Dimming circuit

Abstract

The utility model provides a dimming circuit which comprises an external power supply, a power supply module, a control module and a dimming module. The power supply module comprises a voltage regulating assembly and a voltage stabilizing assembly, the voltage regulating assembly is connected to an external power supply and reduces the voltage of the external power supply and transmits the voltage to the voltage stabilizing assembly, and the voltage stabilizing assembly outputs power supply voltage. The voltage regulating assembly supplies power to the operational amplifier assembly, and the output end of the voltage stabilizing assembly is connected with the control module and used for supplying power to the control module. The dimming module comprises an operational amplifier assembly and a switch piece, the control module is connected with the in-phase input end of the operational amplifier assembly, and reference voltage is connected to the inverted input end of the operational amplifier assembly. The output end of the operational amplifier assembly is connected with the switch piece, and the switch piece is used for being switched on or switched off according to an output signal of the operational amplifier assembly. The switch piece is connected with the cathode end of the lamp strip, and the anode end of the lamp strip is connected with an external power supply. The problem that the lamp strip flickers when equipment is powered off or OTA is upgraded is solved by driving the switch of the lamp strip through in-phase dimming.

Description

Technical Field

[0001] The utility model relates to the technical field of LED dimming, in particular to a dimming circuit. Background Art

[0002] The existing constant voltage driving high-power light strip power supply generally adopts a control method in which the PWM dimming signal and the driving MOS tube switch signal are in opposite phases, such as Figure 1 , that is, when PWM is low, the MOS tube drive signal is high, the MOS tube is turned on, and the light strip is on. Under this control mode, when the PWM output is 0, the MOS tube gate drive signal is high, the MOS tube is turned on, the light is on, and when the PWM output is 1, the MOS tube gate drive signal is zero level, the MOS tube is cut off, and the light is off. When the device is powered on, due to the power timing, the MCU cannot work immediately to output PWM control, that is, the PWM output is 0 at this time, the MOS tube is turned on first, causing the light to be on, and when the MCU starts working, it controls the PWM output to 1 to turn off the light. At this time, the light flickers. When the device is OTA upgraded, the MCU will reset once the upgrade is completed. During this reset process, the MCU is completely uncontrolled. At this time, the PWM output IO port state defaults to the initial state 0. At this time, because it is inverted control, the light will be in a bright state. After the reset is completed, the MCU can control normally and will control the light to turn off. The phenomenon at this time is the light flickering phenomenon, that is, when the device is powered on or OTA upgraded, the light strip will flicker uncontrollably. Utility Model Content

[0003] In order to solve the above problems, the purpose of the utility model is to provide a dimming circuit, which inputs the control signal of the control module to the same-phase input terminal of the dimming module, and drives the switch of the light strip through the same-phase dimming, so as to solve the problem that the light strip will flicker when the device is powered on or off or OTA upgraded.

[0004] The utility model is realized by the following technical solutions:

[0005] A dimming circuit comprises: an external power supply; a power supply module, the power supply module comprises a voltage regulating component and a voltage stabilizing component, the voltage regulating component is connected to the external power supply and reduces the voltage of the external power supply and transmits it to the voltage stabilizing component, the voltage stabilizing component outputs a supply voltage; a control module, the output end of the voltage stabilizing component is connected to the control module, and is used to power the control module; a dimming module, the dimming module comprises an operational amplifier component and a switch element, the control module is connected to the same-phase input end of the operational amplifier component, and the inverting input end of the operational amplifier component is connected to a reference voltage; the output end of the operational amplifier component is connected to the switch element, the switch element is used to be turned on or off according to the output signal of the operational amplifier component, and the voltage regulating component supplies power to the operational amplifier component; wherein the switch element is connected to the negative terminal of a light strip, and the positive terminal of the light strip is connected to the external power supply.

[0006] Furthermore, at least two groups of dimming modules are provided; each of the switch elements is connected to light strips of different modes in a one-to-one correspondence.

[0007] Furthermore, the operational amplifier component amplifier, the in-phase input terminal of the amplifier is connected to the output terminal of the control module, the inverting input terminal of the amplifier is connected to the reference voltage, and the output terminal of the amplifier is connected to the switch element; the output terminal of the voltage regulating component supplies power to the amplifier.

