A low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer

Abstract

The present invention discloses a low-cost and low-power standby circuit for an electrical appliance powered by a power-frequency transformer. The circuit includes an AC input terminal, and a control circuit electrically connected to the AC input terminal and used for controlling the electrical appliance to achieve low-cost and low-power standby; a micro-control unit is also electrically connected in the control circuit. The standby circuit has extremely low cost. Compared with the commonly used small-power switching power supplies and small power-frequency transformers in the industry, it has great advantages in terms of cost, is simple and reliable, and is convenient for production. Moreover, if the power-frequency transformer consumes 5W of power when directly connected to the AC, and the power consumption is 1W after using this circuit, then an electrical appliance saves 4W of power. Since the circuit operates at an extremely low switching frequency, there is no EMC problem caused by the switching power supply, and the temperature rise of the transformer during standby of the circuit is very low, effectively extending the service life; moreover, the circuit occupies a small PCB space, can save the space inside the whole machine, and reduce the volume of the whole machine.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical appliance power consumption control processing, and particularly relates to a low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer. Background Art

[0002] Currently, among electrical appliances powered by small power frequency transformers on the market, especially for electric door openers, since the no-load power consumption of the power frequency transformer can be as high as about 5W, it causes serious waste of electric power resources. At the same time, the temperature rise of the transformer is also relatively high, accelerating the aging of the transformer.

[0003] In the industry, the low-power standby problem is often solved in two ways: using a small-power switching power supply or a tiny power frequency transformer specifically for the system standby. When the electrical appliance receives a wake-up instruction and wakes up from the standby state, it switches to the main power frequency transformer for power supply. Both of the above methods have the problems of high cost and large volume. The small-power switching power supply scheme may also introduce EMC interference problems.

[0004] Therefore, in view of the above technical problems and defects of high cost, large volume, and high power consumption, it is urgent to design and develop a low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies and difficulties of the prior art, the purpose of the present invention is to provide a low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer, so as to achieve the technical effect of low cost and low power consumption of the electrical appliance.

[0006] The purpose of the present invention is achieved as follows: The circuit includes an AC input terminal, and a control circuit electrically connected to the AC input terminal and used for controlling the electrical appliance to achieve low-cost and low-power standby.

[0007] A micro control unit is also electrically connected in the control circuit.

[0008] Further, a 33V to 5V power supply for supplying power to the micro control unit is also provided in the control circuit.

[0009] The 33V to 5V power supply is a DC-DC conversion circuit with the BM0150HV chip as the core, or a power conversion circuit with a similar function.

[0010] The micro control unit is an MCU processing unit with the CBM7320FBS1A or a similar function as the core.

[0011] The model of the AC input terminal is RT-C08-F2-WH.

[0012] Furthermore, a small power frequency transformer is also provided in the control circuit;

[0013] One end of the input of the power frequency transformer is respectively connected to one end of the fifth varistor, one end of the sixth triac, and one end of the ninth resistor; the other end of the fifth varistor, the other end of the sixth triac, one end of the eighth capacitor, one end of the second varistor, one end of the first fuse, and one end of the sixteenth resistor are connected;

[0014] The other end of the first fuse is connected to one end of the AC input; the other end of the AC input is respectively connected to the other end of the second varistor, the other end of the eighth capacitor, and the other end of the input of the power frequency transformer;

[0015] The G pole of the sixth triac, the third pin of the fourth rectifier bridge, and the other end of the ninth resistor are connected; the other end of the sixteenth resistor is connected to the fourth pin of the fourth rectifier bridge; the first pin of the fourth rectifier bridge is respectively connected to one end of the seventeenth resistor and the anode of the eleventh thyristor; the cathode of the eleventh thyristor is respectively connected to the second pin of the fourth rectifier bridge and the third pin of the ninth optocoupler;

[0016] The other end of the seventeenth resistor is connected to one end of the eighteenth resistor; the other end of the eighteenth resistor is respectively connected to the control pole of the eleventh thyristor and the fourth pin of the ninth optocoupler;

