A wide voltage input dryer control circuit and a dryer

Abstract

The application discloses a wide-voltage-input dryer control circuit, comprising a wide-voltage-input circuit, an isolated DC-DC module, a control module, a constant-temperature heating circuit and a plurality of function modules. The wide-voltage-input circuit is provided with a rectifier circuit, which converts AC power of different voltages into DC power, and then a PFC voltage-boosting circuit is used to boost the DC power into high-voltage DC power, so that the voltage output by the PFC can realize stable power output under grid fluctuation; then the isolated DC-DC module is used to convert the high-voltage DC power into stable low-voltage DC power output, and the low-voltage DC power is used to supply power to each function module of the dryer, so that the dryer can normally work under different input voltages.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a dryer control circuit and a dryer with a wide voltage input. Background Technology

[0002] Dryers dry objects by outputting hot air to accelerate the evaporation of moisture. Due to their small size, portability, and high drying efficiency, they are popular all over the world.

[0003] Because different countries / regions use different voltage standards, dryer manufacturers need to manufacture different control circuit boards according to different national voltage standards when manufacturing dryers. The variety of circuit boards with different input voltages requires companies to invest more in research and development. Furthermore, the increase in product categories due to different voltages leads to the accumulation of more inventory, thereby increasing business risks. Utility Model Content

[0004] This utility model provides a dryer control circuit and dryer with a wide voltage input, in order to solve the technical problem that the control circuit of current dryers cannot adapt to different voltage inputs.

[0005] To achieve the above objectives, this utility model provides a wide voltage input control circuit for a dryer, comprising: a wide voltage input circuit, including an input rectifier circuit and a PFC boost circuit, wherein the input rectifier circuit is connected to AC mains power, rectifies the AC mains power into DC power, and outputs it to the PFC boost circuit, which converts the rectified AC mains power into high-voltage DC power; an isolated DC-DC module, the input terminal of which is connected to the PFC boost circuit, which converts the high-voltage DC power into low-voltage DC power for output; a control module, which is electrically connected to the isolated DC-DC module and powered by the low-voltage DC power; a constant temperature heating circuit, the power supply terminal of which is connected to the AC mains power, and the control terminal of which is connected to the control module; and several functional modules, the power supply terminals of which are connected to the isolated DC-DC module, and the control terminals of which are connected to the control module.

[0006] Preferably, the PFC boost circuit includes a PFC controller, a first MOSFET, a first inductor, and a first capacitor. The input terminal of the first inductor is connected to the output terminal of the input rectifier circuit. The output terminal of the first inductor is connected to one end of the first capacitor, the drain of the first MOSFET, and the power supply terminal of the PFC controller. The other end of the first capacitor is grounded. The source of the first MOSFET is grounded. The gate of the first MOSFET is connected to the GATE port of the PFC controller.

[0007] Preferably, the PFC controller U10 is configured in critical conduction mode, and the duty cycle adjustment formula for the control signal output by its GATE port is:

[0008] D = 1 - V in_pk / VBUS (1)

[0009] Where D is the duty cycle, V in_pk V is the peak voltage of the output voltage of the input rectifier circuit. BUS This is the high-voltage DC output of the PFC boost circuit.

[0010] Preferably, the isolated DC-DC module includes a transformer, a rectifier drive controller, a second MOSFET, a first resistor, a second capacitor, and a third capacitor. The two ends of the primary side of the transformer are respectively connected to the first inductor and the drain of the second MOSFET. One end of the secondary side of the transformer is grounded, and the other end is connected to the source. The drain of the second MOSFET is connected to one end of the third capacitor and outputs a first low-voltage DC current. The other end of the third capacitor is grounded. The gate of the second MOSFET is connected to the control terminal of the rectifier drive controller. The first and sixth ports of the rectifier drive controller are connected to the drain of the second MOSFET. The second port of the rectifier drive controller is connected to the drain of the second MOSFET. The third port of the rectifier drive controller is connected to the drain of the second MOSFET through the first resistor. The fourth port of the rectifier drive controller is connected to the drain of the second MOSFET through the second capacitor.