[0008] Furthermore, the switch element includes an NMOS tube, the gate of the NMOS tube is connected to the output end of the operational amplifier component, the source of the NMOS tube is grounded, and the drain is connected to the negative electrode of the light strip; the drain of the NMOS tube is connected to the positive electrode of the light strip through a diode.

[0009] Furthermore, each of the switch elements is connected in parallel with an identical switch element.

[0010] Furthermore, the dimming circuit also includes a protection module, which includes a detection component and a protection component connected to the output end of the detection component, the detection component is respectively connected to the output ends of the external power supply and the voltage stabilizing component, the detection component is used to derive a short-circuit signal based on the voltage signal of the external power supply and the voltage signal of the voltage stabilizing component, and transmit the short-circuit signal to the protection component; the protection component is also connected to the signal output end of the control module, and the protection component is used to pull down the output signal of the control module according to the short-circuit signal.

[0011] Furthermore, the detection component includes a comparator, the non-inverting input terminal of the comparator is connected to the output terminal of the voltage stabilizing component, the inverting input terminal of the comparator is connected to the positive terminal of the light strip, and the switch element is also connected to the positive terminal of the light strip through a diode; the output terminal of the comparator is connected to the protection component; and the output terminal of the voltage stabilizing component supplies power to the comparator.

[0012] Furthermore, the protection component includes an NMOS tube, a gate of the NMOS tube is connected to the output end of the detection component, a source is grounded, and a drain is connected to the in-phase input end of the operational amplifier component.

[0013] Furthermore, the voltage regulating component includes a step-down chip, the input end of the step-down chip is connected to the external power supply, a Schottky diode is connected in series between the external power supply and the step-down chip, a TVS tube is connected to the common end of the Schottky diode and the external power supply, and the other end of the TVS tube is grounded; the output end of the step-down chip is connected to the voltage stabilizing component through an inductor.

[0014] Furthermore, the voltage stabilizing component includes a voltage stabilizing chip, the input end of the voltage stabilizing chip is connected to the output of the voltage regulating component, a Schottky diode is also connected in series between the voltage regulating component and the voltage stabilizing chip, the input and output ends of the voltage stabilizing chip are both connected to a filter capacitor, and the other end of the filter capacitor is grounded.

[0015] Compared with the prior art, the technical solution of the utility model and its beneficial effects are as follows:

[0016] (1) The utility model. The dimming module includes an operational amplifier component and a switch component. The control module is connected to the in-phase input terminal of the operational amplifier component. The in-phase input terminal of the operational amplifier component is connected to the reference voltage. The output terminal of the operational amplifier component is connected to the switch component. The switch component is used to turn on or off according to the output signal of the operational amplifier component. The switch component is connected to the negative terminal of the light strip, and the positive terminal of the light strip is connected to an external power supply. The on and off of the light strip is controlled by turning on or off the switch component. The control signal of the control module is input to the in-phase input terminal of the dimming module. The switch of the light strip is driven by the in-phase dimming to solve the problem that the light strip flickers when the device is powered on or off or OTA upgraded.

[0017] (2) The utility model is provided with multiple sets of dimming modules, so that different light strip modes can be switched.

[0018] (3) Each switch tube of the utility model is connected in parallel with an identical switch tube, thereby reducing the temperature rise when carrying a large current.

[0019] (4) In the protection module of the utility model, when any one of the output terminals V+ and RGBCW of the light strip is short-circuited, the voltage of the external power supply 12V / 24V is instantly reduced, and the detection component outputs a high-level signal to the protection component. The protection component pulls down the PWM dimming control signal, thereby turning off the dimming drive circuit and protecting the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the principle diagram of the existing dimming drive circuit provided by the utility model;

[0021] Figure 2 This is a principle block diagram of a dimming circuit provided by an embodiment of the utility model;

[0022] Figure 3 It is a circuit schematic diagram of the voltage regulating assembly provided in the embodiment of the utility model;

[0023] Figure 4 It is a circuit schematic diagram of a voltage stabilizing component provided in an embodiment of the utility model;

