Toaster heating circuit structure

Abstract

The utility model relates to the technical field of toaster heating circuits, and discloses a toaster heating circuit structure which comprises a heating wire, a power board circuit and a key board circuit, a contact in the middle of the heating wire is a negative electrode of a control circuit, one end of the heating wire is a positive electrode and a zero line of the control circuit, and the other end of the heating wire is a negative electrode of the control circuit. A control circuit of the heating wire is connected to the power panel circuit, the other end of the heating wire is a live wire, a fuse and a silicon controlled rectifier are arranged on a power supply loop of the heating wire in the power panel circuit, and the silicon controlled rectifier and the fuse are matched to serve as a protection device with a secondary protection function. A relay serving as a secondary protection device in a traditional toaster is replaced, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of toaster heating circuits, and specifically relates to a toaster heating circuit structure. Background Art

[0002] In the heating circuit of the existing toaster, the thyristor is directly connected in series with the fuse in case of a short circuit. The theoretical short-circuit current is infinite and the consistency is poor. The protection phenomenon is inconsistent in different environments. There is no problem in testing under the environment of a voltage regulator / variable-frequency power supply, but there is an obvious explosion sound in the actual power grid.

[0003] In the current toaster heating circuit, there is a significant problem that the thyristor is directly connected in series on the fuse. When a short circuit occurs in the circuit, the current will increase sharply and approach infinity, because the resistance is almost zero during a short circuit and the current is no longer restricted and climbs rapidly. In actual operation, we observe that the consistency of this short-circuit current is poor, which means that under different test conditions, the magnitude and performance of the short-circuit current are not stable.

[0004] This inconsistency is particularly obvious in various environments. Under laboratory conditions, when testing with a voltage regulator or variable-frequency power supply, the system seems to work normally without obvious abnormal phenomena. However, when we connect the toaster to the actual power grid, the situation is quite different. The complexity of the power grid makes the short-circuit phenomenon more difficult to predict and control, and there is often an obvious explosion sound, which not only damages the equipment itself but also greatly increases the safety risk. Content of the Utility Model

[0005] (1) Technical Problem to be Solved

[0006] In view of the deficiencies of the prior art, the utility model provides a toaster heating circuit structure, which has the advantages of stable short-circuit current and rapid fuse melting, and solves the problems of infinite short-circuit current and poor consistency.

[0007] (2) Technical Solution

[0008] To achieve the above object, the utility model provides the following technical solution:

[0009] A toaster heating circuit structure includes a heating wire, a power board circuit and a keypad circuit. The contact point in the middle of the heating wire is the negative pole of the control circuit. One end of the heating wire is the positive pole and the neutral wire of the control circuit. The control circuit of the heating wire is connected to the power board circuit. The other end of the heating wire is the live wire. A fuse and a thyristor are arranged on the power supply loop of the heating wire in the power board circuit. The thyristor and the fuse are used together as a protection device with a secondary protection function to replace the relay used as the secondary protection device in the traditional toaster, thereby reducing costs.

[0010] Preferably, it includes a thyristor circuit, which is installed in the power supply board circuit. The thyristor circuit includes thyristor TR1, resistor R6, resistor R2, capacitor C2, chip CN2, diode D1, and relay coil L1.

[0011] Preferably, the keypad circuit includes a single-chip microcomputer U1, a potentiometer, a thyristor delay trigger protection circuit, and a keypad peripheral circuit.

[0012] Preferably, the top pin of the potentiometer is connected to the 5V power supply, the bottom pin of the potentiometer is grounded, and the middle pin of the potentiometer is connected to the PA2 pin of the single-chip microcomputer U1 after being connected in series with resistor R9.

[0013] Preferably, the thyristor delay trigger protection circuit includes triode Q2, triode Q3, diode D2, resistor R10, resistor R12, resistor R13, resistor R14, capacitor C6, and capacitor C7;

[0014] One end of resistor R13 is electrically connected to resistor R14, capacitor C7, and the base of triode Q3 respectively. The other end of resistor R13 is electrically connected to the PA1 pin of the single-chip microcomputer U1. The other end of resistor R14, the other end of capacitor C7, and the emitter of triode Q3 are grounded. The collector of triode Q3 is electrically connected to one end of resistor R12. The other end of resistor R12 is electrically connected to one end of capacitor C6 and the base of triode Q2 respectively. The other end of capacitor C6 is electrically connected to the collector of triode Q2. Resistor R10 is connected in parallel across both ends of capacitor C6. The emitter of triode Q2 is electrically connected to the positive pole of diode D2.

