CN219761383U - DALI adjustable current driving power supply - Google Patents

Abstract

The utility model provides a DALI adjustable current driving power supply which comprises an EMC filtering rectification circuit, a flyback circuit, a buck conversion circuit, a digital signal processing circuit, an isolation transmission circuit and a digital signal processor. The EMC filtering rectifying circuit is connected to the mains supply, the flyback circuit is connected with the output end of the EMC filtering rectifying circuit, the buck converting circuit is connected with the output end of the flyback circuit, the digital signal processing circuit is used for being connected with the DALI signal and is switched on and off according to the DALI signal, and the isolation transmission circuit is connected between the digital signal processing circuit and the digital signal processor. The dimming circuit framework adopting the DALI protocol has strong bidirectional communication capability. The variable frequency dimming mode is adopted, so that the dimming process is softer, step jitter is avoided, and the dimming depth can reach one thousandth.

Description

DALI adjustable current driving power supply

Technical Field

The utility model relates to the field of LED illumination, in particular to a DALI adjustable current driving power supply.

Background

Along with the gradual development of LED illumination, the requirements of more and more customers on illumination environment are higher and higher, the LED dimming lamp is widely applied to daily life work, the requirements of users on dimming depth are also higher and higher, the dimming depth of the conventional LED dimming lamp is generally 1%, the digital LED illumination power supply becomes a mainstream product due to the energy saving requirement, and the DALI adopts a standard communication protocol to accelerate the use of group control and intelligent illumination energy-saving products. Architects are also very concerned with the compatibility of lighting group control communication protocols and devices, and the use of DALI dimming systems allows seamless interconnection of products produced by different lighting manufacturers.

Disclosure of Invention

In order to solve the problems, the utility model is realized by the following technical scheme:

a DALI adjustable current drive power supply comprising:

the EMC filtering rectification circuit is connected with the mains supply and used for rectifying and filtering the mains supply;

the flyback circuit is connected with the output end of the EMC filtering rectification circuit and is used for converting the filtered and rectified mains supply into constant voltage;

the buck conversion circuit is connected with the output end of the flyback circuit and is used for realizing constant output of the constant voltage;

the digital signal processing circuit is used for accessing the DALI signal and switching on and switching off according to the DALI signal; and

the isolation transmission circuit is connected between the digital signal processing circuit and the digital signal processor and is used for transmitting different signals to the digital signal processor according to the on-off state of the digital signal processing circuit; the digital signal processor is also connected with the buck conversion circuit, and is used for sending dimming signals to the buck conversion circuit according to the different signals.

Further, the buck conversion circuit comprises an LED driving chip, the LED driving chip adopts MP24881, 3 pins and 4 pins of the LED driving chip are connected with the digital signal processor, and 2 pins of the LED driving chip are connected with the output end of the flyback circuit.

Further, the buck conversion circuit further comprises an induced voltage detection circuit, the induced voltage detection circuit comprises thirty-one resistors, thirty-one resistors and twenty-nine resistors which are connected in parallel between the 5 pins and the 6 pins of the LED driving chip, a fourth inductor is further connected between the 7 pins and the 6 pins of the LED driving chip, and a common mode inductor is arranged between the 5 pins of the LED driving chip and the load LED.

Further, twenty-four capacitors and twenty-seven resistors connected in series are connected between the 7 pins and the 8 pins of the LED driving chip.

Further, the digital signal processor comprises a processing chip, a voltage dividing circuit connected with the processing chip and a power supply circuit for supplying power to the processing chip; the voltage of the power supply circuit is divided by the voltage dividing circuit to provide different voltage signals to the processing chip.

Further, the processing chip adopts STM32G030K6.

Further, the voltage dividing circuit comprises a fifty-three resistor and a fifty-seven resistor which are connected between the power supply circuit and the ground, and a plurality of resistors with different resistance values which are connected in parallel with the common end of the fifty-three resistor and the fifty-seven resistor, and a dial switch which is connected with the other end of the resistor with different resistance values; and the common end of the fifty-three resistors and the fifty-seven resistors is connected with the processing chip.

Further, the isolation transmission circuit comprises a first photoelectric coupler, a light emitter of the first photoelectric coupler is connected with the digital signal processing circuit, and a light receiver of the first photoelectric coupler is connected with the digital signal processor; when the digital signal processing circuit is connected with a low level, the first photoelectric coupler is connected, and when the digital signal processing circuit is connected with a high level, the first photoelectric coupler is disconnected.