[0024] Figure 5 It is a circuit schematic diagram of a control module provided by an embodiment of the utility model;

[0025] Figure 6 It is a circuit schematic diagram of a dimming module provided in an embodiment of the utility model;

[0026] Figure 7 This is a circuit schematic diagram of a group of dimming modules provided in an embodiment of the utility model;

[0027] Figure 8 It is a circuit schematic diagram of the detection component provided by the embodiment of the utility model;

[0028] Fig. 9 It is a circuit schematic diagram of the detection component provided in the embodiment of the utility model. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0030] See also Figure 2A dimming circuit includes an external power supply, a power module, a control module and a dimming module. The power module includes a voltage regulating component and a voltage stabilizing component. The voltage regulating component is connected to the external power supply and reduces its voltage and transmits it to the voltage stabilizing component, and the voltage stabilizing component outputs the supply voltage. The voltage regulating component supplies power to the operational amplifier component, and the output end of the voltage stabilizing component is connected to the control module for supplying power to the control module. The dimming module includes an operational amplifier component and a switch component. The control module is connected to the in-phase input end of the operational amplifier component, and the inverting input end of the operational amplifier component is connected to the reference voltage. The output end of the operational amplifier component is connected to the switch component, and the switch component is used to turn on or off according to the output signal of the operational amplifier component. The switch component is connected to the negative terminal of the light strip, and the positive terminal of the light strip is connected to the external power supply. The on and off of the light strip is controlled by the on or off of the switch component. The control signal of the control module is input to the in-phase input end of the dimming module, and the switch of the light strip is driven by the in-phase dimming, so as to solve the problem that the light strip flickers when the device is powered off or OTA upgraded.

[0031] See also Figure 3 The voltage regulating component includes a buck chip U1, the input end of the buck chip U1 is connected to the external power supply VCC_+24V, a Schottky diode D11 is connected in series between the external power supply and the buck chip U1, a TVS tube TVS3 is connected to the common end of the Schottky diode D11 and the external power supply, and the other end of the TVS tube is grounded; the output end of the buck chip U1 is connected to the voltage regulating component through the inductor L1. The voltage regulating component steps down the external power supply 24V or 12V to output 10V.

[0032] See also Figure 4 The voltage stabilizing component includes a voltage stabilizing chip U2, the input end of the voltage stabilizing chip U2 is connected to the output of the voltage regulating component, and a Schottky diode D13 is connected in series between the voltage regulating component and the voltage stabilizing chip U2. The input and output ends of the voltage stabilizing chip are connected to filter capacitors (C12, C8, C9, C10, C11), and the other end of the filter capacitor is grounded. The voltage stabilizing component adjusts the 10V voltage to a stable 3.3V voltage output.

[0033] See also Figure 5 The control module includes a wireless transmission chip PCB1, which adopts Zigbee technology and outputs five control signals of PWM_R, PWM_G, PWM_B, PWM_C, and PWM_W. Each control signal independently controls a group of dimming modules.

[0034] See also Figure 6 and Figure 7, the dimming module is provided with at least two groups, and each switch element is connected to the negative pole of the light strip of different modes in a one-to-one correspondence. In this embodiment, the dimming module is provided with five groups, which can control the light strips of four modes. The external power supply is connected to the connector J2 through the temperature fuse F1, and the light strips of four modes are connected through the connector J2. One end of the connector J2 is connected to the external power supply, and the other end is connected to one of the switch elements, which is used to control the shutdown of the connector J2, that is, to control the opening and closing of all the light strips. The switch elements of the other four groups of dimming modules correspond to the four dimming modes one by one, and respectively control the opening and closing of one dimming mode, for example, it can be a single-color temperature light strip, a dual-color temperature light strip, an RGBW light strip, and an RGBCW light strip.

[0035] It is worth noting that when some high-power power supplies are short-circuited, the short-circuit state is low voltage and high current. In this state, if any end of the output light strip terminal V+ and RGBCW is short-circuited, then when we control the NMOS tube (Q1-Q5) to be turned on, it will cause the output circuit to be short-circuited. At this time, the NMOS tube (Q1-Q5) will heat up seriously under the action of large current, and the temperature fuse F1 can disconnect the current loop in time to provide protection.

