CN111916310B - Relay control circuit and electric appliance - Google Patents
Relay control circuit and electric appliance Download PDFInfo
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- CN111916310B CN111916310B CN202010906548.8A CN202010906548A CN111916310B CN 111916310 B CN111916310 B CN 111916310B CN 202010906548 A CN202010906548 A CN 202010906548A CN 111916310 B CN111916310 B CN 111916310B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/001—Functional circuits, e.g. logic, sequencing, interlocking circuits
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Abstract
The invention discloses a relay control circuit and an electric appliance, wherein the relay control circuit comprises a control unit, a buffer circuit, a first drive circuit, a second drive circuit, a first control circuit and a second control circuit, wherein the first drive circuit is connected to a relay B1, the second drive circuit is connected to a relay B2, the relay B1 is closed when the first drive circuit is switched on, the relay B2 is closed when the second drive circuit is switched on, the control unit comprises a control chip Z1, and the control chip Z1 controls the switching on of the first drive circuit and the second drive circuit through an IO pin, so that the switching on and off of the relay B1 and the relay B2 are controlled. Compared with the prior art, the relay control circuit only needs one IO pin, so that the use of the IO port of a chip is saved, and the cost is reduced.
Description
Technical Field
The invention relates to the field of electric appliances, in particular to a relay control circuit and an electric appliance.
Background
In both fixed frequency and variable frequency electrical products, two relays are often used to control the activation of the electrical appliance. In the prior art, an independent chip IO port is independently used for controlling each relay in a relay control circuit for starting an electric appliance. Then, the IO port resources of the chip are very precious. When designing a circuit, if a chip IO port is lacked, a higher-level chip is often needed, thereby causing waste of cost.
Therefore, how to design a relay control circuit, control of the relay can be realized through a single IO port, and the use of the IO port of the chip is saved, which is a technical problem to be solved urgently in the industry.
Disclosure of Invention
The invention provides a relay control circuit and an electric appliance, and aims to solve the problems that in the prior art, a relay control circuit usually needs a plurality of chip IO ports, and IO resources are wasted.
The technical scheme of the invention provides a relay control circuit, which comprises: the relay B1 is connected in series with a resistor for limiting impact current during electrification, the relay B2 is arranged in parallel with the relay B1, and the control unit comprises a control chip Z1, wherein the control chip Z1 controls the on-off of the relay B1 and the relay B2 through an IO pin;
the relay control circuit further includes: the first control circuit and the buffer circuit are connected with the IO pin, the first drive circuit is connected with the first control circuit, the second drive circuit is connected with the buffer circuit, and the second control circuit is connected between the buffer circuit and the first control circuit;
when the control unit receives an electric appliance starting signal, the control unit sequentially controls the first driving module to be switched on, the second driving module to be switched on and the first driving module to be switched off;
and when the control unit receives an electrical appliance disconnection signal, the control unit controls the first driving module and the second driving module to be disconnected.
Further, the first driving module comprises a resistor R3, a resistor R4 and a triode Q1, the base of the triode Q1 is connected with the first control circuit after being connected with the resistor R3 in series, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected with the relay B1, and the resistor R4 is connected between the base and the emitter of the triode Q1.
Further, the second driving module comprises a resistor R6, a resistor R7 and a triode Q2, wherein a base of the triode Q2 is connected with the buffer circuit in series after being connected with the resistor R6, an emitter of the triode Q2 is grounded, a collector of the triode Q2 is connected with the relay B2, and the resistor R7 is connected between the base and the emitter of the triode Q2.
Further, the first control circuit comprises a resistor R2 and a resistor R10, one end of the resistor R2 is connected with the IO pin, the other end of the resistor R2 is connected with the resistor R3, one end of the resistor R10 is connected between the resistor R2 and the resistor R3, and the other end of the resistor R10 is connected to the second control circuit.
Further, the second control circuit comprises a resistor R8, a resistor R9 and a triode Q3, wherein a collector of the triode Q3 is connected with the resistor R10, a base of the triode Q3 is connected with the buffer circuit after being connected with the resistor R8 in series, and an emitter of the triode Q3 is grounded; the resistor R9 is connected between the base and emitter of the transistor Q3.
