Dimming current calibration circuit of DALI switching power supply

Abstract

The utility model relates to the technical field of dimming, in particular to a dimming current calibration circuit of a DALI (Digital Addressable Lighting Interface) switching power supply, which comprises a digital-to-analog conversion unit, a controller unit and a communication unit, when the controller unit transmits a dimming driving signal to the switching power supply through the communication unit, the controller unit receives a dimming current signal from the digital-to-analog conversion unit; when the dimming current signal is greater than a standard value corresponding to the dimming driving signal, the controller unit transmits a level-down dimming driving signal to the switching power supply through the communication unit; when the dimming current signal is smaller than the standard value, the controller unit transmits a level-up dimming driving signal to the switching power supply through the communication unit; when the dimming current signal is equal to the standard value, the controller unit transmits a storage signal to the switching power supply through the communication unit; the communication unit is also used for being controlled by the controller unit to open or close the dimming current calibration circuit; the digital-to-analog conversion frequency is small, the circuit structure and the calibration process are simple, the energy consumption is low, and more calibration modes can be expanded.

Description

Technical Field

[0001] The utility model relates to the technical field of dimming, in particular to a dimming current calibration circuit of a DALI switching power supply. Background Art

[0002] With the popularization and development of intelligent lighting systems, the requirements for the accuracy of dimming current are getting higher and higher. High-precision dimming current can meet more complex scenarios and personalized needs, and realize the intelligent management and control of lighting systems; therefore, the accuracy of dimming current plays a vital role in DALI switching power supply, which not only affects the performance and user experience of the lighting system, but also affects the energy efficiency and system reliability. In particular, the current DALI switching power supply is based on the buck circuit to dim through analog signals (dimming current), which has high requirements for voltage accuracy. A small voltage change will also cause the output dimming current to be different; and because of the difference in resistance value accuracy, the dimming current output by the DALI switching power supply with the same design will also be different, which will eventually lead to inconsistent brightness. Therefore, when the DALI switching power supply is used for dimming of the lighting system, it is necessary to fully consider the accuracy of the dimming current, calibrate the dimming current output by the DALI switching power supply in real time, so that each output dimming current can correspond to its corresponding brightness, which can ensure the normal operation and good performance of the lighting system.

[0003] At present, the calibration method of the dimming current calibration circuit of the DALI switching power supply is to connect a calibration module in series between the dimming drive output end of the switching power supply and the lamp. When the switching power supply outputs a dimming signal, it is checked by the calibration module and then outputs a dimming current that meets the standard. That is, the analog signal (dimming current) output by the switching power supply is first collected, and then a digital-to-analog conversion is performed. The converted digital signal is transmitted to the controller to determine whether the dimming current output by the switching power supply at this time meets the accuracy requirements. If not, the controller outputs the correct dimming current as a digital signal after correction, and then a digital-to-analog conversion is performed to transmit the correct analog signal (dimming current) to the lamp to complete the calibration.

[0004] However, the above calibration method requires multiple digital-to-analog conversion processes on the signal, and the calibration module needs to be used for a long time. The circuit structure and calibration process are complex and the energy consumption is high. Utility Model Content

[0005] In view of the above-mentioned defects, the purpose of the utility model is to propose a dimming current calibration circuit for a DALI switching power supply, which has a small number of digital-to-analog conversions, a simple circuit structure and a calibration process, low energy consumption, and can expand more calibration methods.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A dimming current calibration circuit for a DALI switching power supply, comprising a digital-to-analog conversion unit, a controller unit and a communication unit; a positive dimming output terminal of the switching power supply is electrically connected to a positive input terminal of the digital-to-analog conversion unit, a positive input terminal of a lamp is electrically connected to a negative input terminal of the digital-to-analog conversion unit, an output terminal of the digital-to-analog conversion unit is electrically connected to an input terminal of the controller unit, a control terminal of the controller unit is electrically connected to a control terminal of the communication unit, and an output terminal of the communication unit is electrically connected to a dimming driving terminal of the switching power supply;

[0008] When the controller unit transmits a dimming drive signal to the switching power supply through the communication unit, the controller unit receives a dimming current signal from the digital-to-analog conversion unit; when the dimming current signal is greater than a standard value corresponding to the dimming drive signal, the controller unit transmits a dimming drive signal of a lower level to the switching power supply through the communication unit; when the dimming current signal is less than the standard value, the controller unit transmits a dimming drive signal of a higher level to the switching power supply through the communication unit; when the dimming current signal is equal to the standard value, the controller unit transmits a save signal to the switching power supply through the communication unit;

[0009] The communication unit is also used to turn on or off the dimming current calibration circuit under the control of the controller unit.

