Double-auxiliary safety control circuit of toaster

Abstract

The utility model relates to a double-auxiliary safety control circuit for a toaster, which comprises a fuse and a double-pole switch which are connected in series with power supplies, a bidirectional silicon controlled rectifier is connected in parallel between the power supplies, and the circuit also comprises a control chip which is supplied with power by extracting voltage from a heating wire of the toaster. The control chip is electrically connected with the bidirectional silicon controlled rectifier through a silicon controlled rectifier control module, the silicon controlled rectifier control module is used for controlling the conduction direction of the bidirectional silicon controlled rectifier, and the control chip is further electrically connected with an electromagnet through a double-loop driving module. And the double-loop driving module controls the on and off of the electromagnet through high-level driving and PWM driving respectively, so as to control the on and off of the double-pole switch. For a toaster product, the double-loop driving electromagnet is combined to attract the double-pole switch, and when the double-pole switch is not switched off within the longest bread toasting time + 60 seconds of the product, the silicon controlled rectifier is short-circuited to cut off the power supply of the heating wire, so that the multi-circuit safety protection is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of toaster circuit safety, specifically relates to a kind of toaster double auxiliary safety control circuit. BACKGROUND

[0002] To ensure the electrical safety of toaster product, according to the safety specification requirements of domestic electric cooking and food processor standard, at least two additional auxiliary control circuits are needed to control the disconnection of heating wire in the case of cutting off heating wire fault.For most of the toasters on the market, due to cost reasons, the heating wire is driven by chip, and generally only one-way control of double-blade plate is provided without secondary loop protection.If the circuit board of the chip is powered by switching power supply, an additional set of relays is needed to control the loop separately, which greatly increases the cost.Furthermore, the working principle of these toasters on the market is generally as follows: press the handle of the toaster, the double-blade switch is connected, the heating wire is powered to heat, the heating wire supplies AC12V alternating current to the electronic board, the PCBA rectifies, filters and stabilizes the voltage to supply power to the chip, the chip controls the electromagnetic iron to attract and hold the double-blade switch, the product normally toasts bread, when the toasting time reaches, the chip controls the electromagnetic iron to be powered off, the double-blade switch is disconnected, and the toaster handle is released to end the work.In this process, once the double-blade switch is directly connected and cannot be disconnected due to structure or electromagnetic iron abnormality after the toasting time reaches, not only a great risk to safety is caused, but also the internal components, especially the chip, are more likely to be damaged by heat for a long time of power connection, resulting in more serious loss.Therefore, it is urgent to increase secondary safety protection on this basis. SUMMARY

[0003] To solve the problems of the prior art, the utility model aims to provide a kind of toaster double auxiliary safety control circuit.The utility model is directed to the toaster product, combines double-loop driving electromagnetic iron to attract double-blade switch, and when the double-blade switch cannot be disconnected within the longest toasting time of product+60 seconds, the heating wire power is disconnected by using silicon controlled rectifier short circuit, so as to have multiple circuit safety protection.

[0004] The utility model discloses a kind of toaster double auxiliary safety control circuit, including fuse and double-blade switch in series with power supply, and bidirectional silicon controlled rectifier is connected in parallel between the power supply, the control chip that the circuit also includes the heating wire of toaster extraction pressure power supply, the control chip is electrically connected with the bidirectional silicon controlled rectifier by silicon controlled rectifier control module, the silicon controlled rectifier control module is used to control the conduction direction of the bidirectional silicon controlled rectifier, the control chip is also electrically connected with electromagnetic iron by double-loop driving module, the double-loop driving module is respectively controlled by high level drive and PWM drive The conduction and disconnection of the electromagnetic iron, to control the closure and power-off of the double-blade switch.

[0005] In one of the embodiments, the double-loop driving module comprises a diode D21 connected in parallel with the electromagnet, one end of the diode D21 is connected with 12V DC voltage, the other end of the diode D21 is connected with a first triode Q12 and a second triode Q13 in series and connected with a common terminal, the base of the first triode Q12 is connected with the No.1 pin of the control chip, and the base of the second triode Q13 is connected with the No.3 pin of the control chip.

[0006] In one of the embodiments, the No.1 pin of the control chip and the first triode Q12 are connected with a resistor R59, a capacitor C14, a diode D23, a resistor R58 and a diode D22 in series, the capacitor C14 and the diode D23 are connected with a common terminal through a reverse connection diode D24, the diode D23 and the resistor R58 are connected with a common terminal through a connection with a polar capacitor E11, and the diode D22 and the first triode Q12 are connected with 5V DC voltage through a connection with a series resistor R57 and a polar capacitor E9.

[0007] In one of the embodiments, the second triode Q13 and the No.3 pin of the control chip are connected with a resistor R64, the No.3 pin of the control chip and the resistor R64 are connected with a resistor R63, and the other end of the resistor R63 is connected with 5V DC voltage.