Further, the isolation transmission circuit further comprises a second photoelectric coupler; and the light emitter of the second photoelectric coupler is connected with the digital signal processor, and the light receiver of the second photoelectric coupler is connected with the second isolation transmission circuit.

Compared with the prior art, the technical scheme of the utility model has the following beneficial effects:

(1) The mains supply is input into the EMC filtering rectification circuit, is subjected to filtering rectification, is converted into constant voltage through the flyback circuit, and is subjected to constant current output through the buck conversion circuit. The DALI signal is rectified and then is processed by the digital signal processing circuit, then the digital signal is transmitted to the digital signal processor through the isolation transmission circuit for judgment, on one hand, the digital signal processor sends an instruction to be fed back to the DALI signal end through the isolation transmission circuit, on the other hand, the digital signal processor sends an analog dimming signal and a PWM dimming signal to the buck conversion circuit, dimming of the load LED lamp is achieved, and the dimming circuit framework of the DALI protocol is adopted, so that the digital signal processor has strong bidirectional communication capability.

(2) According to the utility model, the PWM signal is added on the PWM pin, and the PWM or analog signal is added on the ADIM pin to realize mixed dimming, so that the dimming depth can reach one thousandth, the dimming is more accurate, and the dimming effect is good.

Drawings

FIG. 1 is a schematic block diagram of a DALI adjustable current drive power supply provided by an embodiment of the present utility model;

fig. 2 is a schematic diagram of an EMC filter rectifying circuit according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram of a flyback circuit provided by an embodiment of the present utility model;

FIG. 4 is a schematic diagram of a buck conversion circuit according to an embodiment of the present utility model;

FIG. 5 is a schematic diagram of a digital signal processor provided by an embodiment of the present utility model;

fig. 6 is a schematic diagram of a digital signal processing circuit and an isolated transmission circuit according to an embodiment of the present utility model.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, a DALI adjustable current drive power supply includes an EMC filter rectifying circuit, a flyback circuit, a buck converting circuit, a digital signal processing circuit, an isolation transmission circuit, and a digital signal processor. The EMC filtering rectifying circuit is connected to the mains supply, the flyback circuit is connected with the output end of the EMC filtering rectifying circuit, the buck converting circuit is connected with the output end of the flyback circuit, the digital signal processing circuit is used for being connected with the DALI signal and is switched on and off according to the DALI signal, and the isolation transmission circuit is connected between the digital signal processing circuit and the digital signal processor. The mains supply is input into an EMC filtering rectification circuit, is subjected to filtering rectification, is converted into constant voltage through a flyback circuit, and is subjected to constant current output through a buck conversion circuit. The DALI signal is rectified and then is processed by the digital signal processing circuit, then the digital signal is transmitted to the digital signal processor through the isolation transmission circuit for judgment, on one hand, the digital signal processor sends out an instruction to be fed back to the DALI signal end through the isolation transmission circuit, and on the other hand, the digital signal processor sends out an analog dimming signal and a PWM dimming signal to the buck conversion circuit, so that the dimming of the load LED lamp is realized.

Referring to fig. 2, the present embodiment provides an EMC filtering rectifying circuit, which is mainly used for rectifying filtering and preventing surge impact. CON1 is connected to the live wire and the zero wire of the commercial power, and is protected by a fuse F1, filtered and rectified by a common-mode inductor L1, a common-mode inductor L2, an inductor L3, a capacitor C1, a capacitor C2 and an ECM of a rectifier bridge DB1, and then transmitted to a flyback circuit. The voltage dependent resistor RV1 acts as a discharging surge.

Referring to fig. 3, the present embodiment provides a flyback circuit, which includes a start-up auxiliary power supply circuit, a voltage stabilizing circuit, an overcurrent protection circuit, a driving circuit, a PWM control circuit, and an output rectifying and filtering circuit.

