Conversion circuit for dimming and lamp

Abstract

The utility model provides a conversion circuit for dimming and a lamp, and the circuit comprises an input signal conversion module which is used for converting an input analog signal into a corresponding PWM signal; the adjusting module is connected with the input signal conversion module and used for adjusting the input voltage range of the input signal conversion module and switching the duty ratio of the output PWM signal to be in positive correlation or negative correlation with the voltage value of the input analog signal; the isolation module is connected with the input signal conversion module; and the output signal conversion module is connected with the isolation module and is used for converting the PWM signal into an output analog signal. The input signal conversion module is adjusted through the adjusting module, input analog signals adaptive to different voltage ranges are achieved, the adaptive use range can be expanded, the positive logic dimming control effect and the negative logic dimming control effect can be selected and switched according to the use scene requirement, and the requirements of different application scenes can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of lighting dimming circuits, in particular to a conversion circuit for dimming and a lamp. Background Art

[0002] With the development of LED lighting technology, in order to make LED lamps more compact and improve the heat dissipation efficiency, more and more LED lamps use the DOB (Driver on Board) circuit solution. DOB integrates the drive circuit on the circuit board of the LED lamp, without the need for external driver connection, achieving the effects of saving space and making the structure more compact. In addition, in order to meet the needs of the usage scenario, the dimming function of LED lamps has become a common function option. Lamps with dimming functions allow users to adjust the lighting brightness of LED lamps through a dimmer or the like.

[0003] Existing dimming circuits generally support positive logic dimming, that is, when the input voltage is the maximum voltage, the output voltage is also the maximum voltage. Usually, they do not support negative logic dimming, that is, when the input voltage is the maximum voltage, the output voltage is the minimum voltage, and even less able to allow users to freely select positive logic dimming or negative logic dimming according to the usage requirements, restricting the range of usage scenarios. In addition, the input voltage range of existing dimming circuits is fixed and cannot adapt to dimmers with different voltage output ranges, resulting in limited adaptation usage range. The limitations of the usage scenario range and the adaptation usage range cause problems of inconvenient and troublesome use.

[0004] Therefore, how to adapt to different dimming voltage input ranges and flexibly switch between positive logic and negative logic dimming according to the scenario requirements is an urgent problem to be solved. Summary of the Utility Model

[0005] The utility model provides a conversion circuit for dimming and a lamp, which are used to solve the defects that the dimming circuit in the prior art cannot adapt to different voltage input ranges and cannot flexibly switch between positive logic and negative logic for dimming.

[0006] The utility model provides a conversion circuit for dimming, including:

[0007] An input signal conversion module, the input end of the input signal conversion module is used to obtain an input analog signal, and the input signal conversion module is used to convert the input analog signal into a corresponding PWM signal;

[0008] An adjustment module, connected to the input signal conversion module;

[0009] An isolation module, connected to the output end of the input signal conversion module;

[0010] An output signal conversion module is connected to the output end of the isolation module. The output signal conversion module is used to convert a PWM signal into a corresponding output analog signal;

[0011] Wherein, the adjustment module is used to adjust the input voltage range of the input signal conversion module, and / or the adjustment module is used to adjust the input signal conversion module so that the voltage value of the input analog signal and the duty cycle of the PWM signal output by the input signal conversion module are positively or negatively correlated.

[0012] According to a conversion circuit for dimming provided by the present invention, the adjustment module includes a logic switching circuit. The input signal conversion module includes a comparator circuit and a triangular wave generating circuit. The logic switching circuit is respectively connected to the non-inverting input terminal and the inverting input terminal of the comparator circuit. The first input terminal of the logic switching circuit is used to be connected to an analog signal input interface, and the second input terminal of the logic switching circuit is connected to the triangular wave generating circuit. The output terminal of the comparator circuit is connected to the input terminal of the isolation module. The logic switching circuit is used to switch between a first state and a second state. The first state is that the first input terminal is connected to the non-inverting input terminal of the comparator circuit and the second input terminal is connected to the inverting input terminal of the comparator circuit. The second state is that the first input terminal is connected to the inverting input terminal of the comparator circuit and the second input terminal is connected to the non-inverting input terminal of the comparator circuit.

[0013] According to a conversion circuit for dimming provided by the present invention, the adjustment module further includes a voltage range switching circuit connected to the triangular wave generating circuit. The voltage range switching circuit is used to adjust the amplitude of the triangular wave output by the triangular wave generating circuit.

[0014] According to a conversion circuit for dimming provided by the present invention, the voltage range switching circuit includes a first resistor, a second resistor, a third resistor and a switching switch. One end of the second resistor and one end of the third resistor are both connected to the switching switch. The other end of the second resistor is respectively connected to the other end of the third resistor, one end of the first resistor and the triangular wave generating circuit. The other end of the first resistor is grounded. The switching switch is used to switch to one of the one end of the second resistor and the one end of the third resistor, so that the second resistor or the third resistor is connected to a first reference voltage.

