Portable intelligent lunch box circuit

Abstract

The application discloses a portable intelligent lunch box circuit, which comprises a main control circuit, a switching power supply circuit, a power supply control circuit, an electric quantity detection circuit, a battery management circuit, a heating circuit and a temperature detection circuit; the power supply control circuit is connected with the switching power supply circuit, the battery and the heating circuit respectively; the battery is connected with the electric quantity detection circuit, the battery management circuit and the switching power supply circuit respectively; and the main control circuit is connected with the power supply control circuit, the electric quantity detection circuit, the heating circuit and the temperature detection circuit respectively. The portable intelligent lunch box circuit has both mains power supply and battery power supply, and is more convenient to use.

Description

Technical Field

[0001] This utility model relates to the field of portable lunch box technology, and more specifically to a portable smart lunch box circuit. Background Technology

[0002] As people become increasingly health-conscious, more and more office workers are choosing to bring their own lunches to work. However, the taste of cold food is greatly diminished, and waiting in line for a microwave is time-consuming. Therefore, portable lunchboxes that can heat and keep food warm have become a popular choice for many consumers. However, most portable smart lunchboxes on the market currently only have one power supply method and cannot be powered by both AC power and batteries, making them inconvenient to use. Utility Model Content

[0003] To overcome the above-mentioned shortcomings of the prior art, this utility model provides a portable smart lunchbox circuit that can be powered by both mains power and battery, making it more convenient to use.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a portable smart lunchbox circuit, including a main control circuit, a switching power supply circuit, a power supply control circuit, a power detection circuit, a battery management circuit, a heating circuit and a temperature detection circuit; The power supply control circuit is connected to the switching power supply circuit, the battery, and the heating circuit. The battery is connected to the power detection circuit, the battery management circuit, and the switching power supply circuit. The main control circuit is connected to the power supply control circuit, the power detection circuit, the heating circuit, and the temperature detection circuit.

[0005] In a preferred embodiment, the portable smart lunchbox circuit further includes a button circuit, a display circuit, and a buzzer circuit, with the main control circuit connected to the button circuit, the display circuit, and the buzzer circuit respectively.

[0006] In a preferred embodiment, the main control circuit includes a control chip U6; the first pin of the control chip U6 is grounded, the twenty-eighth pin of the control chip U1 is connected to a 5V DC voltage terminal, and the first pin and the twenty-eighth pin of the control chip U1 are connected through a capacitor C23.

[0007] In a preferred embodiment, the switching power supply circuit includes EMC devices, a rectifier bridge BR1, a transformer T1, a voltage regulator chip U1, and an optocoupler U2. One side of the EMC device is connected to an external power supply via fuse FUSE1, and the other side is connected to the input terminal of rectifier bridge BR1 via thermistor NTC1. The positive output terminal of rectifier bridge BR1 is connected to the primary winding of transformer T1. The primary winding of transformer T1 is connected to voltage regulator chip U1, and the secondary winding of transformer T1 is connected to a 12V DC voltage terminal. The 12V DC voltage terminal is connected to the input terminal of optocoupler U2, and the output terminal of optocoupler U2 is connected to voltage regulator chip U1.

[0008] In a preferred embodiment, the EMC device includes a capacitor CX1, resistors R13, R14, R16, R17, and an inductor L1. The capacitor CX1 is connected in parallel with the series-connected resistors R13 and R14, and the series-connected resistors R16 and R17. The two ends of the capacitor CX1 are connected to the first and second ends of the inductor L1, respectively. The third and fourth ends of the inductor L1 are connected to the input terminals of the rectifier bridge BR1. A thermistor NTC1 is connected between the third end of the inductor L1 and the rectifier bridge BR1.