[0017] The first pin of the ninth optocoupler is connected to the power saving control pin of the microcontroller unit; the second pin of the ninth optocoupler is connected to one end of the twenty-seventh resistor; the other end of the twenty-seventh resistor is connected to the collector of the first triode; the emitter of the first triode is grounded; the base of the first triode is respectively connected to one end of the tenth capacitor and the anode of the fourteenth zener diode; the cathode of the fourteenth zener diode is respectively connected to the other end of the tenth capacitor and one end of the twenty-sixth resistor; the other end of the twenty-sixth resistor is respectively connected to the cathode of the fourth diode, the cathode of the second diode, the anode of the first polarized capacitor, one end of the second capacitor, and the power supply in the microcontroller unit;

[0018] The cathode of the first polarized capacitor, the other end of the second capacitor, and the ground terminal in the microcontroller unit are commonly grounded;

[0019] The anode of the fourth diode is respectively connected to the cathode of the third diode and one end of the output of the power frequency transformer; the anode of the second diode is respectively connected to the cathode of the first diode and the other end of the output of the power frequency transformer; the anode of the third diode and the anode of the first diode are commonly grounded.

[0020] Further, the model of the sixth triac is BT137-600E or T405-600B.

[0021] Further, the model of the eleventh thyristor is PCR606.

[0022] Further, the model of the fourth rectifier bridge is MB10S.

[0023] Further, the model of the ninth optocoupler is EL817S1.

[0024] Further, the model of the first polarized capacitor is 2200uF / 50V.

[0025] Further, the model of the first fuse is SQT3.15M.

[0026] Further, the models of the fifth varistor and the second varistor are both 10D471K.

[0027] The present invention relates to a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer, including an AC input terminal, and a control circuit electrically connected to the AC input terminal and used for controlling the electrical appliance to achieve low-cost and low-power standby; a microcontrol unit is also electrically connected in the control circuit. The standby circuit has extremely low cost. Compared with the commonly used small-power switch power supply and small power frequency transformer in the industry, it has great advantages in cost, is simple and reliable, and is convenient for production. It has high social and economic benefits. Moreover, if the power frequency transformer consumes 5W of power when directly connected to the AC, and the power consumption is 1W after using this circuit, then an electrical appliance saves 4W of power. The feeling of a single user may not be obvious, but if an electrical appliance manufacturer produces 100,000 electrical appliances and puts them on the market in a year, the saved electric power reaches 400KW. Since the circuit operates at an extremely low switching frequency, there is no EMC problem caused by the switch power supply, and the temperature rise of the transformer during standby of the circuit is very low, effectively extending the service life; moreover, the circuit occupies a small PCB space, can save the space inside the whole machine, and reduce the volume of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts;

[0029] Figure 1 It is a schematic diagram of the low-cost and low-power standby circuit architecture of an electrical appliance powered by a power frequency transformer according to the present invention;

[0030] Figure 2It is a schematic diagram of a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to the present invention;

[0031] Figure 3 It is a waveform diagram of the primary side of the transformer in the low-power mode of a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to the present invention

[0032] Figure 4 It is a schematic diagram of the VCC voltage waveform in the low-power mode of a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to the present invention;

[0033] In the figure: R5 - the fifth varistor; Q6 - the sixth triac; C8 - the eighth capacitor; R2 - the second varistor; F1 - the first fuse; R16 - the sixteenth resistor; AC1 - the AC input terminal; D4 - the fourth rectifier bridge; R16 - the sixteenth resistor; R17 - the seventeenth resistor; D11 - the eleventh thyristor; U9 - the ninth optocoupler; R18 - the eighteenth resistor; R27 - the twenty-seventh resistor; Q1 - the first triode; C10 - the tenth capacitor; D14 - the fourteenth zener diode; R26 - the twenty-sixth resistor; D4 - the fourth diode; D2 - the second diode; C1 - the first polarized capacitor; C2 - the second capacitor; D3 - the third diode; D1 - the first diode; R9 - the ninth resistor;

