Phase-cut dimming input signal detection circuit and method

Abstract

The invention discloses a phase-cut dimming input signal detection circuit, comprising: a voltage average value acquisition unit, connected to the output end of a phase-cut dimming module to acquire and output a voltage average value signal, the phase-cut dimming module is also connected to the input end of a power module, the power module comprises a control unit, the control unit receives the voltage average value signal and controls the input of the power module; and also comprises an instantaneous voltage acquisition unit connected to the output end of the phase-cut dimming module, the control unit receives the instantaneous voltage signal and determines whether to receive the voltage average value signal and whether to cut off the input of the power module according to the instantaneous voltage signal; the invention also discloses a phase-cut dimming input signal detection method; the invention can detect the effective value voltage of the input signal and detect the zero crossing point and abnormal point of the input signal, and the optimized processing of the signal can realize the fast following situation and avoid the interference of abnormal signals.

Description

Technical Field

[0001] The present invention relates to the field of dimming technology, and in particular to a phase-cut dimming input signal detection circuit and method. Background Art

[0002] In the context of energy conservation and environmental protection, LED lamps are increasingly used in home and commercial lighting due to their high light output efficiency and good focusing performance.

[0003] In order to meet the needs of changing lighting brightness, LED lamps also need to be equipped with dimming circuits. The front and rear phase shift dimming system is a common dimming method. When this dimming method is used in LED lamps, it often causes waveform abnormalities and waveform loss problems under low power factor loads. There are two types of conventional signal detection. The first is continuous and rapid monitoring. If there is an abnormal input waveform, the output waveform will quickly change with the input, causing an abnormality. The second is to average a large amount of data after sampling at a fixed interval, which can eliminate the interference caused by some abnormal signals, but the follow-up performance is poor. When the power is suddenly cut off, it cannot be quickly shut down, resulting in insufficient energy supply and abnormal output.

[0004] The existing holding circuit mainly uses resistance and capacitance to consume energy to maintain a certain output current to ensure that the input signal is abnormal, but the existence of resistance and capacitance will generate a lot of heat. Summary of the invention

[0005] In view of this, the present invention provides a phase-cut dimming input signal detection circuit to solve the above technical problem.

[0006] A phase-cut dimming input signal detection circuit, comprising:

[0007] A voltage average value acquisition unit is connected to the output end of the phase-cut dimming module to collect and output a voltage average value signal. The phase-cut dimming module is also connected to the input end of the power module. The power module includes a control unit. The control unit receives the voltage average value signal and controls the input of the power module.

[0008] It also includes an instantaneous voltage acquisition unit connected to the output end of the phase-cut dimming module. The control unit receives an instantaneous voltage signal and determines whether to receive an average voltage signal and whether to cut off the input of the power supply module according to the instantaneous voltage signal.

[0009] Preferably, the instantaneous voltage acquisition unit includes a first resistor and a second resistor, one end of the first resistor is connected to the positive electrode of the output end of the phase-cut dimming module, the other end of the first resistor is connected to the signal input end of the control unit as a sampling point, the other end of the first resistor is simultaneously connected in series with the second resistor, and the other end of the second resistor is grounded.

[0010] Preferably, a maintenance module for maintaining normal operation of the phase-cut dimming module is connected to the output end of the phase-cut dimming module.

[0011] Preferably, the maintaining module includes a controllable reference source, a switching unit, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor, the third resistor, the seventh resistor and the eighth resistor are connected in series, the other end of the third resistor is connected to the positive electrode of the output end of the phase-cut dimming module, and the other end of the eighth resistor is grounded, the controllable reference source includes a reference electrode connected to between the third resistor and the seventh resistor, a cathode connected to one end of the fourth resistor and a grounded anode, the other end of the fourth resistor is connected to the positive electrode of the output end of the phase-cut dimming module, and the cathode is also connected to the control end of the switching unit, the positive electrode connection end of the switching unit is connected to one end of the fifth resistor, the fifth resistor is connected to the positive electrode of the output end of the phase-cut dimming module, the negative electrode connection end of the switching unit is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected between the seventh resistor and the eighth resistor.

[0012] Preferably, the sampling point of the instantaneous voltage acquisition unit is the negative connection terminal of the switch unit.

