CN1467433A - Safety circuit of electric oven - Google Patents
Safety circuit of electric oven Download PDFInfo
- Publication number
- CN1467433A CN1467433A CNA021242151A CN02124215A CN1467433A CN 1467433 A CN1467433 A CN 1467433A CN A021242151 A CNA021242151 A CN A021242151A CN 02124215 A CN02124215 A CN 02124215A CN 1467433 A CN1467433 A CN 1467433A
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- China
- Prior art keywords
- microcomputer
- relay
- current path
- transistor
- electric oven
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Abstract
The invention discloses safety circuit for the electronic oven, which can monitor the condition when the build-in execution controlling function fails and the breakdown of the computer, then performs the corresponding status transfer according to the condition. The monitoring is realized by the DC resistance capacitance, when the malfunction occurs, the charged voltage can discharged to control the driving component by the capacitance, making it into off-state.
Description
Technical field
The invention relates to electric oven, particularly be a kind of safety return circuit of electric oven.
Background technology
Electric oven is to possess magnetron (reaching) or heater, and carries out the making machine of making function according to the heat of microwave or heater.Electric oven is not only simple in structure, and can finish cooking at short notice, so by being comprised family, and the public place of convenience store etc. uses widely.Such electric oven can be stored a lot of cooking databases, and can be based on make the cooking of selecting according to the user automatically with the cooking database of setting.So, in order to store and management database, and control, be provided with multiple electronic unit in the electric oven.
Recently, can adopt multiple control modes along with the universalness of electronic unit and advanced.Representative in this type of electrical component is exactly a microcomputer.Microcomputer can be used in all electronic products as control assembly.Particularly will control in the product of a lot of cooking databases as electric oven, microcomputer is indispensable.
But under the situation of utilizing microcomputer to control, might produce according to the malfunctioning of microcomputer and generation work, and then can produce the damage of device and the problem that threatens consumer's safety.
Learn about the problem that the malfunctioning situation of microcomputer of electric oven produces below with reference to Fig. 1.As shown in the figure, in order to drive the magnetron of electric oven, for the power relay R Y12 of the service voltage of controlling the magnetron that can drive electric oven; With in order to control and necessary various fan electromotors to the driving of other devices, the main relay RY11 of the driving of lamp etc. is being controlled by microcomputer 20.Between the terminal of main relay RY11 and microcomputer 20, connect NPN transistor Q12, and between the terminal of power relay R Y12 and microcomputer 20, also connecting NPN transistor Q13.
That is, the base terminal of transistor Q12 is connected with the terminals P 10 of microcomputer 20, and its emitter terminal is connected on the ground, and collector terminal is connected on the relay R Y11 by resistance R 13.
Simultaneously, the base terminal of transistor Q13 is connecting the terminals P 11 of microcomputer 20, and collector terminal is connected in relay R Y12, and emitter terminal is connected on the collector terminal of transistor Q12 by two machine pipe D13.
On the original electric oven that is constituted with above-mentioned structure, be to control driving by following process: power supply externally is entered under the inner state that constitutes of product, microcomputer 20 at first judge whether typing the cooking that requires according to the user begin key.If the cooking initiation command is entered into microcomputer 20 by the selection of button, microcomputer 20 will start power relay R Y12 and main relay RY11.
Microcomputer 20 is exported high territory signal from lead-out terminal p10.High territory signal communication transistor Q12, and the current path of formation main relay RY11.Main relay RY11 reaches ground potential by resistance R 13 and transistor Q12, forms current path by this path, and begins to drive.
After main relay RY11 began to drive, under transistorized control, power relay R Y12 also began to drive.Usually power relay R Y12 is than the about pulse of the late startup of main relay.
That is, the driving of power relay R Y12 is to make transistor Q13 convert connected state to by the high territory signal in the lead-out terminal P11 of microcomputer 20 output to finish driving.
When transistor Q13 converts connected state to, converted the current path of the transistor Q12 formation power relay R Y12 of connected state to by driving for main relay RY11.