When the power supply is started, the GATE pin of the power supply chip U1 is charged through the resistor R2, the resistor R3 and the resistor R5 and the diode built in the power supply chip U1, when VGATE reaches the GATE threshold value of the switching tube Q1, the switching tube Q1 is conducted, and the power supply chip U1 charges the VCC pin through the built-in current source by using the cascading MOSFET framework. When VCC reaches the IC switching threshold, the power supply chip U1 initializes the minimum duty cycle and on-time generator coefficients. And stops charging VCC and pulls down the MULT pin through the internal pull down resistor. The MULT internal pull-down resistor and resistors R2, R3, R5 form a resistor divider to detect the input voltage. Once the peak voltage on the MULT pin of power chip U1 exceeds the threshold, power chip U1 begins a soft start switch. After the power chip U1 is started, an auxiliary winding TR1C (1-2 winding), a resistor R6, a diode D2, a capacitor C6 and an electrolytic capacitor CE1 of the transformer supply power for the chip power chip U1. The voltage of the auxiliary winding TR1C is in direct proportion to the voltage of the secondary winding TR1B, a voltage divider consisting of the auxiliary winding of the transformer, the resistor R6, the resistor R9, the resistor R10, the resistor R11, the capacitor C7 and the resistor R8 is arranged, the voltage of the detection capacitor C7 (namely the ZCD pin) of the power chip U1 is compared with the internal reference voltage of the power chip U1, and the voltage of the secondary winding is regulated to be constant. The power chip U1 of the present embodiment adopts MP4078.

When the switching tube Q1 is conducted, a primary winding TR1A (4-5 windings) of the transformer TR1, the switching tube Q1, a MOS tube arranged in the power chip U1, a resistor R13 and a resistor R14 form a loop, the rectified input voltage enables primary current to increase linearly, the transformer stores energy, and a diode D3 on a secondary winding is reversely biased. When the switching tube Q1 is turned off, the diode D3 is turned on to charge the electrolytic capacitor CE2 of the secondary, and the energy stored in the transformer is transferred to the secondary load. The power chip U1 detects the current by detecting the voltage on the S pin (R13, R14) and when the voltage on the S pin reaches the internal current limit, the device immediately stops switching.

The high-frequency signal of the secondary winding TR1B of the transformer TR1 is rectified and filtered by a diode D3 and an electric connection capacitor CE2, so that direct-current constant-voltage output is realized. The electrolytic capacitor CE2 is rapidly discharged during shutdown through the switching tube Q2, the switching tube Q3, the diode D4, the zener diode DZ3, the resistor R16, the resistor R17, the resistor R18, the resistor R19, the resistor R20, the resistor R21 and the capacitor C13.

Referring to fig. 4, the present embodiment provides a buck conversion circuit, which includes an LED driving chip U2, wherein the LED driving chip U2 employs MP24881, and two NMOS tubes connected in series are built in the LED driving chip, wherein a drain electrode of one NMOS tube is connected to a VIN pin (2 pins), a source electrode of the one NMOS tube is connected to a SW pin (7 pins), an upper tube is abbreviated as an upper tube, a drain electrode of the other NMOS tube is connected to the SW pin (7 pins), and a source electrode of the other NMOS tube is connected to GND (1 pins), and an lower tube is abbreviated as a lower tube.

The 3 pin and the 4 pin of the LED driving chip U2 are connected with the digital signal processor, and the 2 pin is connected with the output end of the flyback circuit. The 2 pin of the LED driving chip U2 is grounded through a capacitor C14, the 3 pin of the LED driving chip U2 is grounded through a resistor R35, and the 4 pin of the LED driving chip U2 is grounded through a resistor R39. A capacitor C24 and a resistor R27 which are connected in series are connected between the 7 pins and the 8 pins of the LED driving chip. A resistor R31, a resistor R30 and a resistor R29 are connected in parallel between the pins 5 and 6 of the LED driving chip, an inductor L4 is also connected between the pins 7 and 6 of the LED driving chip, and a common mode inductor L5 is connected between the pin 5 of the LED driving chip and a load LED. And a capacitor C25 and a resistor R40 are also connected between the 5 pins of the LED driving chip and the ground.

