CN104470149B - Dimming circuit adaptive to multiple dimming modes - Google Patents

Abstract

The present invention relates to the field of dimming technology, and in particular to a dimming circuit adapted to multiple dimming modes. On the one hand, the circuit converts all received dimming signals into PWM signals through a PWM generation module, and then a signal conditioning module conditions the PWM signal, so that the dimming circuit can adapt to different types of dimmers. On the other hand, the signal conditioning module of the dimming circuit obtains the base B voltage of the LED drive circuit and outputs a drive signal according to the base B voltage of the LED drive circuit when the PWM signal is suspended. Therefore, even if the dimmer or the dimming circuit works and causes the PWM signal receiving end to be suspended, the signal conditioning module can still output a drive signal to drive the LED drive circuit when it detects that the base B voltage is non-zero (the LED drive circuit works normally), thereby preventing the LED drive circuit from stopping outputting the drive signal.

Description

A dimming circuit adaptable to multiple dimming modes

technical field

The invention relates to the technical field of dimming, in particular to a dimming circuit adapted to various dimming modes.

Background technique

With the development of semiconductor technology and LED lighting technology, LED lighting fixtures have the advantages of energy saving, environmental protection and long life. More and more lighting occasions use LED lighting fixtures to replace traditional incandescent lamps and other lamps to achieve lighting. These lighting occasions also Including many occasions where dimming is required.

In the current dimming technology, the solution of the dimmer is generally that the dimmer sends a dimming signal to the dimming circuit, and the dimming circuit sends a driving signal to the LED driving circuit according to the dimming signal, so as to control the output of the LED driving circuit . However, at present, there are many types of dimmers, which can be divided into wired and remote control dimmers in terms of connection methods, and can be divided into resistive dimming, voltage dimming and PWM dimming in terms of dimming methods. Therefore, the signal type of the dimming signal received by the dimming circuit is various, it may be a resistance signal, it may be a linear voltage signal, and it may be a PWM signal, and for different signal, the conditioning circuit required is different, so the dimming circuit needs to be changed according to the selection of the dimmer, which is inconvenient in industrial applications. It is necessary to provide a dimming circuit that can adapt to various dimming modes very necessary.

On the other hand, in order to adapt to a variety of dimmers, the current dimming circuit has an increasingly complex structure, usually with an MCU module, and the MCU module is more likely to fail, and the dimmer is unavoidable during use. There is a possibility of failure, for example, there are more possibilities of open circuit in resistive dimmers. In the prior art, the extinguishing of normal LED etc. is realized by turning off the LED driving circuit. The function of the dimmer, that is, the dimming circuit is only to adjust the brightness, but the output of the driving voltage of the LED drive circuit depends on the output of the dimming circuit. When the dimmer or the dimming circuit fails and there is no output, the LED driver The circuit will stop working and turn off the LED light, that is to say, the LED will suddenly go out due to the failure of the dimmer during normal operation, which will affect the normal operation of the LED.

Contents of the invention

The purpose of the present invention is to avoid the disadvantages of the above-mentioned prior art and provide a dimming circuit capable of simultaneously matching multiple dimming modes, and the dimming circuit can also maintain output when the dimmer or dimming circuit fails , so as to avoid the sudden extinguishing of the LED caused by the stop of the LED drive circuit.

The object of the present invention is achieved through the following technical solutions:

Provided is a dimming circuit adapted to multiple dimming modes, including a PWM generating module and a signal conditioning module, the PWM generating module generates a PWM signal according to a received dimming signal sent by a dimmer, and the PWM The generating module sends the PWM signal to the PWM signal receiving end of the signal conditioning module, and the signal conditioning module outputs a driving signal to the LED driving circuit according to the received PWM signal, and the signal conditioning module obtains the LED driving circuit The base B voltage of the LED drive circuit outputs the driving signal according to the base B voltage of the LED driving circuit when the PWM signal receiving end is suspended.

Wherein, the signal conditioning module includes a filter follower circuit and an anti-suspension circuit, the input end of the anti-suspension circuit is connected to the base B of the LED drive circuit, the output end of the anti-suspension circuit is connected to the input end of the filter follower circuit, The three terminals of the PWM signal receiving end are connected to a common contact point. When the PWM signal receiving end is not suspended, the voltage value of the common contact point follows the PWM signal receiving end. When the PWM signal receiving end is suspended, the voltage value of the common contact point follows the anti-suspension circuit. output terminal.