[0010] Furthermore, the communication unit includes a driving power supply circuit, a communication circuit and a diode D1; the control ends of the driving power supply circuit and the communication circuit are both used as control ends of the communication unit, and the cathode and anode of the diode D1 are both used as output ends of the communication unit;

[0011] The output ends of the driving power supply circuit and the communication circuit are both electrically connected to the cathode of the diode D1;

[0012] The driving power supply circuit is used to turn on or off the power supply under the control of the controller unit;

[0013] The communication circuit is used for receiving the dimming driving signal from the controller unit and transmitting it to the switching power supply.

[0014] Further, the driving power supply circuit includes a DC / DC chip M1, a resistor R42, a resistor R48, a resistor R24, a resistor R38, a resistor R18, a resistor R40, a MOS tube Q5, a capacitor C15, a capacitor C16, a capacitor C17, a transistor Q2, a transistor Q3 and a diode D3; one end of the resistor R42 is used as a control end of the driving power supply circuit, and the cathode of the diode D3 is used as an output end of the driving power supply circuit;

[0015] The other end of the resistor R42 and one end of the resistor R48 are electrically connected to the gate of the MOS transistor Q5, the other end of the resistor R48 and the source of the MOS transistor Q5 are grounded, the drain of the MOS transistor Q5 and the GND end of the DC / DC chip M1 are electrically connected to the negative electrode of the capacitor C16, the positive electrode of the capacitor C16 and the VIN end of the DC / DC chip M1 are connected to a 5V power supply, the Vo+ end of the DC / DC chip M1, one end of the resistor R24, the positive electrode of the capacitor C17, one end of the capacitor C15, and the emitter of the transistor Q3 are connected One end of the resistor R38 is electrically connected, the other end of the resistor R38 and the base of the transistor Q3 are electrically connected to the emitter of the transistor Q2, the collector of the transistor Q3 and the base of the transistor Q2 are electrically connected to one end of the resistor R18, the collector of the transistor Q2 and one end of the resistor R40 are electrically connected to the anode of the diode D3, and the other end of the resistor R40, the other end of the resistor R18, the negative electrode of the capacitor C17, the other end of the capacitor C15, the other end of the resistor R24 ​​and the Vo- end of the DC / DC chip M1 are all grounded.

[0016] Furthermore, the communication circuit includes a diode D6, a MOS tube Q7, a resistor R56, a resistor R57, a resistor R61, a resistor R62, a resistor R67, a capacitor C24, a voltage stabilizing diode DZ1, a transistor Q5, a transistor Q6, a photocoupler U7 and a photocoupler U8; the anode of the diode D6 is used as the output end of the communication circuit, and the emitter of the photocoupler U7 and one end of the resistor R62 are used as the control ends of the communication circuit;

[0017] The cathode of the diode D6, one end of the resistor R56, and the emitter of the transistor Q6 are all electrically connected to the drain of the MOS tube Q7, the other end of the resistor R56 and the base of the transistor Q6 are all electrically connected to the emitter of the transistor Q5, one end of the resistor R57 and the collector of the transistor Q6 are all electrically connected to the base of the transistor Q5, the other end of the resistor R57 is grounded, the collector of the transistor Q5 is electrically connected to the anode of the photocoupler U7, the collector of the photocoupler U7 is connected to the 3V3 power supply, and the emitter of the photocoupler U7 is electrically connected to one end of the resistor R61. , the other end of the resistor R61 is grounded, the cathode of the photocoupler U7, the collector of the photocoupler U8, and one end of the capacitor C24 are electrically connected to the cathode of the voltage stabilizing diode DZ1, the other end of the capacitor C24 and the anode of the voltage stabilizing diode DZ1 are grounded, the anode of the photocoupler U8 is connected to a 3V3 power supply, the cathode of the photocoupler U8 is electrically connected to the other end of the resistor R62, the emitter of the photocoupler U8 is electrically connected to one end of the resistor R67, the other end of the resistor R67 is electrically connected to the gate of the MOS tube Q7, and the source of the MOS tube Q7 is grounded.

