A power conversion circuit and its control method and device

Abstract

This invention provides a power conversion circuit and its control method and apparatus. The circuit includes a power conversion control subcircuit, a first resistor, and several feedback resistor adjustment circuits. The power conversion control subcircuit includes a power conversion control chip. The first terminal of the power conversion control chip is connected to an external input voltage, the second terminal is connected to an external chip control signal, the third terminal is connected to the load and one end of the first resistor, and the feedback input terminal is connected to the other end of the first resistor. Each feedback resistor adjustment circuit is connected in parallel and then connected to the feedback input terminal of the power conversion control chip. Each feedback resistor adjustment circuit consists of a feedback resistor and a switching circuit connected in series. The control terminal of the switching circuit is connected to the input control signal of the feedback resistor. By controlling the on / off state of the feedback resistor adjustment circuits, different power supply voltages can be provided according to different load requirements, and multiple power conversion circuits are not required, saving on the production cost of electrical equipment.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, specifically to a power conversion circuit and its control method and device. Background Technology

[0002] As home appliances become increasingly feature-rich, the power supply voltage required for different functions varies. For example, fans have multiple operating speeds, each corresponding to a different power supply voltage; the faster the fan speed, the higher the voltage required. Therefore, to meet the diverse power supply needs of electrical appliances, power conversion circuits are typically included.

[0003] Currently, conventional power conversion circuits such as Figure 1 As shown, the circuit consists of a power conversion control chip U2 and peripheral circuitry. VIN is the input voltage. EN is the power conversion control chip's shutdown signal input, controlled by the main control chip's I / O port. A high EN indicates normal operation, while a low EN indicates shutdown, controlled by a signal from the main control chip. GND is system ground. VOUT is the output voltage. FB is the feedback input pin, connected to the center point of an external resistor divider; VFB is the feedback threshold voltage. The output voltage VOUT is determined by feedback resistors R10 and R0: VOUT = VFB * (1 + R10 / R0). The load is connected between VOUT and GND. With R10 and R0 fixed, the output voltage VOUT is a fixed value, insufficient to meet the needs of multiple different output voltages. Therefore, when multiple different output voltages are required, multiple power conversion circuits are often needed, significantly increasing the production cost of household appliances. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a power conversion circuit and its control method and apparatus to overcome the problem that the power conversion circuits in the prior art cannot meet multiple different output voltage requirements, thereby increasing the production cost of electrical equipment.

[0005] This invention provides a power conversion circuit, comprising:

[0006] The circuit includes a power conversion control sub-circuit, a first resistor, and several feedback resistor adjustment circuits.

[0007] The power conversion control sub-circuit includes: a power conversion control chip, the first terminal of the power conversion control chip is externally connected to the input voltage, the second terminal is externally connected to the chip control signal, the third terminal is respectively connected to the load and one end of the first resistor, and the feedback input terminal is connected to the other end of the first resistor;

[0008] Each of the aforementioned feedback resistor adjustment circuits is connected in parallel and then connected to the feedback input terminal of the power conversion control chip;

[0009] Each feedback resistor adjustment circuit consists of a feedback resistor and a switching circuit connected in series. The control terminal of the switching circuit is externally connected to the input control signal of the feedback resistor.

[0010] Optionally, the power conversion circuit further includes:

[0011] A power supply control circuit, comprising: a first controlled switch, wherein the control terminal of the first controlled switch is connected to the second terminal of the power conversion control chip, so as to control the power supply control circuit to be turned on or off according to the chip control signal;

[0012] The power supply control circuit is connected in series between the first terminal of the power conversion control chip and the input voltage, or the power supply control circuit is located between the load and the ground terminal.

[0013] Optionally, the power conversion circuit further includes:

[0014] The main control chip includes a first output terminal and several second signal output terminals, wherein...

[0015] The first output terminal is connected to the second terminal of the power conversion control chip to provide chip control signals to the power conversion control chip;

[0016] Each of the second signal output terminals is configured to correspond one-to-one with the feedback resistor adjustment circuit. The second signal output terminal is connected to the control terminal of the switching circuit in its corresponding feedback resistor adjustment circuit to provide the corresponding switching circuit with the input control signal for the feedback resistor.

[0017] Optionally, the power conversion circuit further includes:

[0018] The circuit is configured such that its input terminal is connected to the access control signal of the feedback resistor of each feedback resistor adjustment circuit, and its output terminal is connected to the second terminal of the power conversion control chip, so as to convert the access control signal of the feedback resistor of each feedback resistor adjustment circuit into the chip control signal of the power conversion control chip.