[0008] In one of the embodiments, the silicon controlled module comprises a resistor R51 connected in parallel between the anode and the trigger of the bidirectional silicon controlled, the trigger of the bidirectional silicon controlled is further connected with a common terminal through a connection with a series resistor R52 and a third triode Q11 in series, and the base of the third triode Q11 is connected with the No.2 pin of the control chip through a resistor R53.

[0009] In one of the embodiments, the control chip adopts an SN8P2722 type single-chip microcomputer.

[0010] In one of the embodiments, the bidirectional silicon controlled adopts a BT137 type.

[0011] Compared with the prior art, the beneficial effects of the technical scheme of the utility model are as follows:

[0012] The utility model aims at the safety of toaster products, combines the double-loop driving electromagnet attraction and the disconnection of the double-blade switch as a primary control loop, and when the double-blade switch fails to disconnect within the longest toast time of the product + 60 seconds, uses the silicon controlled short circuit to disconnect the power supply of the heating wire as a secondary control loop, so as to have the effect of multiple circuit safety protection, ensure that the toaster can be successfully powered off, and try to protect the undamaged electrical components from additional secondary damage due to overlong power-on or short circuit. BRIEF DESCRIPTION OF DRAWINGS

[0013] Fig. 1 is a connection diagram of a double auxiliary safety control circuit of the toaster of the utility model;

[0014] Fig. 2 is a connection diagram of the double loop driving module of the utility model;

[0015] Fig. 3 is a connection diagram of the thyristor control module of the utility model. DETAILED DESCRIPTION

[0016] The drawings are only for illustrative purposes, and should not be understood as limiting the patent; in order to better illustrate the embodiments, some components of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0017] In the description of the utility model, it should be pointed out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection" should be broadly understood, for example, can be fixedly connected, can also be detachably connected, or integrally connected;It can be mechanically connected, or electrically connected;It can be directly connected, or indirectly connected through an intermediate medium, and it can be said that the two elements are connected internally.For those skilled in the art, the above-mentioned terms can be understood in the specific meaning of the utility model according to the specific circumstances.The technical solutions of the utility model are further described below in conjunction with the drawings and examples.

[0018] As Figs. 1-3As shown, the utility model discloses a toaster double auxiliary safety control circuit, including the fuse F1 and the double knife switch S10 and S11 in series connection with power supply, and the power supply has the bidirectional thyristor SRQ4 in parallel, and this circuit still includes the control chip MCU from the heating wire of toaster and draws pressure power supply, and the control chip MCU is electrically connected with the bidirectional thyristor SRQ4 through the thyristor control module, and the thyristor control module is used for controlling the conduction direction of bidirectional thyristor SRQ4, and the control chip MCU still is electrically connected with the electromagnet L3 through the double circuit driving module, and the double circuit driving module respectively through high level drive and PWM drive control electromagnet L3's conduction and open, to control the closure and power off of double knife switch S10 and S11. The utility model discloses in view of the safety of toaster product, to meet the requirement of safety regulation, combine double circuit driving electromagnet L3 and open double knife switch S10 and S11 as a primary control circuit, and double circuit driving module needs high level drive and PWM drive signal release simultaneously to make electromagnet L3 conduct, and when disconnecting, just one place can make electromagnet L3 power off, to make double knife switch S10 and S11 disconnect, and in the longest toast bread time of product + 60 seconds, can adjust the time of timer according to actual situation, if double knife switch S10 and S11 can not disconnect due to failure, trigger bidirectional thyristor SRQ4 and form short circuit, to make the fuse F1 and disconnect the power supply of heating wire as secondary control circuit. So it can make toaster circuit have multiple circuit safety protection effect, ensure that toaster double knife switch S10 and S11 disconnect or heating wire can successfully power off, and try to protect the undamaged electrical components from being damaged by partial element failure.

[0019] In one embodiment, the double circuit driving module includes a diode D21 connected in parallel with the electromagnet L3 as an overcurrent protection for the electromagnet L3, which consumes the induced electromotive force generated by the coil when the current disappears. One end of the diode D21 is connected to a 12V DC voltage, and the other end of the diode D21 is connected in series with a first triode Q12 and a second triode Q13 and connected to a common terminal. The base of the first triode Q12 is connected to pin 1 of the control chip MCU, and the base of the second triode Q13 is connected to pin 3 of the control chip MCU. The conduction of the electromagnet L3 requires the simultaneous conduction of the first triode Q12 and the second triode Q13, and their two bases are connected to the control chip MCU. The 1-pin output of the control chip MCU drives the first triode Q12 to conduct, while the 3-pin of the control chip MCU is PWM driven, i.e., pulse width modulation driven. The digital output of the microprocessor is used to control the analog circuit, thereby conducting the second triode Q13, making the control more efficient, accurate and stable. When the electromagnet L3 is disconnected, as long as one of the drives can disconnect the triode, a circuit is formed, and the double circuit driving of the electromagnet L3 is completed.