[0036] Specifically, the operational amplifier assembly includes amplifiers (U3A, U3B, U3C, U3D, U4), and the in-phase input of the amplifier is respectively connected to the five dimming control signals of PWM_R, PWM_G, PWM_B, PWM_C, and PWM_W, and the reverse input of the amplifier is connected to the reference voltage. The output of the amplifier is connected to the switch, wherein the output voltage 10V of the voltage regulating assembly is used to power the amplifier. Under the in-phase dimming drive of the present application, the light strip will not flicker when the device is powered off or OTA upgraded. Resistors (R11-R15) are connected in series between each amplifier and the wireless transmission chip PCB1, and the in-phase inputs of the five groups of amplifiers are grounded through capacitors (C13-C17) and resistors (R16, R18, R20, R22, and R24), and the in-phase inputs of the five groups of amplifiers are connected to their outputs through resistors (R62-R66).

[0037] The switch element comprises an NMOS tube (Q1-Q5), the gate of the NMOS tube is connected to the output end of the amplifier, the source of the NMOS tube is grounded, the drain is connected to the negative electrode of the light strip, the drain of the NMOS tube is connected to the positive electrode of the light strip through a diode (D1-D5), that is, connected to an external power supply, and the anode of the diode is connected to the drain of the NMOS tube.

[0038] Taking the first dimming power supply as an example, when the PWM output is 0, the gate drive signal of NMOS tube Q1 is zero level, at this time NMOS tube Q1 is cut off, the light is off, when the PWM output is 1, the gate drive signal of NMOS tube Q1D is high level, at this time NMOS tube Q1 is turned on, the light is on, and when the device is powered off, due to the power timing, the MCU cannot work immediately to output and control PWM, that is, the PWM output is 0 at this time, at this time NMOS tube Q1 is cut off, the light is off, when the MCU (control module) starts to work, the control PWM output is still 0, at this time the light will not flicker. When the device is OTA upgraded, the MCU will reset once the upgrade is completed. During this reset process, the MCU is completely uncontrolled. At this time, the PWM output IO port state defaults to the initial state 0. At this time, because it is in-phase control, the light is still off. After the reset is completed, the MCU can work normally and still control the light to turn off, so the light will not flicker.

[0039] In this embodiment, each switch tube is connected in parallel with an identical switch tube, that is, MOS tube Q1 is connected in parallel with MOS tube Q11, MOS tube Q2 is connected in parallel with MOS tube Q12, MOS tube Q3 is connected in parallel with MOS tube Q13, and MOS tube Q4 is connected in parallel with MOS tube Q14, thereby reducing the temperature rise when carrying a large current.

[0040] See also Figure 8 and Fig. 9 The dimming circuit also includes a protection module, which includes a detection component and a protection component connected to the output end of the detection component. The detection component is respectively connected to the output ends of the external power supply and the voltage stabilizing component. The detection component is used to obtain a short-circuit signal based on the voltage signal of the external power supply and the voltage signal of the voltage stabilizing component, and transmit the short-circuit signal to the protection component; the protection component is also connected to the signal output end of the control module, and the protection component is used to pull down the output signal of the control module according to the short-circuit signal.

[0041] Specifically, the detection component includes a comparator U5, the in-phase input terminal of the comparator U5 is connected to the output terminal 3.3V of the voltage stabilizing component, the reverse input terminal of the comparator U5 is connected to the positive terminal of the light strip, that is, connected to the external power supply; the output terminal of the comparator is connected to the protection component; the output terminal of the voltage stabilizing component powers the comparator.

[0042] The protection component comprises an NMOS tube, a gate of the NMOS tube is connected to the output end of the detection component, a source is grounded, and a drain is connected to the in-phase input end of the operational amplifier component.

[0043] When any one of the output lamp strip terminals V+ and RGBCW is short-circuited, if the switch is in the cut-off state, the circuit is still in the open state. When the control switch is turned on, the output lamp strip terminal is short-circuited, and the output circuit will be short-circuited instantly. The external power supply 12V / 24V voltage is instantly reduced. After the comparator U5 compares the voltage, a high-level signal SCD3V3 is output to the protection component. The SCD3V3 level signal is output to the MOS tube (Q16-Q20) of the protection component, and the MOS tube (Q16-Q20) is turned on, pulling down the PWM dimming control signal (PWM_R, PWM_G, PWM_B, PWM_C, PWM_W), thereby turning off the dimming drive circuit.