[0013] Preferably, the instantaneous voltage acquisition unit includes a first resistor and a second resistor, one end of the first resistor (R1) is connected to the negative connection end of the switch unit, the other end of the first resistor is connected to the signal input end of the control unit as a sampling point, the other end of the first resistor is simultaneously connected in series with the second resistor, and the other end of the second resistor is grounded.

[0014] Preferably, the maintenance module further includes at least one of a second capacitor, a third capacitor and a fourth capacitor;

[0015] One end of the second capacitor is connected to the reference electrode of the controllable reference source, and the other end is grounded;

[0016] Two ends of the third capacitor are respectively connected to the reference electrode and cathode of the controllable reference source;

[0017] Two ends of the fourth capacitor are respectively connected to the control end and the positive connection end of the switch unit.

[0018] Preferably, the voltage average value acquisition unit includes a ninth resistor, a tenth resistor and a first capacitor;

[0019] After the ninth resistor and the tenth resistor are connected in series, the other end of the ninth resistor is connected to the positive electrode of the output end of the phase-cut dimming module, and the other end of the tenth resistor is grounded;

[0020] One end of the first capacitor is connected between the ninth resistor and the tenth resistor and serves as a sampling point, and the other end is grounded.

[0021] A method for detecting a phase-cut dimming input signal comprises the following steps:

[0022] (1) Collecting the instantaneous voltage signal at the output end of the phase-cut dimming module and transmitting it to the control unit in the power module;

[0023] (2) The control unit determines whether the instantaneous voltage signal is normal. If so, the process proceeds to step (3). Otherwise, the process returns to step (1). When the number of consecutive cycles of steps (1) and (2) exceeds a preset value, the process proceeds to step (4).

[0024] (3) collecting a voltage average value signal at the output end of the phase-cut dimming module, and the control unit (301) receives and outputs a load control signal according to the voltage average value signal;

[0025] (4) The control unit cuts off the output of the power module.

[0026] Preferably, in the step, the control unit determines that the instantaneous voltage signal is normal when the following two conditions are met at the same time:

[0027] 2.1 Relative to the previous N instantaneous voltage signals, whether the current instantaneous voltage signal is a periodic signal;

[0028] 2.2 Whether the change of the instantaneous voltage signal exceeds the set value M, where M is the trend of the first N signals and the estimated change of the next N+1 signals.

[0029] Technical effects of the present invention:

[0030] The phase-cut dimming input signal detection circuit and method of the present invention can detect the effective value voltage of the input signal and detect the zero-crossing point and abnormal point of the input signal. The optimized processing of the signal by this method can achieve fast following and avoid interference from abnormal signals. At the same time, it can realize the conduction maintenance resistance when the input voltage is low. In this way, the current generated under the same maintenance current will be much smaller than the resistance-capacitance maintenance scheme, thereby improving energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The embodiments of the present invention are described below in conjunction with the accompanying drawings, wherein:

[0032] Figure 1 The structure wireframe diagram of a phase-cut dimming input signal detection circuit according to an embodiment of the present invention.

[0033] Figure 2 FIG. 4 is a circuit diagram of a phase-cut dimming input signal detection circuit according to an embodiment of the present invention.

[0034] Figure 3 It is a structural wireframe diagram of a phase-cut dimming input signal detection circuit according to another embodiment of the present invention.

[0035] Figure 4 for Figure 3 Circuit diagram of a phase-cut dimming input signal detection circuit.

[0036] Figure 5 FIG. 4 is a circuit diagram of a phase-cut dimming input signal detection circuit according to another embodiment of the present invention.

[0037] Figure 6 FIG. 4 is a circuit diagram of a phase-cut dimming input signal detection circuit according to another embodiment of the present invention.

[0038] Figure 7 FIG. 4 is a circuit diagram of a phase-cut dimming input signal detection circuit according to another embodiment of the present invention.

[0039] Figure 8 It is a wireframe flow chart of the phase-cut dimming input signal detection method of the present invention. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are further described in detail below based on the accompanying drawings. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.