[0018] Further, the digital-to-analog conversion unit includes a digital-to-analog conversion chip U9, a resistor R16, a resistor R19, a resistor R1, a resistor R5, a capacitor C21, a capacitor C22, a diode D5 and a diode D8; the anode of the diode D8 is used as the positive input terminal of the digital-to-analog conversion unit, the cathode of the diode D8 is used as the negative input terminal of the digital-to-analog conversion unit, and the SDA terminal and the SCL terminal of the digital-to-analog conversion chip U9 are used as the output terminals of the digital-to-analog conversion unit;

[0019] One end of the resistor R16 and one end of the resistor R19 are both connected to the VDD power supply, the other end of the resistor R16 is electrically connected to the SCL end of the digital-to-analog conversion chip U9, the other end of the resistor R19 is electrically connected to the SDA end of the digital-to-analog conversion chip U9, the VSS end of the digital-to-analog conversion chip U9 is grounded, the VDD end of the digital-to-analog conversion chip U9 and one end of the capacitor C22 are both connected to the VDD power supply, the other end of the capacitor C22 and one end of the resistor R5 are both grounded, the other end of the resistor R5, one end of the capacitor C21, one end of the resistor R1, the anode of the diode D5, and the cathode of the diode D8 are all electrically connected to the VIN- end of the digital-to-analog conversion chip U9, and the other end of the capacitor C21, the other end of the resistor R1, the cathode of the diode D5, and the anode of the diode D8 are all electrically connected to the VIN+ end of the digital-to-analog conversion chip U9.

[0020] Furthermore, it also includes a visualization unit; the input end of the visualization unit is electrically connected to the visualization output end of the controller unit;

[0021] The visualization unit is used for data interaction with the controller unit to display data of the dimming current calibration process of the controller unit.

[0022] Furthermore, it also includes a prompt unit; the input end of the prompt unit is electrically connected to the prompt output end of the controller unit;

[0023] The prompt unit is used to issue a prompt when the dimming current signal is greater than or less than the standard value, or to issue a prompt when the dimming current signal is equal to the standard value.

[0024] Furthermore, the prompt unit includes a resistor R8, a resistor R11, a transistor Q1 and a buzzer BZ1; one end of the resistor R11 is used as an input end of the prompt unit;

[0025] The other end of the resistor R11 is electrically connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 and one end of the resistor R8 are electrically connected to the negative electrode of the buzzer BZ1, and the other end of the resistor R8 and the positive electrode of the buzzer BZ1 are connected to a 5V power supply.

[0026] The technical solution provided by the utility model may include the following beneficial effects: when the controller unit (such as MCU) transmits a dimming drive signal to the switching power supply through the communication unit, the switching power supply will output a dimming current to dim the lamp according to the dimming drive signal. At this time, the digital-to-analog conversion unit can receive the dimming current output by the switching power supply, convert the analog signal into a digital signal, generate a dimming current signal and feed it back to the controller unit. The controller unit can compare the dimming current signal with its corresponding standard value to know how much the dimming current differs from the standard value due to the accuracy error of the switching power supply, and correspondingly increase or decrease the value by one level (for example, relative to the original value). The dimming percentage increases by 1% or decreases by 1%), and the dimming drive signal is re-output, and the dimming current signal is checked again until the dimming current signal is equal to the standard value. It can be known that the dimming drive signal corresponding to the dimming percentage at this time is desired, and the switching power supply is enabled to save. The next time the dimming percentage instruction is received at this time, the adjusted dimming drive signal is output to generate a dimming current corresponding to the dimming percentage, thereby solving the problem of low dimming accuracy caused by the internal error of the switching power supply, and adapting to the dimming error calibration of different types of switching power supplies. At the same time, the number of digital-to-analog conversions is small, the circuit structure is simple, and the dimming process is simple, and the dimming calibration of the switching power supply can be completed quickly.

[0027] More importantly, the communication unit is also used to be controlled by the controller unit to turn on or off the dimming current calibration circuit. After the calibration is completed (that is, all dimming percentages are calibrated), the dimming current calibration circuit can be turned off to prevent the lighting system from being in a calibration state all the time and consuming too much energy. It is even possible to expand more calibration methods by controlling the opening and closing of the dimming current calibration circuit to match more complex lighting systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a schematic diagram of a dimming current calibration circuit of a DALI switching power supply according to one embodiment of the present invention.

[0029] Figure 2 Yes Figure 1 The circuit diagram of the communication unit is shown.

[0030] Figure 3 Yes Figure 1 The circuit diagram of the digital-to-analog conversion unit is shown.

[0031] Figure 4 Yes Figure 1 The circuit diagram of the prompt unit is shown.

[0032] Wherein: digital-to-analog conversion unit 11, controller unit 12, communication unit 13, drive power supply circuit 131, communication circuit 132, diode D1, DC / DC chip M1, resistor R42, resistor R48, resistor R24, resistor R38, resistor R18, resistor R40, MOS tube Q5, capacitor C15, capacitor C16, capacitor C17, transistor Q2, transistor Q3, diode D3, diode D6, MOS tube Q7, resistor R56, Resistor R57, resistor R61, resistor R62, resistor R67, capacitor C24, voltage zener diode DZ1, transistor Q5, transistor Q6, photocoupler U7, photocoupler U8, digital-to-analog conversion chip U9, resistor R16, resistor R19, resistor R1, resistor R5, capacitor C21, capacitor C22, diode D5, diode D8, visualization unit 14, prompt unit 15, resistor R8, resistor R11, transistor Q1, buzzer BZ1. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] In the description of the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0036] Combine the following Figures 1 to 4 , describes a dimming current calibration circuit of a DALI switching power supply in an embodiment of the utility model.