When the voltage of the 2 pins of the LED driving chip U2 is higher than the starting threshold value of the chip by 5.2V, the LED driving chip is started. LED driving chip U2 detects induced voltage V _ICS+-ICS- (the voltage across the resistors formed by the parallel connection of ICS+ and ICS-, i.e. R29, R30, R31) to regulate the output current. After the upper tube is conducted, the loop is continuously increased to a high threshold (typical value 115 mV) by the upper tube, an inductor L4, a resistor R29, a resistor R30, a resistor R31, an inductor L5, an LED lamp string, an electrolytic capacitor CE2 and a capacitor C14, the lower tube is opened while the upper tube is closed, inductive current is conducted until the temperature between ICS+ and ICS-is lower than a low threshold (typical value 85 mV), then the lower tube is closed, and the upper tube is opened repeatedly, so that the average value between ICSICS+ and ICS-is 100mV, namely the LED lamp current is in a constant current state.

The LED driving chip U2 supports three dimming modes of PWM dimming, analog dimming and analog and PWM mixed dimming. The analog dimming is to apply an analog signal of 0.5 to 1.5V (allowing a PWM signal to be directly input) to the 3 pin (ADIM pin) of the LED driving chip U2 to change the induced voltage V _ICS+-ICS- Is realized by the value of (a). PWM dimming is achieved by inputting a PWM signal of 100hz to 25khz to the PWM pin (4 pin). The hybrid dimming is achieved by applying a PWM signal to the PWM pin and a PWM or analog signal to the ADIM pin. The dimming depth of the hybrid dimming is 1 per mill, the dimming is performed in the hybrid dimming mode in this embodiment, and signals of the ADIM pin and the PWM are provided by the digital signal processor.

Referring to fig. 5, the digital signal processor includes a processing chip U3, a voltage dividing circuit connected to the processing chip U3, and a power supply circuit for supplying power to the processing chip, where the voltage dividing circuit includes a dial switch SW1 and different resistors (R28, R32, R33) connected to different gears of the dial switch SW 1. The power supply circuit comprises a chip U4, a capacitor C22, a capacitor C26, a capacitor C29, a resistor R25, a resistor R26, a capacitor C31, an inductor L6, a capacitor C28, a resistor R22 and a resistor R24, and is used for supplying power to the processing chip U3 and supplying a low-ripple 3.3V power supply voltage without peak when the processing chip U3 is started.

When the processing chip U3 receives the digital signal fed back by the U6B (and U6A in the isolation transmission circuit is a photoelectric coupler), a PWM dimming signal is sent to an ADIM pin and a PWM pin of the U2 to realize mixed dimming. The present embodiment uses a new technology of variable frequency dimming, which is a technology relative to fixed frequency dimming. The fixed-frequency dimming is that the frequency of the PWM is fixed, namely the PWM period is fixed, and the effective level time of the PWM is changed to adjust the duty ratio. Under the condition that the fixed dimming frequency is high, the cycle time is short, the number of PWM adjustable stages is small, smooth adjustment cannot be achieved during dimming, the dimming step jitter problem is caused, and the dimming is particularly obvious at low brightness. The variable frequency dimming mode adopts fixed PWM effective level, and the duty ratio is adjusted by changing PWM frequency, so that the PWM adjustable level number is improved, smooth dimming is realized, the problem of low-brightness step dithering can be solved, and the dimming effect is softer.

The resistors R53, R28, R32, R33 and R57 form a multi-gear voltage divider by toggling the dial switch SW1, different voltage signals are provided for the U3, and the analog signals and the digital signals sent to the U2 are regulated to realize the setting of outputting multi-gear currents. The processing chip U3 also judges whether the output is short-circuited or open-circuited by detecting the voltage at two ends of the capacitor C25, if the output is short-circuited or open-circuited, the processing chip U3 sends out a signal, and the voltage of the pin ADIM of the LED driving chip U2 is pulled down, so that the LED driving chip U2 stops working, and the short-circuit and open-circuit protection is realized.

Referring to fig. 6, the present embodiment further provides a digital signal processing circuit and an isolation transmission circuit, when a low-voltage digital signal is input to the DALI terminal, the transistor Q6 and the transistor Q8 are turned on, and the digital signal is fed back to the processing chip U3 through the optocoupler U6A. When the DALI end inputs high-voltage commercial power, the triode Q9 is conducted through rectification filtering and surge absorption, and signals are fed back to the processing chip U3 through the U6A. When the processing chip U3 sends out signals, the signals are fed back to the isolation transmission circuit through the U7A, so that the signals are transmitted back to the DALI host after the triode Q5 and the triode Q7 are conducted.

