CN213240861U - Isolated anti-failure heater control circuit and heating equipment - Google Patents
Isolated anti-failure heater control circuit and heating equipment Download PDFInfo
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- CN213240861U CN213240861U CN202022118772.9U CN202022118772U CN213240861U CN 213240861 U CN213240861 U CN 213240861U CN 202022118772 U CN202022118772 U CN 202022118772U CN 213240861 U CN213240861 U CN 213240861U
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- pass filter
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 19
- 238000002955 isolation Methods 0.000 claims abstract description 17
- 239000003990 capacitor Substances 0.000 claims description 56
- 238000010025 steaming Methods 0.000 claims description 4
- 238000010304 firing Methods 0.000 abstract description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 abstract description 4
- 230000003287 optical effect Effects 0.000 abstract description 4
- 229910052710 silicon Inorganic materials 0.000 abstract description 4
- 239000010703 silicon Substances 0.000 abstract description 4
- 238000012938 design process Methods 0.000 abstract description 3
- 238000013021 overheating Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010411 cooking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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Abstract
The utility model discloses a heater control circuit and firing equipment of inefficacy are prevented to isolated form, control circuit includes: a single chip microcomputer; the input end of the RC high-pass filter circuit is connected with the single chip microcomputer; the input end of the isolation circuit is connected with the output end of the RC high-pass filter circuit; the output end of the heater is also connected with the heater; the single chip microcomputer sends out a driving signal, and the on-off of the isolation circuit is controlled through the RC high-pass filter circuit, so that the heating control of the heater is realized. The utility model abandons the optical coupler and the silicon controlled rectifier device, and reduces the hardware cost in the design process; the alternating current heater isolation driving control is realized by adopting a mode control mode of a single chip microcomputer and a relay, the heating function of low-cost household appliances is realized, and the risks of overheating and firing of the alternating current heater and the like caused by failure of a driving circuit are prevented.
Description
Technical Field
The utility model relates to a circuit protection's technical field, concretely relates to heater control circuit and firing equipment that became invalid are prevented to isolated form.
Background
At present, with the improvement of the living standard of people and the development of science and technology, various intelligent household appliances come into operation, wherein the intelligent household appliances comprise heating household appliances for cooking, such as a range hood, a steaming oven and the like, and a heater driving circuit is arranged in the appliances.
At present, as shown in fig. 1, a heater driving circuit in the market generally adopts an alternating current heater controlled by a single chip microcomputer, an optical coupler and a silicon controlled rectifier. But its shortcoming has that hardware cost is high, singlechip drive signal inefficacy leads to the alternating current heater to heat and risk problems such as fire continuously. And the existing research and development personnel or enterprises neglect the innovation improvement of the part of the application due to ink conservation and technology improvement limitation. Directly causes objective phenomena such as low product reliability, high development process cost, reduced brand quality and the like.
SUMMERY OF THE UTILITY MODEL
The utility model provides a heater control circuit and firing equipment of inefficacy are prevented to isolated form, it can overcome above-mentioned defect, can avoid the singlechip drive inefficacy to lead to the heater to last the heating to cause the risk.
In order to achieve the above object, the utility model adopts the following technical scheme:
an isolated fail-safe heater control circuit, the control circuit comprising:
a single chip microcomputer;
the input end of the RC high-pass filter circuit is connected with the single chip microcomputer;
the input end of the isolation circuit is connected with the output end of the RC high-pass filter circuit; the output end of the heater is also connected with the heater;
the single chip microcomputer sends out a driving signal, the on-off of the isolation circuit is controlled through the RC high-pass filter circuit, and the heating control of the heater is realized.
Preferably, the RC high-pass filter circuit includes a first capacitor and a first resistor connected in series.
Preferably, the isolation circuit includes a relay and a second capacitor; the coil of the relay is connected with the second capacitor in parallel; a common connecting end of the second capacitor and the coil of the relay is used as an input end of the isolating circuit and is connected with an output end of the RC high-pass filter circuit; the contact of the relay is used as the output end of the isolation circuit and is connected in the heating loop of the heater. More preferably, the contacts of the relay are a pair of normally open contacts.
Preferably, the second capacitor is a polar electrolytic capacitor, and an anode of the second capacitor is connected to a power supply and a cathode of the second capacitor is connected to an output terminal of the RC high-pass filter circuit.
The capacitance value of the second capacitor is larger than that of the first capacitor.
The driving signal sent by the singlechip is a PWM signal.
A heating device comprises the isolated anti-failure heater control circuit and a device body, wherein the device body comprises an alternating current PTC heater assembly.
Preferably, the above-mentioned equipment body is a range hood body or a steaming and baking oven body equipped with an ac PTC heater assembly.
After the technical scheme is implemented, the utility model abandons the optical coupler and the silicon controlled rectifier device, and reduces the hardware cost in the design process; the alternating current heater isolation driving control is realized by adopting a mode control mode of a single chip microcomputer and a relay, the heating function of low-cost household appliances is realized, and the risks of overheating and firing of the alternating current heater and the like caused by failure of a driving circuit are prevented.