[0011] Preferably, the isolated DC-DC module further includes a linear regulator, the input terminal of which is connected to the drain of the second MOSFET, the ground terminal of which is grounded, and the output terminal of which outputs a +5V VCC voltage.

[0012] Preferably, the constant temperature heating circuit includes a first thyristor, a first optocoupler, and a second resistor. The input terminal of the light-emitting end of the first optocoupler is connected to the control module, the output terminal of the light-emitting end of the first optocoupler is grounded, the input terminal of the light-receiving end of the first optocoupler is connected to the input terminal of the first thyristor and the mains power line after passing through the second resistor, the output terminal of the light-receiving end of the first optocoupler is connected to the control terminal of the first thyristor, the output terminal of the first thyristor is connected to the first terminal of the heating element socket, and the second terminal of the heating element socket is connected to the mains neutral line.

[0013] Preferably, the constant temperature heating circuit further includes a temperature fuse and a temperature switch connected in series, the input terminal of the temperature fuse is connected to the second terminal of the heating element socket, and the output terminal of the temperature switch is connected to the neutral wire of the mains power.

[0014] Preferably, the functional module includes a fan control circuit, an ozone generator control circuit, and an ultraviolet light control circuit.

[0015] Preferably, the dryer control circuit further includes a zero-crossing detection circuit, which includes a third resistor, a second optocoupler, and a pull-up resistor. The input terminal of the light-emitting end of the second optocoupler is connected to the mains live wire after passing through the third resistor. The output terminal of the light-emitting end of the second optocoupler is connected to the mains neutral wire. The input terminal of the light-receiving end of the second optocoupler is connected to the first terminal of the pull-up resistor and the zero-crossing detection port OVERZERO_DET of the control module. The second terminal of the pull-up resistor is connected to the +5V VCC power supply.

[0016] On the other hand, this application also provides a dryer, including a dryer body and a dryer control circuit as described above disposed in the dryer body.

[0017] The present invention provides the following advantages: A dryer control circuit with a wide voltage input capability converts AC power input at different voltages into DC power through a rectifier circuit, then boosts the DC power to high voltage DC power through a PFC boost circuit, and finally converts the high voltage DC power into low voltage DC power output through an isolated DC-DC module. The low voltage DC power is then used to supply power to the various functional modules of the dryer, enabling the dryer to operate normally under different input voltages, thus reducing the manufacturer's R&D design costs and inventory risks.

[0018] In addition to the objectives, features, and advantages described above, the embodiments of this utility model have other objectives, features, and advantages. The embodiments of this utility model will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the embodiments of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the system structure of the wide voltage input dryer control circuit of this utility model;

[0021] Figure 2 This is a schematic diagram of the input rectifier circuit of the wide voltage input dryer control circuit of this utility model.

[0022] Figure 3 This is a schematic diagram of the circuit structure of the PFC boost circuit and the isolated DC-DC module of the wide voltage input dryer control circuit of this utility model.

[0023] Figure 4 This is a schematic diagram of the constant temperature heating circuit of the dryer control circuit with wide voltage input according to this utility model.

[0024] Figure 5 This is a schematic diagram of the circuit structure of the control module of the wide voltage input dryer control circuit of this utility model;

[0025] Figure 6 This is a schematic diagram of the zero-crossing detection circuit of the wide voltage input dryer control circuit of this utility model.

[0026] Figure 7 This is a schematic diagram of the fan control circuit of the wide voltage input dryer control circuit of this utility model;

[0027] Figure 8 This is a schematic diagram of the ozone generator control circuit of the wide voltage input dryer control circuit of this utility model.

[0028] Figure 9 This is a schematic diagram of the ultraviolet light control circuit of the wide voltage input dryer control circuit of this utility model.

[0029] Figure 10 This is a schematic diagram of the mains voltage detection circuit of the wide voltage input dryer control circuit of this utility model.