[0009] In a preferred embodiment, the power supply control circuit includes a step-down chip U4, MOSFETs Q1, Q2, Q5, and Q6. The output terminal VEXT of the switching power supply circuit is connected to the heating voltage output terminal through diodes D2 and D3 in parallel. The heating voltage output terminal is grounded through capacitor C6. The source of MOSFET Q1 is connected to the output terminal VEXT of the switching power supply circuit. The drain of MOSFET Q1 is connected to the source of MOSFET Q2. The drain of MOSFET Q2 is connected to the positive terminal of the battery. The gate of MOSFET Q2 is connected to the collector of transistor Q3 through resistor R6, and is also connected to the drain of MOSFET Q2 through resistor R2. The emitter of transistor Q3 is grounded. The drain of MOSFET Q5 is connected to the heating voltage output terminal. The source of MOSFET Q5 is connected to the drain of MOSFET Q6. The source of MOSFET Q6 is connected to the positive terminal of the battery. The gate of MOSFET Q6 is connected to the collector of transistor Q7 through resistor R26 and to the source of MOSFET Q6 through resistor R24. The emitter of transistor Q7 is grounded. The positive terminal of the battery is connected to the input terminal of the step-down chip U4 through diode D7, and the output terminal of the step-down chip U4 is connected to the 5V DC voltage terminal; The tenth pin of the control chip U6 is connected to the output terminal VEXT of the switching power supply circuit through resistor R7 and grounded through resistor R11. The second pin is connected to the gate of MOSFET Q1 through resistor R12 and to the base of transistor Q3 through resistor R9. The twenty-fifth pin is connected to the gate of MOSFET Q5 through resistor R30 and to the base of transistor Q7 through resistor R29.

[0010] In a preferred embodiment, the battery management circuit includes a power management chip U5, a MOSFET Q9 and a MOSFET Q10, and the battery includes batteries B1, B2 and B3 connected in series. The positive terminal of the battery is connected to the first pin of the power management chip U5 via diode D10 and resistor R39 in sequence. The first pin of the power management chip U5 is connected to the negative terminal of the battery through a parallel diode D13 and capacitor C17. The second pin is connected to the positive terminal of the battery through resistor R42 and is also connected to the third pin. The fourth pin is connected to the negative terminal of battery B1 through resistor R46. The fifth pin is connected to the negative terminal of battery B2 through resistor R51. The sixth and seventh pins are connected to the negative terminal of the battery. The seventh pin is connected to the second, fourth, and fifth pins through capacitors C21, C20, and C19 respectively. The eighth pin is connected to the negative terminal of the battery through capacitor C22. The ninth pin is connected to the gate of MOSFET Q9 through resistor R59. Pin 10 is connected to the emitter of transistor Q8 via resistor R53; pin 11 is grounded via resistor R56; pin 12 is connected to the negative terminal of the battery via resistor R49; pins 13, 14, and 15 are connected to one end of thermistor NTC2 via resistors R47, R45, and R43 respectively, and the other end of thermistor NTC2 is connected to the negative terminal of the battery; pin 16 is connected to the negative terminal of the battery via capacitor C18; pin 8 of power management chip U5 is also connected to one end of resistor R61 and the source of MOSFET Q9 via resistor R57, and the other end of resistor R61 is connected to the negative terminal of battery B3; The base of transistor Q8 is connected to the negative terminal of the battery through resistor R58. The collector of transistor Q8 is connected to the anode of diode D22. The cathode of diode D22 is connected to the gate of MOSFET Q10 and grounded through resistor R60. The drain of MOSFET Q10 is connected to the drain of MOSFET Q9, and the source of MOSFET Q10 is grounded.

[0011] In a preferred embodiment, the power detection circuit includes a capacitor C24 and a resistor R69 connected in parallel. The eighth pin of the control chip U6 is connected to the positive terminal of the battery through a resistor R63 and grounded through the capacitor C24 and the resistor R69 connected in parallel.

[0012] In a preferred embodiment, the heating circuit includes a heating wire P1 and a MOSFET Q11. The first pin of the heating wire P1 is connected to the heating voltage output terminal, and the second pin is connected to the drain of the MOSFET Q11. The gate of the MOSFET Q11 is connected to the twenty-sixth pin of the control chip U6 through a resistor R66, and the source of the MOSFET Q11 is connected to the third pin of the control chip U6 through a resistor R68 and grounded through a resistor R73. The third pin of the control chip U6 is grounded through a capacitor C25.

[0013] In a preferred embodiment, the buzzer circuit includes a buzzer LS1 and a transistor Q12; one end of the buzzer LS1 is connected to a 5V DC voltage terminal, and the other end is connected to the collector of the transistor Q12. The emitter of the transistor Q12 is grounded, and the base of the transistor Q12 is connected to the 27th pin of the control chip U6 through a resistor R71.