[0015] Preferably, the thyristor delay trigger protection circuit is further connected to chip CN3, triode Q1, switch S3, and resistor R7;

[0016] The four pins of chip CN3 are sequentially electrically connected to the collector of triode Q1, the 12V power supply, the ground wire, and the negative pole of diode D2 respectively. The base of triode Q1 is electrically connected to one end of resistor R7 and one end of switch S3 respectively. Switch S3 is connected to the emitter of triode Q1 and then grounded. The other end of resistor R7 is electrically connected to the PA0 pin of the single-chip microcomputer U1.

[0017] Preferably, the keypad peripheral circuit includes thermistor RT1, resistor R1, resistor R8, capacitor C1, and capacitor C4;

[0018] One end of the thermistor RT1 is grounded. The other end of the thermistor RT1, one end of the resistor R8, and one end of the resistor R1 are electrically connected together. The other end of the resistor R8, one end of the capacitor C4, and the PB2 pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C4 is grounded. The other end of the resistor R1, one end of the capacitor C1, and the VDD pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C1 is electrically connected to the VSS pin of the single-chip microcomputer U1 and then grounded.

[0019] Preferably, a resistor R11 is connected in series with the 12V power supply in the keypad circuit. The other end of the resistor R11 is electrically connected to the negative electrode of the voltage-regulating diode ZD1. The 5V power supply in the keypad circuit is electrically connected to the positive electrode of the electrolytic capacitor EC1. The negative electrode of the electrolytic capacitor EC1 is electrically connected to the positive electrode of the voltage-regulating diode ZD1 and grounded together. The positive electrode of the electrolytic capacitor EC1 is electrically connected to the negative electrode of the voltage-regulating diode ZD1.

[0020] (III)Advantages

[0021] Compared with the prior art, the present utility model provides a toaster heating circuit structure, which has the following advantages:

[0022] In this toaster heating circuit structure, by changing the traditional power supply polarity, the point connected in the middle of the heating wire is used as the negative electrode of the control circuit, one end of the heating wire is used as the positive electrode and the neutral wire of the control circuit, and the other end is used as the live wire. After the change, the power supply circuit is used as a short-circuit current limiter, which has the advantages of stable short-circuit current and can quickly fuse the fuse, solves the problem of infinite short-circuit current and poor consistency, and uses a thyristor to replace the relay used as the secondary protection device in the traditional toaster, reducing costs. Description of the Drawings

[0023] Figure 1 It is the circuit diagram of the heating wire in the toaster heating circuit structure of the present utility model.

[0024] Figure 2 It is the circuit diagram of the power supply board circuit in the toaster heating circuit structure of the present utility model.

[0025] Figure 3 It is the circuit diagram of the keypad circuit in the toaster heating circuit structure of the present utility model.

[0026] Figure 4 It is the circuit diagram of the thyristor circuit in the toaster heating circuit structure of the present utility model. Detailed Embodiment

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0028] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality" means two or more, unless otherwise specifically defined.

[0030] Embodiment 1:

[0031] This embodiment provides a toaster heating circuit structure with the following technical features.

[0032] Please refer to Figures 1-3 , a toaster heating circuit structure, including a heating wire, a power board circuit, and a keypad circuit. The contact point in the middle of the heating wire is the negative pole of the control circuit. One end of the heating wire is the positive pole and the neutral wire of the control circuit. The control circuit of the heating wire is connected to the power board circuit. The other end of the heating wire is the live wire. A fuse and a thyristor are arranged in the power supply loop of the heating wire in the power board circuit. The thyristor and the fuse are used in cooperation as protection devices for the secondary protection function, replacing the relay as the secondary protection device in the traditional toaster, thereby reducing costs.

[0033] In an optional embodiment, it includes a thyristor circuit. The thyristor circuit is installed in the power board circuit. The thyristor circuit includes a thyristor TR1, a resistor R6, a resistor R2, a capacitor C2, a chip CN2, a diode D1, and a relay coil L1.

[0034] In an alternative embodiment, the keypad circuit includes a microcontroller U1, a potentiometer, a thyristor delay trigger protection circuit, and a keypad peripheral circuit.