[0037] A dimming current calibration circuit for a DALI switching power supply comprises a digital-to-analog conversion unit 11, a controller unit 12 and a communication unit 13; a positive dimming output terminal of the switching power supply 2 is electrically connected to a positive input terminal of the digital-to-analog conversion unit 11, a positive input terminal of a lamp 3 is electrically connected to a negative input terminal of the digital-to-analog conversion unit 11, an output terminal of the digital-to-analog conversion unit 11 is electrically connected to an input terminal of the controller unit 12, a control terminal of the controller unit 12 is electrically connected to a control terminal of the communication unit 13, and an output terminal of the communication unit 13 is electrically connected to a dimming driving terminal of the switching power supply 2;

[0038] When the controller unit 12 transmits a dimming drive signal to the switching power supply 2 through the communication unit 13, the controller unit 12 receives a dimming current signal from the digital-to-analog conversion unit 11; when the dimming current signal is greater than the standard value corresponding to the dimming drive signal, the controller unit 12 transmits a dimming drive signal of a lower level to the switching power supply 2 through the communication unit 13; when the dimming current signal is less than the standard value, the controller unit 12 transmits a dimming drive signal of a higher level to the switching power supply 2 through the communication unit 13; when the dimming current signal is equal to the standard value, the controller unit 12 transmits a save signal to the switching power supply 2 through the communication unit 13;

[0039] The communication unit 13 is also used to be controlled by the controller unit 12 to turn on or off the dimming current calibration circuit.

[0040] The utility model proposes a preferred embodiment of a dimming current calibration circuit of a DALI switching power supply, such as Figure 1 As shown, the dimming current calibration principle is: when the controller unit 12 (such as MCU) transmits a dimming drive signal to the switching power supply 2 through the communication unit 13, the switching power supply 2 will output a dimming current to dim the lamp 3 according to the dimming drive signal. At this time, the digital-to-analog conversion unit 11 can receive the dimming current output by the switching power supply 2, convert the analog signal into a digital signal, generate a dimming current signal and feed it back to the controller unit 12. The controller unit 12 can compare the dimming current signal with its corresponding standard value to know how much the dimming current differs from the standard value due to the accuracy error of the switching power supply 2, and correspondingly increase or decrease one level (for example, relative to the original The dimming percentage increases by 1% or decreases by 1%), and the dimming drive signal is re-output, and the dimming current signal is checked again until the dimming current signal is equal to the standard value. It can be known that the dimming drive signal corresponding to the dimming percentage at this time is desired, and the switching power supply 2 is enabled to save. The next time the instruction of the dimming percentage is received at this time, the adjusted dimming drive signal is output to generate a dimming current corresponding to the dimming percentage, thereby solving the problem of low dimming accuracy caused by the internal error of the switching power supply 2, and adapting to the dimming error calibration of different types of switching power supplies 2. At the same time, the number of digital-to-analog conversions is small, the circuit structure is simple, and the dimming process is simple, and the dimming calibration of the switching power supply 2 can be completed quickly.

[0041] More importantly, the communication unit 13 is also used to be controlled by the controller unit 12 to turn on or off the dimming current calibration circuit. After the calibration is completed (that is, all dimming percentages are calibrated), the dimming current calibration circuit can be turned off to prevent the lighting system from being in a calibration state all the time and consuming too much energy. It is even possible to expand more calibration methods by controlling the opening and closing of the dimming current calibration circuit to match more complex lighting systems.

[0042] Furthermore, the communication unit 13 includes a driving power supply circuit 131, a communication circuit 132 and a diode D1; the control ends of the driving power supply circuit 131 and the communication circuit 132 are both used as control ends of the communication unit 13, and the cathode and anode of the diode D1 are both used as output ends of the communication unit 13;

[0043] The output ends of the driving power supply circuit 131 and the communication circuit 132 are both electrically connected to the cathode of the diode D1;

[0044] The driving power supply circuit 131 is used to turn on or off the power supply under the control of the controller unit 12;

[0045] The communication circuit 132 is used to receive the dimming driving signal from the controller unit 12 and transmit it to the switching power supply 2 .