Power relay R Y12 reaches ground potential by transistor Q13 and diode D13 and transistor Q12 thereof.Form current path by this loop and form driving.As the driven words of power relay R Y12, just begin to finish the driving of magnetron to the magnetron service voltage, then to make-up room internal feed microwave, and the making of arranging.By the driving of main relay RY11, provide voltage to fan electromotor and oven lamp.
So electric oven is to drive main relay RY11 by the signal that the lead-out terminal p10 from microcomputer 20 exports, and carries out the driving of power relay R Y12 by the signal from microcomputer 20 lead-out terminal P11 output.That is, the current path of main relay RY11 is to form by the transistor Q12 that microcomputer 20 is controlled.The current path of power relay R Y12 is to form by the transistor Q13 that microcomputer 20 is controlled.
So, by transistor Q12, the duty of the duty of Q13 decision power relay and main relay.And transistor Q12, the duty of Q13 is by the decision of the output signal of microcomputer 20.
In sum, according to the generation of the malfunctioning situation of microcomputer 20, the output signal of microcomputer 20 continues to keep high territory signal, and transistor Q12, Q13 will continue to drive main relay RY11 and power relay R Y12.Promptly on original electric oven, be not equipped with safety return circuit according to the malfunctioning situation of microcomputer.So electric oven originally can bring the problem that causes fire under the malfunctioning situation of microcomputer producing, reduce the reliability of device thus and threaten consumer safety.
Summary of the invention
In order to overcome the problem of above-mentioned existence, the invention provides a kind ofly when microcomputer has produced malfunctioning situation, prevent to cause the safety return circuit of the electric oven that fire takes place.
To achieve these goals, the present invention adopts following scheme to implement: the safety return circuit of electric oven of the present invention comprises, for the power relay of controlling electric oven and the work of main relay, and the microcomputer of output control signal; The main relay control signal that acceptance is exported from microcomputer, and the 1st current path opening and closing device of the current path of switching main relay; Acceptance is from the power relay control signal of microcomputer output, and the current path of adjusting power relay, the 2nd current path opening and closing device that itself and the 1st current path opening and closing device are coupled together; Be connected on the microcomputer, between the lead-out terminal and the 1st current path opening and closing device of output main relay control signal, in order to block the direct current signal occluding device that produces the direct current signal of introducing under the malfunctioning situation at microcomputer; When microcomputer is normally exported the main relay control signal, charge, and when the malfunctioning situation of microcomputer took place, the charge and discharge device that utilizes charging voltage to control the state transitions of the 1st current path opening and closing device constituted.
In sum, effect of the present invention is, according to the safety return circuit of electric oven of the present invention, and the main relay in the time of can blocking microcomputer malfunctioning situation takes place or the driving that continues of (reaching) power relay.In addition, can prevent the damage of the device that brings because of misoperation and the threat that the protection consumer is not subjected to fire.And then the present invention can prevent the misoperation of device, and can improve the reliability for device.
Description of drawings
Fig. 1 is the safety return circuit figure of the electric oven of original technology.
Fig. 2 is the safety return circuit figure of electric oven of the present invention.
Fig. 3 a is the oscillogram that the main relay exported from microcomputer drives signal.
Fig. 3 b is the oscillogram of the power relay drive signal exported from microcomputer.
Among the figure:
20: microcomputer RY11: main relay
RY12: power relay Q11, Q12, Q13: transistor
D11, D12, D13: diode R11, R12, R13: resistance
C11, C12: capacitor P 10, P11: terminal
The specific embodiment
Below in conjunction with the drawings and specific embodiments the present invention is described in further detail: Fig. 2 is the safety return circuit figure of electric oven of the present invention.As shown in the figure, it monitors the generation of the malfunctioning situation of microcomputer 20, and when the malfunctioning situation of microcomputer takes place, just changes current working state.