[0044] The above description shows and describes the preferred embodiments of the utility model. It should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the utility model concept of this article through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A dimming circuit, characterized in that: include: External power supply; A power module, the power module comprising a voltage regulating component and a voltage stabilizing component, the voltage regulating component is connected to an external power source and reduces its voltage and transmits it to the voltage stabilizing component, and the voltage stabilizing component outputs a supply voltage; A control module, the output end of the voltage stabilizing component is connected to the control module for supplying power to the control module; A dimming module, the dimming module includes an operational amplifier component and a switch component, the control module is connected to the in-phase input terminal of the operational amplifier component, and the inverting input terminal of the operational amplifier component is connected to a reference voltage; the output terminal of the operational amplifier component is connected to the switch component, and the switch component is used to turn on or off according to the output signal of the operational amplifier component, and the voltage regulating component supplies power to the operational amplifier component; Wherein, the switch element is connected to the negative terminal of the light strip, and the positive terminal of the light strip is connected to an external power source.

2. A dimming circuit according to claim 1, characterized in that: The dimming module is provided with at least two groups; each of the switch elements is connected to a light strip of a different mode in a one-to-one correspondence.

3. A dimming circuit according to claim 1, characterized in that: The operational amplifier component amplifier, the amplifier's in-phase input terminal is connected to the output terminal of the control module, the amplifier's inverting input terminal is connected to the reference voltage, and the amplifier's output terminal is connected to the switch component; the output terminal of the voltage regulating component supplies power to the amplifier.

4. A dimming circuit according to claim 1, characterized in that: The switch element comprises an NMOS tube, the gate of the NMOS tube is connected to the output end of the operational amplifier component, the source of the NMOS tube is grounded, and the drain is connected to the negative electrode of the light strip; the drain of the NMOS tube is connected to the positive electrode of the light strip through a diode.

5. A dimming circuit according to claim 2, characterized in that: Each of the switch elements is connected in parallel with an identical switch element.

6. A dimming circuit according to claim 1, characterized in that: It also includes a protection module, which includes a detection component and a protection component connected to the output end of the detection component, the detection component is respectively connected to the output ends of the external power supply and the voltage stabilizing component, the detection component is used to derive a short-circuit signal based on the voltage signal of the external power supply and the voltage signal of the voltage stabilizing component, and transmit the short-circuit signal to the protection component; the protection component is also connected to the signal output end of the control module, and the protection component is used to pull down the output signal of the control module according to the short-circuit signal.

7. A dimming circuit according to claim 6, characterized in that: The detection component includes a comparator, the non-inverting input end of the comparator is connected to the output end of the voltage stabilizing component, the inverting input end of the comparator is connected to the positive end of the light strip, and the switch element is also connected to the positive end of the light strip through a diode; the output end of the comparator is connected to the protection component; the output end of the voltage stabilizing component supplies power to the comparator.

8. A dimming circuit according to claim 6, characterized in that: The protection component comprises an NMOS tube, a gate of the NMOS tube is connected to the output end of the detection component, a source is grounded, and a drain is connected to the in-phase input end of the operational amplifier component.

9. A dimming circuit according to claim 1, characterized in that: The voltage regulating component includes a step-down chip, the input end of the step-down chip is connected to the external power supply, a Schottky diode is connected in series between the external power supply and the step-down chip, a TVS tube is connected to the common end of the Schottky diode and the external power supply, and the other end of the TVS tube is grounded; the output end of the step-down chip is connected to the voltage stabilizing component through an inductor.

10. The dimming circuit according to claim 1, characterized in that: The voltage stabilizing component includes a voltage stabilizing chip, the input end of the voltage stabilizing chip is connected to the output of the voltage regulating component, a Schottky diode is also connected in series between the voltage regulating component and the voltage stabilizing chip, the input and output ends of the voltage stabilizing chip are both connected to a filter capacitor, and the other end of the filter capacitor is grounded.

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