Lamp dimming control system and method for automatically judging dimming range of lamp

Abstract

The invention relates to a lamp dimming control system and a method for automatically judging a dimming range of a lamp, and the method comprises the following steps: (A) in a dimming detection period, gradually reducing the periodic average voltage of a driving signal output to a light-emitting part; and (B) during the dimming detection period, recording critical dimming information of the current of the light-emitting part corresponding to the condition that the light-emitting part begins to flicker or be turned off. And (C) reducing a dimming range according to the critical dimming information to obtain dimming lower limit information corresponding to the condition before the light-emitting part begins to flicker or is turned off. And (D) in a normal operation period, outputting the driving signal which is not lower than the dimming range corresponding to the dimming lower limit information. Therefore, the dimming lower limit information of each light-emitting part can be automatically detected, the condition that the light-emitting parts flicker or are extinguished in the dimming process can be avoided, and the maximum dimming range of each light-emitting part can be fully utilized.

Description

Technical Field

[0001] The present invention relates to a control system and an automatic determination method, and in particular to a lamp dimming control system and a method for automatically determining a dimming range of a lamp. Background Art

[0002] In recent years, light-emitting diodes (LEDs) have become the mainstream in ceiling fan lighting systems due to their advantages of energy saving and long life. Figure 1 At present, the dimming method used in LED lamps mainly uses a three-terminal bidirectional alternating current switch (TRIAC, not shown) to provide power, and changes the waveform of the output voltage 11 provided to the LED lamp by controlling the on-time t of the three-terminal bidirectional alternating current switch, so as to achieve the effect of dimming the brightness of the LED lamp. In practice, for the convenience of management, a fixed dimming range (for example, corresponding to the on-time t of 4ms to 8.3ms) is directly set in the system to provide users with dimming within this range. However, since the dimming ranges of LED lamps of various manufacturers are different, when the lower limit of the dimming range set by the system is lower than the lower limit of the dimming range of the installed LED lamp, the LED lamp will start to flicker or go out directly during the process of dimming the LED lamp by the user due to insufficient voltage. When the lower limit of the dimming range set by the system is higher than the lower limit of the dimming range of the installed LED lamp, the LED lamp will maintain a higher brightness and cannot be dimmed further. Summary of the invention

[0003] The object of the present invention is to provide a lamp dimming control system which can automatically determine a suitable dimming range according to various LED lamps.

[0004] The lamp dimming control system of the present invention comprises a light emitting element, a driving circuit, a current detecting circuit, and a control unit.

[0005] The driving circuit is electrically connected to the light emitting element and is used for outputting a driving signal to drive the light emitting element to emit light.

[0006] The current detection circuit is electrically connected to the light emitting element, detects the current of the light emitting element and outputs a current signal.

[0007] The control unit is electrically connected to the driving circuit and the current detection circuit, receives the current signal and controls the operation of the driving circuit. During the dimming detection period, the control unit controls the driving circuit to gradually reduce the periodic average voltage of the driving signal to adjust the light of the light-emitting device from bright to dark, and records the critical dimming information at this time when the current signal corresponds to the light-emitting device starting to flicker or turn off. The control unit reduces the dimming range according to the critical dimming information and obtains the dimming lower limit information corresponding to before the light-emitting device starts to flicker or turns off. During normal operation, the control unit controls the driving circuit to output the driving signal of the dimming range not lower than the dimming lower limit information.

[0008] The lamp dimming control system of the present invention, the driving circuit includes a driving switch controlled by the control unit to output the driving signal, the control unit controls the conduction time of the driving switch so that the driving signal starts to be output after the opening time after zero o'clock and continues until the next zero o'clock. During the dimming detection period, the control unit controls the driving switch so that the opening time is gradually delayed so that the periodic average voltage of the driving signal gradually decreases.

[0009] In the lamp dimming control system of the present invention, the critical dimming information is related to the conduction time of the driving switch or to the opening time.