Drawings
FIG. 1 is a circuit diagram of the prior art;
fig. 2 is a circuit diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
As shown in fig. 2, the utility model discloses a heater control circuit that became invalid is prevented to isolated form, this control circuit includes:
a single chip microcomputer 1; in this embodiment, the driving signal sent by the single chip microcomputer 1 is a PWM signal, which can avoid the risk of the heater failing to be continuously turned on.
The input end of the RC high-pass filter circuit 2 is connected with the singlechip 1; in the present embodiment, it comprises a first capacitor C32 and a first resistor R49 connected in series. It can avoid the risk of turning on the heater for a long time due to the fact that the 'HEAT _ DRV 1' of the single chip microcomputer fails to be low level. In the application, the RC high-pass filter circuit 2 allows the high-frequency PWM output signal of the single chip microcomputer 1 to pass smoothly, and still provides a PWM signal through the high-frequency PWM output signal, thereby preventing a phenomenon of normally high or normally low caused by the failure of the single chip microcomputer 1.
The isolation circuit 3 comprises a relay REL3 and a second capacitor EC 9; the coil REL3 of the relay is connected in parallel with a second capacitor EC 9; in this embodiment, the second capacitor EC9 is a polar electrolytic capacitor, the positive electrode of the second capacitor EC9 is connected to the power supply, and the negative electrode of the second capacitor EC9 and a common connection end of the coil of the relay REL3 are used as the input end of the isolation circuit 3 and connected to the output end of the RC high-pass filter circuit 2; the contact of the relay REL3 is connected as an output of the isolating circuit 3 in the heating circuit of the heater 4. In this embodiment, the contacts of relay REL3 are a pair of normally open contacts.
In addition, in the present embodiment, the capacitance value of the second capacitor EC9 is greater than the capacitance value C32 of the first capacitor. In specific implementation, the charging and discharging process of the second capacitor EC9 can control the on and off of the relay REL 3. That is, the second capacitor EC9 is still a PWM signal after the high frequency PWM of the single chip microcomputer 1 passes through the high pass filter circuit 2, and when the PWM is positive, the second capacitor EC9 discharges through the coil 3-4 pin of the relay REL3, and maintains the relay REL3 to be turned on; when the PWM is negative, the 5V supply recharges the second capacitor EC9 (to store energy for the next PWM level transition to positive), and also supplies power to relay REL 3.
The singlechip 1 sends out a drive signal which is a PWM signal, and controls the on-off of the isolation circuit 3 through the RC high-pass filter circuit 2, so as to realize the heating control of the heater 4.
Specifically, in implementation, when a driving signal sent by the "HEAT _ DRV 1" of the single chip microcomputer 1 is at a low level, an external power supply (preferably, a 5V power supply is used in this embodiment) forms a path with the second capacitor EC9, the first capacitor C32, the first resistor R49, and the "HEAT _ DRV 1" of the single chip microcomputer 1, and the external power supply charges the second capacitor EC9 and the first capacitor C32; and the voltages of the second capacitor EC9 and the first capacitor C32 are at a high level after the time of three times of the charging time constant "t-3 × (R49 × (C50// C32)". At this time, since the capacitance value of the second capacitor EC9 is much larger than that of the first capacitor C32, when the charging is completed, the voltage on the second capacitor EC9 is close to the power voltage of 5V; when the charging voltage of the second capacitor EC9 reaches the threshold voltage of the coil of the relay REL3, the coil of the relay REL3 is electrified and conducted at the moment, and the pin 1-2 of the normally open contact of the relay REL3 is attracted; at this time, the second capacitor EC9 is continuously charged, and when the second capacitor EC9 is completely charged, the current on the coil of the relay REL3 is 0.
At this time, the singlechip 1 controls the drive signal at the end of the "HEAT _ DRV 1" to be converted into high level, and then the second capacitor EC9 and the first capacitor C32 enter a discharging and energy releasing process; the second capacitor EC9 and the coil of the relay REL3 form a loop, the loop discharges through the coil of the relay REL3, and when the voltage at two ends of the second capacitor EC9 is reduced to the threshold voltage of the coil of the relay REL3 through discharging, the contact 1-2 pin of the relay is converted from a closed state to a normally open state; at this time, when the driving signal of the end of the single chip microcomputer control "HEAT _ DRV 1" is converted into the low level again, the second capacitor EC9 and the first capacitor C32 are charged again, and the contact 1-2 pin of the relay can be continuously controlled to be in the attraction state, so that the heater is controlled to continuously work, and the failure is prevented.
Therefore, it is understood that the relay REL3 can perform isolation control of the ac heater 4.