[0020] Further, the No. 1 pin of the control chip MCU is connected with the first transistor Q12 in series with the resistor R59, the capacitor C14, the diode D23, the resistor R58 and the diode D22 in turn, the capacitor C14 and the diode D23 are connected to a common terminal through the reverse connection diode D24, the diode D23 and the resistor R58 are connected to a common terminal through the connection of the polar capacitor E11, the diode D22 and the first transistor Q12 are connected to 5V DC voltage through the series resistor R57 and the polar capacitor E9 in turn. In the high-level driving circuit, the control chip MCU and the first transistor Q12 are connected through multiple elements to stabilize and filter the circuit, protect the circuit from failure and control accurately. The No. 3 pin of the control chip MCU is connected with the resistor R64, and the No. 3 pin of the control chip MCU is connected with the resistor R63, and the other end of the resistor R63 is connected to 5V DC voltage. The PWM driving circuit is basically controlled by the control chip MCU to control whether the second transistor Q13 is turned on or not, further ensuring that the electromagnet L3 can be absolutely powered off, and the double-knife switch S10 and S11 can be disconnected.

[0021] In one embodiment, the thyristor control module includes a resistor R51 connected in parallel between the anode and the trigger of the bidirectional thyristor SRQ4, the trigger of the bidirectional thyristor SRQ4 is further connected to a common terminal through a series resistor R52 and a third transistor Q11 in turn, and the base of the third transistor Q11 is connected to the No. 2 pin of the control chip MCU through the resistor R53. The No. 2 pin of the control chip MCU controls the conduction of the third transistor Q11 by outputting a high level, thereby triggering the bidirectional thyristor SRQ4 to conduct a short circuit of the AC power supply, and further causing the fuse F1 to be burned out, and the subsequent toaster heating wire circuit connected in parallel across the bidirectional thyristor SRQ4 is disconnected.

[0022] In addition, the control chip MCU adopts the SN8P2722 type single-chip microcomputer, which is an 8-pin special chip for toasters with PWM function, providing timing, thawing, reheating, selecting double-sided or single-sided baking, etc. The bidirectional thyristor SRQ4 adopts the BT137 type, which can be triggered and conducted in both forward and reverse directions. After being triggered by the above-mentioned thyristor control module, the fuse F1 is burned out to protect the heating wire and stop the machine from working.

[0023] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, horizontal" and "top, bottom" and the like indicated orientation or position relationship is generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the device or element indicated must have a particular orientation or be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the scope of protection of the present application.

[0024] In the drawings, the position relationship is only used for example description, and cannot be understood as a limitation of the patent; obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not a limitation on the embodiments of the present application. For ordinary skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A toaster dual auxiliary safety control circuit, characterized by, The circuit includes a fuse and a double-blade switch in series with a power supply, and a bidirectional thyristor in parallel between the power supplies, and further includes a control chip for extracting power from the heating wire of the toaster, the control chip being electrically connected with the bidirectional thyristor through a thyristor control module for controlling the conduction direction of the bidirectional thyristor, and the control chip being further electrically connected with an electromagnet through a double-loop driving module for controlling the conduction and disconnection of the electromagnet through high-level driving and PWM driving, thereby controlling the closure and disconnection of the double-blade switch.

2. The dual auxiliary safety control circuit for a toaster of claim 1, wherein, The double-loop driving module includes a diode D21 connected in parallel with the electromagnet, one end of the diode D21 being connected with a 12V DC voltage, the other end of the diode D21 being connected in series with a first triode Q12 and a second triode Q13 and then connected to a common terminal, the base of the first triode Q12 being connected to a No. 1 pin of the control chip, and the base of the second triode Q13 being connected to a No. 3 pin of the control chip.

3. The dual auxiliary safety control circuit for a toaster of claim 2, wherein, A resistor R59, a capacitor C14, a diode D23, a resistor R58 and a diode D22 are connected in series between the No. 1 pin of the control chip and the first triode Q12, the capacitor C14 and the diode D23 being connected to the common terminal through a reverse diode D24, the diode D23 and the resistor R58 being connected to the common terminal through a polar capacitor E11, and the diode D22 and the first triode Q12 being connected to a 5V DC voltage through a resistor R57 and a polar capacitor E9 in series.

4. The double auxiliary safety control circuit of a toaster according to claim 2 or 3, characterized in that, A resistor R64 is connected between the second triode Q13 and the No. 3 pin of the control chip, and a resistor R63 is connected between the No. 3 pin of the control chip and the resistor R64, the other end of the resistor R63 being connected with a 5V DC voltage.

5. The dual auxiliary safety control circuit for a toaster of claim 1 wherein, The thyristor control module includes a resistor R51 connected in parallel between the anode and the trigger electrode of the bidirectional thyristor, the trigger electrode of the bidirectional thyristor being further connected to the common terminal through a resistor R52 and a third triode Q11 in series, and the base of the third triode Q11 being connected to a No. 2 pin of the control chip through a resistor R53.

6. The dual auxiliary safety control circuit for a toaster of claim 4 wherein, The control chip adopts an SN8P2722 type single-chip microcomputer.

7. The dual auxiliary safety control circuit for a toaster of claim 5 wherein, The bidirectional thyristor adopts a BT137 type.

Images