[0041] like Figure 1 and 2 As shown, the phase-cut dimming input signal detection circuit 1000 of this embodiment includes a voltage average value acquisition unit 100 and an instantaneous voltage acquisition unit 400. The purpose of the phase-cut dimming input signal detection circuit 1000 is to detect the phase-cut dimming input signal output from the phase-cut dimming module 200. The phase-cut dimming module 200 is connected to the high-voltage power supply end (mains power), and the output end is connected to the power module 300 that supplies power to the lamp. The voltage average value acquisition unit 100 is connected to the output end of the phase-cut dimming module 200 to collect and output the voltage average value signal. The phase-cut dimming module 200 is also connected to the input end of the power module 300. The power module 300 includes a control unit 301, which receives the voltage average value signal and controls the input of the power module 300; the instantaneous voltage acquisition unit 400 is connected to the output end of the phase-cut dimming module 200, and the control unit 301 receives the instantaneous voltage signal and determines whether to receive the voltage average value signal and whether to cut off the input of the power module 300 according to the instantaneous voltage signal.

[0042] The above-mentioned phase-cut dimming module 200 and power module 300 are both prior art and will not be described in detail here. The control unit 301 can be a single-chip microcomputer, which has mature technology, powerful functions and is easy to purchase.

[0043] The instantaneous voltage acquisition unit 400 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the positive electrode of the output end of the phase-cut dimming module 200, the other end of the first resistor R1 is connected to the signal input end of the control unit 301 as a sampling point, the other end of the first resistor R1 is connected in series with the second resistor R2, and the other end of the second resistor R2 is grounded.

[0044] The voltage average value acquisition unit 100 includes a ninth resistor R9, a tenth resistor R10 and a first capacitor C1; after the ninth resistor R9 and the tenth resistor R10 are connected in series, the other end of the ninth resistor R9 is connected to the positive electrode of the output end of the phase-cut dimming module 200, and the other end of the tenth resistor R10 is grounded; one end of the first capacitor C1 is connected between the ninth resistor R9 and the tenth resistor R10 and serves as a sampling point, and the other end is grounded.

[0045] Each resistor in this embodiment is for illustration only, and the actual number and form (series and parallel) of each resistor may vary according to actual conditions.

[0046] like Figure 8 As shown, the phase-cut dimming input signal detection method of this embodiment includes the following steps:

[0047] (1) Collecting the instantaneous voltage signal at the output end of the phase-cut dimming module 200 and transmitting it to the control unit 301 in the power module 300;

[0048] (2) The control unit 301 determines whether the instantaneous voltage signal is normal. If so, the process proceeds to step (3). Otherwise, the process returns to step (1). When the number of consecutive cycles of steps (1) and (2) exceeds a preset value, the process proceeds to step (4). The control unit 301 determines whether the instantaneous voltage signal is normal when the following two conditions are met at the same time:

[0049] 2.1 Relative to the previous N instantaneous voltage signals, whether the current instantaneous voltage signal is a periodic signal;

[0050] 2.2 Whether the change of the instantaneous voltage signal exceeds the set value M, where M is the trend of the first N signals and the estimated change of the next N+1 signals. N is a positive integer, generally between 5 and 20.

[0051] (3) collecting the voltage average value signal at the output end of the phase-cut dimming module 200, and the control unit 301 receives and outputs a load control signal according to the voltage average value signal;

[0052] (4) The control unit 301 cuts off the output of the power module 300 .

[0053] like Figure 3 and 4As shown, in another embodiment, the phase-cut dimming input signal detection circuit 1000 also includes a maintenance module 500 connected to the output end of the phase-cut dimming module 200 for maintaining the normal operation of the phase-cut dimming module 200. The maintenance module 500 can prevent the serious distortion of the phase-cut waveform, the loss of half of the waveform or the occurrence of multiple switching spikes to maintain the normal operation of the phase-cut dimmer. In this embodiment, the maintenance module 500 includes a controllable reference source 501, a switch unit 502, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, the third resistor R3, the seventh resistor R7 and the eighth resistor R8 are connected in series, the other end of the third resistor R3 is connected to the positive electrode of the output end of the phase-cut dimming module 200, the other end of the eighth resistor R8 is grounded, the controllable reference source 501 includes a reference electrode r connected between the third resistor R3 and the seventh resistor R7, and the third resistor R3, the seventh resistor R7 and the eighth resistor R8 are connected in series. The cathode k at one end of the fourth resistor R4 and the anode a are grounded, the other end of the fourth resistor R4 is connected to the positive electrode of the output end of the phase-cut dimming module 200, the cathode k is also connected to the control end of the switch unit 502, the positive connection end of the switch unit 502 is connected to one end of the fifth resistor R5, the fifth resistor R5 is connected to the positive electrode of the output end of the phase-cut dimming module 200, the negative connection end of the switch unit 502 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected between the seventh resistor R7 and the eighth resistor R8.