[0046] In this embodiment, Figure 2As shown, because the communication unit 13 needs to realize data exchange between the controller unit 12 and the switching power supply 2, a communication circuit 132 is set; because the communication unit 13 needs to be controlled to turn on or off the dimming current calibration circuit, a driving power supply circuit 131 is set, and whether the switching power supply 2 accepts the calibration of the dimming current calibration circuit is determined by whether the dimming driving end of the switching power supply 2 is powered, and when the dimming current calibration circuit is turned off, the power supply of the driving power supply circuit 131 is turned off, which can greatly reduce the power supply energy consumption.

[0047] Further, the driving power supply circuit 131 includes a DC / DC chip M1, a resistor R42, a resistor R48, a resistor R24, a resistor R38, a resistor R18, a resistor R40, a MOS tube Q5, a capacitor C15, a capacitor C16, a capacitor C17, a transistor Q2, a transistor Q3 and a diode D3; one end of the resistor R42 is used as a control end of the driving power supply circuit 131, and the cathode of the diode D3 is used as an output end of the driving power supply circuit 131;

[0048] The other end of the resistor R42 and one end of the resistor R48 are electrically connected to the gate of the MOS tube Q5, the other end of the resistor R48 and the source of the MOS tube Q5 are grounded, the drain of the MOS tube Q5 and the GND end of the DC / DC chip M1 are electrically connected to the negative electrode of the capacitor C16, the positive electrode of the capacitor C16 and the VIN end of the DC / DC chip M1 are connected to a 5V power supply, the Vo+ end of the DC / DC chip M1, one end of the resistor R24, the positive electrode of the capacitor C17, one end of the capacitor C15, and the emitter of the transistor Q3 are connected to the 5V power supply. It is electrically connected to one end of resistor R38, the other end of resistor R38 and the base of transistor Q3 are electrically connected to the emitter of transistor Q2, the collector of transistor Q3 and the base of transistor Q2 are electrically connected to one end of resistor R18, the collector of transistor Q2 and one end of resistor R40 are electrically connected to the anode of diode D3, the other end of resistor R40, the other end of resistor R18, the negative electrode of capacitor C17, the other end of capacitor C15, the other end of resistor R24 ​​and the Vo- end of DC / DC chip M1 are all grounded.

[0049] In this embodiment, the driving power supply circuit 131 uses the DC / DC chip M1 as the core to form a 5V to 15V boost circuit, and is controlled by the controller unit 12 through the MOS tube Q5 to determine whether to boost the power supply, thereby meeting the design requirements.

[0050] Furthermore, the communication circuit 132 includes a diode D6, a MOS transistor Q7, a resistor R56, a resistor R57, a resistor R61, a resistor R62, a resistor R67, a capacitor C24, a voltage stabilizing diode DZ1, a transistor Q5, a transistor Q6, a photocoupler U7 and a photocoupler U8; the anode of the diode D6 is used as the output end of the communication circuit 132, and the emitter of the photocoupler U7 and one end of the resistor R62 are used as the control end of the communication circuit 132;

[0051] The cathode of the diode D6, one end of the resistor R56, and the emitter of the transistor Q6 are all electrically connected to the drain of the MOS transistor Q7, the other end of the resistor R56 and the base of the transistor Q6 are all electrically connected to the emitter of the transistor Q5, one end of the resistor R57 and the collector of the transistor Q6 are all electrically connected to the base of the transistor Q5, the other end of the resistor R57 is grounded, the collector of the transistor Q5 is electrically connected to the anode of the photocoupler U7, the collector of the photocoupler U7 is connected to the 3V3 power supply, and the emitter of the photocoupler U7 is electrically connected to one end of the resistor R61. The other end of the resistor R61 is grounded, the cathode of the photocoupler U7, the collector of the photocoupler U8, and one end of the capacitor C24 are electrically connected to the cathode of the voltage-stabilizing diode DZ1, the other end of the capacitor C24 and the anode of the voltage-stabilizing diode DZ1 are grounded, the anode of the photocoupler U8 is connected to the 3V3 power supply, the cathode of the photocoupler U8 is electrically connected to the other end of the resistor R62, the emitter of the photocoupler U8 is electrically connected to one end of the resistor R67, the other end of the resistor R67 is electrically connected to the gate of the MOS tube Q7, and the source of the MOS tube Q7 is grounded.

[0052] In this embodiment, the communication circuit 132 has a bidirectional signal transmission function, is controlled by the controller unit 12, and can expand multiple calibration methods; when in the signal receiving state, DALI_TX is a low level, and the signal is transmitted to DALI_RX; when the circuit is in the signal sending state, DALI_TX is a high level, and the signal is sent out from DALI_TX.