[0014] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of this utility model are: A portable smart lunchbox circuit allows switching between a switching power supply circuit and a battery via a power supply control circuit, enabling the lunchbox to operate with both power sources for greater convenience. Simultaneously, a battery management circuit controls battery charging and discharging, preventing overcharging or over-discharging and extending battery life. Furthermore, the switching power supply circuit includes EMC devices to prevent external power interference from affecting circuit operation. Additionally, an optocoupler U2 isolates high-voltage and low-voltage circuits, ensuring safety and effectively preventing electric shock.

[0015] In addition, other advantages of this invention will be set forth in the description which follows, in part will be obvious from the description, or may be learned by practice of this invention. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a circuit diagram of the portable smart lunchbox circuit of this utility model; Figure 2 This is a schematic diagram of the circuit structure of the main control circuit of this utility model; Figure 3 This is a schematic diagram of the circuit structure of the switching power supply circuit of this utility model; Figure 4 This is a schematic diagram of the power supply control circuit of this utility model. Figure 5 This is a schematic diagram of the circuit structure of the battery management circuit of this utility model; Figure 6 This is a schematic diagram of the circuit structure of the power detection circuit of this utility model; Figure 7 This is a schematic diagram of the circuit structure of the heating circuit of this utility model; Figure 8This is a schematic diagram of the circuit structure of the buzzer circuit of this utility model; Figure 9 This is a schematic diagram of the circuit structure of the button circuit of this utility model; Figure 10 This is a schematic diagram of the circuit structure of the display circuit of this utility model. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] In the description of this utility model, it should be understood that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0020] Reference Figure 1-10 This invention describes a portable smart lunchbox circuit according to an embodiment of the present invention, which can be used in portable smart lunchbox products to realize functions such as cooking rice, cooking porridge, cooking soup, and keeping food warm.

[0021] In one embodiment, such as Figure 1-10 As shown, a portable smart lunchbox circuit includes a main control circuit, a switching power supply circuit, a power supply control circuit, a power detection circuit, a battery management circuit, a heating circuit, and a temperature detection circuit. The power supply control circuit is connected to the switching power supply circuit, the battery, and the heating circuit. The battery is connected to the power detection circuit, the battery management circuit, and the switching power supply circuit. The main control circuit is connected to the power supply control circuit, the power detection circuit, the heating circuit, and the temperature detection circuit.

[0022] The main control circuit is used to control all functions of the portable smart lunchbox, including button detection, heating control, display control and working mode control. The switching power supply circuit is used to connect to an external power source and convert the voltage provided by the external power source into an operating voltage, such as 12V, which can be used for battery charging and powering various functional circuits. The external power source can be AC ​​110V~235V mains power, and the operating voltage can be DC 12V. The power supply control circuit is used to switch between external power supply and battery power supply to ensure that the two power supply methods do not conflict with each other. The power supply control circuit is also used to supply power to the heating circuit. In specific implementation, the battery can be a rechargeable lithium battery or other types of rechargeable battery. The power detection circuit is used to detect the battery power and send it to the main control circuit; The battery management circuit is used to control the charging and discharging of the battery, prevent overcharging or over-discharging, and extend the battery's lifespan. The heating circuit is used to drive the heating element built into the portable smart lunchbox to heat up. The heating element is preferably a heating wire, which is easy to install. The temperature detection circuit is used to detect whether the heating temperature has reached the preset temperature value, and sends an alarm signal to the main control circuit when the temperature exceeds the preset value.

[0023] In practice, the aforementioned portable smart lunchbox circuit can be powered by mains electricity or batteries. When powered by mains electricity, it can achieve full-power heating; when powered by batteries, it can achieve low-power heating or low-power heat preservation functions.

[0024] The portable smart lunchbox circuit provided in the above embodiment can switch between a switching power supply circuit and a battery through a power supply control circuit, thereby realizing the switching control of the power supply mode. This allows the lunchbox to have both power supply modes, making it more convenient to use. At the same time, by setting up a battery management circuit, the charging and discharging of the battery can be controlled to prevent overcharging or over-discharging of the battery and extend the battery life.

[0025] In this embodiment, the portable smart lunchbox circuit also includes a button circuit, a display circuit, and a buzzer circuit, with the main control circuit connected to the button circuit, the display circuit, and the buzzer circuit respectively.