The DALI adjustable current driving power supply adopts a light-adjusting circuit framework of the DALI protocol and has strong bidirectional communication capability. The flyback and BUCK circuit frame is adopted, output ripple is small, no stroboscopic effect of the LED lamp can be achieved, damage to a human body caused by the stroboscopic effect of the LED is avoided, and the requirement of people on a high-quality light source is met. The mixed dimming is realized by adding a PWM signal on the PWM pin and adding a PWM or analog signal on the ADIM pin, so that the dimming depth can reach one thousandth, the dimming is more accurate, and the dimming effect is good.

While the foregoing description illustrates and describes the preferred embodiments of the present utility model, it is to be understood that the utility model is not limited to the forms disclosed herein, but is not to be construed as limited to other embodiments, but is capable of use in various other combinations, modifications and environments and is capable of changes or modifications within the scope of the inventive concept, either as described above or as a matter of skill or knowledge in the relevant art. And that modifications and variations which do not depart from the spirit and scope of the utility model are intended to be within the scope of the appended claims.

Claims (9)

1. A DALI adjustable current drive power supply comprising:

the EMC filtering rectification circuit is connected with the mains supply and used for rectifying and filtering the mains supply;

the flyback circuit is connected with the output end of the EMC filtering rectification circuit and is used for converting the filtered and rectified mains supply into constant voltage;

the buck conversion circuit is connected with the output end of the flyback circuit and is used for realizing constant output of the constant voltage;

the digital signal processing circuit is used for accessing the DALI signal and switching on and switching off according to the DALI signal; and

the isolation transmission circuit is connected between the digital signal processing circuit and the digital signal processor and is used for transmitting different signals to the digital signal processor according to the on-off state of the digital signal processing circuit; the digital signal processor is also connected with the buck conversion circuit, and is used for sending dimming signals to the buck conversion circuit according to the different signals.

2. The DALI adjustable current drive power supply of claim 1, wherein the buck conversion circuit comprises an LED driver chip, the LED driver chip is MP24881, pins 3 and 4 of the LED driver chip are connected to the digital signal processor, and pin 2 is connected to the output of the flyback circuit.

3. The DALI adjustable current drive power supply of claim 2, wherein the buck converter circuit further comprises an induced voltage detection circuit comprising thirty-one, thirty-one and twenty-nine resistors connected in parallel between pins 5 and 6 of the LED driver chip, a fourth inductance being further connected between pins 7 and 6 of the LED driver chip, and a common mode inductance between pins 5 of the LED driver chip and the load LED.

4. The DALI adjustable current drive power supply of claim 2, wherein twenty-four capacitors and twenty-seven resistors are connected in series between the 7 pins and 8 pins of the LED driver chip.

5. The DALI adjustable current drive power supply of claim 1, wherein the digital signal processor comprises a processing chip, a voltage divider circuit connected to the processing chip, and a power supply circuit for supplying power to the processing chip; the voltage of the power supply circuit is divided by the voltage dividing circuit to provide different voltage signals to the processing chip.

6. The DALI adjustable current drive power supply of claim 5, wherein the processing chip uses STM32G030K6.

7. The DALI adjustable current drive power supply of claim 5, wherein the voltage divider circuit comprises fifty-three resistors and fifty-seven resistors connected between the power supply circuit and ground, a plurality of resistors of different resistance values connected in parallel to a common terminal of the fifty-three resistors and the fifty-seven resistors, and a dial switch connected to the other terminal of the resistors of different resistance values; and the common end of the fifty-three resistors and the fifty-seven resistors is connected with the processing chip.

8. The DALI adjustable current drive power supply of claim 1, wherein the isolated transmission circuit comprises a first photo-coupler, the light emitter of the first photo-coupler being connected to the digital signal processing circuit, the light receiver of the first photo-coupler being connected to the digital signal processor; when the digital signal processing circuit is connected with a low level, the first photoelectric coupler is connected, and when the digital signal processing circuit is connected with a high level, the first photoelectric coupler is disconnected.

9. The DALI adjustable current drive power supply of claim 8, wherein the isolated transmission circuit further comprises a second optocoupler; and the light emitter of the second photoelectric coupler is connected with the digital signal processor, and the light receiver of the second photoelectric coupler is connected with the second isolation transmission circuit.