[0030] The attached diagram is labeled as follows: 100, wide voltage input circuit; 110, input rectifier circuit; 120, PFC boost circuit; 200, isolated DC-DC module; 300, control module; 400, constant temperature heating circuit; 500, functional module; 510, fan control circuit; 520, ozone generator control circuit; 530, ultraviolet light control circuit; 600, zero-crossing detection circuit. Detailed Implementation

[0031] The technical solutions of the present utility model embodiments are further described in detail below with reference to the accompanying drawings and specific examples. Furthermore, unless otherwise defined, the technical or scientific terms used in this application description should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. Terms indicating orientation, such as "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," used in this application description are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. Terms such as "first," "second," "third," and similar terms used in this application description are only used for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. Terms such as "a," "one," or "the," used in this application description, should not be construed as an absolute limitation on quantity, but should be understood as indicating the existence of at least one. The use of terms such as "including" or "comprising" in the description of this application means that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0032] It should also be noted that, unless otherwise explicitly specified and limited, the terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also refer to the internal connection of two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0033] like Figures 1 to 5As shown, the wide voltage input dryer control circuit of this embodiment includes: a wide voltage input circuit 100, including an input rectifier circuit 110 and a PFC boost circuit 120. The input rectifier circuit 110 is connected to the mains power, rectifies the mains power into DC power, and outputs it to the PFC boost circuit 120. The PFC boost circuit 120 converts the rectified mains power into high voltage DC power; and an isolated DC-DC module 200, the input terminal of which is connected to the PFC boost circuit 120. Module C 200 is used to convert high-voltage DC power into low-voltage DC power output; control module 300 is electrically connected to isolated DC-DC module 200 and is powered by low-voltage DC power; constant temperature heating circuit 400 is connected to AC power at its power supply terminal and connected to control module 300 at its control terminal; and several functional modules 500 are connected to isolated DC-DC module 200 at their power supply terminal and connected to control module 300 at their control terminal.

[0034] Among them, such as Figure 2 As shown, the input rectifier circuit 110 includes a fuse FUSE connected in series with the live wire for overcurrent protection, and a capacitor CX1 and a resistor R6 connected in parallel between the live wire and the neutral wire, forming an RC filter. It should be noted that AC220L and AC220N in the figure are design reference nominal values, representing that when the input is 220VAC mains power, the voltage at this point is approximately 220VAC. The actual voltage of AC220L should be consistent with the mains power. It also includes a rectifier module U7, which can be a general-purpose rectifier bridge. The first interface of the rectifier module U7 is connected to the live wire of the mains power, the second interface is connected to the neutral wire of the mains power, the third interface is grounded, and the fourth interface outputs the rectified DC power.

[0035] Specifically, in this embodiment, the control module 300 is an MCU chip, which has logic operation functions and multiple I / O interfaces. It can output high / low levels through the I / O interfaces. In other embodiments, the control module 300 can also be a DSP, FPGA, CPU or other control chips.

[0036] The wide voltage input dryer control circuit of this embodiment converts AC power of different input voltages into DC power through a rectifier circuit, then boosts the DC power to high voltage DC power through a PFC boost circuit, and then converts the high voltage DC power into low voltage DC power output through an isolated DC-DC module. The low voltage DC power supplies power to the various functional modules of the dryer, enabling the dryer to work normally under different input voltages, reducing the manufacturer's R&D design costs and inventory risks.

[0037] In some embodiments, such as Figure 3As shown, the PFC boost circuit 120 includes a PFC controller U10, a first MOSFET Q32, a first inductor L4, and a first capacitor EC1. The input terminal of the first inductor L4 is connected to the output terminal of the input rectifier circuit 110. The output terminal of the first inductor L4 is connected to one end of the first capacitor EC1, the drain of the first MOSFET Q32, and the power supply terminal of the PFC controller U10. The other end of the first capacitor EC1 is grounded. The source of the first MOSFET Q32 is grounded. The gate of the first MOSFET Q32 is connected to the GATE port of the PFC controller U10.