[0019] Optionally, the switching circuit includes a second controlled switch, which is used to control the feedback resistor to be connected or disconnected based on the connection control signal of the feedback resistor.

[0020] Optionally, the OR circuit includes: a plurality of multiplexing circuits, wherein,

[0021] Each multiplexing circuit is configured to correspond one-to-one with each feedback resistor adjustment circuit;

[0022] The multiplexing circuit includes a conversion device, one end of which is connected to the input control signal of the feedback resistor of its corresponding feedback resistor adjustment circuit, and the other end is connected to the second end of the power conversion control chip to convert the input control signal of the feedback resistor into the chip control signal.

[0023] Optionally, the number of feedback resistor adjustment circuits and / or the resistance value of the feedback resistor in the feedback resistor adjustment circuit are determined by the load's requirements for different supply voltages and the resistance value of the first resistor.

[0024] Optionally, the power conversion circuit further includes:

[0025] The second resistor has one end connected to the feedback input terminal of the power conversion control chip, and the other end grounded.

[0026] Optionally, the first controlled switch or the second controlled switch is a transistor or a MOSFET.

[0027] Optionally, the OR circuit includes a multi-input OR gate, wherein the input terminals of the multi-input OR gate are configured to correspond one-to-one with the feedback resistor adjustment circuit.

[0028] This invention also provides a power conversion circuit control method, applied to a power conversion circuit as provided in another embodiment of this invention, the method comprising:

[0029] Obtain the current supply voltage requirement of the load;

[0030] Based on the current power supply voltage requirement, determine the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit;

[0031] A control signal for connecting the feedback resistor is sent to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and a chip control signal is sent to the power conversion control chip to make the power conversion control chip work.

[0032] Optionally, the method further includes:

[0033] When the load is detected to have stopped working, the input control signal for the feedback resistor and the chip control signal are stopped, so that the power conversion circuit stops working.

[0034] This invention also provides a power conversion circuit control device, applied to a power conversion circuit as provided in another embodiment of this invention, the device comprising:

[0035] The acquisition module is used to acquire the current power supply voltage requirement of the load;

[0036] The first processing module is used to determine the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit based on the current power supply voltage requirement.

[0037] The first processing module is used to send an access control signal for the feedback resistor to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and to send a chip control signal to the power conversion control chip to make the power conversion control chip work.

[0038] The technical solution of this invention has the following advantages:

[0039] 1. The power conversion circuit provided in this embodiment of the invention includes: a power conversion control sub-circuit, a first resistor, and several feedback resistor adjustment circuits. The power conversion control sub-circuit includes: a power conversion control chip; a first terminal of the power conversion control chip is externally connected to an input voltage; a second terminal is externally connected to a chip control signal; a third terminal is connected to the load and one end of the first resistor; and a feedback input terminal is connected to the other end of the first resistor. Each feedback resistor adjustment circuit is connected in parallel and then connected to the feedback input terminal of the power conversion control chip. Each feedback resistor adjustment circuit consists of a feedback resistor and a switching circuit connected in series. The control terminal of the switching circuit is externally connected to an input control signal for the feedback resistor. By setting the input control signal for the feedback resistor of each feedback resistor adjustment circuit, the feedback resistor connected to the power conversion circuit is controlled to adjust the power supply voltage supplied to the load. Therefore, by setting multiple feedback resistor adjustment circuits at the power supply output terminal of a traditional power conversion circuit, and controlling the on / off state of the feedback resistor adjustment circuits to control the total resistance value of the feedback resistor connected to the power conversion circuit, different power supply voltages can be provided according to different load requirements. Furthermore, multiple power conversion circuits are not required, saving on the production cost of electrical equipment.

[0040] 2. The power conversion circuit control method and apparatus provided in this embodiment of the invention obtains the current supply voltage requirement of the load; based on the current supply voltage requirement, determines the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit; sends an access control signal for the feedback resistor to the control terminal of the switching circuit in each feedback resistor adjustment circuit to turn on the switching circuit to connect the feedback resistor, and sends a chip control signal to the power conversion control chip to make the power conversion control chip work. Thus, according to the different supply voltage requirements of the load, the total resistance value of the feedback resistors connected to the power conversion circuit is controlled so that the power conversion circuit outputs the supply voltage required by the load, realizing flexible adjustment of the output voltage of the power conversion circuit, and eliminating the need for multiple power conversion circuits, thus saving production costs of electrical equipment. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of an existing power conversion circuit.