Further, the buffer circuit comprises a resistor R1 and a capacitor C1, the resistor R1 is connected between the IO pin and the resistor R6, one end of the capacitor C1 is connected between the resistor R1 and the resistor R6, and the other end of the capacitor C1 is grounded.
Furthermore, an electrical bus is connected to two ends of the relay B1, and when the relay B1 is closed, the electrical bus is communicated.
Furthermore, an electrical bus is further connected to two ends of the relay B2, and when the relay B2 is closed, the electrical bus is conducted.
Further, the ratio of the resistor R7 to the resistor R6 is greater than the ratio of the resistor R9 to the resistor R8.
The invention also provides an electric appliance, and the electric appliance adopts the relay control circuit.
Compared with the prior art, the invention has at least the following beneficial effects:
can realize the control in proper order to the relay through an IO pin of control chip, compare in the circuit of two current IO pins, save the use of control chip pin, be favorable to reduce cost.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic diagram of a relay control circuit according to the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, 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.
Thus, a feature indicated in this specification will serve to explain one of the features of one embodiment of the invention, and does not imply that every embodiment of the invention must have the stated feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.
The principles and construction of the present invention will be described in detail below with reference to the drawings and examples.
First, each component of the relay control circuit of the present invention will be described, where U1, U2, and U3 are power supply voltages, and GND is ground. And G1 and G2 are respectively electrical buses at two ends of the relay. K1, K2, K3 are nodes. B1 and B2 are relays, B1 and B2 are switches inside relays B1 and B2, respectively, and D1 and D2 are diodes. R5 is a resistor for limiting impact current when power is on, Z1 is a control chip, X is an input end of an electric appliance starting signal, and Y is an input end of an electric appliance turning-off signal.
The relay control circuit of the present invention includes a control unit, a first control circuit, a second control circuit, a first drive circuit, a second drive circuit, and a buffer circuit. The control unit comprises a control chip Z1, the first control circuit comprises a resistor R2 and a resistor R10, the second control circuit comprises a resistor R8, a resistor R9 and a triode Q3, the first driving circuit comprises a resistor R3, a resistor R4 and a triode Q1, the second driving circuit comprises a resistor R6, a resistor R7 and a triode Q2, and the buffer circuit comprises a resistor R1 and a capacitor C1.
The control chip Z1 has two input pins, which are respectively connected to the input terminal X of the electrical appliance start signal and the input terminal Y of the electrical appliance shutdown signal. The control chip Z1 further has an IO pin, the IO pin is connected to the resistor R2 of the first control circuit and the resistor R1 of the buffer circuit, when the control chip Z1 is in an initial state, the IO pin outputs a low level, when the control chip Z1 receives an electrical appliance start signal, the IO pin outputs a high level, and when the control chip Z1 receives an electrical appliance turn-off signal, the IO pin outputs a low level.
The first control circuit is connected between the control unit and the first drive circuit, wherein one end of the resistor R2 is connected with the resistor R3 of the first drive module, the other end of the resistor R2 is connected with the IO pin of the connection node K1 of the control chip Z1, one end of the resistor R10 is connected between the resistor R2 and the resistor R3, and the other end of the resistor R10 is connected with the collector of the triode Q3 of the second control circuit.
The first driving circuit is connected between the first control circuit and a relay B1, wherein the base of a transistor Q1 is connected with a resistor R2 after being connected with a resistor R3 in series, the collector of the transistor Q1 is connected with a relay B1, the emitter of the transistor is connected with the ground, and a resistor R4 is connected between the base of the transistor Q1 and the emitter of the transistor Q1.
The buffer circuit is respectively connected to the control unit, the second driving circuit and the second control circuit, wherein one end of the resistor R1 is connected to the IO pin of the connection node K1 of the control chip Z1, the other end of the resistor R6 is connected to the second driving circuit, one end of the capacitor C1 is connected between the resistor R1 and the resistor R6, and the other end of the capacitor C1 is grounded.
The second control circuit is respectively arranged between the buffer circuit and the first control circuit, wherein a triode Q3 series resistor R8 is connected with a resistor R1 of the buffer circuit, an emitter of the triode Q3 is grounded, a collector of the triode Q3 is connected with a resistor R10 of the first control circuit, and a resistor R9 is connected between a base of the triode Q3 and an emitter of the triode Q3.