Wherein, the anti-suspension circuit includes a comparison circuit composed of an operational amplifier, the non-inverting terminal of the comparison circuit is connected to the base B of the LED driving circuit, the inversion terminal of the comparison circuit is connected to the power ground, and the comparison circuit The output end of the connection is connected with the output end of the anti-suspension circuit.

Wherein, the non-inverting terminal of the operational amplifier is connected to the base B of the LED driving circuit through a resistor R302, the inverting terminal of the operational amplifier is connected to the power ground through a resistor R300, and the output terminal of the operational amplifier is connected to the power supply ground through a resistor R300. Resistor R301 feeds back to its inverting terminal, and on the other hand feeds back to its non-inverting terminal via resistors R304 and R303, where (R304+R303)/R302≥R301/R300.

Wherein, the filter follower circuit includes a filter regulator circuit and a voltage follower circuit, the filter regulator circuit filters the signal received from the common contact and outputs it to the voltage follower circuit, and the voltage follower circuit outputs the drive signal to LED drive circuit.

Wherein, the filtering and stabilizing circuit includes a voltage stabilizing diode ZD301, and the stabilizing diode ZD301 makes the output voltage of the stabilizing and filtering circuit less than or equal to a first threshold.

Wherein, the output end of the voltage follower circuit is provided with a back-end filter circuit, and the driving signal output by the voltage follower circuit is filtered by the back-end filter circuit and then sent to the LED drive circuit.

Wherein, the PWM generating module includes a main control chip, and the main control chip includes a mechanical dimming signal receiving end and a wireless dimming signal receiving end, and the mechanical dimming signal receiving end is connected to a mechanical dimming signal receiving end. circuit.

Wherein, the mechanical dimming signal receiving circuit receives the dimming signal output by the resistive dimmer, the voltage dimmer or the PWM dimmer and converts it into a linear voltage signal to be sent to the PWM generating module.

Wherein, the mechanical dimming signal receiving circuit includes a signal receiving end, a power supply circuit, a front-end filter circuit and a Zener diode ZD300, and the power supply circuit provides a reference voltage when the signal receiving end is connected to a resistive dimmer, and the The front-end filter circuit filters the signal input from the signal receiving end to form a linear voltage signal, and the Zener diode ZD300 is connected to the output end of the filter circuit so that the mechanical dimming signal receiving circuit sends the linear voltage to the PWM generating module The signal is less than or equal to the second threshold.

Beneficial effects of the present invention: the present invention provides a dimming circuit capable of automatically matching multiple dimming modes. On the one hand, the dimming circuit converts all received dimming signals into PWM signals through a PWM generating module, and then The PWM signal is conditioned by the signal conditioning module, so that the dimming circuit can adapt to different types of dimmers. On the other hand, the signal conditioning module of the dimming circuit obtains the base B voltage of the LED drive circuit and When the PWM signal is suspended, the drive signal is output according to the base B voltage of the LED drive circuit, so even if the dimmer or the dimming circuit works and the PWM signal receiving end is suspended, the signal conditioning module can detect that the base B voltage is non-zero ( The LED drive circuit is working normally) to output the drive signal to drive the LED drive circuit to prevent the LED drive circuit from stopping to output the drive signal.

Description of drawings

The present invention is further described by using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without paying creative work, other embodiments can also be obtained according to the following accompanying drawings Attached picture.

FIG. 1 is a circuit block diagram of a dimming circuit adapted to multiple dimming modes according to the present invention.

FIG. 2 is a circuit diagram of a PWM generation module of a dimming circuit adapted to multiple dimming modes according to the present invention.

FIG. 3 is a circuit diagram of a signal conditioning module of a dimming circuit adapted to multiple dimming modes according to the present invention.

detailed description

The present invention is further described in conjunction with the following examples.

Example

A specific implementation of a dimming circuit adaptable to multiple dimming modes of the present invention, as shown in Figure 1 and Figure 2, includes: PWM generation module 1 and signal conditioning module 2, PWM generation module 1 according to the signal received by The dimming signal sent by the dimmer generates a PWM signal, and the PWM generating module 1 sends the PWM signal to the PWM signal receiving end of the signal conditioning module 2, and the signal conditioning module 2 outputs a driving signal to the LED according to the received PWM signal Drive circuit.