[0035] In an alternative embodiment, the top pin of the potentiometer is connected to the 5V power supply, the bottom pin of the potentiometer is grounded, and the middle pin of the potentiometer is electrically connected to the PA2 pin of the microcontroller U1 after being serially connected with a resistor R9.

[0036] In an alternative embodiment, the thyristor delay trigger protection circuit includes a triode Q2, a triode Q3, a diode D2, a resistor R10, a resistor R12, a resistor R13, a resistor R14, a capacitor C6, and a capacitor C7;

[0037] One end of the resistor R13 is electrically connected to the resistor R14, the capacitor C7, and the base of the triode Q3 respectively. The other end of the resistor R13 is electrically connected to the PA1 pin of the microcontroller U1. The other end of the resistor R14, the other end of the capacitor C7, and the emitter of the triode Q3 are grounded. The collector of the triode Q3 is electrically connected to one end of the resistor R12. The other end of the resistor R12 is electrically connected to one end of the capacitor C6 and the base of the triode Q2 respectively. The other end of the capacitor C6 is electrically connected to the collector of the triode Q2. A resistor R10 is connected in parallel across both ends of the capacitor C6. The emitter of the triode Q2 is electrically connected to the positive electrode of the diode D2.

[0038] In an alternative embodiment, the thyristor delay trigger protection circuit is further connected to a chip CN3, a triode Q1, a switch S3, and a resistor R7;

[0039] The four pins of the chip CN3 are sequentially electrically connected to the collector of the triode Q1, the 12V power supply, the ground wire, and the negative electrode of the diode D2 respectively. The base of the triode Q1 is electrically connected to one end of the resistor R7 and one end of the switch S3 respectively. The switch S3 is connected to the emitter of the triode Q1 and then grounded. The other end of the resistor R7 is electrically connected to the PA0 pin of the microcontroller U1.

[0040] In an alternative embodiment, the keypad peripheral circuit includes a thermistor RT1, a resistor R1, a resistor R8, a capacitor C1, and a capacitor C4;

[0041] One end of the thermistor RT1 is grounded. The other end of the thermistor RT1, one end of the resistor R8, and one end of the resistor R1 are electrically connected together. The other end of the resistor R8, one end of the capacitor C4, and the PB2 pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C4 is grounded. The other end of the resistor R1, one end of the capacitor C1, and the VDD pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C1 is electrically connected to the VSS pin of the single-chip microcomputer U1 and then grounded.

[0042] In an optional embodiment, a resistor R11 is connected in series with the 12V power supply in the keypad circuit. The other end of the resistor R11 is electrically connected to the negative electrode of the voltage-regulating diode ZD1. The 5V power supply in the keypad circuit is electrically connected to the positive electrode of the electrolytic capacitor EC1. The negative electrode of the electrolytic capacitor EC1 is electrically connected to the positive electrode of the voltage-regulating diode ZD1 and grounded together. The positive electrode of the electrolytic capacitor EC1 is electrically connected to the negative electrode of the voltage-regulating diode ZD1.

[0043] Working principle: Before modification, the thyristor was directly connected in series with the fuse and short-circuited. The theoretical short-circuit current was infinite and the consistency was poor. The protection phenomenon was inconsistent in different environments (no problem was found in the test under the environment of a voltage regulator / frequency conversion power supply, but there was an obvious explosion sound in the actual power grid). After modification, the power supply circuit is used as a short-circuit current limiter. The current heating wire power is 800W@120V, the resistance of the heating wire is 18R, the output of the power supply circuit is 12V, the voltage division ratio is 10:1, and the resistance of the power supply circuit is 1.8R. When the thyristor is short-circuited, the maximum root-mean-square short-circuit current is 66.7A, and the peak short-circuit current is 94A. It can be found from the fuse specification that the fusing time of the 8A resettable fuse under the current conditions is less than 10mS.

[0044] In summary, for the toaster heating circuit structure, by changing the traditional power supply polarity, the point connected to the middle of the heating wire is used as the negative electrode of the control circuit, one end of the heating wire is used as the positive electrode and the neutral line of the control circuit, and the other end is used as the live wire. After modification, the power supply circuit is used as a short-circuit current limiter, which has the advantages of stable short-circuit current and can quickly fuse the fuse, and solves the problem of infinite short-circuit current and poor consistency.