[0043] Figure 2 This is a schematic diagram of a first structure of the power conversion circuit according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of a second structure of the power conversion circuit according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of a third structure of the power conversion circuit according to an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the fourth structure of the power conversion circuit according to an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the fifth structure of the power conversion circuit according to an embodiment of the present invention;

[0048] Figure 7 This is a flowchart of the power conversion circuit control method according to an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of the power conversion circuit control device according to an embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] To address the above problems, embodiments of the present invention provide a power conversion circuit, such as... Figure 2As shown, the power conversion circuit includes: a power conversion control sub-circuit 101, a first resistor R10, and several feedback resistor adjustment circuits 102. The power conversion control sub-circuit 101 includes: a power conversion control chip 11. The first terminal of the power conversion control chip 11 is externally connected to the input voltage VIN, the second terminal is externally connected to the chip control signal EN, and the third terminal VOUT is connected to the load (…). Figure 2 (Not shown in the image) and one end of the first resistor R10 are connected, and the feedback input terminal FB is connected to the other end of the first resistor R10; each feedback resistor adjustment circuit 102 is connected in parallel and then connected to the feedback input terminal FB of the power conversion control chip 11; each feedback resistor adjustment circuit 102 is composed of a feedback resistor R and a switching circuit 21 connected in series, and the control terminal of the switching circuit 21 is externally connected to the input control signal of the feedback resistor ( Figure 2 (Not shown in the diagram), by setting the feedback resistor R of each feedback resistor adjustment circuit 102 to be connected to the control signal, the feedback resistor R connected to the power conversion circuit is controlled to adjust the power supply voltage supplied to the load. For example, the load can be an electric fan with multiple power supply voltage requirements, with different fan speeds corresponding to different power supply voltage requirements.

[0053] Among them, such as Figure 2 As shown, the power conversion circuit provided in this embodiment of the invention is based on, for example... Figure 1 This is an improvement upon the power conversion circuit shown. The peripheral circuits of the power conversion control chip in the above power conversion control sub-circuit are as follows... Figure 1 The relevant circuit designs of the power conversion circuits shown in the prior art are all the same, and will not be described again here.

[0054] Specifically, the aforementioned switching circuit 21 includes a second controlled switch, which is used to control the connection or disconnection of the feedback resistor based on the connection control signal of the feedback resistor. The second controlled switch can be a switching device such as a transistor or a MOSFET. The aforementioned switching circuit can be composed of the second controlled switch and its driving circuit. The design of the driving circuit can be implemented with reference to the existing design of transistor or MOSFET driving circuits, and will not be described in detail here.

[0055] Through the synergistic cooperation of the above-mentioned components, the power conversion circuit provided in this embodiment of the invention can provide different power supply voltages according to different load requirements by setting multiple feedback resistor adjustment circuits at the power supply output terminal of a traditional power conversion circuit and controlling the on / off state of the feedback resistor adjustment circuits to control the total resistance value of the feedback resistor connected to the power conversion circuit. Furthermore, it eliminates the need to set up multiple power conversion circuits, thus saving production costs for electrical equipment.

[0056] Specifically, in one embodiment, such as Figure 2As shown, the power conversion circuit described above further includes a power supply control circuit 103. The power supply control circuit 103 includes a first controlled switch, the control terminal of which is connected to the second terminal of the power conversion control chip to control the power supply control circuit to turn on or off according to the chip's control signal. In this embodiment of the invention, the power supply control circuit 103 is described as being positioned between the load and the ground terminal. In practical applications, the power supply control circuit can also be connected in series between the first terminal of the power conversion control chip and the input voltage.

[0057] The first controlled switch is similar to the second controlled switch mentioned above; both can be transistors or MOSFETs, etc. For details, please refer to the relevant description of the second controlled switch mentioned above, which will not be repeated here.

[0058] Due to such Figure 1 When the power conversion control chip stops working, the output voltage of the power conversion circuit shown is VOUT = VIN, meaning the output voltage equals the input voltage. Therefore, there is still output voltage supplied to the load, and the load cannot be effectively shut off. For example... Figure 2 and 3 As shown, by setting up a power supply control circuit, the first controlled switch can be turned off when the chip control signal of the power conversion control chip is at a low level, so as to ensure that the load is completely turned off, avoid safety hazards caused by the power supply to the load, and reduce unnecessary energy consumption.