The second driving circuit is connected between the buffer circuit and a relay B2, wherein the base of a transistor Q2 is connected with a resistor R6 in series and then connected with a resistor R1 of the buffer circuit, the emitter of the transistor Q2 is grounded, the collector of a transistor Q2 is connected with a relay B2, and a resistor R7 is connected between the base of the transistor Q2 and the emitter of a transistor Q2.
The relay B1 is also connected with two ends of an electric appliance bus, a resistor R5 is also connected in series outside the relay B1, the relay B2 is connected with two ends of the electric appliance bus, and when the relay B1 and the relay B2 are closed, internal switches B1 and B2 are also closed, so that the electric appliance bus is conducted.
Specifically, a node K1 is arranged between the IO pin and the resistor R1, a node K2 is arranged between the resistor R1 and the resistor R6, and a node K3 is arranged between the resistor R2 and the resistor R3. When the control chip Z1 is in an initial state, the IO pin outputs a low level, and when the control chip Z1 does not receive a start signal of an electrical appliance, the IO pin of the connection node K1 of the control chip Z1 outputs a low level, and the node K1 is a low level. At this time, the node K2 and the node K3 are also at a low level, the transistor Q1 and the transistor Q2 are turned off, the switch B1 and the switch B2 inside the relay B1 and the relay B2 are both turned on, the space between the G1 and the G2 of the electrical apparatus bus is opened, and the electrical apparatus does not work.
When a user needs to start the electric appliance, an electric appliance starting signal is input from the electric appliance starting input end X, the IO pin output is changed from a low level to a high level after the control chip Z1 receives the electric appliance starting signal, and the level at the node K1 is changed to the high level. Due to the current limitation of the resistor R1 and the charging effect of the capacitor C1, the level at the node K2 will rise slower than that of the node K1, at this time, the voltage at the node K3 will rise to a value larger than the on-state voltage u1 of the transistor to turn on the transistor Q1, and since the rising rate of the voltage at the node K2 is behind the node K3, the voltage between the base and the emitter of the transistor Q3 has not yet reached the on-state requirement of the transistor Q3 within a certain time interval t1 after the voltage at the node K3 rises to the value u1, and the transistor Q3 is in the off-state. After the voltage at the node K3 begins to rise to u1, the transistor Q1 is turned on, thereby turning on the relay B1.
Due to the charging effect of the capacitor C1, the voltage at node K2 rises behind node K1. The voltage at the node K2 rises to a certain voltage u 2. The voltage between the base electrode and the emitter electrode of the triode Q2 can firstly reach the conduction requirement by adjusting the ratio of the resistors R6 and R7 to the resistors R8 and R9, so that the triode Q2 is conducted, and the relay B2 is closed. Here, R7/R6> R9/R8 is provided, since the divided voltage of the resistors R6 and R7 is proportional to the resistors, and the divided voltage of the resistors R8 and R9 is also proportional to the resistors, there are Ur7/Ur 6> Ur9/Ur8, and the voltage at the node K2 is constant, when Ur7/Ur 6> Ur9/Ur8, the voltage at the base of the triode Q2 is higher than the voltage at the base of the triode Q3. Therefore, when the voltage at the node K1 rises to the voltage value u2, the transistor Q2 starts to conduct, and when the voltage at the node K1 does not rise to a certain voltage value u3 that is greater than the voltage value u2, the transistor Q3 does not conduct. At this time, relay B1 is turned on, and relay B2 is turned on.
After the transistor Q2 is turned on for a certain time, as the voltage at the node K2 further increases, the voltage between the base and the emitter of the transistor Q3 finally reaches the value u3 of the on-voltage of the transistor Q3, and the transistor Q3 is turned on. After the transistor Q3 is turned on, the transistor Q2 is still turned on, the resistor R2 is connected to the ground through the resistor R10 and the transistor Q2, when the resistor R10 is much smaller than the resistor R2, the voltage value at the node K3 will drop to a value insufficient to turn on the transistor Q1, the transistor Q1 is turned off, and the switch B1 inside the relay B1 is turned off. Finally, the voltage at node K2 is maintained above the voltage that causes transistor Q2 and transistor Q3 to turn on, transistor Q2 and transistor Q3 are turned on, transistor Q1 is turned off, relay B2 is closed and relay B1 is open. This achieves the entire start-up process of first closing relay B1, then closing relay B2, and finally opening relay B1.