[0015] According to a conversion circuit for dimming provided by the present invention, the isolation module includes an optocoupler and a voltage regulating circuit. The output terminal of the input signal conversion module is connected to the light emitting element of the optocoupler. The voltage regulating circuit is connected to the light receiving element of the optocoupler. The voltage regulating circuit is connected to the input terminal of the output signal conversion module.

[0016] According to a conversion circuit for dimming provided by the present utility model, the voltage regulating circuit includes a fourth resistor and a fifth resistor. One end of the fourth resistor is connected to a second reference voltage, the other end of the fourth resistor is respectively connected to a light-receiving component of the optocoupler and one end of the fifth resistor, and the other end of the fifth resistor is grounded.

[0017] According to a conversion circuit for dimming provided by the present utility model, the output signal conversion module includes a first voltage follower and a filtering circuit. The input end of the first voltage follower is connected to the output end of the isolation module, the output end of the first voltage follower is connected to the filtering circuit, and the output end of the filtering circuit is used to be connected to a controlled end of a driving circuit.

[0018] According to a conversion circuit for dimming provided by the present utility model, the filtering circuit includes an active RC filtering circuit and an output filtering capacitor. The output end of the first voltage follower is connected to the input end of the active RC filtering circuit, the output end of the active RC filtering circuit is connected to one end of the output filtering capacitor, the other end of the output filtering capacitor is grounded, and the output end of the active RC filtering circuit is used to be connected to a controlled end of a driving circuit.

[0019] The present utility model also provides a lamp, which includes a lamp body, a circuit board and a lighting module arranged in the lamp body. The driving circuit and the above conversion circuit for dimming are integrated on the circuit board. The input end of the input signal conversion module is used to be connected to an external dimmer, the output end of the output signal conversion module is connected to the driving circuit, and the driving circuit is connected to the lighting module.

[0020] According to the lamp provided by the present utility model, the driving circuit includes a rectifier bridge, a driving control chip and a power tube. The rectifier bridge is connected to the driving control chip and the lighting module, the power tube is connected to the lighting module, the driving control chip is connected to the controlled end of the power tube, and the driving control chip is provided with a feedback end;

[0021] It further includes an adjustment circuit, and the adjustment circuit includes a sixth resistor, a seventh resistor and an eighth resistor. One end of the sixth resistor is connected to the output end of the output signal conversion module, the other end of the sixth resistor is respectively connected to one end of the seventh resistor and one end of the eighth resistor, the other end of the seventh resistor is connected to the feedback end of the driving control chip, and the other end of the eighth resistor is connected to the power tube.

[0022] The dimming conversion circuit and lamp provided by the present utility model have at least the following beneficial effects: Through the adjustment module, the input voltage range is regulated by the input signal conversion module, enabling the input signal conversion module to adapt to input analog signals with different voltage ranges. The input signal conversion module converts the input analog signal into a first PWM signal and transmits it to the isolation module. While implementing the electrical isolation function, the isolation module converts the first PWM signal into a second PWM signal with a constant output voltage range. Even if the voltage range of the input analog signal changes, the voltage range of the second PWM signal remains fixed. Furthermore, the second PWM signal is processed and converted into a corresponding output analog signal by the output signal conversion module, and the voltage range of the output analog signal is also within a fixed voltage range, avoiding the output voltage range from changing with the input voltage range. For input analog signals with different voltage ranges, output analog signals with a consistent voltage range can be formed to stably control the driving circuit, achieving adaptation to input analog signals with different voltage ranges. Additionally, through the adjustment module, the duty cycle of the first PWM signal output by the input signal conversion module is switched to be positively or negatively correlated with the voltage value of the input analog signal. The duty cycle of the second PWM signal corresponds to that of the first PWM signal, such that the output analog signal formed by converting the second PWM signal is also positively or negatively correlated with the original input analog signal, achieving the effect of switching between positive logic and negative logic dimming control. In this way, it is possible to adapt to input analog signals with different voltage ranges, and thus adapt to different types of dimmers, which is beneficial for expanding the adaptation and usage range. Moreover, according to the requirements of the usage scenario, the effect of switching between positive logic and negative logic dimming control can be selected, which is beneficial for meeting the requirements of different application scenarios and making the use more convenient. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a structural block diagram of one embodiment of a dimming conversion circuit provided by the present utility model;

[0025] Figure 2 It is a circuit diagram of one embodiment of the lamp provided by the present utility model;

[0026] Figure 3 It is a signal waveform diagram of positive logic dimming in a dimming conversion circuit provided by the present utility model;

[0027] Figure 4It is a signal waveform diagram of negative logic dimming in a dimming conversion circuit provided by the present utility model.