[0010] In the lamp dimming control system of the present invention, during the dimming detection period, the control unit records the turn-on time when the light-emitting element starts to flash or turn off as the critical dimming information, and subtracts the adjustment value from the recorded turn-on time as the dimming lower limit information, and then uses the period corresponding to the calculated turn-on time as the usable dimming range. During the normal operation period, the control unit controls the drive circuit to output the drive signal corresponding to the usable dimming range.

[0011] In the lamp dimming control system of the present invention, the control unit determines that the light-emitting element is turned off when the current corresponding to the current signal is lower than a low current value, and determines that the light-emitting element starts to flash when the current corresponding to the current signal starts to oscillate up and down.

[0012] The object of the present invention is to provide a method for automatically determining a dimming range of a lamp, which can automatically determine a suitable dimming range according to various LED lamps.

[0013] The method for automatically determining the dimming range of a lamp of the present invention is applied to a lamp dimming control system, the lamp dimming control system comprises a control unit, a drive circuit and a light-emitting element, the control unit is used to control the drive circuit to output a drive signal to make the light-emitting element emit light, and the method for automatically determining the dimming range of a lamp comprises the following steps:

[0014] (A) During the dimming detection period, the control unit controls the driving circuit to gradually reduce the periodic average voltage of the driving signal to adjust the light of the light-emitting element from bright to dark.

[0015] (B) During the dimming detection period, the control unit detects the current of the light-emitting element, and records the critical dimming information when the current of the light-emitting element corresponds to the light-emitting element starting to flicker or turn off.

[0016] (C) The control unit reduces the dimming range according to the critical dimming information to obtain the dimming lower limit information corresponding to before the light-emitting element starts to flicker or turn off.

[0017] (D) During normal operation, the control unit controls the driving circuit to output the driving signal that is not lower than the dimming range corresponding to the dimming lower limit information.

[0018] The method for automatically determining the dimming range of a lamp of the present invention, the driving circuit includes a driving switch controlled by the control unit to output the driving signal, the control unit controls the conduction time of the driving switch so that the driving signal starts to be output after the start time after zero o'clock and continues until the next zero o'clock. In step (A), the control unit controls the conduction time of the driving switch so that the start time is gradually delayed so that the periodic average voltage of the driving signal gradually decreases.

[0019] In the method for automatically determining the dimming range of a lamp of the present invention, the critical dimming information is related to the conduction time of the driving switch or to the opening time.

[0020] The method for automatically determining the dimming range of a lamp of the present invention comprises: in step (B), the control unit records the turn-on time when the light-emitting element starts to flash or turn off as the critical dimming information; in step (C), the control unit subtracts an adjustment value from the recorded turn-on time as the dimming lower limit information, and then uses the period corresponding to the calculated turn-on time as the usable dimming range; in step (D), the control unit controls the drive circuit to output the drive signal corresponding to the usable dimming range.

[0021] In the method for automatically determining the dimming range of a lamp of the present invention, in step (B), the control unit determines that the light-emitting element is turned off when the current corresponding to the current signal is lower than a low current value, and determines that the light-emitting element starts to flash when the current corresponding to the current signal starts to oscillate up and down.

[0022] The beneficial effect of the present invention is that: by setting the driving circuit and the current detection circuit, and cooperating with the control unit during the dimming detection period, the periodic average voltage of the driving signal is controlled to gradually decrease, and the dimming lower limit information is obtained according to the critical dimming information when the light-emitting component starts to flicker or turn off, and then the driving signal is output during the normal operation period according to the dimming lower limit information. The present invention can automatically detect the dimming range applicable to each light-emitting component, and can avoid the user from experiencing the situation where the light-emitting component flickers or goes out during the dimming process, and can make full use of the maximum dimming range of each light-emitting component. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram illustrating a waveform of an output voltage for brightness modulation of an LED lamp in the prior art;

[0024] Figure 2 is a block diagram of an embodiment of a lamp dimming control system of the present invention;

[0025] Figure 3 is a waveform diagram of a driving signal used to dim a light emitting element in the embodiment; Figure 4 It is a flow chart of an embodiment of a method for automatically determining a dimming range of a lamp of the present invention. DETAILED DESCRIPTION

[0026] See also Figure 2 An embodiment of the lamp dimming control system of the present invention comprises a light emitting element 3, a driving circuit 4, a current detection circuit 5, and a control unit 7. The lamp dimming control system may further comprise a power supply circuit 2, and a communication unit 6 for communicating with a remote controller 9.