[0034] The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0035] For a better understanding of the purpose, technical solution and advantages of the present invention, the following further describes the present invention in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0036] The present invention can also be implemented or applied through other different specific examples. Various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0037] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0038] In addition, if the descriptions such as "first" and "second" are involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. Secondly, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] As Figures 1-4 shown, the present invention provides a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer. The circuit includes an AC input terminal AC1 and a control circuit electrically connected to the AC input terminal AC1 and used to control the electrical appliance to achieve low-cost and low-power standby.

[0041] A microcontrol unit is also electrically connected in the control circuit.

[0042] A 33V to 5V power supply for supplying power to the microcontrol unit is also provided in the control circuit.

[0043] The model of the 33V to 5V power supply is a DC-DC conversion circuit with the BM0150HV chip as the core, or a power conversion circuit with a similar function.

[0044] The model of the microcontrol unit is an MCU processing unit with the CBM7320FBS1A or a similar function as the core.

[0045] The model of the AC input terminal AC1 is RT-C08-F2-WH.

[0046] A power frequency transformer is also provided in the control circuit.

[0047] One end of the input terminal of the power frequency transformer is respectively connected to one end of the fifth varistor R5, one end of the sixth triac Q6, and one end of the ninth resistor R9; the other end of the fifth varistor R5, the other end of the sixth triac Q6, one end of the eighth capacitor C6, one end of the second varistor R2, one end of the first fuse F1, and one end of the sixteenth resistor R16 are connected.

[0048] The other end of the first fuse F1 is connected to one end of the AC input terminal AC1; the other end of the AC input terminal AC1 is respectively connected to the other end of the second varistor R2, the other end of the eighth capacitor C6, and the other end of the input terminal of the power frequency transformer;

[0049] The G pole of the sixth triac Q6 is connected to the third pin of the fourth rectifier bridge D4 and the other end of the 9th resistor R9; the other end of the sixteenth resistor R16 is connected to the fourth pin of the fourth rectifier bridge D4; the first pin of the fourth rectifier bridge D4 is respectively connected to one end of the seventeenth resistor R17 and the anode of the eleventh thyristor D11; the cathode of the eleventh thyristor D11 is respectively connected to the second pin of the fourth rectifier bridge D4 and the third pin of the ninth optocoupler U9;

[0050] The other end of the seventeenth resistor R17 is connected to one end of the eighteenth resistor R18; the other end of the eighteenth resistor R18 is respectively connected to the control pole of the eleventh thyristor D11 and the fourth pin of the ninth optocoupler U9;

[0051] The first pin of the ninth optocoupler U9 is connected to the power saving control pin of the microcontrol unit; the second pin of the ninth optocoupler U9 is connected to one end of the twenty-seventh resistor R27; the other end of the twenty-seventh resistor R27 is connected to the collector of the first triode Q1; the emitter of the first triode Q1 is grounded; the base of the first triode Q1 is respectively connected to one end of the tenth capacitor C10 and the anode of the fourteenth voltage regulator diode D14; the cathode of the fourteenth voltage regulator diode D14 is respectively connected to the other end of the tenth capacitor C10 and one end of the twenty-sixth resistor R26; the other end of the twenty-sixth resistor R26 is respectively connected to the cathode of the fourth diode D4, the cathode of the second diode D2, the anode of the first polarized capacitor C1, one end of the second capacitor C2, and the power supply in the microcontrol unit;

[0052] The cathode of the first polarized capacitor C1, the other end of the second capacitor C2 and the ground terminal in the microcontrol unit are commonly grounded;

[0053] The anode of the fourth diode D4 is respectively connected to the cathode of the third diode D3 and one end of the output terminal of the power frequency transformer; the anode of the second diode D2 is respectively connected to the cathode of the first diode D1 and the other end of the output terminal of the power frequency transformer; the anode of the third diode D3 and the anode of the first diode D1 are commonly grounded.