[0028] Reference numerals:

[0029] Input signal conversion module 100; comparator circuit 110; triangular wave generation circuit 120; adjustment module 200; logic switching circuit 210; voltage range switching circuit 220; isolation module 300; optocoupler 310; voltage regulation circuit 320; output signal conversion module 400; first voltage follower 410; filtering circuit 420; active RC filtering circuit 421; filtering capacitor 422; lighting module 500; driving circuit 600; adjustment circuit 700. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions in the present utility model will be clearly and completely described below with reference to the accompanying drawings in the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without making creative efforts shall fall within the protection scope of the present utility model.

[0031] In the existing DOB lighting circuit, the DOB driving chip has the advantages of high cost performance and stable performance. However, the DOB driving chip does not have a dedicated dimming port and cannot adopt the digital dimming method, so there is a lack of a DOB dimming solution. But the DOB driving chip usually has a feedback port for feedback adjustment to stabilize the current for driving lighting, such as a current detection feedback port, etc. Therefore, a dimming conversion circuit provided by the present utility model can be applied to the DOB lighting circuit through the analog signal dimming method, enabling the DOB lighting circuit to also achieve the dimming function.

[0032] The following combines Figure 1 and Figure 2 to describe a dimming conversion circuit of the present utility model, including:

[0033] An input signal conversion module 100, the input end of the input signal conversion module 100 is used to obtain an input analog signal, and the input signal conversion module 100 is used to convert the analog signal into a corresponding PWM signal;

[0034] An adjustment module 200, connected to the input signal conversion module 100;

[0035] An isolation module 300, connected to the output end of the input signal conversion module 100;

[0036] The output signal conversion module 400 is connected to the output end of the isolation module 300, and the output signal conversion module 400 is used to convert the PWM signal into a corresponding analog signal;

[0037] Wherein, the adjustment module is used to adjust the input voltage range of the input signal conversion module, and / or the adjustment module is used to adjust the input signal conversion module so that the voltage value of the input analog signal is positively or negatively correlated with the duty cycle of the PWM signal output by the input signal conversion module.

[0038] Through the adjustment module 200, the input voltage range of the input signal conversion module 100 is adjusted, so that the input signal conversion module 100 adapts to input analog signals with different voltage ranges. The input signal conversion module 100 converts the analog signal into a first PWM signal and transmits it to the isolation module 300. While realizing the electrical isolation function, the isolation module 300 converts the first PWM signal into a second PWM signal with an unchanged output voltage range. Even if the voltage range of the input analog signal changes, the voltage range of the second PWM signal remains fixed. Furthermore, the second PWM signal is processed and converted into a corresponding output analog signal by the output signal conversion module 400, and the voltage range of the output analog signal is also within a fixed voltage range, avoiding the output voltage range from changing with the input voltage range. In this way, for input analog signals with different voltage ranges, a stable control drive circuit 600 with an output analog signal having a consistent voltage range can be formed, realizing adaptation to input analog signals with different voltage ranges.

[0039] In addition, through the adjustment module 200, the duty cycle of the first PWM signal output by the input signal conversion module 100 is switched to be positively or negatively correlated with the voltage value of the input analog signal. The duty cycle of the second PWM signal corresponds to that of the first PWM signal, so that the output analog signal formed by the conversion of the second PWM signal is also positively or negatively correlated with the original input analog signal, achieving the effect of switching positive logic and negative logic dimming control.

[0040] In this way, it is possible to adapt to input analog signals with different voltage ranges, and thus to adapt to different models of dimmers, which is beneficial to expanding the adaptation range of use. And according to the requirements of the use scenario, the effect of switching positive logic and negative logic dimming control can be selected, which is beneficial to meeting the requirements of different application scenarios and making the use more convenient.

[0041] After realizing the conversion of input analog signals with different voltage input ranges through positive and negative logic processing and isolation processing into corresponding output analog signals within a fixed voltage range, the output analog signal can be transmitted to the controlled end of the drive circuit 600, such as the feedback port of the DOB drive chip, to achieve the effect of dimming, and at the same time, it can also adapt to the drive circuit 600 of the DOB drive chip without a dimming port.

[0042] Reference Figure 1 and Figure 2 In some embodiments of a conversion circuit for dimming in the present utility model, the adjustment module 200 includes a logic switching circuit 210. The input signal conversion module 100 includes a comparator circuit 110 and a triangular wave generating circuit 120. The logic switching circuit 210 is respectively connected to the non-inverting input terminal and the inverting input terminal of the comparator circuit 110. The first input terminal of the logic switching circuit 210 is used to be connected to an analog signal input interface. The second input terminal of the logic switching circuit 210 is connected to the triangular wave generating circuit 120. The output terminal of the comparator circuit 110 is connected to the input terminal of the isolation module 300. The logic switching circuit 210 is used to switch between a first state and a second state. The first state is that the first input terminal is connected to the non-inverting input terminal of the comparator circuit 110 and the second input terminal is connected to the inverting input terminal of the comparator circuit 110. The second state is that the first input terminal is connected to the inverting input terminal of the comparator circuit 110 and the second input terminal is connected to the non-inverting input terminal of the comparator circuit 110.