[0038] Specifically, in this embodiment, the PFC controller U10 is configured in critical conduction mode, and the duty cycle adjustment formula of the control signal output by its GATE port is: D = 1 - Vin_pk / VBUS, where D is the duty cycle, Vin_pk is the peak voltage of the output voltage of the input rectifier circuit 110, and VBUS is the high voltage DC output by the PFC boost circuit 120.

[0039] When the PFC controller U10 controls the first MOSFET Q32 to turn on through the GATE port, the rectifier module U4 rectifies the mains power into pulsating DC and inputs it into the first inductor L4. The first inductor L4 stores energy and keeps the first capacitor EC1 output. When the PFC controller U10 controls the first MOSFET Q32 to turn off through the GATE port, the first inductor L4 releases energy, and after being superimposed on the input voltage, it charges the first capacitor EC1. Its output voltage Vout = Vin / (1-D), where Vin is the input voltage, that is, the voltage input to the first inductor L4 after rectification. By setting the duty cycle of the PFC controller U10 through the GATE port, the PFC boost circuit 120 can stably output a 310V voltage. Its output voltage is minimally affected by the power grid fluctuations and can convert all mains power inputs of different voltages into the same voltage, realizing a wide voltage input range.

[0040] Specifically, the PFC controller U10 in this embodiment uses a KP2212LGA chip. Its power supply is obtained by rectified pulsating DC through the first inductor L4, resistor R76, resistor R77 and diode D2. The first capacitor EC1 is also connected in parallel with a capacitor C12 for high-frequency filtering.

[0041] In some embodiments, such as Figure 3As shown, the isolated DC-DC module 200 includes a transformer T1, a rectifier drive controller U9, a second MOSFET Q7, a first resistor R14, a second capacitor C2, and a third capacitor EC4. The two ends of the primary side of the transformer T1 are connected to the drains of the first inductor L4 and the second MOSFET Q7, respectively. One end of the secondary side of the transformer T1 is grounded, and the other end is connected to the source. The drain of the second MOSFET Q7 is connected to one end of the third capacitor EC4 and outputs a first low-voltage DC current. The other end of the third capacitor EC4 is grounded. The gate of the second MOSFET Q32 is connected to the control terminal of the rectifier drive controller U9. The first and sixth ports of the rectifier drive controller U9 are connected to the drains of the second MOSFET Q7. The second port of the rectifier drive controller U9 is connected to the drain of the second MOSFET Q7. The third port of the rectifier drive controller U9 is connected to the drain of the second MOSFET Q7 through the first resistor R14. The fourth port of the rectifier drive controller U9 is connected to the drain of the second MOSFET Q7 through the second capacitor C2.

[0042] In this embodiment, the rectifier drive controller U9 specifically uses a KP4060LGA chip. The transformer T1 is a high-frequency transformer, and its primary side is connected to the PFC boost circuit 120 to obtain 310V high-voltage DC. The 310V high-voltage DC is converted into high-frequency AC (KHz level) and output on the secondary side. The KP4060LGA chip detects the voltage phase of the secondary winding of the transformer T1 through pin 1. During the positive half-cycle of the high-frequency AC, the second MOSFET Q7 is immediately turned on, and during the negative half-cycle of the high-frequency AC, the second MOSFET Q7 is immediately turned off. Thus, after the PFC boost circuit 120 completes the power frequency rectification, the KP4060L controls the MOSFET to perform secondary rectification, achieving high-efficiency synchronous rectification. By stepping down the transformer T1 and rectifying with the rectifier drive controller U9 and the second MOSFET Q7, the DC-DC module 200 can output +24V DC. Compared with the conventional diode rectification method, the rectification by controlling the MOSFET with the KP4060L chip has the characteristics of low conductivity resistance, small on-state voltage drop, and low loss.