[0054] The model of the sixth triac Q6 is BT137-600E or T405-600B. The model of the eleventh thyristor D11 is PCR606. The model of the fourth rectifier bridge D4 is MB10S. The model of the ninth optocoupler U9 is EL817S1. The model of the first polarized capacitor C1 is 2200uF / 50V. The model of the first fuse F1 is SQT3.15M. The models of the fifth varistor R5 and the second varistor R2 are both 10D471K.

[0055] Specifically, in a specific embodiment of the solution of the present invention, a low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer is provided; a small number of discrete components are used to control the on-time of the power frequency transformer, so that it is disconnected most of the time and connected for a short time, and the ratio of on-time to off-time can be automatically adjusted according to the load weight, ensuring normal power supply to the MCU and the radio receiving circuit when the electrical appliance is in standby, so as to achieve the purpose of reliable power saving and energy conservation.

[0056] In the project of the Hos door opener ET-GDO6EF, this product achieved a ratio of on-time of 10-20mS and off-time of 4000mS (average 1 / 266), and the energy-saving effect is very obvious. During operation, the power frequency transformer has almost no temperature rise.

[0057] The circuit schematic diagram is as shown in the attached figure; the control principle is as follows:

[0058] Normal operation of the electrical appliance: The power-saving control pin of the single-chip microcomputer outputs a low level, so that the optocoupler U9 is not turned on regardless of the VCC voltage level. The thyristor D11 is turned on within a very short time after the AC zero-crossing, and the triac Q6 is controlled to be always turned on. In this way, the power frequency transformer is always connected to the AC power supply. The VCC voltage waveform is a straight line of about 33V depending on the mains voltage.

[0059] When entering the low-power mode, the working process is as follows:

[0060] A. The power-saving control pin of the single-chip microcomputer outputs a high level. If the VCC voltage is higher than 10V at this time, the zener diode D14 breaks down, the triode Q1 conducts, the optocoupler U9 conducts, and the gate of the unidirectional thyristor D11 is short-circuited, thereby turning off D11 and turning off Q6, and the power frequency transformer is disconnected from the AC power supply.

[0061] B. After the primary of the transformer is disconnected from the AC, due to the energy storage effect of the C1 capacitor, plus the electrical appliance enters the low-power mode to turn off unnecessary external devices, and the MCU enters the low-power mode, the power consumption of the whole machine is very low, and the VCC will slowly drop, as shown in the attached Figure 4 figure.

[0062] C. When VCC drops to around 10V, since VCC cannot break down the voltage regulator diode D14, the triode Q1 is cut off, the optocoupler U9 is not conducting, and the unidirectional thyristor D11 will conduct within a very short time after the AC zero-crossing, thereby turning on the bidirectional thyristor Q6 and connecting the power frequency transformer to the AC power supply.

[0063] D. After the power frequency transformer is connected to the AC power supply, since the shortest conduction time of Q6 is from the trigger to the next AC zero-crossing, there is a short conduction time. Through experiments, this time will cause the VCC voltage to rise to near the peak value.

[0064] E. When VCC rises, the circuit will automatically repeat steps A to D, which is the entire process of the low-power standby operation.

[0065] The present invention relates to a low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer, including an AC input terminal AC1, and a control circuit electrically connected to the AC input terminal AC1 and used for controlling the electrical appliance to achieve low-cost and low-power standby; a micro-control unit is also electrically connected in the control circuit. The standby circuit has extremely low cost. Compared with the commonly used small-power switching power supplies and small power frequency transformers in the industry, it has great advantages in terms of cost, is simple and reliable, and is convenient for production. It has relatively high social and economic benefits. Moreover, if the power consumption of the power frequency transformer is 5W when directly connected to the AC all the time, and the power consumption is 1W after using this circuit, then an electrical appliance saves 4W of power. The feeling of a single user may not be obvious, but if an electrical appliance manufacturer produces 100,000 electrical appliances and puts them on the market in a year, the saved electric power reaches 400KW. Since the circuit operates at a very low switching frequency, there is no EMC problem caused by the switching power supply, and the temperature rise of the transformer during standby is very low, effectively extending its lifespan; moreover, the circuit occupies a small PCB space, can save the space inside the whole machine, and reduce the volume of the whole machine.