[0043] The triangular wave generating circuit 120 generates a triangular wave and transmits it to the comparator circuit 110. The comparator circuit 110 compares the voltage value of the input analog signal with the voltage value of the triangular wave. Since the triangular wave rises and falls periodically, taking the voltage value of the input analog signal as a threshold, a first PWM signal whose duty cycle is related to the voltage value of the input analog signal is generated, realizing the function of converting the input analog signal into the first PWM signal.

[0044] Meanwhile, by changing the connection relationship between the first input terminal, the second input terminal and the non-inverting input terminal, the inverting input terminal of the comparator circuit 110, the logic switching circuit 210 can change the relationship between the duty cycle of the first PWM signal and the voltage value of the input analog signal. Thus, by switching the connection relationship between the input analog signal, the triangular wave and the non-inverting input terminal, the inverting input terminal of the comparator circuit 110, the switching between positive logic and negative logic is realized, and at the same time, the effect of converting the input analog signal into the first PWM signal is achieved. The circuit structure is simple and easy to implement.

[0045] The relationship between the duty cycle of the first PWM signal and the voltage value of the input analog signal is as follows: Connect the first input terminal to the non-inverting input terminal, that is, the input analog signal is transmitted to the non-inverting input terminal, and connect the second input terminal to the inverting input terminal, that is, the triangular wave is transmitted to the inverting input terminal. At this time, when the voltage value of the input analog signal is greater than the voltage value of the triangular wave, the comparator circuit 110 outputs the first PWM signal as a high level, otherwise it is a low level. Therefore, as the voltage value of the input analog signal increases, the duty cycle of the high level in the first PWM signal decreases, that is, the voltage value of the input analog signal and the duty cycle of the first PWM signal are negatively correlated. It can be expressed by the formula: D = 1 - Vi / k, where D is the duty cycle, Vi is the voltage value of the input analog signal, and k is the amplitude of the triangular wave. Conversely, when the first input terminal is connected to the inverting input terminal, that is, the input analog signal is transmitted to the inverting input terminal, and the second input terminal is connected to the non-inverting input terminal, that is, the triangular wave is transmitted to the non-inverting input terminal. At this time, when the voltage value of the input analog signal is greater than the voltage value of the triangular wave, the comparator circuit 110 outputs the first PWM signal as a low level, otherwise it is a high level. Therefore, as the voltage value of the input analog signal increases, the duty cycle of the high level in the first PWM signal also increases, that is, the voltage value of the input analog signal and the duty cycle of the first PWM signal are positively correlated. It can be expressed by the formula: D = Vi / k, where D is the duty cycle, Vi is the voltage value of the input analog signal, and k is the amplitude of the triangular wave.

[0046] In some embodiments of the present invention, the logic switching circuit 210 may be an embodiment including a toggle switch. Refer to Figure 2 , when the toggle switch is in the first state, pin 1 of the toggle switch is connected to pin 2 and pin 6 is connected to pin 5, that is, the input analog signal is transmitted to the non-inverting input terminal of the comparator circuit 110 and the triangular wave is transmitted to the inverting input terminal; when the toggle switch is in the second state, pin 2 of the toggle switch is connected to pin 3 and pin 5 is connected to pin 4, that is, the input analog signal is transmitted to the inverting input terminal of the comparator circuit 110 and the triangular wave is transmitted to the non-inverting input terminal.

[0047] In some embodiments of the present invention, the logic switching circuit 210 may also be an embodiment including a relay, a controller, and a communication circuit. The controller is respectively connected to the communication circuit and the relay. The controller obtains a control instruction through the communication circuit, and then controls the relay to act according to the control instruction to achieve the purpose of switching the connection relationship between the first input terminal, the second input terminal and the non-inverting input terminal, the inverting input terminal of the comparator circuit 110.

[0048] Refer to Figure 1 and Figure 2, in some embodiments of a conversion circuit for dimming in the present utility model, the adjustment module 200 further includes a voltage range switching circuit 220 connected to the triangular wave generating circuit 120, and the voltage range switching circuit 220 is used to adjust the amplitude of the triangular wave output by the triangular wave generating circuit 120.

[0049] By adjusting the amplitude of the triangular wave output by the triangular wave generating circuit 120 through the voltage range switching circuit 220, when the voltage range of the input analog signal increases, the amplitude of the triangular wave is adjusted to increase, so that the duty cycle of the first PWM signal output by the comparator circuit 110 corresponds to the voltage value of the input analog signal, avoiding the situation that the duty cycle of the first PWM signal remains unchanged at 0% or 100% after the voltage value of the input analog signal increases to a certain range; when the voltage range of the input analog signal decreases, the amplitude of the triangular wave is adjusted to decrease, avoiding the situation that the input analog signal only corresponds to occupying a part of the duty cycle of the first PWM signal when changing within the entire voltage range. For example, when the voltage changes in the range of 0% to 100%, the duty cycle may only correspond to changing in the range of 0% to 40% or in the range of 60% to 100%. Appropriately reducing the amplitude of the triangular wave can make full use of the duty cycle resources of the first PWM signal and make the duty cycle response of the first PWM signal more sensitive. In this way, the purpose of adapting to input analog signals with different voltage ranges is achieved.