[0026] The button circuit may include multiple different buttons for powering on / off, starting operation, and setting operating parameters such as operating mode and timer / schedule time. The display circuit can be used to display information such as temperature, time, battery level, and working status of the portable smart lunchbox; The buzzer circuit is used to generate a buzzing sound to remind the user when the working parameters of the portable smart lunchbox are set or when it has completed its work.

[0027] In the above embodiments, the main control circuit obtains the instructions input by the user through the button circuit to control the operation of the heating circuit, and uses the display circuit and buzzer circuit to provide feedback, so that the user can understand the working status of the portable lunch box in a timely manner.

[0028] In this embodiment, as Figure 2 As shown, the main control circuit includes a control chip U6; the first pin of the control chip U6 is grounded, the twenty-eighth pin of the control chip U1 is connected to a 5V DC voltage terminal, and the first pin and the twenty-eighth pin of the control chip U1 are connected through a capacitor C23 to form a filter circuit for the control chip U1, ensuring stable system operation and coping with power fluctuations.

[0029] The 5V DC voltage terminal is obtained by the power supply control circuit from the voltage input of the switching power supply circuit or the battery.

[0030] Specifically, pins 2 (CH_EN), 10 (VEXT_CK), and 25 (BAT_OUT) of the control chip U6 are used to connect to the power supply control circuit; pins 3 (CC_CK) and 26 (HT_CTL) are used to connect to the heating circuit; pin 5 (TEMP_CK) is used to connect to the temperature detection circuit; pin 8 (BAT_CK) is used to connect to the power detection circuit; pin 9 (KEY_CK) is used to connect to the button circuit; pins 11 to 15 (COM1~COM6) and pins 16 to 24 (a1~h1) are used to connect to the display circuit; and pin 27 (BUZZ) is used to connect to the buzzer circuit.

[0031] In this embodiment, as Figure 3 As shown, the switching power supply circuit includes EMC devices, rectifier bridge BR1, transformer T1, voltage regulator chip U1, and optocoupler U2; One side of the EMC device is connected to an external power supply via fuse FUSE1, and the other side is connected to the input terminal of rectifier bridge BR1 via thermistor NTC1. The positive output terminal of rectifier bridge BR1 is connected to the primary winding of transformer T1. The primary winding of transformer T1 is connected to voltage regulator chip U1, and the secondary winding of transformer T1 is connected to a 12V DC voltage terminal. The 12V DC voltage terminal is connected to the input terminal of optocoupler U2, and the output terminal of optocoupler U2 is connected to voltage regulator chip U1.

[0032] The transformer T1 is connected to the fifth pin of the voltage regulator chip U1 via resistors R10, R15, and R22, and is also connected to one end of resistor R8 via parallel resistor R5 and capacitor C2. The drain of MOSFET Q4 is connected to the other end of resistor R8 via diode D4, and the gate of MOSFET Q4 is connected to one end of resistor R23 via parallel diode D5 and resistor R18. The other end of resistor R23 is connected to the sixth pin of the voltage regulator chip U1. Resistor R21 is connected between the source and gate of MOSFET Q4. The third pin of transformer T1 is connected to the drain of MOSFET Q4, and is also connected to the source of MOSFET Q4 through capacitor C5 and resistor R19. The source of MOSFET Q4 is connected to one end of resistor R32 and grounded through parallel resistors R33, R34, R35 and R36. One end of resistor R32 is connected to the fourth pin of voltage regulator chip U1. The fourth pin of transformer T1 is connected to the fifth pin of voltage regulator chip U1 through resistor R27 and diode D6. The sixth pin of transformer T1 is grounded. The thirteenth and fourteenth pins of transformer T1 are connected to the 12V DC voltage terminal through a filter circuit consisting of diode D1, capacitor C4 and resistor R3. The 12V DC voltage terminal is connected to the power supply control circuit through resistor R1, and is connected to the ninth and tenth pins of transformer T1 through parallel capacitor C3 and resistor R4. The ninth and tenth pins of transformer T1 are grounded. The first pin of the voltage regulator chip U1 is grounded, the second and fourth pins are grounded through capacitors C12 and C11 respectively, and the fifth pin is grounded through capacitors C8 and C9 connected in parallel.