[0054] The controllable reference source 501 has a cathode, an anode and a reference terminal. When the voltage of the reference terminal is higher than the internal reference (preset value), the current passing from the anode to the cathode increases. When the reference voltage is lower than the internal reference (preset value), the current passing from the anode to the cathode decreases. The voltage control is achieved by controlling the magnitude of the current passing through to control the resistance voltage drop on its busbar. There are TL431, AS431, AZ431, etc. In this embodiment, TL431 is used, represented by N1. The switch unit 502 in this embodiment uses a MOS tube, represented by Q1.

[0055] The principle of the maintenance module 500 is as follows: the third resistor R3 and the seventh resistor R7 sample the input instantaneous voltage and combine the sampled voltage with N1 to realize that Q1 is turned off at high voltage and Q1 is turned on at low voltage, and the current of the energy-consuming resistor shows a trend of decreasing with the increase of voltage. Among them, the fifth resistor R5 is an energy-consuming resistor, the sixth resistor R6 and the eighth resistor R8 are current setting resistors of the fifth resistor R5, and R4 is a protection resistor.

[0056] like Figure 5As shown, in another embodiment, the sampling point of the instantaneous voltage acquisition unit 400 is the negative connection end of the switch unit 502. Therefore, the operation of collecting the instantaneous voltage signal at the output end of the phase-cut dimming module 200 in step (1) is only performed when the switch unit 502 is turned on, thereby reducing energy consumption and improving energy efficiency.

[0057] like Figure 6 As shown, in another embodiment, the maintenance module 500 also includes a second capacitor C2, a third capacitor C3 and a fourth capacitor C4, one end of the second capacitor C2 is connected to the reference electrode r of the controllable reference source 501, and the other end is grounded; the two ends of the third capacitor C3 are respectively connected to the reference electrode r and the cathode k of the controllable reference source 501; the two ends of the fourth capacitor C4 are respectively connected to the control end and the positive connection end of the switch unit 502.

[0058] like Figure 7 As shown, in another embodiment, the instantaneous voltage acquisition unit 400 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the negative connection end of the switch unit 502, the other end of the first resistor R1 is connected to the signal input end of the control unit 301 as a sampling point, the other end of the first resistor R1 is simultaneously connected in series with the second resistor R2, and the other end of the second resistor R2 is grounded.

[0059] The above-mentioned embodiments of the phase-cut dimming input signal detection method are as follows Figure 8 shown.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.

Claims

1. A phase-cut dimming input signal detection circuit (1000), comprising: A voltage average value collection unit (100) is connected to the output end of the phase-cut dimming module (200) to collect and output a voltage average value signal, the phase-cut dimming module (200) is also connected to the input end of the power module (300), the power module (300) comprises a control unit (301), the control unit (301) receives the voltage average value signal and controls the input of the power module (300); it is characterized by further comprising an instantaneous voltage collection unit (400) connected to the output end of the phase-cut dimming module (200), the control unit (301) receives the instantaneous voltage signal and determines whether to receive the voltage average value signal and whether to cut off the input of the power module (300) according to the instantaneous voltage signal, and when the instantaneous voltage signal is normal, the voltage average value signal is received and the input of the power module (300) is cut off; The control unit (301) determines whether the instantaneous voltage signal is normal when the following two conditions are met simultaneously: 2.1 whether the current instantaneous voltage signal is a periodic signal relative to the previous N instantaneous voltage signals; 2.2 whether the change in the instantaneous voltage signal exceeds a set value M, where M is the trend of the previous N signals and the estimated change of the next N+1 signals.

2. The phase-cut dimming input signal detection circuit (1000) according to claim 1, characterized in that: The instantaneous voltage acquisition unit (400) comprises a first resistor (R1) and a second resistor (R2), one end of the first resistor (R1) is connected to the positive electrode of the output end of the phase-cut dimming module (200), the other end of the first resistor (R1) is connected to the signal input end of the control unit (301) as a sampling point, the other end of the first resistor (R1) is simultaneously connected in series with the second resistor (R2), and the other end of the second resistor (R2) is grounded.

3. The phase-cut dimming input signal detection circuit (1000) according to claim 1, characterized in that: A maintenance module (500) is connected to the output end of the phase-cut dimming module (200) and is used to maintain the normal operation of the phase-cut dimming module (200).