[0050] Reference Figure 2 , in some embodiments of a conversion circuit for dimming in the present utility model, the voltage range switching circuit 220 includes a first resistor R1, a second resistor R2, a third resistor R3, and a switching switch S1. One end of the second resistor R2 and one end of the third resistor R3 are both connected to the switching switch S1. The other end of the second resistor R2 is respectively connected to the other end of the third resistor R3, one end of the first resistor R1, and the triangular wave generating circuit 120. The other end of the first resistor R1 is grounded. The switching switch S1 is used to switch to one of one end of the second resistor R2 and one end of the third resistor R3, so that either the second resistor R2 or the third resistor R3 is connected to the first reference voltage.

[0051] Configure the resistance values of the first resistor R1, the second resistor R2, and the third resistor R3. Through the switching switch S1, make the first resistor R1 and the second resistor R2 form a voltage dividing circuit, or make the first resistor R1 and the third resistor R3 form a voltage dividing circuit, so as to perform voltage division processing with different ratios on the same first reference voltage, form different voltages and transmit them to the triangular wave generating circuit 120, and then adjust the amplitude of the triangular wave output by the triangular wave generating circuit 120.

[0052] In some embodiments of the present utility model, the voltage range of the input analog signal can include 0V to 5V and 0V to 10V. According to these two ranges, by adjusting the switching switch S1, the amplitude of the triangular wave output by the triangular wave generating circuit 120 corresponds to the two voltage ranges, that is, the maximum amplitude of the triangular wave is 5V and 10V.

[0053] In some embodiments of the present utility model, the switching switch can be a physical switch, and the switching is realized by manual operation of the user; the switching switch can also be realized by using devices such as relays. For example, by setting a controller and a communication circuit, the controller is respectively connected to the communication circuit and the relay. The controller obtains a control instruction through the communication circuit, and then controls the relay to act according to the control instruction to realize the switching function.

[0054] In some embodiments of the present utility model, the triangular wave generating circuit 120 can be an implementation manner including a comparator U1B, a resistor R4, a resistor R5, and a capacitor C1. The non-inverting input terminal of the comparator U1B is respectively connected to the other end of the second resistor R2, the other end of the third resistor R3, one end of the resistor R1, and one end of the resistor R4. The inverting input terminal of the comparator U1B is respectively connected to one end of the resistor R5, one end of the capacitor C1, and the logic switching circuit 210. The output terminal of the comparator U1B is respectively connected to the other end of the resistor R4 and the other end of the resistor R5. The other end of the capacitor C1 is grounded.

[0055] In this way, a triangular wave generating circuit based on a comparator is formed. The charging and discharging processes of the capacitor C1 cause the voltage at the inverting input terminal of the comparator U1B to change. When the voltage of the capacitor C1 is greater than the voltage of the voltage range switching circuit 220, the comparator U1B outputs a low level, the capacitor C1 discharges and the voltage gradually decreases. When the voltage of the capacitor C1 is less than the voltage of the voltage range switching circuit 220, the comparator U1B outputs a high level, the capacitor C1 charges and the voltage gradually rises. Repeating the above process, the voltage waveform of the capacitor C1 forms a triangular wave and is transmitted to the logic switching circuit 210.

[0056] Reference Figure 1 and Figure 2 In some embodiments of a conversion circuit for dimming in the present utility model, the isolation module 300 includes an optocoupler 310 and a voltage regulating circuit 320. The light emitting element of the optocoupler 310 is connected to the output terminal of the input signal conversion module 100. The light receiving element of the optocoupler 310 is connected to the voltage regulating circuit 320. The voltage regulating circuit 320 is connected to the input terminal of the output signal conversion module 400.

[0057] Utilize the processing process of electrical signal - optical signal - electrical signal of the optocoupler 310 to achieve electrical isolation between the input end and the output end. At the same time, utilize the characteristic that the voltage can be considered unchanged when the light-receiving component in the optocoupler 310 is conducting. The first PWM signal corresponding to the input analog signal in different voltage ranges only controls whether the light-receiving component in the optocoupler 310 is conducting or not. Therefore, the voltage range of the second PWM signal formed by the optocoupler 310 and the voltage regulation circuit 320 is fixed and unchanged. In this way, while realizing the electrical isolation function, the voltage range of the second PWM signal remains unchanged.