[0045] It should be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0046] Although the embodiments of the present utility model have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model, and the scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A toaster heating circuit structure, characterized in that, It includes a heating wire, a power board circuit and a keypad circuit. The contact point in the middle of the heating wire is the negative pole of the control circuit. One end of the heating wire is the positive pole and the neutral wire of the control circuit. The control circuit of the heating wire is connected to the power board circuit. The other end of the heating wire is the live wire. In the power board circuit, a fuse and a thyristor are arranged on the power supply loop of the heating wire, and the thyristor and the fuse are used in cooperation as protection devices for the secondary protection function.

2. The toaster heating circuit structure according to claim 1, characterized in that, It includes a thyristor circuit. The thyristor circuit is installed in the power board circuit. The thyristor circuit includes a thyristor TR1, a resistor R6, a resistor R2, a capacitor C2, a chip CN2, a diode D1 and a relay coil L1.

3. The multi-toaster heating circuit structure according to claim 2, characterized in that, The keypad circuit includes a single-chip microcomputer U1, a potentiometer, a thyristor delay trigger protection circuit and a peripheral circuit of the keypad.

4. The toaster heating circuit structure according to claim 3, characterized in that, The top pin of the potentiometer is connected to the 5V power supply, the bottom pin of the potentiometer is grounded, and the middle pin of the potentiometer is electrically connected to the PA2 pin of the single-chip microcomputer U1 after being connected in series with a resistor R9.

5. The multi-toaster heating circuit structure according to claim 3, characterized in that, The thyristor delay trigger protection circuit includes a triode Q2, a triode Q3, a diode D2, a resistor R10, a resistor R12, a resistor R13, a resistor R14, a capacitor C6 and a capacitor C7. One end of the resistor R13 is electrically connected to the resistor R14, the capacitor C7 and the base of the triode Q3 respectively. The other end of the resistor R13 is electrically connected to the PA1 pin of the single-chip microcomputer U1. The other end of the resistor R14, the other end of the capacitor C7 and the emitter of the triode Q3 are grounded. The collector of the triode Q3 is electrically connected to one end of the resistor R12. The other end of the resistor R12 is electrically connected to one end of the capacitor C6 and the base of the triode Q2 respectively. The other end of the capacitor C6 is electrically connected to the collector of the triode Q2. A resistor R10 is connected in parallel across both ends of the capacitor C6. The emitter of the triode Q2 is electrically connected to the positive pole of the diode D2.

6. The heating circuit structure of a toaster according to claim 5, characterized in that, The thyristor delay trigger protection circuit is also connected to a chip CN3, a triode Q1, a switch S3 and a resistor R7. The four pins of the chip CN3 are sequentially electrically connected to the collector of the triode Q1, the 12V power supply, the ground wire and the negative pole of the diode D2 respectively. The base of the triode Q1 is electrically connected to one end of the resistor R7 and one end of the switch S3 respectively. The switch S3 and the emitter of the triode Q1 are connected together and then grounded. The other end of the resistor R7 is electrically connected to the PA0 pin of the single-chip microcomputer U1.

7. The heating circuit structure of a toaster according to claim 3, characterized in that, The peripheral circuit of the keypad includes a thermistor RT1, a resistor R1, a resistor R8, a capacitor C1 and a capacitor C4. One end of the thermistor RT1 is grounded. The other end of the thermistor RT1, one end of the resistor R8 and one end of the resistor R1 are electrically connected together. The other end of the resistor R8, one end of the capacitor C4 and the PB2 pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C4 is grounded. The other end of the resistor R1, one end of the capacitor C1 and the VDD pin of the single-chip microcomputer U1 are electrically connected together. The other end of the capacitor C1 and the VSS pin of the single-chip microcomputer U1 are electrically connected together and then grounded.

8. The heating circuit structure of a toaster according to claim 1, characterized in that, A resistor R11 is connected in series with the 12V power supply in the keypad circuit. The other end of the resistor R11 is electrically connected to the negative electrode of the voltage stabilizing diode ZD1. The 5V power supply in the keypad circuit is electrically connected to the positive electrode of the electrolytic capacitor EC1. The negative electrode of the electrolytic capacitor EC1 is electrically connected to the positive electrode of the voltage stabilizing diode ZD1 and grounded together. The positive electrode of the electrolytic capacitor EC1 is electrically connected to the negative electrode of the voltage stabilizing diode ZD1.

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