[0033] At the output of optocoupler U2, its third pin is grounded, and its fourth pin is connected to the second pin of voltage regulator chip U1 through resistor R38. At the input of optocoupler U2, its first pin is connected to a 12V DC voltage terminal through resistor R20, and its second pin is connected to the cathode of thyristor U3. It is also connected to the control electrode of thyristor U3 through capacitor C7, resistor R31, and capacitor C10. Resistor R31 and capacitor C10 are connected in series, and capacitor C7 is connected in parallel with the series resistor R31 and capacitor C10. The anode of thyristor U3 is grounded, and the control electrode of thyristor U3 is also connected to a 12V DC voltage terminal through resistor R25 and grounded through resistor R37. Resistor R28 is connected between the first and second pins of optocoupler U2.

[0034] In the above embodiments, the switching power supply circuit includes EMC devices to prevent external power interference from affecting the circuit operation; at the same time, the optocoupler U2 also achieves isolation between strong and weak currents, ensuring safe use and effectively preventing electric shock.

[0035] In this embodiment, the EMC device includes capacitor CX1, resistors R13, R14, R16, R17 and inductor L1. Capacitor CX1 is connected in parallel with resistors R13 and R14 (series connection), and resistors R16 and R17 (series connection). The two ends of capacitor CX1 are connected to the first and second ends of inductor L1, respectively. The third and fourth ends of inductor L1 are connected to the input of rectifier bridge BR1. A thermistor NTC1 is connected between the third end of inductor L1 and rectifier bridge BR1.

[0036] One end of capacitor CX1 is connected to the first input terminal CP1 of the external power supply through fuse FUSE1, and the other end is connected to the second input terminal CP2 of the external power supply.

[0037] In the above embodiments, the EMC device can isolate the external power supply from the portable smart lunchbox circuit through parallel capacitors, inductors and multiple resistors, so as to avoid external power supply interference affecting the circuit operation.

[0038] In this embodiment, as Figure 4 As shown, the power supply control circuit includes a step-down chip U4, MOSFETs Q1, Q2, Q5, and Q6; The output terminal VEXT of the switching power supply circuit is connected to the heating voltage output terminal HT+ through diodes D2 and D3 connected in parallel. The heating voltage output terminal HT+ is grounded through capacitor C6. The source of MOSFET Q1 is connected to the output terminal VEXT of the switching power supply circuit. The drain of MOSFET Q1 is connected to the source of MOSFET Q2. The drain of MOSFET Q2 is connected to the positive terminal BAT+ of the battery. The gate of MOSFET Q2 is connected to the collector of transistor Q3 through resistor R6, and is also connected to the drain of MOSFET Q2 through resistor R2. The emitter of transistor Q3 is grounded. The drain of MOSFET Q5 is connected to the heating voltage output terminal HT+. The source of MOSFET Q5 is connected to the drain of MOSFET Q6. The source of MOSFET Q6 is connected to the positive terminal BAT+ of the battery. The gate of MOSFET Q6 is connected to the collector of transistor Q7 through resistor R26 and to the source of MOSFET Q6 through resistor R24. The emitter of transistor Q7 is grounded. The positive terminal BAT+ of the battery is connected to the input terminal of the step-down chip U4 through diode D7. The output terminal of the step-down chip U4 is connected to the 5V DC voltage terminal. The input terminal of the step-down chip U4 is grounded through parallel capacitors C15 and C16, and the output terminal of the step-down chip U4 is grounded through parallel capacitors C13 and C14. The tenth pin (VEXT_CK) of the control chip U6 is connected to the output terminal VEXT of the switching power supply circuit through resistor R7 and grounded through resistor R11. The second pin (CH_EN) is connected to the gate of MOSFET Q1 through resistor R12 and to the base of transistor Q3 through resistor R9. The twenty-fifth pin (BAT_OUT) is connected to the gate of MOSFET Q5 through resistor R30 and to the base of transistor Q7 through resistor R29.

[0039] In the above embodiments, the power supply control circuit is used to switch between external power supply and battery power supply to ensure that the two power supply methods do not conflict with each other, and to stabilize the voltage to 5V to obtain a 5V DC voltage terminal that can supply power to each functional circuit; the power supply control circuit is also used to supply power to the heating circuit through the heating voltage output terminal HT+.