[0058] Reference Figure 2 , in some embodiments of a conversion circuit for dimming in the present utility model, the voltage regulation circuit 320 includes a fourth resistor R9 and a fifth resistor R8. One end of the fourth resistor R9 is connected to the second reference voltage, the other end of the fourth resistor R9 is respectively connected to the light-receiving component of the optocoupler 310 and one end of the fifth resistor R8, and the other end of the fifth resistor R8 is grounded.

[0059] The fourth resistor R9 and the fifth resistor R8 form a voltage division circuit to divide the second reference voltage to form the high-level voltage of the second PWM signal. When the light-receiving component of the optocoupler 310 is conducting, the voltage is pulled down to form the low-level of the second PWM signal.

[0060] Reference Figure 3 and Figure 4 , it can be understood that in this structure, the first PWM signal and the second PWM signal are in an inverse relationship. That is, when the first PWM signal is at a high level, the light-emitting component of the optocoupler 310 emits light, and then the light-receiving component of the optocoupler 310 is conducting, pulling down the voltage to form the low-level of the second PWM signal, but this does not affect the function of positive and negative logic switching. Specifically: when the logic switching circuit 210 controls the duty cycle of the first PWM signal output by the input signal conversion module 100 to be positively correlated with the voltage value of the input analog signal, that is, the duty cycle of the first PWM signal is: Db = Vi / k, then the duty cycle of the second PWM signal is: Dc = 1 - Vi / k. At this time, the final output analog signal and the initial input analog signal are in negative logic. When the logic switching circuit 210 controls the duty cycle of the first PWM signal output by the input signal conversion module 100 to be negatively correlated with the voltage value of the input analog signal, that is, the duty cycle of the first PWM signal is: Db = 1 - Vi / k, then the duty cycle of the second PWM signal is: Dc = Vi / k. At this time, the final output analog signal and the initial input analog signal are in positive logic. In the above expressions, Db is the duty cycle of the first PWM signal, Dc is the duty cycle of the second PWM signal, Vi is the voltage value of the input analog signal, and k is a coefficient related to the slope and amplitude of the triangular wave.

[0061] In some embodiments of the present utility model, the connection relationship of components can also be adjusted to make the first PWM signal and the second PWM signal have a positive correlation. For example, the light-receiving component of the optocoupler 310 is connected in parallel with the upper resistor of the voltage-dividing circuit. The resistance value of the upper resistor of the voltage-dividing circuit is set to be relatively large. When the light-receiving component of the optocoupler 310 is cut off, the output voltage of the voltage-dividing circuit is relatively low. When the light-receiving component of the optocoupler 310 is turned on, the output voltage of the voltage-dividing circuit increases.

[0062] Reference Figure 1 and Figure 2 In some embodiments of a conversion circuit for dimming in the present utility model, the output signal conversion module 400 includes a first voltage follower 410 and a filtering circuit 420. The input end of the first voltage follower 410 is connected to the output end of the isolation module 300. The output end of the first voltage follower 410 is connected to the filtering circuit 420. The output end of the filtering circuit 420 is used to be connected to the controlled end of the driving circuit 600.

[0063] The isolation module 300 transmits the second PWM signal to the first voltage follower 410, and the first voltage follower 410 transmits the second PWM signal to the filtering circuit 420 for filtering and voltage stabilization processing, so that the second PWM signal is converted into an output analog signal. Reference Figure 3 and Figure 4 Among them, the voltage value of the output analog signal corresponds to the duty cycle of the second PWM signal. When the duty cycle is relatively large, the average voltage of the second PWM signal is also relatively large, and thus the voltage value of the output analog signal formed by filtering will also be relatively large. Since the duty cycle of the second PWM signal is determined by the input analog signal, the voltage value of the output analog signal is determined by the original input analog signal, and according to the switching between positive logic and negative logic, the voltage value of the output analog signal and the voltage value of the input analog signal are positively or negatively correlated.

[0064] The first voltage follower 410 has the advantages of high input impedance and low output impedance, can enhance the load-carrying capacity of the second PWM signal, and the first voltage follower 410 does not change the waveform of the second PWM signal.

[0065] Reference Figure 2 In some embodiments of a conversion circuit for dimming in the present utility model, the filtering circuit 420 includes an active RC filtering circuit 421 and an output filtering capacitor 422. The output end of the first voltage follower 410 is connected to the input end of the active RC filtering circuit 421. The output end of the active RC filtering circuit 421 is connected to one end of the output filtering capacitor 422. The other end of the output filtering capacitor 422 is grounded. The output end of the active RC filtering circuit 421 is used to be connected to the controlled end of the driving circuit 600.

[0066] The active RC filter circuit 421 performs active filtering on the second PWM signal to form an output analog signal. The output terminal of the active RC filter circuit 421 is connected to the output filter capacitor 422, which can further filter the output analog signal to make the output analog signal more stable.