In addition, when the voltage of "HEAT _ DRV 1" of the single chip microcomputer 1 is PWM (pulse width modulation): the conventional single chip microcomputer has the problem that the IO port is in a high level or a low level for a long time due to software running logic failure or common IO port failure, namely, the optocoupler U11 in the figure risks to conduct the heater 4 for a long time due to the fact that the HEAT _ DRV1 fails to be in a low level;
however, in the present invention, the RC high-pass filter circuit 2 is used, and only when the "HEAT _ DRV 1" signal is PWM, the normal on-state current is maintained between the contacts 1-2 of the relay REL3, and the on-state current is turned on. When the PWM is negative period: the second capacitor EC9 charges the stored energy, and the pins 1-2 of the contact of the relay REL3 pull in due to the conduction current. When the PWM is a positive period: the second capacitor EC9 and the first capacitor C32 discharge and release energy, but the second capacitor EC9 continues to pull in due to the fact that the discharging current of the second capacitor EC9 obtains conducting current between the contact 1-2 pins of the relay REL3 in the process of releasing energy; at this point, the normal hold-on current of relay REL3 can be maintained for continuous operation if the PWM enters the next cycle. That is, this is novel, sets for certain PWM signal then can realize that relay REL3 normally opens, avoids because the inefficacy leads to alternating current heater overheated risk such as catching fire.
Example 2
The utility model also discloses a heating equipment, it includes foretell isolated form heater control circuit and the equipment body of preventing becoming invalid, the equipment body include interchange PTC heater module.
In specific implementation, the equipment body is a range hood body or a steaming and baking oven body provided with an alternating current PTC heater assembly.
The range hood or the steam oven using the control circuit of the embodiment 1 has the advantages that on one hand, the hardware cost in the design process is reduced due to the fact that an optical coupler and a silicon controlled rectifier are abandoned; on the other hand, because this control circuit adopts the mode control mode of singlechip + relay, realizes alternating current heater isolation drive control, realizes low-cost household electrical appliances heating function, and prevents to lead to the alternating current heater risk such as getting on fire because drive circuit loses efficacy, simultaneously, because adopt RC high pass filter circuit 2 cooperation singlechip 1 software code, realizes preventing that the inefficacy lasts to heat risk such as getting on fire.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. An isolated fail-safe heater control circuit, comprising:
a single chip microcomputer;
the input end of the RC high-pass filter circuit is connected with the single chip microcomputer;
the input end of the isolation circuit is connected with the output end of the RC high-pass filter circuit; the output end of the heater is connected with the heater;
the single chip microcomputer sends out a driving signal, the on-off of the isolation circuit is controlled through the RC high-pass filter circuit, and the heating control of the heater is realized.
2. An isolated fail-safe heater control circuit as claimed in claim 1, wherein: the RC high-pass filter circuit comprises a first capacitor and a first resistor which are connected in series.
3. An isolated fail-safe heater control circuit as claimed in claim 2, wherein: the isolation circuit comprises a relay and a second capacitor; the coil of the relay is connected with the second capacitor in parallel; a common connecting end of the second capacitor and the coil of the relay is used as an input end of the isolating circuit and is connected with an output end of the RC high-pass filter circuit; the contact of the relay is used as the output end of the isolation circuit and is connected in the heating loop of the heater.
4. An isolated fail-safe heater control circuit as claimed in claim 3, wherein: the contacts of the relay are a pair of normally open contacts.
5. An isolated fail-safe heater control circuit as claimed in claim 3 or 4, wherein: the second capacitor is a polar electrolytic capacitor, the anode of the second capacitor is connected with a power supply, and the cathode of the second capacitor is connected with the output end of the RC high-pass filter circuit.
6. An isolated fail-safe heater control circuit as claimed in claim 5, wherein: the capacitance value of the second capacitor is larger than that of the first capacitor.
7. An isolated fail-safe heater control circuit as claimed in claim 1, wherein: the driving signal sent by the singlechip is a PWM signal.
8. A heating appliance comprising an isolated fail-safe heater control circuit as claimed in any one of claims 1 to 7 and an appliance body, said appliance body including an ac PTC heater assembly.
9. The heating apparatus according to claim 8, wherein: the equipment body is a range hood body provided with an alternating current PTC heater assembly.
10. The heating apparatus according to claim 8, wherein: the equipment body is a steaming and baking oven body provided with an alternating current PTC heater assembly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022118772.9U CN213240861U (en) | 2020-09-24 | 2020-09-24 | Isolated anti-failure heater control circuit and heating equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022118772.9U CN213240861U (en) | 2020-09-24 | 2020-09-24 | Isolated anti-failure heater control circuit and heating equipment |
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| Publication Number | Publication Date |
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| CN213240861U true CN213240861U (en) | 2021-05-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202022118772.9U Active CN213240861U (en) | 2020-09-24 | 2020-09-24 | Isolated anti-failure heater control circuit and heating equipment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113741233A (en) * | 2021-07-21 | 2021-12-03 | 三门康创电子科技有限公司 | Control circuit of steaming and baking machine, steaming and baking machine and control method of steaming and baking machine |
-
2020
- 2020-09-24 CN CN202022118772.9U patent/CN213240861U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113741233A (en) * | 2021-07-21 | 2021-12-03 | 三门康创电子科技有限公司 | Control circuit of steaming and baking machine, steaming and baking machine and control method of steaming and baking machine |
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