The voltage rising rate of the node K2 can be regulated by selecting a proper resistor R1 and a proper capacitor C1, the larger the resistor R1 is, the smaller the current flowing through the resistor R1 is, the smaller the voltage rising rate of the node K2 is when the capacitor C1 is charged, the larger the capacitor C1 is, the longer the charging time is, the smaller the voltage rising rate of the node K2 is when the capacitor C1 is charged is, and the voltage rising rate of the node K2 can be regulated when the capacitor C1 is charged according to the regulation resistor R1 and the capacitor C1. Meanwhile, after the triode Q2 is conducted, the triode Q3 is conducted only after a period of time, and the time can be adjusted by adjusting the ratio of the R7/R6 to the R9/R8 by adjusting the resistor R1, the resistor R6, the resistor R7, the resistor R8, the resistor R9 and the capacitor C1, so that the larger the value of R7/R6-R9/R8 is, the longer the time of the triode Q2 is, and the longer the triode Q3 is conducted.
It should be noted here that since the circuit generates a large current peak at the starting moment of power-on at the start, and there is a possibility of burning out the elements in the circuit, a resistor needs to be connected in series at the start to reduce the current overshoot, and a buffer resistor R5 for preventing the overshoot is connected in series in the related circuit of the relay B1. However, the resistor R5 generally has more than tens of ohms, and the current is large, which causes a large extra power loss if the resistor R5 is connected in series in the circuit all the time during the operation of the circuit. Therefore, the operating circuit must not have resistor R5 in series in it. Therefore, when the circuit is operated, the relay B1 is closed, then the relay B2 is closed, and finally the relay B1 is opened.
When the electric appliance needs to be turned off, a signal for turning off the relay is input into an input end Y of an electric appliance turn-off signal, after the control chip Z1 receives the signal for turning off the relay, the output of an IO pin is changed from high level to low level, the node K1 is changed into low level, the node K2 and the node K3 are also changed into low level, the triodes Q2 and Q3 are cut off, the relay B2 is turned off, the internal switch B2 is turned off, and the G1 and the G2 are turned off (the relay B1 is turned off after the electric appliance is turned on).
In the whole starting and running engineering of the electric appliance, if the control chip Z1 wants to turn off the relay, the level of the K1 can be changed to be low level at any time to turn off the relays B1 and B2. The resistor R1 with a larger resistance value and the R6, R7, R8 and R9 with smaller resistance values compared with the resistor R1 can be selected to ensure that the capacitor C1 is charged slowly, and meanwhile, the discharging speed of the capacitor C1 is higher, so that the relays B1 and B2 are switched off quickly when the control chip Z1 sends a command of switching off the relays.
Compared with the prior art, the invention realizes the control of two relays B1 and B2 through one output end, realizes the process that the relay B1 is firstly closed, then the relay B2 is closed, and finally the relay B1 is opened, saves the use of an IO port of a control chip Z1, and plays a remarkable role in reducing the cost.
The invention also provides an electric appliance, and the electric appliance adopts the relay control circuit.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A relay control circuit comprising: the relay B1 is connected in series with a resistor for limiting impact current during electrification, the relay B2 is arranged in parallel with the relay B1, and the control unit is characterized by comprising a control chip Z1, wherein the control chip Z1 controls the on-off of the relay B1 and the relay B2 through an IO pin;
the relay control circuit further includes: the first control circuit and the buffer circuit are connected with the IO pin, the first drive circuit is connected with the first control circuit, the second drive circuit is connected with the buffer circuit, and the second control circuit is connected between the buffer circuit and the first control circuit;
when the control unit receives an electric appliance starting signal, the control unit sequentially controls the first driving circuit to be switched on, the second driving circuit to be switched on and the first driving circuit to be switched off;
and when the control unit receives an electrical appliance disconnection signal, the control unit controls the first drive circuit and the second drive circuit to be disconnected.
2. The relay control circuit as claimed in claim 1, wherein the first driving circuit comprises a resistor R3, a resistor R4, and a transistor Q1, wherein a base of the transistor Q1 is connected in series with the resistor R3 and then connected to the first control circuit, an emitter of the transistor Q1 is grounded, a collector of the transistor Q1 is connected to the relay B1, and the resistor R4 is connected between the base and the emitter of the transistor Q1.