[0059] Specifically, in one embodiment, the power conversion circuit described above further includes:

[0060] Main control chip ( Figure 2 (Not shown in the image) The main control chip includes a first output terminal and several second signal output terminals. The first output terminal is connected to the second terminal of the power conversion control chip to provide chip control signals to the power conversion control chip. Each second signal output terminal is configured to correspond one-to-one with a feedback resistor adjustment circuit. The second signal output terminal is connected to the control terminal of the switching circuit in its corresponding feedback resistor adjustment circuit to provide the corresponding switching circuit with the access control signal for the feedback resistor.

[0061] The main control chip is the MCU of the load connected to the power conversion circuit, i.e., the electrical appliance being used. Examples include the MCU of an electric fan, but this invention is not limited to this.

[0062] Specifically, in one embodiment, the power conversion circuit described above further includes:

[0063] The circuit can be connected to the input terminal of the feedback resistor adjustment circuit, which is connected to the input control signal of each feedback resistor adjustment circuit. The output terminal is connected to the second terminal of the power conversion control chip to convert the input control signal of each feedback resistor adjustment circuit into the chip control signal of the power conversion control chip.

[0064] Specifically, the circuit includes: several multiplexing circuits, wherein each multiplexing circuit is configured in a one-to-one correspondence with each feedback resistor adjustment circuit; the multiplexing circuit includes: a conversion device, one end of which is connected to the input control signal of the feedback resistor of its corresponding feedback resistor adjustment circuit, and the other end is connected to the second end of the power conversion control chip, so as to convert the input control signal of the feedback resistor into a chip control signal.

[0065] Specifically, the aforementioned conversion device is a diode. The forward input terminal of the diode is connected to the input control signal of the feedback resistor of its corresponding feedback resistor adjustment circuit, and the reverse input terminal is connected to the second terminal of the power conversion control chip.

[0066] Specifically, in another alternative embodiment, the above-mentioned OR circuit includes a multi-input OR gate, with each input terminal of the multi-input OR gate corresponding to a feedback resistor adjustment circuit. Furthermore, in practical applications, the above-mentioned OR circuit can also be constructed from a multi-input comparator, with each input terminal of the comparator connected to the input control signal of the feedback resistor adjustment circuit. The specific operation is similar to that of the multi-input OR gate and will not be described in detail here.

[0067] By setting up an OR circuit, the chip control signal of the power conversion control chip can be provided not by the I / O port of the main control chip, but by the OR circuit, thereby reducing the number of I / O ports used by the main control chip and maximizing the saving of I / O port resources of the main control chip.

[0068] Specifically, in one embodiment, the number of feedback resistor adjustment circuits and / or the resistance value of the feedback resistor in the feedback resistor adjustment circuit are determined by the load's demand for different supply voltages and the resistance value of the first resistor. In practical applications, the number of feedback resistor adjustment circuits can be reduced when so much output voltage is not required, and when more output voltage is required, a feedback resistor adjustment circuit consisting of a feedback resistor and a switching circuit can be added as needed to achieve flexible adjustment and meet the different power supply requirements of different loads.

[0069] Specifically, in one embodiment, the power conversion circuit described above further includes:

[0070] The second resistor has one end connected to the feedback input terminal of the power conversion control chip, and the other end grounded.

[0071] In practical applications, such as Figure 4 As shown, the second resistor is Figure 4R0 in the figure. Specifically, the resistance value of the second resistor can be set according to the minimum power supply voltage required by the load, so as to ensure the basic power needs of the load. When the load has other power supply needs, a feedback resistor is connected according to the actual situation to adjust the power supply voltage of the load. The present invention is not limited thereto.

[0072] The working principle and specific working process of the power conversion circuit provided in the embodiments of the present invention will be described in detail below with reference to specific application examples.

[0073] With Figure 1 Similar to existing power conversion circuits shown, the present invention provides, as illustrated in the embodiments, [the following is a description of the circuits]. Figure 3 In the power conversion circuit shown, VIN is the input voltage, EN is the chip control signal (i.e., the chip shutdown signal input), GND is system ground, VOUT is the output, FB is the feedback input pin, and the additional V- is one end of the load; the load requiring power is connected between VOUT and V-. The "Partial Power Conversion Circuit" includes prior art such as... Figure 1 The power conversion circuit shown contains common components such as filter capacitors, energy storage inductors, switching devices, diodes, and control chips, which are used to form common BUCK, BOOST, and BUCK-BOOST topologies in the prior art. The power supply control circuit is as follows: Figure 3 The "Switching Circuit X" shown is used to cut off the load power supply, solving the problem of ineffective load shutdown in existing technologies. Switching Circuit X consists of switching devices such as transistors or MOSFETs and their driving circuits. The switching of Switching Circuit X is controlled by the signal ENX from the I / O port of the main control chip. When ENX is high, the switching device is turned on, and the output VOUT flows through the load to V- and then through the switching device to GND, allowing the load to operate. When ENX is low, the switching device is turned off, and the output VOUT has no path after flowing through the load to V-, completely shutting off the load. In practical applications, the signal EN can be used instead of ENX, meaning that the load is completely shut off simultaneously with the control chip stopping operation. Switching Circuit X can be connected between V- and GND, or in series between VIN and part of the power conversion circuit; its function and principle are similar.