As shown in the figure, control drives the power relay R Y12 of service voltage of magnetron of electric oven and the control that the main relay RY11 that is controlled at the driving of various fan electromotors necessary in the driving of other devices and lamp is subjected to microcomputer 20.
Main relay RY11 is according to the connection work formation current loop of NPN transistor Q12.Power relay R Y12 forms current loop according to NPN transistor Q13.Be to be connected with safety return circuit on the base terminal of transistor Q12,, and be connected on the relay R Y11 by resistance R 13 on the collector terminal on the emitter terminal ground of ining succession.And the terminals P 11 of the microcomputer 20 of ining succession on the base terminal of transistor Q13, and collector terminal is connected on the relay R Y12, emitter terminal is connected on the collector terminal of transistor Q12 by D13.
Monitor the generation of the malfunctioning situation of microcomputer 20, and prevent that the safety return circuit of the generation of fire from being to constitute like this: on the output P10 of microcomputer 20, connecting direct-current blocking-up electric capacity C11.Connecting by capacitor C 11 on the base terminal of PNP transistor Q11, and the emitter terminal of transistor Q11 is connected in 5 volts power supply supply side.Its collector terminal is connected on the charge and discharge capacitance C12.Be connected with resistance R 12 at the lead-out terminal P10 of microcomputer 20 and direct-current blocking-up on the contact point between the electric capacity C11, the opposite side of resistance R 12 is connected on the base terminal of transistor Q12 of the current path that opens and closes main relay R11.
With electric oven of the present invention is example, working condition to the safety return circuit when the malfunctioning situation of microcomputer takes place: externally power supply has been entered under the situation of product inside, microcomputer 20, at first judge whether typing the cooking that requires according to the user begin key.If the cooking initiation command is entered into microcomputer 20 by the selection of button, microcomputer 20 will start power relay R Y12 and main relay RY11.
Microcomputer 20 in order to drive main relay RY11 from lead-out terminal p10 output signal.At this moment Shu Chu signal is a signal that is indicated on Fig. 3 a.That is, the driving signal of the main relay RY11 of normal output is that high territory signal and low territory signal are with some cycles AC type signal repeatedly from the microcomputer 20.
Above-mentioned signal is communicated with transistor Q11 by direct-current blocking-up with electric capacity C11.If transistor is connected, the voltage by transistor Q11 fills on capacitor C 11.The transistor Q12 that drives main relay RY11 is connected, and forms the current path of relay R Y11, finishes the driving of relay R Y11.
RY11 is driven as main relay, and microcomputer 20 will be controlled the driving of power relay R Y12.That is, the low territory signal that microcomputer 20 is exported from lead-out terminal P11 as Fig. 3 b, and according to this signal communication transistor Q13.And form the current switching loop of power relay R Y12 according to the connection work of transistor Q13, finish the driving of power relay R Y12 then.The driving of power relay R Y12 also means to the magnetron service voltage, and finishes the driving of magnetron.
The main relay RY11 of electric oven is according to the low territory signal as Fig. 3 b at transistor Q13 with power relay R Y12, keep under the situation of opening, be communicated with repeatedly or disconnect transistor Q12 according to a signal of Fig. 3 a, and the driving of control main relay RY11 and power relay R Y12.
In finish the process of making cooking by above work, might produce the malfunctioning situation of microcomputer 20.And be that two lead-out terminal P10, P11 of microcomputer 20 will continue to keep high territory signal or keep low territory signal in the malfunctioning situation of generation.
At this moment, the high territory signal from microcomputer 20 lead-out terminal P11 output continues to keep high territory state by transistor Q13.But power relay R Y12 is before being controlled by the duty of transistor Q13, and the transistor Q12 that can be subjected to connecting with main relay RY11 is communicated with the control of work.Then the relatively work of the malfunctioning situation of microcomputer 20 is as long as the work of the transistor Q12 that power relay R Y12 and main relay RY11 both are controlled is controlled just passable.But when the malfunctioning situation of microcomputer 20 takes place, all be direct current signal from a or the b of Fig. 3 a of lead-out terminal P10 output.So, can be blocked its signal with electric capacity C11 by direct-current blocking-up.Q11 can keep off-state according to this working transistor, because this work just can not be controlled at the transistor Q12 that any duty takes place to be in after the malfunctioning situation for microcomputer 20.