[0067] The active RC filter circuit 421 can be an embodiment including an RC filter circuit and a second voltage follower. The RC filter circuit filters the second PWM signal. The high input impedance characteristic of the second voltage follower can reduce the influence of the equivalent resistance of the load on the active RC filter circuit, which is beneficial to making the filtering effect more stable and reliable. In some embodiments of the present invention, the active filter circuit 421 can also be an embodiment including multiple RC filter circuits and a second voltage follower. The multiple RC filter circuits are cascaded to improve the filtering effect, and then the output analog signal formed after filtering is output through the second voltage follower.

[0068] Reference Figure 2 Moreover, the present invention also provides a lamp, which includes a lamp body, a circuit board and a lighting module 500 arranged in the lamp body. The circuit board is integrated with a driving circuit 600 and the above-mentioned conversion circuit for dimming. The input end of the input signal conversion module 100 is used to connect to an external dimmer. The output end of the output signal conversion module 400 is connected to the driving circuit 600, and the driving circuit 600 is connected to the lighting module 500.

[0069] For the input analog signals with different voltage ranges generated by different models of dimmers, through the adjustment module 200, the input voltage range of the input signal conversion module 100 is adjusted to make the input signal conversion module 100 adapt to the input analog signals with different voltage ranges. The input signal conversion module 100 converts the input analog signal into a first PWM signal and transmits it to the isolation module 300. While realizing the electrical isolation function, the isolation module 300 converts the first PWM signal into a second PWM signal with an unchanged output voltage range. The second PWM signal is processed and converted into a corresponding output analog signal by the output signal conversion module 400, and the voltage range of the output analog signal is also within a fixed voltage range, avoiding the change of the output voltage range with the change of the input voltage range. For the input analog signals with different voltage ranges, output analog signals with consistent voltage ranges can be formed to stably control the driving circuit 600, so it is adaptable to different models of dimmers.

[0070] In addition, reference Figure 3 and Figure 4, by adjusting module 200, the duty cycle of the first PWM signal output by the input signal conversion module 100 is switched to be positively or negatively correlated with the voltage value of the input analog signal, and the duty cycle of the second PWM signal corresponds to that of the first PWM signal, so that the output analog signal formed by converting the second PWM signal is also positively or negatively correlated with the original input analog signal, achieving the effect of switching positive logic and negative logic dimming control.

[0071] In this way, the lamp can be adapted to different models of dimmers, which is beneficial to expanding the applicable range of use, avoiding the situation where the required dimmer cannot be used in combination, and being able to select and switch the effects of positive logic and negative logic dimming control according to the requirements of the usage scenario, which is beneficial to meeting the needs of different application scenarios and making the use more convenient.

[0072] The circuit board is integrated with a drive circuit 600 and the above-mentioned conversion circuit for dimming, that is, applying the DOB circuit scheme, which is beneficial to making the structure more compact, reducing the occupied space and improving the performance.

[0073] Reference Figure 2 , in some embodiments of the lamp of the present utility model, the drive circuit 600 includes a rectifier bridge, a drive control chip and a power tube. The rectifier bridge is connected to the drive control chip and the lighting module 500. The power tube is connected to the lighting module 500 to control the current flowing through the lighting module 500. The drive control chip is connected to the controlled end of the power tube. The drive control chip is provided with a feedback end, and the feedback end is connected to the power tube to detect the current flowing through the power tube.

[0074] The rectifier bridge rectifies the commercial power to form direct current. Under the control of the drive control chip for the power tube, the lighting module 500 is driven to work for lighting. The output signal conversion module 400 is connected to the feedback end so that the output analog signal and the feedback signal are superimposed, and the drive control chip controls the conduction and cut-off of the power tube based on the output analog signal and the feedback signal to control the average current flowing through the lighting module 500, achieving the dimming effect.

[0075] Reference Figure 2 , in some embodiments of the lamp of the present utility model, an adjustment circuit 700 is further included. The adjustment circuit 700 includes a sixth resistor R11, a seventh resistor R12 and an eighth resistor R13. One end of the sixth resistor R11 is connected to the output end of the output signal conversion module 400. The other end of the sixth resistor R11 is respectively connected to one end of the seventh resistor R12 and one end of the eighth resistor R13. The other end of the seventh resistor R12 is connected to the feedback end of the drive control chip. The other end of the eighth resistor R13 is connected to the power tube.

[0076] Therefore, the current of the output analog signal passing through the sixth resistor R11 and the eighth resistor R13 forms a voltage between the seventh resistor R12 and the eighth resistor R13 and is transmitted to the feedback terminal of the drive control chip. The feedback voltage formed by the current of the power transistor at the resistor R14 is also superimposed and transmitted to the feedback terminal of the drive control chip, enabling the drive control chip to control the power transistor under the action of the output analog signal and the feedback signal, so as to control the current flowing through the lighting module 500 and achieve the purpose of dimming.