[0074] Figure 3The three switching circuits are used for feedback resistor adjustment. They consist of switching devices such as transistors or MOSFETs and their driving circuits. The switching devices are controlled by signals FB0, FB1, and FB2 from the main control chip's I / O port. When the main control chip outputs a high level, the switching devices are turned on; when the main control chip outputs a low level, the switching devices are turned off. One end of each switching circuit is connected to the feedback resistor, and the other end is connected to V- or GND. When the output voltage VOUT0 is needed to supply the load, FB0 is at a high level, and FB1 and FB2 are at a low level, VOUT0 = VFB * (1 + R10 / R0); when the output voltage VOUT1 is needed to supply the load, FB1 is at a high level, and FB0 and FB2 are at a low level, VOUT1 = VFB * (1 + R10 / R1); when the output voltage VOUT2 is needed to supply the load, FB2 is at a high level, and FB0 and FB1 are at a low level, VOUT2 = VFB * (1 + R10 / R2); when no output voltage is needed, EN, FB0, FB1, FB2 and ENX are all at a low level, the load is completely disconnected from power, and the power conversion control chip also enters the shutdown state.

[0075] Figure 3 The circuit block diagram shown can output three voltages: OUT0, OUT1, and OUT2. If so many output voltages are not needed, any one of the feedback resistor adjustment circuits can be deleted. If more output voltages are needed, a feedback resistor adjustment circuit consisting of a feedback resistor and a switching circuit can be added as needed.

[0076] because Figure 3 The circuit shown requires a large number of I / O ports on the main control chip. It's evident that 5 I / O ports are needed when 3 output voltages are required, and n+2 I / O ports are needed when n output voltages are required. This invention proposes... Figure 4 and Figure 5 Two circuit block diagrams, the feedback resistor adjustment circuit and the switching circuit are the same as those described above. Figure 3 The circuit function and structure are similar to those in the previous circuit. In this circuit, the controller signal EN is no longer provided by the main control chip's I / O ports, but by an OR circuit, i.e., a multiplexing circuit. The multiplexing circuit consists of conversion devices, which can be diodes or comparators, etc. The multiplexing circuit can be composed of a single conversion device or multiple conversion devices. These conversion devices convert the signals FB0, FB1, FB2, etc., provided by the main control chip's I / O ports into the control signal EN, thereby reducing the occupation of the main control chip's I / O ports, alleviating chip resource consumption, and reducing production costs. EN is high when any one of these signals (FB0, FB1, FB2, etc.) is high, and EN is low when all of these signals (FB0, FB1, FB2, etc.) are low. Figure 4In the circuit block diagram, when an output voltage VOUT0 is needed to supply the load, FB0 is high, FB1 is low, and EN is high, VOUT0 = VFB * (1 + R10 / R0); when an output voltage VOUT1 is needed to supply the load, FB0 is low, FB1 is high, and EN is high, VOUT1 = VFB * (1 + R10 / R1); when an output voltage VOUT2 is needed to supply the load, FB0 is high, FB1 is high, and EN is high, VOUT2 = VFB * {1 + R10 / [R0R1 / (R0 + R1)]}; when no output voltage is needed to supply the load, FB0 is low, FB1 is low, and EN is also low, the load is completely disconnected from power, and the power conversion control chip enters a shutdown state. Figure 5 In the circuit block diagram, when the output voltage VOUT0 is needed to supply the load, FB1 is high, FB2 is low, and EN is high, VOUT0 = VFB * {1 + R10 / [R0R1 / (R0 + R1)]}; when the output voltage VOUT1 is needed to supply the load, FB1 is low, FB2 is high, and EN is high, VOUT1 = VFB * {1 + R10 / [R0R2 / (R0 + R2)]}; when the output voltage VOUT2 is needed to supply the load, FB1 is high, FB2 is high, and EN is high, VOUT2 = VFB * {1 + R10 / [R0R1R2 / (R0R1 + R0R2 + R1R2)]}; when no output voltage is needed to supply the load, FB0 is low, FB1 is low, and EN is also low, the load is completely disconnected from power, and the power conversion control chip also enters the shutdown state.