[0066] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer, characterized in that, the circuit includes an AC input terminal, and a control circuit that is electrically connected to the AC input terminal and is used to control the electrical appliance to achieve low-cost and low-power standby; a microcontroller unit is also electrically connected in the control circuit; a power frequency transformer is also provided in the control circuit; one end of the input terminal of the power frequency transformer is respectively connected to one end of a fifth varistor, one end of a sixth triac, and one end of a ninth resistor; the other end of the fifth varistor, the other end of the sixth triac, one end of an eighth capacitor, one end of a second varistor, one end of a first fuse, and one end of a sixteenth resistor are connected; the other end of the first fuse is connected to one end of the AC input terminal; the other end of the AC input terminal is respectively connected to the other end of the second varistor, the other end of the eighth capacitor, and the other end of the input terminal of the power frequency transformer; the G pole of the sixth triac, the third pin of the fourth rectifier bridge, and the other end of the ninth resistor are connected; the other end of the sixteenth resistor is connected to the fourth pin of the fourth rectifier bridge; the first pin of the fourth rectifier bridge is respectively connected to one end of a seventeenth resistor and the anode of an eleventh thyristor; the cathode of the eleventh thyristor is respectively connected to the second pin of the fourth rectifier bridge and the third pin of a ninth optocoupler; the other end of the seventeenth resistor is connected to one end of an eighteenth resistor; the other end of the eighteenth resistor is respectively connected to the control pole of the eleventh thyristor and the fourth pin of the ninth optocoupler; the first pin of the ninth optocoupler is connected to the power-saving control pin of the microcontroller unit; the second pin of the ninth optocoupler is connected to one end of a twenty-seventh resistor; the other end of the twenty-seventh resistor is connected to the collector of a first triode; the emitter of the first triode is grounded; the base of the first triode is respectively connected to one end of a tenth capacitor and the anode of a fourteenth zener diode; the cathode of the fourteenth zener diode is respectively connected to the other end of the tenth capacitor and one end of a twenty-sixth resistor; the other end of the twenty-sixth resistor is respectively connected to the cathode of a fourth diode, the cathode of a second diode, the anode of a first polarized capacitor, one end of a second capacitor, and the power supply in the microcontroller unit; the cathode of the first polarized capacitor, the other end of the second capacitor, and the ground terminal in the microcontroller unit are commonly grounded; the anode of the fourth diode is respectively connected to the cathode of a third diode and one end of the output terminal of the power frequency transformer; the anode of the second diode is respectively connected to the cathode of a first diode and the other end of the output terminal of the power frequency transformer; the anode of the third diode and the anode of the first diode are commonly grounded.

2. The low-cost and low-power standby circuit for electrical appliances powered by a power frequency transformer according to claim 1, characterized in that, a 33V to 5V power supply for supplying power to the microcontroller unit is also provided in the control circuit; the 33V to 5V power supply is a DC-DC conversion circuit with the BM0150HV chip as the core; The micro-control unit is composed of an MCU processing unit with CBM7320FBS1A as the core; The model of the AC input terminal is RT-C08-F2-WH.

3. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the sixth triac is BT137-600E or T405-600B.

4. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the eleventh thyristor is PCR606.

5. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the fourth rectifier bridge is MB10S.

6. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the ninth optocoupler is EL817S1.

7. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the first polarized capacitor is 2200uF / 50V.

8. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The model of the first fuse is SQT3.15M.

9. A low-cost and low-power standby circuit for an electrical appliance powered by a power frequency transformer according to claim 1, characterized in that, The models of the fifth varistor and the second varistor are both 10D471K.

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