[0043] Specifically, the third capacitor EC4 is used for filtering, and a resistor is connected in parallel with the third capacitor EC4 to form an RC filter circuit. The resistor consists of resistors R1 and R16 connected in series. An RC snubber circuit (R1 / C1) is connected in parallel between the source and drain of the second MOSFET Q7 to suppress turn-off voltage spikes. The isolated DC-DC module 200 also includes an optocoupler U8. The input of the light-emitting terminal of the optocoupler U8 is connected to +24V DC, and the output terminal is grounded. The input of the light-receiving terminal of the optocoupler U8 is connected to the second port of the PFC controller U10, and the output terminal is grounded. When the second MOSFET Q7 is turned on, the optocoupler U8 emits light, which grounds the second port of the PFC controller U10, allowing the PFC controller U10 to receive feedback from the secondary winding side of the transformer T1, making the circuit control more precise.

[0044] In some embodiments, the isolated DC-DC module 200 further includes a linear regulator U2, the input terminal of which is connected to the drain of the second MOSFET Q7, the ground terminal of which is grounded, and the output terminal of which outputs a +5V VCC voltage.

[0045] In some embodiments, such as Figure 4 As shown, the constant temperature heating circuit 400 includes a first thyristor J20, a first optocoupler Q9, and a second resistor R39. The input terminal of the light-emitting end of the first optocoupler Q9 is connected to the control module 300, and the output terminal of the light-emitting end of the first optocoupler Q9 is grounded. The input terminal of the light-receiving end of the first optocoupler Q9 is connected to the input terminal of the first thyristor J20 and the mains power line after passing through the second resistor R39. The output terminal of the light-receiving end of the first optocoupler Q9 is connected to the control terminal of the first thyristor J20. The output terminal of the first thyristor J20 is connected to the first terminal of the heating element socket J5, and the second terminal of the heating element socket J5 is connected to the mains neutral line.

[0046] Specifically, the constant temperature heating circuit 400 includes two parallel thyristors for enhanced reliability. Since the two thyristor circuits have identical structures, this embodiment will use one thyristor circuit as an example for detailed explanation. A PWM wave is output through the HOT-ENB / TEP_DET port of the control module. When the PWM wave is high, the light-emitting terminal of the optocoupler Q9 is turned on, causing the first thyristor J20 to conduct, thus energizing the heating element socket J5. The effective voltage V of the heating element socket J5... 有效 =V 电网 *√(Conduction Angle / 180°), the voltage waveform after the thyristor is adjusted is a chopped sine wave. By controlling the thyristor to adjust the conduction angle, the effective working voltage of the heating element can be changed. When the thyristor temperature is <70℃, the conduction angle can be increased to improve the heating power. When the thyristor temperature is ≥70℃, the conduction angle can be decreased to maintain a constant temperature or reduce the temperature, thereby controlling the thyristor temperature below 70℃ and eliminating the need for a heat sink.

[0047] In some embodiments, the constant temperature heating circuit 400 further includes a temperature fuse FUSE4 and a temperature switch HOT2 connected in series. The input terminal of the temperature fuse FUSE4 is connected to the second terminal of the heating element socket J5, and the output terminal of the temperature switch HOT2 is connected to the neutral wire of the mains power.

[0048] Specifically, the trigger threshold of temperature switch HOT2 is 70°C. When the temperature of the thyristor is greater than 70°C, the temperature switch is turned off. The trigger temperature of temperature fuse FUSE4 can be set slightly higher than 70°C, such as 75°C. Through the dual hardware protection of temperature fuse FUSE4 and temperature switch HOT2, the temperature of the thyristor is ensured to be controlled below 70°C.