[0077] Figure 4 and Figure 5 The circuit block diagram can output three voltages: OUT0, OUT1, and OUT2. When so many output voltages are not needed, the feedback resistor adjustment circuit and the multiplexing circuit can be removed as needed. When more output voltages are needed, the multiplexing circuit and the feedback resistor adjustment circuit composed of feedback resistors and switching circuits can be added as needed. In the overall circuit composed of n feedback resistor adjustment circuits, a maximum of 2n-1 output voltages can be output by control.

[0078] Figure 6 According to Figure 5A specific implementation example of circuit block diagram design. The circuit consists of capacitors C1 (for filtering), C2 (for filtering), C3 (for filtering), and C4 (for filtering), inductor L1 (for energy storage), diode D11 (for rectification), and power conversion control chip U2. Diodes D1 (for I / O isolation and multiplexing) and D2 (for I / O isolation and multiplexing) form a multiplexing circuit. Resistors R11 (for current limiting) and R12 (for pull-down) form an enable circuit. Resistors R13 (for current limiting), R14 (for pull-down), MOSFET U1, and capacitor C1 (for anti-static) form a switching circuit. Resistors R15 (for current limiting) and transistor Q1 form a switching circuit. Resistors R16 (for current limiting) and transistor Q2 form a switching circuit. Resistors R10, R0, R1, and R2 are feedback resistors; R1 and the switching circuit form a feedback resistor adjustment circuit, and R2 and the switching circuit form another feedback resistor adjustment circuit. CN2 is a connector for the load.

[0079] like Figure 6 As shown, the above multiplexing circuit consists of two diodes. FB1 is connected to the anode of diode D1, and FB2 is connected to the anode of diode D2. The cathodes of D1 and D2 are both connected to EN. Due to the unidirectional conduction characteristic of diodes, FB1 and FB2 do not affect each other. When FB1 is high and FB2 is low, EN is high; when FB1 is low and FB2 is high, EN is also high; and when both FB1 and FB2 are low, EN is low. The multiplexing circuit can also be composed of comparators, with the same principle as the diode-based circuit. FB1 and FB2 do not affect each other, and when FB1 is high and FB2 is low, EN is high; when both FB1 and FB2 are low, EN is low.

[0080] Through the synergistic cooperation of the above-mentioned components, the power conversion circuit provided in this embodiment of the invention can provide different power supply voltages according to different load requirements by setting multiple feedback resistor adjustment circuits at the power supply output terminal of a traditional power conversion circuit and controlling the on / off state of the feedback resistor adjustment circuits to control the total resistance value of the feedback resistor connected to the power conversion circuit. Furthermore, it eliminates the need to set up multiple power conversion circuits, thus saving production costs for electrical equipment.

[0081] This invention also provides a power conversion circuit control method, applied to the control chip of the power conversion circuit in the above embodiments. This control chip can be the MCU of the electrical device where the power conversion circuit is located, such as the MCU of an electric fan, etc. Figure 7 As shown, the power conversion circuit control method specifically includes the following steps:

[0082] Step S101: Obtain the current power supply voltage requirement of the load.

[0083] Taking a fan as an example, the current power supply voltage requirement is the power supply voltage value required by the fan at its current operating speed.

[0084] Step S102: Based on the current power supply voltage requirements, determine the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit.

[0085] Specifically, since the resistance value of the feedback resistor in the feedback resistor adjustment circuit is set, the total resistance value of all feedback resistors connected to the power conversion circuit can be calculated based on the required power supply voltage value of the load and the resistance value of the first resistor mentioned above. Then, the feedback resistor adjustment circuit to be connected is selected based on the design value of the feedback resistor in each feedback resistor adjustment circuit.

[0086] Step S103: Send the feedback resistor access control signal to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and send the chip control signal to the power conversion control chip to make the power conversion control chip work.

[0087] Specifically, the main control chip of the fan, i.e., the MCU, outputs corresponding control signals through its I / O port, so that the power conversion control chip is in normal working mode and controls the conduction of each feedback resistor adjustment circuit to be connected, so that the feedback resistor is connected and the required power supply voltage is output to the load.

[0088] Specifically, in one embodiment, the power conversion circuit control method described above further includes the following steps:

[0089] Step S104: When the load stops working, stop sending the feedback resistor access control signal and the chip control signal so that the power conversion circuit stops working.