[0053] The following will analyze in detail the working process in two different states:

[0054] In the receiving state, DALI_TX is in a low level state, and the signal is transmitted to DALI_RX; DALI_TX is in a low level state, and the U8B side of the photocoupler U8 is cut off. When the anode of the diode D6 is a high voltage, the current flows through the constant current circuit composed of the transistor Q5 and the transistor Q6, and then the current flows through the U8B side of the photocoupler U8 and the voltage regulator diode DZ1. At this time, the U7B side of the photocoupler U7 is turned on, and DALI_RX is a high level; when the anode of the diode D6 is a low voltage, the transistor Q5, the transistor Q6, the photocoupler U7, and the voltage regulator diode DZ1 have no current, and DALI_RX is a low level; so when in the receiving state, the DALI_RX signal positively follows the anode level of the diode D6;

[0055] In the sending state, when DALI_TX is at a high level, the U8B side of the photocoupler U8 is turned on, and the anode signal of the diode D6 passes through the transistor Q5, the transistor Q6, the photocoupler U7A of the photocoupler U7, the photocoupler U8B of the photocoupler U8 and the MOS tube Q7, so that the MOS tube Q7 is in a conducting state, and the Vds voltage of the MOS tube Q7 is at a low level, thereby pulling down the anode signal of the diode D6; when DALI_TX is at a low level, the photocoupler U8 is cut off, and the anode signal of the diode D6 passes through the transistor Q5, the transistor Q6, the photocoupler U7A of the photocoupler U7, the photocoupler U8B of the photocoupler U8 and the voltage regulator diode DZ1, so that the MOS tube Q7 is in a cut-off state, and the Vds voltage of the MOS tube Q7 is at a high level, and the anode signal of the diode D6 is at a high level; therefore, when in the sending state, the DALI_TX signal is opposite to the anode signal of the diode D6.

[0056] Further, the digital-to-analog conversion unit 11 includes a digital-to-analog conversion chip U9, a resistor R16, a resistor R19, a resistor R1, a resistor R5, a capacitor C21, a capacitor C22, a diode D5 and a diode D8; the anode of the diode D8 is used as the positive input terminal of the digital-to-analog conversion unit 11, the cathode of the diode D8 is used as the negative input terminal of the digital-to-analog conversion unit 11, and the SDA terminal and the SCL terminal of the digital-to-analog conversion chip U9 are used as the output terminals of the digital-to-analog conversion unit 11;

[0057] One end of resistor R16 and one end of resistor R19 are both connected to the VDD power supply, the other end of resistor R16 is electrically connected to the SCL end of the digital-to-analog conversion chip U9, the other end of resistor R19 is electrically connected to the SDA end of the digital-to-analog conversion chip U9, the VSS end of the digital-to-analog conversion chip U9 is grounded, the VDD end of the digital-to-analog conversion chip U9 and one end of capacitor C22 are both connected to the VDD power supply, the other end of capacitor C22 and one end of resistor R5 are both grounded, the other end of resistor R5, one end of capacitor C21, one end of resistor R1, the anode of diode D5, and the cathode of diode D8 are all electrically connected to the VIN- end of the digital-to-analog conversion chip U9, and the other end of capacitor C21, the other end of resistor R1, the cathode of diode D5, and the anode of diode D8 are all electrically connected to the VIN+ end of the digital-to-analog conversion chip U9.

[0058] In this embodiment, Figure 3 As shown, the digital-to-analog conversion unit 11 uses the digital-to-analog conversion chip U9 as the core to build a digital-to-analog conversion circuit for converting analog signals into digital signals, and collects the dimming current (analog signal) from the positive output end of the switching power supply 2 and converts it into a digital signal that can be recognized by the controller unit 12.

[0059] Furthermore, it also includes a visualization unit 14; the input end of the visualization unit 14 is electrically connected to the visualization output end of the controller unit 12;

[0060] The visualization unit 14 is used for data interaction with the controller unit 12 and displaying data of the dimming current calibration process of the controller unit 12 .

[0061] In this embodiment, in order to enable technical personnel to clearly understand the specific calibration process, the error problem existing in the switching power supply 2 is analyzed from the calibration process data (such as dimming drive signal, dimming current signal, standard value, comparison result of dimming current signal and standard value, etc.), and a visualization unit 14 can be set in the dimming current calibration circuit, that is, for example, an LCD screen display is set.

[0062] Furthermore, it also includes a prompt unit 15; the input end of the prompt unit 15 is electrically connected to the prompt output end of the controller unit 12;

[0063] The prompt unit 15 is used to issue a prompt when the dimming current signal is greater than or less than the standard value, or to issue a prompt when the dimming current signal is equal to the standard value.