That is, take place at microcomputer under the situation of malfunctioning state, transistor Q12 can keep that duty after the malfunctioning generation always.If at this moment transistor Q12 maintains the state of disconnection, because relay R Y11, RY12 is in off-state, so what problem can not occur.
But,,, make and continue to keep connected state because the malfunctioning situation of microcomputer 20 can not be subjected to the control of transistor Q11 if the duty of its transistor Q12 is kept connected state.
At this moment when transistor Q11 is communicated with work, is filling the capacitor C 12 of voltage and can emit charging voltage.At this moment discharge voltage can be controlled the duty of transistor Q12, and transistor Q12 can change its duty according to the discharge voltage of capacitor C 12 as a result.Can control two relay R Y11 according to such work, RY12 is an off-state, and prevents to continue to drive when the malfunctioning situation of microcomputer takes place.
Safety return circuit according to electric oven of the present invention constitutes, and when with the microcomputer of carrying out controlling function at device inside malfunctioning situation taking place, monitors the generation of this situation.For reaching, utilize direct-current blocking-up electric capacity, monitor the generation of malfunctioning situation, when malfunctioning situation takes place, utilize the discharge electric capacity of emitting charging voltage.
In addition, the present invention such as microcomputer are used in and use control to control with parts on the control loop of power supply switching and other various work together.So, in the present invention, be that example describes with the electric oven, but the present invention only is limited on the electric oven.
Claims (1)
1. the safety return circuit of an electric oven is characterized in that, the safety return circuit of electric oven is by the power relay (RY12) of control electric oven and the work of main relay (RY11), the microcomputer (20) of output control signal; Acceptance is from main relay (RY11) control signal of microcomputer (20) output, and the 1st current path opening and closing device of the current path of switching main relay (RY11); Acceptance is from power relay (RY12) control signal of microcomputer (20) output, and the current path of adjusting power relay (RY12), the 2nd current path opening and closing device that itself and the 1st current path opening and closing device are coupled together; Be connected between the lead-out terminal (P10) and the 1st current path opening and closing device of output main relay (RY11) control signal on the microcomputer (20), in order to block the direct current signal occluding device that produces the direct current signal of introducing under the malfunctioning situation at microcomputer (20); When microcomputer (20) is normally exported main relay (RY11) control signal, charge, and when the malfunctioning situation of microcomputer (20) took place, the charge and discharge device that utilizes charging voltage to control the state transitions situation of the 1st current path opening and closing device constituted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021242151A CN100334394C (en) | 2002-07-12 | 2002-07-12 | Safety circuit of electric oven |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021242151A CN100334394C (en) | 2002-07-12 | 2002-07-12 | Safety circuit of electric oven |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1467433A true CN1467433A (en) | 2004-01-14 |
| CN100334394C CN100334394C (en) | 2007-08-29 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021242151A Expired - Fee Related CN100334394C (en) | 2002-07-12 | 2002-07-12 | Safety circuit of electric oven |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100334394C (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4633067A (en) * | 1984-08-22 | 1986-12-30 | General Electric Company | Touch control arrangement for an electrical appliance |
| US5218509A (en) * | 1986-05-30 | 1993-06-08 | Robertshaw Controls Company | Electrically operated control device and system for an appliance and method of operating the same |
| US5486725A (en) * | 1993-12-27 | 1996-01-23 | Keizer; Daniel J. | Security power interrupt |
| JP3257441B2 (en) * | 1997-04-08 | 2002-02-18 | 松下電器産業株式会社 | High frequency heating equipment |
-
2002
- 2002-07-12 CN CNB021242151A patent/CN100334394C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CN100334394C (en) | 2007-08-29 |
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Granted publication date: 20070829 |