4. The phase-cut dimming input signal detection circuit (1000) according to claim 3, characterized in that: The maintaining module (500) comprises a controllable reference source (501), a switch unit (502), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7) and an eighth resistor (R8), wherein the third resistor (R3), the seventh resistor (R7) and the eighth resistor (R8) are connected in series, the other end of the third resistor (R3) is connected to the positive electrode of the output end of the phase-cut dimming module (200), and the other end of the eighth resistor (R8) is grounded, and the controllable reference source (501) comprises a reference electrode (r) connected between the third resistor (R3) and the seventh resistor (R7), and a reference electrode (r) connected to the third resistor (R3) and the seventh resistor (R7). A cathode (k) at one end of the fourth resistor (R4) and an anode (a) connected to the ground, the other end of the fourth resistor (R4) is connected to the positive electrode of the output end of the phase-cut dimming module (200), the cathode (k) is also connected to the control end of the switch unit (502), the positive connection end of the switch unit (502) is connected to one end of the fifth resistor (R5), the fifth resistor (R5) is connected to the positive electrode of the output end of the phase-cut dimming module (200), the negative connection end of the switch unit (502) is connected to one end of the sixth resistor (R6), and the other end of the sixth resistor (R6) is connected between the seventh resistor (R7) and the eighth resistor (R8).

5. The phase-cut dimming input signal detection circuit (1000) according to claim 4, characterized in that: The sampling point of the instantaneous voltage acquisition unit (400) is the negative electrode connection terminal of the switch unit (502).

6. The phase-cut dimming input signal detection circuit (1000) according to claim 4, characterized in that: The instantaneous voltage acquisition unit (400) comprises a first resistor (R1) and a second resistor (R2), one end of the first resistor (R1) is connected to the negative connection end of the switch unit (502), the other end of the first resistor (R1) is connected to the signal input end of the control unit (301) as a sampling point, the other end of the first resistor (R1) is simultaneously connected in series with the second resistor (R2), and the other end of the second resistor (R2) is grounded.

7. The phase-cut dimming input signal detection circuit (1000) according to claim 4, characterized in that: The maintaining module (500) further comprises at least one of a second capacitor (C2), a third capacitor (C3) and a fourth capacitor (C4); one end of the second capacitor (C2) is connected to the reference electrode (r) of the controllable reference source (501), and the other end is grounded; the two ends of the third capacitor (C3) are respectively connected to the reference electrode (r) and cathode (k) of the controllable reference source (501); and the two ends of the fourth capacitor (C4) are respectively connected to the control end and the positive connection end of the switch unit (502).

8. The phase-cut dimming input signal detection circuit (1000) according to any one of claims 1 to 7, characterized in that: The voltage average value acquisition unit (100) comprises a ninth resistor (R9), a tenth resistor (R10) and a first capacitor (C1); after the ninth resistor (R9) and the tenth resistor (R10) are connected in series, the other end of the ninth resistor (R9) is connected to the positive electrode of the output end of the phase-cut dimming module (200), and the other end of the tenth resistor (R10) is grounded; one end of the first capacitor (C1) is connected between the ninth resistor (R9) and the tenth resistor (R10) and serves as a sampling point, and the other end is grounded.

9. A phase-cut dimming input signal detection method, characterized in that: The method comprises the following steps: (1) collecting an instantaneous voltage signal at the output end of a phase-cut dimming module (200) and transmitting the signal to a control unit (301) in a power module (300); (2) the control unit (301) determines whether the instantaneous voltage signal is normal, and if so, proceeds to step (3); otherwise, returns to step (1); when the number of consecutive cycles of steps (1) and (2) exceeds a preset value, proceeds to step (4); (3) collecting an average voltage signal at the output end of the phase-cut dimming module (200), the control unit (301) receives the signal and outputs a load control signal according to the average voltage signal; (4) the control unit (301) cuts off the output of the power module (300); In step (2), the control unit (301) determines that the instantaneous voltage signal is normal when the following two conditions are met simultaneously: 2.1 Whether the current instantaneous voltage signal is a periodic signal relative to the previous N instantaneous voltage signals; 2.2 Whether the change in the instantaneous voltage signal exceeds a set value M, where M is the trend of the previous N signals and the estimated change of the next N+1 signals.

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