[0027] The power supply circuit 2 is used to receive an external power supply (eg, AC power), stabilize and transform the external power supply, and then provide it to the internal drive circuit 4, the current detection circuit 5, the control unit 7 and other circuits.

[0028] The light emitting element 3 is a light emitting diode (LED) which emits light upon receiving a driving signal.

[0029] The driving circuit 4 is electrically connected to the light-emitting element 3, receives control from the control unit 7 and outputs the driving signal. The driving circuit 4 includes a driving switch 41 that is controlled by the control unit 7 to output the driving signal. The driving switch 41 is, for example, a three-terminal bidirectional alternating current switch (TRIAC for short), and is controlled by the control unit 7 to be turned on or off to adjust the conduction angle of the driving signal, thereby changing the brightness of the light emitted by the light-emitting element 3. When the driving switch 41 is turned on, the driving signal outputs power, and when the driving switch 41 is not turned on, the driving signal does not output power. Figure 2 and Figure 3 The driving switch 41 is controlled by the control unit 7 to control the conduction time, so that the driving signal is turned on at a time p1, p2, p after zero. n ,p n+1 After that, the output starts and continues until the next zero point. Since those skilled in the art can infer the expanded details of the driving circuit 4 according to the above description, no further description is given.

[0030] The current detection circuit 5 is electrically connected to the light emitting element 3 , detects the current of the light emitting element 3 and outputs a current signal.

[0031] The communication unit 6 is electrically connected to the control unit 7, and is used for the control unit 7 to communicate with the remote controller 9, so that the user can control the operation of the lamp by operating the remote controller 9. For example, the user can operate the remote controller 9 (for example, by pressing a specific button within a predetermined time (for example, 30 seconds or 60 seconds) after power-on) to execute the process of the method for automatically determining the dimming range of the lamp described later. The remote controller 9 can be a general handheld remote control device, and can communicate with the communication unit 6 using short-range wireless communication technologies such as Bluetooth, infrared, Wi-Fi, etc., or the remote controller 9 can also be set as a wall-controlled switch, and is connected to the communication unit 6 by wire.

[0032] The control unit 7 is electrically connected to the power supply circuit 2, the drive circuit 4 and the current detection circuit 5, receives the current signal and controls the operation of the drive circuit 4. During a dimming detection period, the control unit 7 controls the drive circuit 4 to gradually reduce the periodic average voltage of the drive signal to adjust the light of the light-emitting element 3 from bright to dark, and when the current signal corresponds to the light-emitting element 3 starting to flicker or turn off, a critical dimming information at this time is recorded, and the control unit 7 reduces the dimming range according to the critical dimming information to obtain a dimming lower limit information corresponding to the light-emitting element 3 before it starts to flicker or turn off. The control unit 7 stores the dimming lower limit information, and during a normal operation period, controls the drive circuit 4 to output the drive signal that is not lower than the dimming range corresponding to the dimming lower limit information. The control unit 7 can be designed as a circuit with functions such as calculation and storage, for example, it can be implemented using a microcontroller (MCU).

[0033] The following is an explanation based on actual application:

[0034] When the user wants to execute the function of automatically determining the dimming range, the remote controller 9 can be operated to control the control unit 7 via the communication unit 6. For example, the automatic dimming detection function can be activated by pressing a specific button within 30 seconds of power-on, or the remote controller 9 can be set to perform the automatic dimming detection function when paired with the lamp, or the lamp dimming control system can be set to automatically perform the automatic dimming detection programming each time it is powered on, and store the available dimming range for use during the normal operation.