[0077] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0078] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A dimming conversion circuit, characterized in that: include: An input signal conversion module, wherein the input end of the input signal conversion module is used to obtain an input analog signal, and the input signal conversion module is used to convert the input analog signal into a corresponding PWM signal; An adjustment module connected to the input signal conversion module; An isolation module connected to the output end of the input signal conversion module; An output signal conversion module, connected to the output end of the isolation module, and configured to convert the PWM signal into a corresponding output analog signal; The adjustment module is used to adjust the input voltage range of the input signal conversion module, and / or the adjustment module is used to adjust the input signal conversion module so that the voltage value of the input analog signal is positively or negatively correlated with the duty cycle of the PWM signal output by the input signal conversion module.

2. The dimming conversion circuit according to claim 1, characterized in that: The adjustment module includes a logic switching circuit, and the input signal conversion module includes a comparator circuit and a triangular wave generating circuit. The logic switching circuit is respectively connected to the same-phase input terminal and the inverting input terminal of the comparator circuit. The first input terminal of the logic switching circuit is used to be connected to the analog signal input interface, the second input terminal of the logic switching circuit is connected to the triangular wave generating circuit, the output terminal of the comparator circuit is connected to the input terminal of the isolation module, and the logic switching circuit is used to switch between a first state and a second state. The first state is that the first input terminal is connected to the same-phase input terminal of the comparator circuit and the second input terminal is connected to the inverting input terminal of the comparator circuit. The second state is that the first input terminal is connected to the inverting input terminal of the comparator circuit and the second input terminal is connected to the same-phase input terminal of the comparator circuit.

3. The dimming conversion circuit according to claim 2, characterized in that: The adjustment module also includes a voltage range switching circuit connected to the triangular wave generating circuit, and the voltage range switching circuit is used to adjust the amplitude of the triangular wave output by the triangular wave generating circuit.

4. The dimming conversion circuit according to claim 3, characterized in that: The voltage range switching circuit includes a first resistor, a second resistor, a third resistor and a switching switch, one end of the second resistor and one end of the third resistor are both connected to the switching switch, the other end of the second resistor is respectively connected to the other end of the third resistor, one end of the first resistor and the triangular wave generating circuit, the other end of the first resistor is grounded, and the switching switch is used to switch to one of one end of the second resistor and one end of the third resistor so that the second resistor or the third resistor is connected to the first reference voltage.

5. The dimming conversion circuit according to claim 3, characterized in that: The isolation module includes a photoelectric coupler and a voltage regulating circuit. The output end of the input signal conversion module is connected to the light-emitting element of the photoelectric coupler, the voltage regulating circuit is connected to the light-receiving element of the photoelectric coupler, and the voltage regulating circuit is connected to the input end of the output signal conversion module.

6. The dimming conversion circuit according to claim 5, characterized in that: The voltage regulating circuit includes a fourth resistor and a fifth resistor, one end of the fourth resistor is connected to the second reference voltage, the other end of the fourth resistor is respectively connected to the light receiving element of the photocoupler and one end of the fifth resistor, and the other end of the fifth resistor is grounded.

7. The dimming conversion circuit according to claim 3, characterized in that: The output signal conversion module includes a first voltage follower and a filter circuit, the input end of the first voltage follower is connected to the output end of the isolation module, the output end of the first voltage follower is connected to the filter circuit, and the output end of the filter circuit is used to connect to the controlled end of the drive circuit.

8. The dimming conversion circuit according to claim 7, characterized in that: The filter circuit includes an active RC filter circuit and an output filter capacitor. The output end of the first voltage follower is connected to the input end of the active RC filter circuit, the output end of the active RC filter circuit is connected to one end of the output filter capacitor, the other end of the output filter capacitor is grounded, and the output end of the active RC filter circuit is used to be connected to the controlled end of the drive circuit.

9. A lamp, characterized in that: The invention comprises a lamp body, a circuit board and a lighting module arranged in the lamp body, wherein the circuit board is integrated with a driving circuit and a dimming conversion circuit as claimed in any one of claims 1 to 8, the input end of the input signal conversion module is used to connect to an external dimmer, the output end of the output signal conversion module is connected to the driving circuit, and the driving circuit is connected to the lighting module.

10. The lamp according to claim 9, characterized in that: The driving circuit includes a rectifier bridge, a driving control chip and a power tube, the rectifier bridge is connected to the driving control chip and the lighting module, the power tube is connected to the lighting module, the driving control chip is connected to the controlled end of the power tube, and the driving control chip is provided with a feedback end; It also includes an adjustment circuit, which includes a sixth resistor, a seventh resistor and an eighth resistor. One end of the sixth resistor is connected to the output end of the output signal conversion module, the other end of the sixth resistor is respectively connected to one end of the seventh resistor and one end of the eighth resistor, the other end of the seventh resistor is connected to the feedback end of the drive control chip, and the other end of the eighth resistor is connected to the power tube.

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