[0049] In this embodiment, as Figure 6As shown, the dryer control circuit also includes a zero-crossing detection circuit 600. The zero-crossing detection circuit 600 includes a third resistor R12, a second optocoupler U4, and a pull-up resistor. The input terminal of the light-emitting end of the second optocoupler U4 is connected to the mains live wire after passing through the third resistor R12. The output terminal of the light-emitting end of the second optocoupler U4 is connected to the mains neutral wire. The input terminal of the light-receiving end of the second optocoupler U4 is connected to the first terminal of the pull-up resistor and the zero-crossing detection port OVERZERO_DET of the control module 300. The second terminal of the pull-up resistor is connected to the +5V VCC power supply.

[0050] Specifically, when the mains power is at 0 voltage or in the negative half-cycle, the light-emitting end of the second optocoupler U4 will not conduct, and the zero-crossing detection port OVERZERO_DET of the control module 300 is directly connected to the +5V VCC power supply through a pull-up resistor. The zero-crossing detection port OVERZERO_DET detects a high level. When the mains power changes from 0 to the positive half-cycle, the light-emitting end of the second optocoupler U4 conducts, making the light-receiving end of the second optocoupler U4 conduct, thereby directly grounding the zero-crossing detection port OVERZERO_DET of the control module 300. The zero-crossing detection port OVERZERO_DET detects a low level. Therefore, when the zero-crossing detection port OVERZERO_DET detects a falling edge, it means that the phase of the mains power is 0 at this time, thus realizing the zero-crossing detection of the mains power. Based on the zero-crossing point of the mains power, the control module 300 can more accurately control the conduction angle of the thyristor.

[0051] In some embodiments, such as Figures 7 to 9 As shown, the functional module 500 includes a fan control circuit 510, an ozone generator control circuit 520, and an ultraviolet light control circuit 530.

[0052] Among them, such as Figure 7 The fan control circuit 510 includes a fan socket J13, a first-speed control circuit, and a second-speed control circuit. The fan socket J13 can connect to several fans. The first end of the fan socket J13 is connected to a 24V VCC power supply. The first-speed control circuit includes a transistor Q2. The emitter of transistor Q2 is grounded, and the base of transistor Q2 is connected to the FAN-ONE port of the control module 300. The collector of transistor Q2 is connected to the second end of the fan socket J13 after passing through a series of resistors R79, R37, R55, and R26. The second-speed control circuit includes a transistor Q1. The emitter of transistor Q1 is grounded, and the base of transistor Q2 is connected to the FAN-TWO port of the control module 300. The collector of transistor Q2 is connected to the second end of the fan socket J13.

[0053] When the FAN-ONE port of the control module 300 outputs a high level, transistor Q2 is turned on, and the 24V power is grounded after passing through the fan and multiple resistors. The voltage division of the multiple resistors prevents the fan from obtaining all of the 24V power for operation. When the FAN-TWO port of the control module 300 outputs a high level, transistor Q1 is turned on, and the 24V power is grounded after passing through the fan. All of the 24V power is applied to the fan, making the fan power higher than that of the fan at the first speed. The fan of the dryer in this embodiment is powered by an isolated DC-DC module, which can adapt to various mains voltages. The operation / stop of the fan can be controlled by the control module.

[0054] like Figure 8 As shown, the ozone generator control circuit 520 includes a transistor Q3 and an ozone generator socket J2. The first terminal of the ozone generator socket J2 is connected to a 24V VCC power supply, and the second terminal of the ozone generator socket J2 is connected to the collector of the transistor Q3. The emitter of the transistor Q3 is grounded, and the base of the transistor Q3 is connected to the OZONE-UTAL-RAY-EN port of the control module 300. When the OZONE-UTAL-RAY-EN port outputs a high level, the transistor Q3 is turned on, the ozone generator socket J2 is powered on, and the ozone generator can work normally.