[0064] In this embodiment, during the calibration process, it is not necessary to always look at the display screen to understand the calibration progress. Therefore, a prompt unit 15 can be set to facilitate prompting the technician of the calibration progress; when the dimming percentage of the switching power supply 2 with an error is small, the prompt unit 15 can be set to issue a prompt when the dimming current signal is greater than or less than the standard value, informing the technician that there is an error in the dimming percentage; or when the dimming percentage of the switching power supply 2 with an error is large, the prompt unit 15 can be set to issue a prompt when the dimming current signal is equal to the standard value, ignoring the calibration process, and informing the technician that the calibration is completed.

[0065] Furthermore, the prompt unit 15 includes a resistor R8, a resistor R11, a transistor Q1 and a buzzer BZ1; one end of the resistor R11 is used as an input end of the prompt unit 15;

[0066] The other end of the resistor R11 is electrically connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 and one end of the resistor R8 are electrically connected to the negative electrode of the buzzer BZ1, and the other end of the resistor R8 and the positive electrode of the buzzer BZ1 are connected to a 5V power supply.

[0067] In this embodiment, Figure 4 As shown, the prompt unit 15 can implement the prompt function by sending out a buzzer sound through a buzzer circuit to prompt the technician.

[0068] Other structures and operations of the dimming current calibration circuit of a DALI switching power supply according to the embodiment of the utility model are known to ordinary technicians in the field and will not be described in detail here.

[0069] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0070] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A dimming current calibration circuit for a DALI switching power supply, characterized in that: It includes a digital-to-analog conversion unit, a controller unit and a communication unit; the positive dimming output terminal of the switching power supply is electrically connected to the positive input terminal of the digital-to-analog conversion unit, the positive input terminal of the lamp is electrically connected to the negative input terminal of the digital-to-analog conversion unit, the output terminal of the digital-to-analog conversion unit is electrically connected to the input terminal of the controller unit, the control terminal of the controller unit is electrically connected to the control terminal of the communication unit, and the output terminal of the communication unit is electrically connected to the dimming driving terminal of the switching power supply; When the controller unit transmits a dimming driving signal to the switching power supply through the communication unit, the controller unit receives a dimming current signal from the digital-to-analog conversion unit; When the dimming current signal is greater than the standard value corresponding to the dimming drive signal, the controller unit transmits the dimming drive signal of a lower level to the switching power supply through the communication unit; when the dimming current signal is less than the standard value, the controller unit transmits the dimming drive signal of a higher level to the switching power supply through the communication unit; when the dimming current signal is equal to the standard value, the controller unit transmits a save signal to the switching power supply through the communication unit; The communication unit is also used to turn on or off the dimming current calibration circuit under the control of the controller unit.

2. The dimming current calibration circuit of a DALI switching power supply according to claim 1, characterized in that: The communication unit includes a driving power supply circuit, a communication circuit and a diode D1; the control ends of the driving power supply circuit and the communication circuit are both used as control ends of the communication unit, and the cathode and anode of the diode D1 are both used as output ends of the communication unit; The output ends of the driving power supply circuit and the communication circuit are both electrically connected to the cathode of the diode D1; The driving power supply circuit is used to turn on or off the power supply under the control of the controller unit; The communication circuit is used for receiving the dimming driving signal from the controller unit and transmitting it to the switching power supply.

3. The dimming current calibration circuit of a DALI switching power supply according to claim 2, characterized in that: The driving power supply circuit includes a DC / DC chip M1, a resistor R42, a resistor R48, a resistor R24, a resistor R38, a resistor R18, a resistor R40, a MOS tube Q5, a capacitor C15, a capacitor C16, a capacitor C17, a transistor Q2, a transistor Q3 and a diode D3; one end of the resistor R42 is used as a control end of the driving power supply circuit, and the cathode of the diode D3 is used as an output end of the driving power supply circuit; The other end of the resistor R42 and one end of the resistor R48 are electrically connected to the gate of the MOS transistor Q5, the other end of the resistor R48 and the source of the MOS transistor Q5 are grounded, the drain of the MOS transistor Q5 and the GND end of the DC / DC chip M1 are electrically connected to the negative electrode of the capacitor C16, the positive electrode of the capacitor C16 and the VIN end of the DC / DC chip M1 are connected to a 5V power supply, the Vo+ end of the DC / DC chip M1, one end of the resistor R24, the positive electrode of the capacitor C17, one end of the capacitor C15, and the emitter of the transistor Q3 are connected One end of the resistor R38 is electrically connected, the other end of the resistor R38 and the base of the transistor Q3 are electrically connected to the emitter of the transistor Q2, the collector of the transistor Q3 and the base of the transistor Q2 are electrically connected to one end of the resistor R18, the collector of the transistor Q2 and one end of the resistor R40 are electrically connected to the anode of the diode D3, and the other end of the resistor R40, the other end of the resistor R18, the negative electrode of the capacitor C17, the other end of the capacitor C15, the other end of the resistor R24 ​​and the Vo- end of the DC / DC chip M1 are all grounded.