[0040] In this embodiment, as Figure 5 As shown, the battery management circuit includes a power management chip U5, a MOSFET Q9 and a MOSFET Q10, and the battery includes batteries B1, B2 and B3 connected in series. The positive terminal BAT+ of the battery is connected to the first pin of the power management chip U5 via diode D10 and resistor R39 in sequence. The first pin of the power management chip U5 is connected to the negative terminal BAT- of the battery through a parallel diode D13 and capacitor C17. The second pin is connected to the positive terminal BAT+ of the battery through resistor R42 and is also connected to the third pin. The fourth pin is connected to the negative terminal of battery B1 through resistor R46. The fifth pin is connected to the negative terminal of battery B2 through resistor R51. The sixth and seventh pins are connected to the negative terminal BAT- of the battery. The seventh pin is connected to the second, fourth, and fifth pins through capacitors C21, C20, and C19 respectively. The eighth pin is connected to the negative terminal BAT- of the battery through capacitor C22. The ninth pin is connected to the gate of MOSFET Q9 through resistor R59. Pin 10 is connected to the emitter of transistor Q8 via resistor R53; pin 11 is grounded via resistor R56; pin 12 is connected to the negative terminal BAT- of the battery via resistor R49; pins 13, 14, and 15 are connected to one end of thermistor NTC2 via resistors R47, R45, and R43 respectively; the other end of thermistor NTC2 is connected to the negative terminal BAT- of the battery; pin 16 is connected to the negative terminal BAT- of the battery via capacitor C18; pin 8 of power management chip U5 is also connected to one end of resistor R61 and the source of MOSFET Q9 via resistor R57; the other end of resistor R61 is connected to the negative terminal BAT- of battery B3. The base of transistor Q8 is connected to the negative terminal BAT- of the battery through resistor R58. The collector of transistor Q8 is connected to the anode of diode D22. The cathode of diode D22 is connected to the gate of MOSFET Q10 and grounded through resistor R60. The drain of MOSFET Q10 is connected to the drain of MOSFET Q9, and the source of MOSFET Q10 is grounded.

[0041] Among them, the positive electrode BAT+ is the positive electrode of battery B1, and the negative electrode BAT- is the negative electrode of battery B3.

[0042] The above embodiments provide a battery management circuit that can control the charging and discharging of the battery, prevent overcharging or over-discharging, and thus extend the battery's lifespan.

[0043] In this embodiment, as Figure 6 As shown, the power detection circuit includes a capacitor C24 and a resistor R69 connected in parallel. The eighth pin (BAT_CK) of the control chip U6 is connected to the positive terminal BAT+ of the battery through a resistor R63, and is grounded through the capacitor C24 and the resistor R69 connected in parallel.

[0044] The power detection circuit in the above embodiment is used to detect the battery power in real time and send it to the control chip U6. The control chip U6 can send the battery power to the display circuit for display so that the user can keep track of the battery power status in a timely manner.

[0045] In this embodiment, as Figure 7 As shown, the heating circuit includes a heating wire P1 and a MOSFET Q11. The first pin of the heating wire P1 is connected to the heating voltage output terminal HT+, and the second pin is connected to the drain of the MOSFET Q11. The gate of the MOSFET Q11 is connected to the 26th pin (HT_CTL) of the control chip U6 through resistor R66. The source of the MOSFET Q11 is connected to the third pin (CC_CK) of the control chip U6 through resistor R68, and is grounded through resistor R73. The third pin (CC_CK) of the control chip U6 is grounded through capacitor C25. The MOSFET Q11 is an NMOS transistor.

[0046] In practice, the temperature detection circuit includes resistors R65 and R72. One end of resistor R65 is connected to the 5V DC voltage terminal, and the other end is connected to the fifth pin (TEMP_CK) of the control chip U6 and one end of resistor R72. The other end of resistor R72 is grounded.

[0047] The heating circuit provided in the above embodiment heats the food through heating wire P1 and can realize the heating function of the portable smart lunchbox circuit under the control of control chip U6.

[0048] In this embodiment, as Figure 8As shown, the buzzer circuit includes a buzzer LS1 and a transistor Q12; one end of the buzzer LS1 is connected to a 5V DC voltage terminal, and the other end is connected to the collector of the transistor Q12. The emitter of the transistor Q12 is grounded, and the base of the transistor Q12 is connected to the 27th pin (BUZZ) of the control chip U6 through a resistor R71.

[0049] The above embodiments provide a buzzer circuit that, under the control of the control chip U6, can emit a buzzer sound to remind the user when the user sets the working parameters of the portable smart lunchbox or when the portable smart lunchbox has finished heating, making it more convenient to use.