Specifically, the PWM generation module 1 is based on the SH88F2051A MCU chip, which mainly converts the received dimming signal into a PWM signal, so that the signal conditioning module can effectively condition the signal. The chip includes a mechanical dimming signal receiving terminal and The wireless dimming signal receiving end, the mechanical dimming signal receiving end is connected to a mechanical dimming signal receiving circuit 21, the wireless dimming signal receiving end is connected to the wireless signal receiving circuit 22 to receive the wireless dimming signal, the mechanical dimming signal The signal receiving circuit 21 includes a signal receiving end, a power supply circuit, a front-end filter circuit and a Zener diode ZD300, the power supply circuit is formed by a 12V voltage through a resistor R311, and provides a reference voltage when the signal receiving end is connected to a resistive dimmer, so The front-end filter circuit is composed of a resistor R312 and a capacitor C309, which is used to filter the signal input from the signal receiving end to form a linear voltage signal. The Zener diode ZD300 is connected to the output end of the filter circuit to enable mechanical dimming The linear voltage signal sent by the signal receiving circuit 21 to the PWM generating module 1 is less than or equal to the second threshold, so that the dimming signal output by the resistive, voltage or PWM dimmer can be simultaneously received and converted into a linear voltage signal for input to the PWM generating module 1, and at the same time, the Zener diode ZD300 limits the linear voltage signal to prevent it from exceeding the carrying capacity of the PWM generating module 1. The wireless signal receiving module is mainly used to receive infrared and other wireless dimming signals, and it also converts the dimming signals and inputs them to the PWM generation module 1 .

The signal conditioning module 2 includes a PWM signal receiving end, a filter follower circuit and an anti-suspension circuit 31. The output end of the anti-suspension circuit 31, the input end of the filter follower circuit, and the three terminals of the PWM signal receiving end are connected to a common contact point. The receiving end receives the PWM signal output by the PWM generating module 1, and the signal is generated by the SH88F2051A MCU chip. Therefore, when the MCU chip has a PWM signal output (that is, when the PWM signal receiving end is not suspended), the common contact The voltage value must follow the PWM signal receiving end, that is, the input end of the filter follower circuit receives the PWM signal output by the MCU chip. When there is no PWM signal output from the MCU chip (that is, when the PWM signal receiving end is suspended), The voltage value of the contact must follow the output terminal of the anti-suspension circuit 31 , that is, the input terminal of the filter follower circuit receives the output signal of the anti-suspension circuit 31 . Therefore, compared with the prior art, when the PWM signal receiving end is suspended due to the operation of the dimmer or the dimming circuit, the anti-suspension circuit 31 can provide a signal to the filter follower circuit, so that the filter follower circuit can still output the driving signal.

Specifically, the above-mentioned anti-suspension circuit 31 includes an operational amplifier (U4 in FIG. 2 includes two operational amplifiers, one for the floating circuit and one for the voltage follower circuit), and the non-inverting terminal of the operational amplifier is connected to the The base B of the LED drive circuit, the inverting terminal of the operational amplifier is connected to the power ground through the resistor R300, the output terminal of the operational amplifier is fed back to the inverting terminal through the resistor R301 on the one hand, and the inverting terminal is fed back to the inverting terminal through the resistor R304 and the resistor R304 on the other hand. Resistor R303 feeds back to its non-inverting terminal, where (R304+R303)/R302=R301/R300, the operational amplifier constitutes a comparison circuit, the non-inverting terminal of the comparison circuit is connected to the base B of the LED drive circuit 1, the comparison The inverting end of the circuit is connected to the power ground, and the output end of the comparison circuit is connected to the output end of the floating circuit. Therefore, as long as the base B voltage of the LED driving circuit 1 is non-zero (that is, the LED driving circuit 1 works normally), the anti-suspension circuit 31 outputs a positive voltage (in this embodiment, the driving signal generated by the positive voltage is adjusted by parameter adjustment) is the maximum driving value, that is, the lamp is brightest under this voltage, of course, those skilled in the art can adjust it flexibly). And when the base B voltage of the LED driving circuit 1 is zero (that is, the LED driving circuit 1 stops working), the output of the anti-suspension circuit 31 is zero, which will not cause any impact on the LED driving circuit 1 .