[0055] like Figure 9 As shown, the ultraviolet light control circuit 530 includes a transistor Q6 and an ultraviolet lamp connection socket J3. The first terminal of the ultraviolet lamp connection socket J3 is connected to a 24V VCC power supply, and the second terminal of the ultraviolet lamp connection socket J3 is connected to the collector of the transistor Q6. The emitter of the transistor Q6 is grounded, and the base of the transistor Q6 is connected to the OZONE-UTAL-RAY-EN port of the control module 300. When the OZONE-UTAL-RAY-EN port outputs a high level, the transistor Q3 is turned on. Since the ozone generator and the ultraviolet lamp purify and disinfect the air simultaneously in the dryer, the ozone generator and the ultraviolet lamp are controlled through the same port of the control module 300. When the OZONE-UTAL-RAY-EN port outputs a high level, the ozone generator and the ultraviolet lamp are powered on and work simultaneously.

[0056] In some embodiments, such as Figure 10As shown, the wide voltage input dryer control circuit also includes a mains voltage detection circuit, including an optocoupler U6. The input terminal of the light-emitting end of the optocoupler U6 is connected to a 310V high-voltage DC power supply, and the output terminal of the light-emitting end of the optocoupler U6 is grounded. The input terminal of the light-receiving end of the optocoupler U6 is connected to a +5V VCC power supply, and the output terminal of the light-receiving end of the optocoupler U6 is connected to the AC_VOLTAGE_DET port of the control module 300. When the PFC boost circuit 120 is working normally and outputting a 310V high-voltage DC power supply, the optocoupler U6 is turned on, making the AC_VOLTAGE_DET port of the control module 300 high level. When the optocoupler U6 is turned off, the AC_VOLTAGE_DET port of the control module 300 is grounded through resistor R72. Therefore, the optocoupler U6 can realize isolated mains voltage detection.

[0057] The wide voltage input dryer control circuit provided in the above embodiments of this application has at least the following characteristics:

[0058] 1. By integrating a primary-side feedback PFC circuit, it can support 90-265VAC input and achieve stable power output under grid fluctuations.

[0059] 2. High-efficiency synchronous rectification is achieved through high-frequency rectification by transformer T1 and control of MOSFET Q7 by rectifier drive controller U9, which stably outputs +24V VCC power. Further, a linear regulator is used to stabilize the output of +5V VCC power, providing power to various functional modules of the dryer.

[0060] 3. By using a dual-thyristor parallel power regulation structure, combined with zero-crossing detection to dynamically adjust the conduction angle of the thyristor's operating voltage, the thyristor temperature can be stably controlled at 70℃±1℃ without a heat sink.

[0061] The dryer of this embodiment includes a dryer body and a dryer control circuit with wide voltage input as described in the above embodiment, which is disposed in the dryer body.

[0062] The dryer is also equipped with a fan to blow out hot air, as well as an ozone generator and ultraviolet lamps to purify and disinfect the air. The start / stop of the fan, ozone generator and ultraviolet lamp are all controlled by the control module 300. The dryer in this embodiment has the advantages of wide voltage adaptability, stable temperature control and low heat dissipation cost through the dryer control circuit with wide voltage input.

[0063] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dryer control circuit with wide voltage input, characterized in that, include: The wide voltage input circuit (100) includes an input rectifier circuit (110) and a PFC boost circuit (120). The input rectifier circuit (110) is connected to the mains power and rectifies the mains power into DC power before outputting it to the PFC boost circuit (120). The PFC boost circuit (120) converts the rectified mains power into high voltage DC power. An isolated DC-DC module (200) is provided, the input of which is connected to the PFC boost circuit (120). The isolated DC-DC module (200) is used to convert high-voltage DC power into low-voltage DC power output. Control module (300), which is electrically connected to the isolated DC-DC module (200) and powered by the low-voltage DC power supply; A constant temperature heating circuit (400) is provided, wherein the power supply terminal of the constant temperature heating circuit is connected to the mains power, and the control terminal of the constant temperature heating circuit (400) is connected to the control module (300). The system includes several functional modules (500), the power supply terminals of which are connected to the isolated DC-DC module (200), and the control terminals of which are connected to the control module (300).

