a sixteenth resistor R16, an eleventh resistor R11, a third photocoupler U3, a seventh resistor R7, a thirteenth resistor R13 and a seventh capacitor C7; the first connection end of the third photocoupler U3 is connected to the second input end of the voltage conversion circuit 11, and the eleventh resistor R11 is arranged in series between the second connection end of the third photocoupler U3 and one end of the sixteenth resistor R16; the other end of the sixteenth resistor R16 is connected to the first input end of the voltage conversion circuit 11; the third connection end of the third photocoupler U3 is grounded, and the fourth connection end of the third photocoupler U3 is connected to one end of the seventh resistor R7 and one end of the thirteenth resistor R13; the other end of the thirteenth resistor R13 is connected to one end of the seventh capacitor C7, and the connection point is connected to the fourteenth pin U6_14 of the control chip U6 as a zero-crossing signal output end; the other end of the seventh resistor R7 is connected to the low-voltage power supply end, and the other end of the seventh capacitor C7 is grounded.

[0046] The third photocoupler U3 can detect the AC frequency of the AC phase line, and send the detected frequency information to the control chip from the fourth connection end of the third photocoupler U3. The control chip controls the on-off switching frequency of the unidirectional thyristor SCR1 according to the acquired frequency information, that is, when it is necessary to control the unidirectional thyristor SCR1 to be turned on at the AC phase of 1°-180° (disconnected at 180° to 360°), the switching frequency of the on-off of the unidirectional thyristor SCR1 needs to be controlled to be consistent with the frequency information. For example, if the detected AC frequency is 50Hz, the on-off switching frequency of the unidirectional thyristor SCR1 needs to be controlled to be 50Hz and correspond to the AC phase of 1°-180° when it is turned on. If the detected AC frequency is 60Hz, the on-off switching frequency of the unidirectional thyristor SCR1 needs to be controlled to be 60Hz and correspond to the AC phase of 1°-180° when it is turned on.

[0047] In a specific embodiment, Figure 2 As shown, the adaptive control circuit also includes a key circuit, which includes a fourteenth resistor R14, a ninth resistor R9, a tenth capacitor C10 and a switch button S2; the second connection end of the switch button S2 is grounded, and the first connection end of the switch button S2 is connected to one end of the ninth resistor R9, one end of the fourteenth resistor R14 and one end of the tenth capacitor C10; the other end of the tenth capacitor C10 is grounded, the other end of the ninth resistor R9 is connected to the low-voltage power supply end, and the other end of the fourteenth resistor R14 is connected to the fifteenth pin U6_15 of the control chip U6 as a key signal input end. Figure 8As shown, the power supply circuit includes a first power supply conversion chip U1, a second power supply conversion chip U2, a third diode D3, a fourth diode D4, a first diode D1, a third capacitor C3, a first inductor L1 and a fourth resistor R4; the input pin of the first power supply conversion chip U1 serves as the power supply input end of the power supply circuit, and the output pin of the first power supply conversion chip U1 serves as the voltage-stabilizing output end of the power supply circuit and is simultaneously connected to one end of the third capacitor C3 and the cathode of the third diode D3; the other end of the third capacitor C3 is connected to the first pin U1 of the first power supply conversion chip U1 _1, the cathode of the first diode D1 and one end of the first inductor L1, the anode of the first diode D1 is grounded; the other end of the first inductor L1 is connected to the cathode of the fourth diode D4 and one end of the fourth resistor R4, and the connection point serves as the high-voltage power supply end of the power supply circuit; the anode of the third diode D3 is connected to the anode of the fourth diode D4; the other end of the fourth resistor R4 is connected to the input end (U2_3) of the second power supply conversion chip U2, and the output end (U2_1) of the second power supply conversion chip U2 serves as the low-voltage power supply end of the power supply circuit.

[0048] The user can press the switch button S2 to input a corresponding key signal, and the control chip U6 can receive the key signal input by the user and perform switch control and gear control on the hair dryer.