[0090] Specifically, energy consumption is reduced by controlling the power conversion circuit to stop operating when the load stops working. For a more detailed description of the power conversion circuit control method, please refer to the relevant description of the main control chip in the above power conversion circuit embodiment; it will not be repeated here.

[0091] by Figure 5For example, FB1 and FB2 are the main control chip's I / O ports. When FB1 is high, switch circuit 1 is turned on; when FB1 is low, switch circuit 1 is turned off. When FB2 is high, switch circuit 2 is turned on; when FB2 is low, switch circuit 2 is turned off. When either FB1 or FB2 is high, EN is high, and the power conversion circuit and switch circuit X are activated. When both FB1 and FB2 are low, EN is low, the power conversion circuit enters a shutdown state, and switch circuit X is also turned off.

[0092] Combination Figure 5 The following is a detailed explanation of the main control chip's operation in a specific application scenario: Applied to a fan, VOUT and GND are connected between the positive and negative terminals of the fan motor. When the fan is in standby mode, the main control chip FB1 and FB2 both output low levels, EN is low, the power conversion circuit enters a stop state, the switching circuit X is also turned off, and the entire system is in standby mode, with the fan in standby mode. When the main control chip detects a signal indicating that the fan needs to operate at speed 1, FB1 outputs a high level, and FB2 outputs a low level. Since FB1 is high, EN is also high, the power conversion circuit operates, outputting voltage VOUT0, and the switching circuit X is also turned on, powering the fan, which operates at speed 1. When the main control chip detects a signal indicating that the fan needs to operate at speed 2, FB1 outputs a low level, and FB2 outputs a high level. Since FB2 is high, EN is also high, the power conversion circuit operates, outputting voltage VOUT0, and the switching circuit X is turned on, powering the fan, which operates at speed 1. When the switching circuit is active, the output voltage VOUT1 is activated, and the switching circuit X is also turned on, powering the fan and causing it to operate at speed 2. When the main control chip detects a signal indicating that the fan needs to be turned on at speed 3 (e.g., button press or remote control), both FB1 and FB2 output a high level. Since FB1 and FB2 are both high, EN is also high, activating the power conversion circuit and activating the output voltage VOUT2. The switching circuit X is also turned on, powering the fan and causing it to operate at speed 3. When the main control chip detects a signal indicating that the fan needs to be turned off (e.g., button press or remote control), both FB1 and FB2 output a low level, and EN is low. The power conversion circuit enters a shutdown state, the switching circuit X is turned off, and the entire system enters standby mode, with the fan turning off and entering standby mode. This is how three different voltages, VOUT0, VOUT1, and VOUT2, are output to the fan to control its operation at speeds 1, 2, and 3, and to turn it off and enter standby mode.

[0093] By performing the above steps, the power conversion circuit control method provided in this embodiment of the invention controls the total resistance value of the feedback resistor connected to the power conversion circuit according to the different power supply voltage requirements of the load, so that the power conversion circuit outputs the power supply voltage required by the load, thereby realizing flexible adjustment of the output voltage of the power conversion circuit, and eliminating the need to set up multiple power conversion circuits, thus saving the production cost of electrical equipment.

[0094] This invention also provides a power conversion circuit control device, which is applied to the control chip of the power conversion circuit in the above embodiments. This control chip can be the MCU of the electrical device where the power conversion circuit is located, such as the MCU of an electric fan, etc. Figure 8 As shown, the power conversion circuit control device specifically includes:

[0095] The acquisition module 301 is used to acquire the current power supply voltage requirement of the load. For details, please refer to the relevant description of step S101 in the above method embodiment, which will not be repeated here.

[0096] The first processing module 302 is used to determine the feedback resistor adjustment circuit to be connected from among the feedback resistor adjustment circuits based on the current power supply voltage requirement. For details, please refer to the relevant description of step S102 in the above method embodiment, which will not be repeated here.

[0097] The first processing module 303 is used to send an access control signal for the feedback resistor to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and to send a chip control signal to the power conversion control chip to make the power conversion control chip work. For details, please refer to the relevant description of step S103 in the above method embodiment, which will not be repeated here.

[0098] For a more detailed description of each of the above functional modules, please refer to the relevant descriptions in the above method embodiments, which will not be repeated here.

[0099] Through the synergistic cooperation of the above-mentioned components, the power conversion circuit control device provided in this embodiment of the invention controls the total resistance value of the feedback resistor connected to the power conversion circuit according to the different power supply voltage requirements of the load, so that the power conversion circuit outputs the power supply voltage required by the load, realizing flexible adjustment of the output voltage of the power conversion circuit, and eliminating the need to set up multiple power conversion circuits, thus saving the production cost of electrical equipment.