3. The relay control circuit as claimed in claim 2, wherein the second driving circuit comprises a resistor R6, a resistor R7, and a transistor Q2, wherein the base of the transistor Q2 is connected in series with the resistor R6 and then connected to the snubber circuit, the emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected to the relay B2, and the resistor R7 is connected between the base and the emitter of the transistor Q2.
4. The relay control circuit according to claim 3, wherein the first control circuit comprises a resistor R2 and a resistor R10, one end of the resistor R2 is connected to the IO pin, the other end of the resistor R2 is connected to the resistor R3, one end of the resistor R10 is connected between the resistor R2 and the resistor R3, and the other end of the resistor R10 is connected to the second control circuit.
5. The relay control circuit as claimed in claim 4, wherein the second control circuit comprises a resistor R8, a resistor R9, and a transistor Q3, wherein the collector of the transistor Q3 is connected to the resistor R10, the base of the transistor Q3 is connected to the buffer circuit after being connected in series with the resistor R8, and the emitter of the transistor Q3 is grounded; the resistor R9 is connected between the base and emitter of the transistor Q3.
6. The relay control circuit according to claim 5, wherein the snubber circuit comprises a resistor R1 and a capacitor C1, the resistor R1 is connected between the IO pin and the resistor R6, one end of the capacitor C1 is connected between the resistor R1 and the resistor R6, and the other end of the capacitor C1 is grounded.
7. The relay control circuit of claim 1, wherein an appliance bus is further connected to both ends of the relay B1, and when the relay B1 is closed, the appliance bus is connected.
8. The relay control circuit of claim 1, wherein an appliance bus is further connected to both ends of the relay B2, and when the relay B2 is closed, the appliance bus is turned on.
9. The relay control circuit of claim 5, wherein a ratio of the resistor R7 to the resistor R6 is greater than a ratio of the resistor R9 to the resistor R8.
10. An electrical appliance, characterized in that the electrical appliance employs a relay control circuit according to any one of claims 1 to 9.
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CN202010906548.8A CN111916310B (en) | 2020-09-01 | 2020-09-01 | Relay control circuit and electric appliance |
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CN202010906548.8A CN111916310B (en) | 2020-09-01 | 2020-09-01 | Relay control circuit and electric appliance |
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CN203617218U (en) * | 2013-12-30 | 2014-05-28 | 广东瑞德智能科技股份有限公司 | Circuit for driving two delays through single I/O port |
CN204009465U (en) * | 2014-08-15 | 2014-12-10 | 卡乐电子(苏州)有限责任公司 | For the relay pwm control circuit of panel type electronic thermostat |
CN207194703U (en) * | 2017-09-27 | 2018-04-06 | 南京机电职业技术学院 | A kind of automatic door controller |
CN108198731A (en) * | 2018-02-05 | 2018-06-22 | 厦门拓宝科技有限公司 | A kind of magnetic latching relay control circuit |
CN108845611A (en) * | 2018-08-27 | 2018-11-20 | 珠海格力电器股份有限公司 | Dry contact peripheral interface |
JP2020017891A (en) * | 2018-07-26 | 2020-01-30 | ローム株式会社 | Pulse control device |
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2020
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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CN203617218U (en) * | 2013-12-30 | 2014-05-28 | 广东瑞德智能科技股份有限公司 | Circuit for driving two delays through single I/O port |
CN204009465U (en) * | 2014-08-15 | 2014-12-10 | 卡乐电子(苏州)有限责任公司 | For the relay pwm control circuit of panel type electronic thermostat |
CN207194703U (en) * | 2017-09-27 | 2018-04-06 | 南京机电职业技术学院 | A kind of automatic door controller |
CN108198731A (en) * | 2018-02-05 | 2018-06-22 | 厦门拓宝科技有限公司 | A kind of magnetic latching relay control circuit |
JP2020017891A (en) * | 2018-07-26 | 2020-01-30 | ローム株式会社 | Pulse control device |
CN108845611A (en) * | 2018-08-27 | 2018-11-20 | 珠海格力电器股份有限公司 | Dry contact peripheral interface |
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