[0049] The low voltage power supply end of the power supply circuit is also the +5V power supply end, the high voltage power supply end of the power supply circuit is also the +15V power supply end, and the voltage stabilizing output end of the power supply circuit is also the VCC output end (the fourth pin U1_4 of the first power supply conversion chip U1). The input pins of the first power supply conversion chip U1 include the fifth pin U1_5, the sixth pin U1_6, the seventh pin U1_7 and the eighth pin U1_8 of the first power supply conversion chip U1.

[0050] The adaptive control circuit for AC variable voltage provided in the embodiment of the utility model includes a voltage conversion circuit, a voltage detection circuit, a rectifier circuit, a power supply circuit, a control chip and a heating control circuit; the first input end of the voltage conversion circuit is connected to the AC phase line, and the second input end is connected to the AC neutral line and the first connection end and the second connection end of the heating control circuit; the first conversion output end of the voltage conversion circuit is connected to the detection input end of the voltage detection circuit and the power supply input end of the power supply circuit, and the second conversion output end of the voltage conversion circuit is grounded; the detection output end of the voltage detection circuit is connected to the sixth pin of the control chip. The above-mentioned adaptive control circuit for AC variable voltage detects the AC voltage through the voltage detection circuit, and controls the unidirectional thyristor of the rectifier circuit and the bidirectional thyristor of the heating control circuit through the control chip, so that the hair dryer can be adapted for use with AC mains of various specifications.

[0051] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An adaptive control circuit for AC variable voltage, characterized in that: The adaptive control circuit includes a voltage conversion circuit, a voltage detection circuit, a rectification circuit, a power supply circuit, a control chip and a heating control circuit; The first input end of the voltage conversion circuit is connected to the AC phase line, and the second input end is connected to the AC neutral line and the first connection end and the second connection end of the heating control circuit; The first conversion output terminal of the voltage conversion circuit is connected to the detection input terminal of the voltage detection circuit and the power supply input terminal of the power supply circuit, and the second conversion output terminal of the voltage conversion circuit is grounded; The detection output end of the voltage detection circuit is connected to the sixth pin of the control chip; The voltage-stabilizing output terminal of the power supply circuit is connected to the voltage-stabilizing input terminal of the heating control circuit; the first power supply terminal of the heating control circuit is connected to the first input terminal of the voltage conversion circuit, the second power supply terminal of the heating control circuit is connected to the second input terminal of the voltage conversion circuit, and the first control terminal, the second control terminal and the third control terminal of the heating control circuit are respectively connected to the seventh pin, the eighth pin and the ninth pin of the control chip; The rectifier circuit includes a unidirectional thyristor, a fifth photocoupler, a third resistor, a seventeenth resistor and an eighteenth resistor; The voltage conversion circuit includes a voltage transformer, a bridge rectifier, a first polarity capacitor and a third polarity capacitor; the two ends of the primary side of the voltage transformer are respectively connected to the AC neutral line and the fourth connection end of the bridge rectifier; the two ends of the secondary side of the voltage transformer are respectively connected to the first input end of the voltage conversion circuit and the third connection end of the bridge rectifier; the first connection end of the bridge rectifier is connected to the positive electrode of the first polarity capacitor, and the connection point serves as the first conversion output end of the voltage conversion circuit; the second connection end of the bridge rectifier is connected to the negative electrode of the third polarity capacitor, and the connection point serves as the second conversion output end of the voltage conversion circuit; the negative electrode of the first polarity capacitor is connected to the positive electrode of the third polarity capacitor, and the connection point is connected to the second connection end of the unidirectional thyristor and one end of the third resistor; The third connection end of the bridge rectifier is also connected to the first connection end of the unidirectional thyristor; the control connection end of the unidirectional thyristor is connected to one end of the eighteenth resistor; the other end of the third resistor is connected to the fourth connection end of the fifth photocoupler, the other end of the eighteenth resistor is connected to the third connection end of the fifth photocoupler, the second connection end of the fifth photocoupler is grounded, and the first connection end of the fifth photocoupler is connected in series with the seventeenth resistor and then connected to the second pin of the control chip.