[0050] In this embodiment, as Figure 9 As shown, the button circuit includes multiple buttons connected in parallel. One end of each button is connected to the ninth pin (KEY_CK) of the control chip U6, and the other end is grounded through its respective series resistor.

[0051] like Figure 9 In the embodiment shown, the button circuit includes buttons S1 (power on / start), S2 (power on / start), S3 (power on / start), S4 (power on / start), S5 (power on / start), and S6 (power on / start), and also includes resistors R62, R64, R67, R70, R74 and R75 connected in series with the buttons S1 to S6 respectively.

[0052] In this embodiment, as Figure 10 As shown, the display circuit includes a display module DIS1 and multiple light-emitting diodes (LEDs). Different LEDs can be used to indicate different working states of the portable smart lunchbox. In a specific implementation, the display circuit can consist of a 4-digit digital tube and 16 LEDs.

[0053] Other configurations and operations of the portable smart lunchbox circuit according to the embodiments of this utility model are known to those skilled in the art and will not be described in detail here.

[0054] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0055] In the description of this specification, references to the terms "embodiment," "specific embodiment," "example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example that is included in at least one embodiment or example of the present invention.

[0056] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined with each other in any suitable manner in one or more embodiments or examples without interference or contradiction.

Claims

1. A portable smart lunchbox circuit, characterized in that: It includes a main control circuit, a switching power supply circuit, a power supply control circuit, a power detection circuit, a battery management circuit, a heating circuit, and a temperature detection circuit; The power supply control circuit is connected to the switching power supply circuit, the battery and the heating circuit respectively, and the battery is connected to the power detection circuit, the battery management circuit and the switching power supply circuit respectively; The main control circuit is connected to the power supply control circuit, the power detection circuit, the heating circuit, and the temperature detection circuit.

2. The portable smart lunchbox circuit according to claim 1, characterized in that: It also includes a button circuit, a display circuit, and a buzzer circuit, with the main control circuit connected to the button circuit, the display circuit, and the buzzer circuit respectively.

3. The portable smart lunchbox circuit according to claim 2, characterized in that: The main control circuit includes a control chip U6; the first pin of the control chip U6 is grounded, the twenty-eighth pin of the control chip U1 is connected to a 5V DC voltage terminal, and the first pin and the twenty-eighth pin of the control chip U1 are connected through a capacitor C23.

4. The portable smart lunchbox circuit according to claim 3, characterized in that: The switching power supply circuit includes EMC devices, a rectifier bridge BR1, a transformer T1, a voltage regulator chip U1, and an optocoupler U2; One side of the EMC device is connected to an external power supply via fuse FUSE1, and the other side is connected to the input terminal of rectifier bridge BR1 via thermistor NTC1. The positive output terminal of rectifier bridge BR1 is connected to the primary winding of transformer T1. The primary winding of transformer T1 is connected to voltage regulator chip U1, and the secondary winding of transformer T1 is connected to a 12V DC voltage terminal. The 12V DC voltage terminal is connected to the input terminal of optocoupler U2, and the output terminal of optocoupler U2 is connected to voltage regulator chip U1.

5. The portable smart lunchbox circuit according to claim 4, characterized in that: The EMC device includes capacitor CX1, resistors R13, R14, R16, R17 and inductor L1; The capacitor CX1 is connected in parallel with resistors R13 and R14 (in series) and R16 and R17 (in series). The two ends of the capacitor CX1 are connected to the first and second ends of the inductor L1, respectively. The third and fourth ends of the inductor L1 are connected to the input of the rectifier bridge BR1. A thermistor NTC1 is connected between the third end of the inductor L1 and the rectifier bridge BR1.