[0035] During the dimming detection period, the control unit 7 controls the driving circuit 4 to gradually reduce the periodic average voltage of the driving signal. For example, the control unit 7 controls the driving switch 41 to start conducting at time points p1, p2, ... p n 、p n+1 (ie, the opening time) is gradually delayed so that the driving signal is Figure 3 The on-times t1, t2, ...t n ,t n+1 In this way, the periodic average voltage of the driving signal gradually decreases, thereby causing the brightness of the light-emitting element 3 to gradually dim.

[0036] Among them, the opening time p1, p2, ... p n 、p n+1 It can be gradually delayed at a fixed time interval Δt (ie, the on-time t1, t2, ... t n ,t n+1The fixed time interval Δt is gradually reduced), or the delay is firstly delayed by the larger time interval Δt1 according to a preset setting, and then changed to the smaller time interval Δt2 for delay.

[0037] The initial opening time may be as follows: Figure 3 As shown in the figure, it is set to a predetermined time p1, or it is set to 0 (that is, the power supply starts to be output after zero). The predetermined time p1 can be set according to actual needs. For example, it can be set to start dimming detection from around the middle value of the general adjustable range (or 1 / 3 or 1 / 4 of the general adjustable range). Taking the commonly used 60Hz driving signal as an example, the general adjustable range is 0 to 8.3ms (if the driving signal is 50Hz, the adjustable range is 0 to 10ms). Therefore, it can be set to start dimming detection from 4.15ms (that is, the middle value), or 2.77ms (that is, about 1 / 3), or 2.08ms (that is, about 1 / 4) after the zero point. In this way, the dimming detection time can be reduced.

[0038] During the dimming detection period, when the on-time of the driving switch 41 is gradually reduced, and the power provided by the driving signal is lower than the power required for the normal operation of the light-emitting element 3 (for example, when the voltage is too low), the light-emitting element 3 will start to flicker or directly turn off (dark out). The control unit 7 detects the current of the light-emitting element 3 through the current detection circuit 5 to determine the time point when the current of the light-emitting element 3 corresponds to flickering or turning off. The judgment method is, for example, when the light-emitting element 3 is operating normally, its current will gradually decrease as the power provided by the driving signal decreases. When the current corresponding to the current signal decreases to a value lower than a low current value (for example, a value close to 0), it means that the current of the light-emitting element 3 is 0, and the control unit 7 determines that the light-emitting element 3 is turned off. When the current corresponding to the current signal begins to oscillate up and down, it is determined that the light-emitting element 3 begins to flicker.

[0039] When the current of the light emitting element 3 corresponds to flickering or turning off, the control unit 7 records the on time (or records the on time) as the critical dimming information. Then, the control unit 7 pushes the recorded on time forward by an adjustment value to obtain a safe dimming lower limit value of the on time (i.e., the dimming lower limit information), and then uses the period corresponding to the dimming lower limit value of the on time as the usable dimming range.

[0040] Among them, the adjustment value can be a pre-set value (for example, 0.1ms, 0.2ms, 0.5ms, 1ms...), or the time interval Δt between the recorded turn-on time and the previous turn-on time, or the time interval Δt between the recorded turn-on time and the previous few (for example, the first two, the first three, or the first four...) turn-on times.

[0041] For example, assuming that the light emitting element 3 is Figure 3 The on-time is reduced to t n+1 , the control unit 7 records the opening time p at this time. n+1 (or record the conduction time t n+1 ), and the recorded opening time p n+1 Subtract the adjustment value to obtain the available dimming range (for example, assuming that the recorded on time p n+1 is 4.5ms, the preset adjustment value is 0.2ms, then the available dimming range is 0-4.3ms, that is, the period from zero to 4.3ms after zero), or the recorded opening time p n+1 Subtract the previous time interval Δt to obtain the previous normal operation start time p n (i.e., return to the on-time t n The opening time p corresponding to the cycle n ), and the previous opening time p n The corresponding period is used as the available dimming range (for example, assuming that the recorded opening time p n+1 is 4.5ms, and the previous time interval Δt is 0.1ms, that is, the previous opening time p n is 4.4ms, then the available dimming range is 0~4.4ms, that is, the period from zero o'clock to 4.4ms after zero o'clock).