2. The adaptive control circuit for AC variable voltage according to claim 1, characterized in that: The heating control circuit includes an eleventh photocoupler, a twelfth photocoupler, a thirteenth photocoupler, a first heating bidirectional thyristor, a second heating bidirectional thyristor, a third heating bidirectional thyristor, a first heating resistor and a second heating resistor; The first connection end of the eleventh photoelectric coupler is grounded, and the second connection end is connected to one end of a sixtieth resistor, and the other end of the sixtieth resistor serves as the second control end of the heating control circuit; The third connection end of the eleventh photocoupler is connected in series with the sixty-fourth resistor and then connected to the first connection end of the second heating bidirectional thyristor and the first connection end of the third heating bidirectional thyristor; the fourth connection end of the eleventh photocoupler is connected in series with the sixty-third resistor and then connected to the control connection end of the second heating bidirectional thyristor; One end of the first heating resistor and the second connection end of the third heating bidirectional thyristor are connected, and the connection point serves as the first power supply end of the heating control circuit; the other end of the first heating resistor is connected to the second connection end of the second heating bidirectional thyristor and the first connection end of the first heating bidirectional thyristor; One end of the second heating resistor is connected to the first connection end of the third heating bidirectional thyristor, and the other end of the second heating resistor is connected to the second connection end of the first heating bidirectional thyristor and one end of the fifty-ninth resistor, and the connection point serves as the second power supply end of the heating control circuit; A fifty-eighth resistor is arranged in series between the fourth connection end of the twelfth photocoupler and the control connection end of the first heating bidirectional thyristor; a fifty-ninth resistor is arranged in series between the third connection end of the twelfth photocoupler and the second connection end of the first heating bidirectional thyristor; a sixty-first resistor is arranged in series between the first connection end of the twelfth photocoupler and the voltage stabilizing input end of the heating control circuit, and the second connection end of the twelfth photocoupler serves as the first control end of the heating control circuit; A sixty-fifth resistor is arranged in series between the third connection terminal of the thirteenth photocoupler and the control connection terminal of the third heating bidirectional thyristor, a sixty-sixth resistor is arranged in series between the fourth connection terminal of the thirteenth photocoupler and the second connection terminal of the third heating bidirectional thyristor, a sixty-seventh resistor is arranged in series between the first connection terminal of the thirteenth photocoupler and the voltage stabilizing input terminal of the heating control circuit, and the second connection terminal of the thirteenth photocoupler serves as the third control terminal of the heating control circuit.

3. The adaptive control circuit for AC variable voltage according to claim 2, characterized in that: The voltage detection circuit includes a twenty-second resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-ninth resistor and a seventeenth capacitor; One end of the twenty-fifth resistor is connected to one end of the twenty-sixth resistor and one end of the twenty-ninth resistor, the twenty-second resistor is connected in series between the other end of the twenty-fifth resistor and the detection input terminal of the voltage detection circuit, the other end of the twenty-ninth resistor and one end of the seventeenth capacitor are grounded, the other end of the seventeenth capacitor is connected to the other end of the twenty-sixth resistor, and the connection point serves as the detection output terminal of the voltage detection circuit.

4. The adaptive control circuit for AC variable voltage according to any one of claims 1 to 3, characterized in that: The voltage conversion circuit also includes a fuse, which is arranged in series between the first input end of the voltage conversion circuit and the AC phase line.

5. The adaptive control circuit for AC variable voltage according to claim 4, characterized in that: The voltage conversion circuit also includes a thermistor and an isolation capacitor. The thermistor is arranged in series between the first input terminal and the second input terminal of the voltage conversion circuit; and the isolation capacitor is arranged in parallel at both ends of the thermistor.

6. The adaptive control circuit for AC variable voltage according to claim 5, characterized in that: The voltage conversion circuit further includes a potentiometer, which is arranged in series between the second connection end of the voltage transformer and the second input end of the voltage conversion circuit.