6. The portable smart lunchbox circuit according to claim 4, characterized in that: The power supply control circuit includes a step-down chip U4, MOSFET Q1, MOSFET Q2, MOSFET Q5, and MOSFET Q6; The output terminal VEXT of the switching power supply circuit is connected to the heating voltage output terminal through diodes D2 and D3 in parallel, and the heating voltage output terminal is grounded through capacitor C6. The source of MOSFET Q1 is connected to the output terminal VEXT of the switching power supply circuit. The drain of MOSFET Q1 is connected to the source of MOSFET Q2. The drain of MOSFET Q2 is connected to the positive terminal of the battery. The gate of MOSFET Q2 is connected to the collector of transistor Q3 through resistor R6 and to the drain of MOSFET Q2 through resistor R2. The emitter of transistor Q3 is grounded. The drain of MOSFET Q5 is connected to the heating voltage output terminal. The source of MOSFET Q5 is connected to the drain of MOSFET Q6. The source of MOSFET Q6 is connected to the positive terminal of the battery. The gate of MOSFET Q6 is connected to the collector of transistor Q7 through resistor R26 and to the source of MOSFET Q6 through resistor R24. The emitter of transistor Q7 is grounded. The positive terminal of the battery is connected to the input terminal of the step-down chip U4 via diode D7, and the output terminal of the step-down chip U4 is connected to the 5V DC voltage terminal. The tenth pin of the control chip U6 is connected to the output terminal VEXT of the switching power supply circuit through resistor R7 and grounded through resistor R11. The second pin is connected to the gate of the MOSFET Q1 through resistor R12 and to the base of the transistor Q3 through resistor R9. The twenty-fifth pin is connected to the gate of the MOSFET Q5 through resistor R30 and to the base of the transistor Q7 through resistor R29.

7. The portable smart lunchbox circuit according to claim 6, characterized in that: The battery management circuit includes a power management chip U5, a MOSFET Q9 and a MOSFET Q10, and the battery includes batteries B1, B2 and B3 connected in series. The positive terminal of the battery is connected to the first pin of the power management chip U5 in sequence through diode D10 and resistor R39; The first pin of the power management chip U5 is connected to the negative terminal of the battery via a parallel diode D13 and capacitor C17. The second pin is connected to the positive terminal of the battery via resistor R42 and is also connected to the third pin. The fourth pin is connected to the negative terminal of battery B1 via resistor R46. The fifth pin is connected to the negative terminal of battery B2 via resistor R51. The sixth and seventh pins are connected to the negative terminal of the battery. The seventh pin is connected to the second, fourth, and fifth pins via capacitors C21, C20, and C19, respectively. The eighth pin is connected to the negative terminal of the battery via capacitor C22. The ninth pin is connected to the gate of MOSFET Q9 via resistor R59. Pin 10 is connected to the emitter of transistor Q8 via resistor R53; pin 11 is grounded via resistor R56; pin 12 is connected to the negative terminal of the battery via resistor R49; pins 13, 14, and 15 are connected to one end of thermistor NTC2 via resistors R47, R45, and R43 respectively, and the other end of thermistor NTC2 is connected to the negative terminal of the battery; pin 16 is connected to the negative terminal of the battery via capacitor C18; pin 8 of the power management chip U5 is also connected to one end of resistor R61 and the source of MOSFET Q9 via resistor R57, and the other end of resistor R61 is connected to the negative terminal of battery B3; The base of transistor Q8 is connected to the negative terminal of the battery through resistor R58. The collector of transistor Q8 is connected to the anode of diode D22. The cathode of diode D22 is connected to the gate of MOSFET Q10 and grounded through resistor R60. The drain of MOSFET Q10 is connected to the drain of MOSFET Q9. The source of MOSFET Q10 is grounded.

8. The portable smart lunch box circuit according to claim 6, wherein: The power detection circuit includes a capacitor C24 and a resistor R69 connected in parallel. The eighth pin of the control chip U6 is connected to the positive terminal of the battery through a resistor R63, and is grounded through the capacitor C24 and the resistor R69 connected in parallel.

9. The portable smart lunch box circuit according to claim 6, wherein: The heating circuit includes a heating wire P1 and a MOSFET Q11. The first pin of the heating wire P1 is connected to the heating voltage output terminal, and the second pin is connected to the drain of the MOSFET Q11. The gate of the MOSFET Q11 is connected to the twenty-sixth pin of the control chip U6 through a resistor R66. The source of the MOSFET Q11 is connected to the third pin of the control chip U6 through a resistor R68, and is grounded through a resistor R73. The third pin of the control chip U6 is grounded through a capacitor C25.

10. The portable smart lunchbox circuit according to any one of claims 3 to 9, characterized in that: The buzzer circuit includes a buzzer LS1 and a transistor Q12; one end of the buzzer LS1 is connected to the 5V DC voltage terminal, and the other end is connected to the collector of the transistor Q12. The emitter of the transistor Q12 is grounded, and the base of the transistor Q12 is connected to the twenty-seventh pin of the control chip U6 through a resistor R71.

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