2. The dryer control circuit with wide voltage input according to claim 1, characterized in that, The PFC boost circuit (120) includes a PFC controller, a first MOSFET, a first inductor, and a first capacitor. The input terminal of the first inductor is connected to the output terminal of the input rectifier circuit (110). The output terminal of the first inductor is connected to one end of the first capacitor, the drain of the first MOSFET, and the power supply terminal of the PFC controller. The other end of the first capacitor is grounded. The source of the first MOSFET is grounded. The gate of the first MOSFET is connected to the GATE port of the PFC controller.

3. The dryer control circuit with wide voltage input according to claim 2, characterized in that, The PFC controller U10 is configured in critical conduction mode, and the duty cycle adjustment formula for the control signal output from its GATE port is as follows: D=1-V in_pk / V BUS (1) Where D is the duty cycle, V in_pk V is the peak voltage of the output voltage of the input rectifier circuit (110). BUS The high voltage DC output of the PFC boost circuit (120).

4. The dryer control circuit with wide voltage input according to claim 2, characterized in that, The isolated DC-DC module (200) includes a transformer, a rectifier drive controller, a second MOSFET, a first resistor, a second capacitor, and a third capacitor. The primary side of the transformer is connected to the drain of the first inductor and the second MOSFET respectively. One end of the secondary side of the transformer is grounded, and the other end is connected to the source. The drain of the second MOSFET is connected to one end of the third capacitor and outputs a first low-voltage DC current. The other end of the third capacitor is grounded. The gate of the second MOSFET is connected to the control terminal of the rectifier drive controller. The first and sixth ports of the rectifier drive controller are connected to the drain of the second MOSFET. The second port of the rectifier drive controller is connected to the drain of the second MOSFET. The third port of the rectifier drive controller is connected to the drain of the second MOSFET through the first resistor. The fourth port of the rectifier drive controller is connected to the drain of the second MOSFET through the second capacitor.

5. The wide voltage input dryer control circuit according to claim 4, characterized in that, The isolated DC-DC module (200) also includes a linear regulator, the input terminal of which is connected to the drain of the second MOS transistor, the ground terminal of which is grounded, and the output terminal of which outputs a +5V VCC voltage.

6. The dryer control circuit with wide voltage input according to claim 1, characterized in that, The constant temperature heating circuit (400) includes a first thyristor, a first optocoupler, and a second resistor. The input terminal of the light-emitting end of the first optocoupler is connected to the control module (300), the output terminal of the light-emitting end of the first optocoupler is grounded, the input terminal of the light-receiving end of the first optocoupler is connected to the input terminal of the first thyristor and the mains live wire after passing through the second resistor, the output terminal of the light-receiving end of the first optocoupler is connected to the control terminal of the first thyristor, the output terminal of the first thyristor is connected to the first end of the heating element socket, and the second end of the heating element socket is connected to the mains neutral wire.

7. The dryer control circuit with wide voltage input according to claim 6, characterized in that, The constant temperature heating circuit (400) also includes a temperature fuse and a temperature switch connected in series. The input end of the temperature fuse is connected to the second end of the heating element socket, and the output end of the temperature switch is connected to the mains neutral line.

8. The dryer control circuit with wide voltage input according to claim 1, characterized in that, The functional module (500) includes a fan control circuit (510), an ozone generator control circuit (520), and an ultraviolet light control circuit (530).

9. The dryer control circuit with wide voltage input according to claim 1, characterized in that, It also includes a zero-crossing detection circuit (600), which includes a third resistor, a second optocoupler, and a pull-up resistor. The input terminal of the light-emitting end of the second optocoupler is connected to the mains live wire after passing through the third resistor. The output terminal of the light-emitting end of the second optocoupler is connected to the mains neutral wire. The input terminal of the light-receiving end of the second optocoupler is connected to the first end of the pull-up resistor and the zero-crossing detection port OVERZERO_DET of the control module (300). The second end of the pull-up resistor is connected to the +5V VCC power supply.

10. A dryer, characterized in that, It includes a dryer body and a dryer control circuit as described in any one of claims 1 to 9 disposed within the dryer body.

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