7. The adaptive control circuit for AC variable voltage according to claim 4, characterized in that: The voltage conversion circuit also includes a control switch; a first connection end of the control switch is connected to the AC phase power, and a second connection end of the control switch is connected to one end of the fuse; a third connection end of the control switch is connected to the gear detection circuit as a gear detection connection end; The gear detection circuit includes a fifteenth resistor, a first resistor, a fourth photocoupler, a tenth resistor, a twelfth resistor and a first capacitor; One end of the fifteenth resistor is connected to the gear detection connection end, and the first resistor is arranged in series between the other end of the fifteenth resistor and the first connection end of the fourth photoelectric coupler; the second connection end of the fourth photoelectric coupler is connected to the second input end of the voltage conversion circuit, the third connection end of the fourth photoelectric coupler is grounded, and the fourth connection end of the fourth photoelectric coupler is connected to one end of the twelfth resistor and one end of the tenth resistor; the other end of the tenth resistor is connected to one end of the first capacitor, and the connection point is connected to the thirteenth pin of the control chip as the gear signal output end; the other end of the first capacitor is grounded; the other end of the twelfth resistor is connected to the low-voltage power supply end.

8. The adaptive control circuit for AC variable voltage according to claim 7, characterized in that: The adaptive control circuit also includes a zero-crossing detection circuit; The zero-crossing detection circuit includes a sixteenth resistor, an eleventh resistor, a third photocoupler, a seventh resistor, a thirteenth resistor and a seventh capacitor; The first connection end of the third photoelectric coupler is connected to the second input end of the voltage conversion circuit, the eleventh resistor is arranged in series between the second connection end of the third photoelectric coupler and one end of the sixteenth resistor; the other end of the sixteenth resistor is connected to the first input end of the voltage conversion circuit; The third connection end of the third photoelectric coupler is grounded, and the fourth connection end of the third photoelectric coupler is connected to one end of the seventh resistor and one end of the thirteenth resistor; the other end of the thirteenth resistor is connected to one end of the seventh capacitor, and the connection point is connected to the fourteenth pin of the control chip as a zero-crossing signal output end; the other end of the seventh resistor is connected to the low-voltage power supply end, and the other end of the seventh capacitor is grounded.

9. The adaptive control circuit for AC variable voltage according to claim 8, characterized in that: The adaptive control circuit further includes a key circuit, and the key circuit includes a fourteenth resistor, a ninth resistor, a tenth capacitor and a switch key; The second connection end of the switch button is grounded, the first connection end of the switch button is connected to one end of the ninth resistor, one end of the fourteenth resistor and one end of the tenth capacitor; the other end of the tenth capacitor is grounded, the other end of the ninth resistor is connected to the low-voltage power supply end, and the other end of the fourteenth resistor is connected to the fifteenth pin of the control chip as a key signal input end.

10. The adaptive control circuit for AC variable voltage according to claim 8, characterized in that: The power supply circuit includes a first power supply conversion chip, a second power supply conversion chip, a third diode, a fourth diode, a first diode, a third capacitor, a first inductor and a fourth resistor; The input pin of the first power supply conversion chip serves as the power supply input end of the power supply circuit, and the output pin of the first power supply conversion chip serves as the voltage-stabilizing output end of the power supply circuit and is simultaneously connected to one end of the third capacitor and the cathode of the third diode; the other end of the third capacitor is connected to the first pin of the first power supply conversion chip, the cathode of the first diode and one end of the first inductor, and the anode of the first diode is grounded; The other end of the first inductor is connected to the cathode of the fourth diode and one end of the fourth resistor, and the connection point serves as the high-voltage power supply end of the power supply circuit; the anode of the third diode is connected to the anode of the fourth diode; The other end of the fourth resistor is connected to the input end of the second power supply conversion chip, and the output end of the second power supply conversion chip serves as a low-voltage power supply end of the power supply circuit.

Images