The filter follower circuit includes a filter regulator circuit 32, a voltage follower circuit 33 and a back-end filter circuit 34. The filter regulator circuit 32 is composed of a resistor R305, a capacitor C302 and a voltage regulator diode ZD301, which will receive After the signal is filtered, it is output to the voltage follower circuit 33, and the Zener diode ZD301 makes the output voltage value of the voltage stabilizer filter circuit less than or equal to the first threshold value, so as to prevent the voltage value output by the filter stabilizer circuit 32 from exceeding the voltage follower circuit 33 or LED The bearing capacity of the drive circuit 1. The voltage follower circuit 33 is composed of an operational amplifier of the chip U4 , and the driving signal outputted by it is filtered by the back-end filter circuit 34 and sent to the LED driving circuit 1 .

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand , the technical solution of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims (9)

1. the light adjusting circuit of the various light-modulating modes of a kind of adaptation, it is characterised in that：Including PWM generation module and signal condition mould Block, the PWM generation module generate pwm signal by the dim signal that dimmer sends according to what is received, and the PWM generates mould The pwm signal is sent to block the pwm signal receiving terminal of the Signal-regulated kinase, and the Signal-regulated kinase is according to reception To LED drive circuit, the LED drive circuit is included for providing the base of reference voltage the pwm signal output drive signal for arriving Pole B, the Signal-regulated kinase obtain the base stage B voltage of the LED drive circuit and when pwm signal receiving terminal is hanging according to The base stage B voltage output drive signal of LED drive circuit；The Signal-regulated kinase includes filtering follow circuit and anti-hanging electricity Road, it is described prevent hanging circuit input be connected with base stage B of LED drive circuit, it is described prevent hanging circuit outfan and filter The input of ripple follow circuit, three end of pwm signal receiving terminal are connected to a contact altogether altogether, when pwm signal receiving terminal is non-hanging The magnitude of voltage of the common contact follows pwm signal receiving terminal, and when pwm signal receiving terminal is hanging, the magnitude of voltage of the common contact follows anti- The outfan of hanging circuit.

2. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 1, it is characterised in that：The anti-hanging electricity Road includes the comparison circuit being made up of operational amplifier, and the in-phase end of the comparison circuit is connected to the base stage of LED drive circuit B, the end of oppisite phase of the comparison circuit are connected to power supply ground, and the output of hanging circuit is prevented in the outfan connection of the comparison circuit End.

3. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 2, it is characterised in that：The operation amplifier The in-phase end Jing resistance R302 of device are connected to base stage B of the LED drive circuit, the end of oppisite phase Jing resistance of the operational amplifier R300 is connected to power supply ground, and the outfan one side Jing resistance R301 of the operational amplifier feeds back to its end of oppisite phase, the opposing party Jing resistance R304 and resistance R303 feed back to its in-phase end in face, wherein（R304+R303）/R302≥R301/R300.

4. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 1, it is characterised in that：The filtering is followed Circuit includes filter regulator circuit, voltage follower circuit, and the filter regulator circuit is by from the signal that contact is received altogether Export after filtering to voltage follower circuit, the voltage follower circuit output drive signal is to LED drive circuit.

5. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 4, it is characterised in that：The filtering voltage regulation Circuit includes that Zener diode ZD301, the Zener diode ZD301 cause the output voltage values of the filter circuit of pressure-stabilizing little In equal to first threshold.

6. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 4, it is characterised in that：The voltage follow The outfan of circuit is provided with rear end filter circuit, rear end filtered electrical described in the drive signal Jing of the voltage follower circuit output LED drive circuit is delivered to after the filtering of road.

7. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 1, it is characterised in that：The PWM is generated Module includes main control chip, and the main control chip includes mechanical dimming signal receiving end and Wireless Light modulating signal receiving end, institute State mechanical dimming signal receiving end and be connected with mechanical dimming signal receiving circuit.

8. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 7, it is characterised in that：The mechanical type is adjusted Optical signal receiving circuit receives the dim signal of resistive dimmers, voltage-type dimmer or PWM formulas dimmer output and turns Turn to linear voltage to be delivered to PWM generation module.

9. the light adjusting circuit of the various light-modulating modes of a kind of adaptation as claimed in claim 7, it is characterised in that：The mechanical type is adjusted Optical signal receiving circuit includes signal receiving end, power supply circuits, front-end filtering circuitry and Zener diode ZD300, the power supply Circuit provides reference voltage when signal receiving end accesses resistive dimmers, and the front-end filtering circuitry is defeated by signal receiving end The signal for entering is filtered to form linear voltage, and the Zener diode ZD300 is connected to the defeated of the filter circuit Go out end so that the linear voltage that mechanical dimming signal receiving circuit is delivered to PWM generation module is less than or equal to the second threshold Value.