[0100] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A power conversion circuit, characterized in that, include: The circuit includes a power conversion control sub-circuit, a first resistor, and several feedback resistor adjustment circuits. The power conversion control sub-circuit includes: a power conversion control chip, the first terminal of the power conversion control chip is externally connected to the input voltage, the second terminal is externally connected to the chip control signal, the third terminal is respectively connected to the load and one end of the first resistor, and the feedback input terminal is connected to the other end of the first resistor; Each of the aforementioned feedback resistor adjustment circuits is connected in parallel and then connected to the feedback input terminal of the power conversion control chip; Each feedback resistor adjustment circuit consists of a feedback resistor and a switching circuit connected in series. The control terminal of the switching circuit is externally connected to the input control signal of the feedback resistor. The power conversion circuit further includes an OR circuit, wherein the input terminal of the OR circuit is externally connected to the access control signal of the feedback resistor of each feedback resistor adjustment circuit, and the output terminal is connected to the second terminal of the power conversion control chip, so as to convert the access control signal of the feedback resistor of each feedback resistor adjustment circuit into the chip control signal of the power conversion control chip.

2. The power conversion circuit according to claim 1, characterized in that, Also includes: A power supply control circuit, comprising: a first controlled switch, wherein the control terminal of the first controlled switch is connected to the second terminal of the power conversion control chip, so as to control the power supply control circuit to be turned on or off according to the chip control signal; The power supply control circuit is connected in series between the first terminal of the power conversion control chip and the input voltage, or the power supply control circuit is located between the load and the ground terminal.

3. The power conversion circuit according to claim 1 or 2, characterized in that, Also includes: The main control chip includes a first output terminal and several second signal output terminals, wherein... The first output terminal is connected to the second terminal of the power conversion control chip to provide chip control signals to the power conversion control chip; Each of the second signal output terminals is configured to correspond one-to-one with the feedback resistor adjustment circuit. The second signal output terminal is connected to the control terminal of the switching circuit in its corresponding feedback resistor adjustment circuit to provide the corresponding switching circuit with the input control signal for the feedback resistor.

4. The power conversion circuit according to claim 1, characterized in that, The switching circuit includes a second controlled switch, which is used to control the connection or disconnection of the feedback resistor based on the connection control signal of the feedback resistor.

5. The power conversion circuit according to claim 1, characterized in that, The circuit includes: a plurality of multiplexed circuits, wherein... Each multiplexing circuit is configured to correspond one-to-one with each feedback resistor adjustment circuit; The multiplexing circuit includes a conversion device, one end of which is connected to the input control signal of the feedback resistor of its corresponding feedback resistor adjustment circuit, and the other end is connected to the second end of the power conversion control chip to convert the input control signal of the feedback resistor into the chip control signal.

6. The power conversion circuit according to claim 1, characterized in that, The number of feedback resistor adjustment circuits and / or the resistance value of the feedback resistor in the feedback resistor adjustment circuit are determined by the load's requirements for different supply voltages and the resistance value of the first resistor.

7. The power conversion circuit according to claim 1, characterized in that, Also includes: The second resistor has one end connected to the feedback input terminal of the power conversion control chip, and the other end grounded.

8. A power conversion circuit control method, characterized in that, The method, applied to the power conversion circuit as described in any one of claims 1-7, comprises: Obtain the current supply voltage requirement of the load; Based on the current power supply voltage requirement, determine the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit; A control signal for connecting the feedback resistor is sent to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and a chip control signal is sent to the power conversion control chip to make the power conversion control chip work.

9. The method according to claim 8, characterized in that, Also includes: When the load is detected to have stopped working, the input control signal for the feedback resistor and the chip control signal are stopped, so that the power conversion circuit stops working.

10. A power conversion circuit control device, characterized in that, The device, applied to the power conversion circuit as described in any one of claims 1-7, comprises: The acquisition module is used to acquire the current power supply voltage requirement of the load; The first processing module is used to determine the feedback resistor adjustment circuit to be connected from each feedback resistor adjustment circuit based on the current power supply voltage requirement. The second processing module is used to send an access control signal for the feedback resistor to the control terminal of the switching circuit in each feedback resistor adjustment circuit to be connected, so that the switching circuit in each feedback resistor adjustment circuit to be connected is turned on to connect the feedback resistor, and to send a chip control signal to the power conversion control chip to make the power conversion control chip work.

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