4. The dimming current calibration circuit of a DALI switching power supply according to claim 2, characterized in that: The communication circuit includes a diode D6, a MOS tube Q7, a resistor R56, a resistor R57, a resistor R61, a resistor R62, a resistor R67, a capacitor C24, a voltage stabilizing diode DZ1, a transistor Q5, a transistor Q6, a photocoupler U7 and a photocoupler U8; the anode of the diode D6 is used as the output end of the communication circuit, and the emitter of the photocoupler U7 and one end of the resistor R62 are used as the control ends of the communication circuit; The cathode of the diode D6, one end of the resistor R56, and the emitter of the transistor Q6 are all electrically connected to the drain of the MOS tube Q7, the other end of the resistor R56 and the base of the transistor Q6 are all electrically connected to the emitter of the transistor Q5, one end of the resistor R57 and the collector of the transistor Q6 are all electrically connected to the base of the transistor Q5, the other end of the resistor R57 is grounded, the collector of the transistor Q5 is electrically connected to the anode of the photocoupler U7, the collector of the photocoupler U7 is connected to the 3V3 power supply, and the emitter of the photocoupler U7 is electrically connected to one end of the resistor R61. , the other end of the resistor R61 is grounded, the cathode of the photocoupler U7, the collector of the photocoupler U8, and one end of the capacitor C24 are electrically connected to the cathode of the voltage stabilizing diode DZ1, the other end of the capacitor C24 and the anode of the voltage stabilizing diode DZ1 are grounded, the anode of the photocoupler U8 is connected to a 3V3 power supply, the cathode of the photocoupler U8 is electrically connected to the other end of the resistor R62, the emitter of the photocoupler U8 is electrically connected to one end of the resistor R67, the other end of the resistor R67 is electrically connected to the gate of the MOS tube Q7, and the source of the MOS tube Q7 is grounded.

5. The dimming current calibration circuit of a DALI switching power supply according to claim 1, characterized in that: The digital-to-analog conversion unit includes a digital-to-analog conversion chip U9, a resistor R16, a resistor R19, a resistor R1, a resistor R5, a capacitor C21, a capacitor C22, a diode D5 and a diode D8; the anode of the diode D8 is used as the positive input terminal of the digital-to-analog conversion unit, the cathode of the diode D8 is used as the negative input terminal of the digital-to-analog conversion unit, and the SDA terminal and the SCL terminal of the digital-to-analog conversion chip U9 are used as the output terminals of the digital-to-analog conversion unit; One end of the resistor R16 and one end of the resistor R19 are both connected to the VDD power supply, the other end of the resistor R16 is electrically connected to the SCL end of the digital-to-analog conversion chip U9, the other end of the resistor R19 is electrically connected to the SDA end of the digital-to-analog conversion chip U9, the VSS end of the digital-to-analog conversion chip U9 is grounded, the VDD end of the digital-to-analog conversion chip U9 and one end of the capacitor C22 are both connected to the VDD power supply, the other end of the capacitor C22 and one end of the resistor R5 are both grounded, the other end of the resistor R5, one end of the capacitor C21, one end of the resistor R1, the anode of the diode D5, and the cathode of the diode D8 are all electrically connected to the VIN- end of the digital-to-analog conversion chip U9, and the other end of the capacitor C21, the other end of the resistor R1, the cathode of the diode D5, and the anode of the diode D8 are all electrically connected to the VIN+ end of the digital-to-analog conversion chip U9.

6. The dimming current calibration circuit of a DALI switching power supply according to claim 1, characterized in that: It also includes a visualization unit; the input end of the visualization unit is electrically connected to the visualization output end of the controller unit; The visualization unit is used for data interaction with the controller unit to display data of the dimming current calibration process of the controller unit.

7. The dimming current calibration circuit of a DALI switching power supply according to claim 1, characterized in that: It also includes a prompt unit; the input end of the prompt unit is electrically connected to the prompt output end of the controller unit; The prompt unit is used to issue a prompt when the dimming current signal is greater than or less than the standard value, or to issue a prompt when the dimming current signal is equal to the standard value.

8. The dimming current calibration circuit of a DALI switching power supply according to claim 7, characterized in that: The prompt unit includes a resistor R8, a resistor R11, a transistor Q1 and a buzzer BZ1; one end of the resistor R11 is used as an input end of the prompt unit; The other end of the resistor R11 is electrically connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 and one end of the resistor R8 are electrically connected to the negative electrode of the buzzer BZ1, and the other end of the resistor R8 and the positive electrode of the buzzer BZ1 are connected to a 5V power supply.

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