[0042] Then, during the normal operation of the lamp, the control unit 7 controls the drive circuit 4 to output the drive signal corresponding to the available dimming range according to the obtained available dimming range, that is, the user can only perform dimming operations within the available dimming range. In this way, not only can the user avoid flickering or extinguishing the lamp during the dimming process, but also the available dimming range of each light-emitting element 3 can be fully utilized.

[0043] See also Figure 2 and Figure 4 An embodiment of the method for automatically determining the dimming range of a lamp of the present invention is applied to the above-mentioned lamp dimming control system. The method for automatically determining the dimming range of a lamp comprises the following steps:

[0044] Step S01: During a dimming detection period, the control unit 7 controls the driving circuit 4 to gradually reduce the periodic average voltage of the driving signal, so as to adjust the light of the light emitting element 3 from bright to dim.

[0045] In step S01 , the control unit 7 controls the on-time of the driving switch 41 to gradually decrease, so that the period average voltage of the driving signal gradually decreases.

[0046] In step S01 , the control unit 7 controls the on-time of the driving switch 41 to gradually delay the on-time so that the periodic average voltage of the driving signal gradually decreases.

[0047] Step S02: During the dimming detection period, the control unit 7 detects the current of the light emitting element 3, and records a critical dimming information when the current of the light emitting element 3 corresponds to the light emitting element 3 starting to flicker or turn off.

[0048] In step S02 , the critical dimming information is related to the conduction time of the driving switch 41 or to the opening time.

[0049] Wherein, in step S02, the control unit 7 records the on time when the light emitting element 3 starts to flash or turn off as the critical dimming information.

[0050] Wherein, in step S02, the control unit 7 determines that the light-emitting element 3 is turned off when the current corresponding to the current signal is lower than a low current value, and determines that the light-emitting element 3 starts to flash when the current corresponding to the current signal starts to oscillate up and down.

[0051] Step S03: the control unit 7 reduces the dimming range according to the critical dimming information to obtain a dimming lower limit information corresponding to before the light emitting element 3 starts to flicker or turn off.

[0052] In step S03 , the control unit 7 subtracts an adjustment value from the recorded on-time as the dimming lower limit information, and then uses the period corresponding to the calculated on-time as an available dimming range.

[0053] Step S04: During a normal operation period, the control unit 7 controls the driving circuit 4 to output the driving signal whose range is not lower than the dimming range corresponding to the dimming lower limit information.

[0054] In step S04 , the control unit 7 controls the driving circuit 4 to output the driving signal corresponding to the available dimming range.

[0055] Through the above description, the effects of this embodiment are as follows:

[0056] By setting the driving circuit 4 and the current detection circuit 5, and cooperating with the control unit 7 during the dimming detection period, the periodic average voltage of the driving signal is controlled to gradually decrease, and the dimming lower limit information is obtained according to the critical dimming information at which the light-emitting component 3 starts to flicker or turn off. Then, during the normal operation period, the control unit 7 controls the driving circuit 4 to output the driving signal of the dimming range corresponding to the dimming lower limit information, so that the dimming lower limit information of each light-emitting component 3 can be automatically detected for use during the normal operation period. In this way, the user can avoid the light-emitting component 3 flickering or turning off during the dimming process, and the maximum dimming range of each light-emitting component 3 can be fully utilized.

[0057] In summary, the lamp dimming control system and the method for automatically determining the dimming range of a lamp of the present invention can indeed achieve the purpose of the present invention.

[0058] The above are merely embodiments of the present invention and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention still fall within the scope of the present invention.

Claims

1. A lamp dimming control system, comprising a light emitting element, a driving circuit, a current detection circuit and a control unit, characterized in that: The driving circuit is electrically connected to the light emitting element and is used to output a driving signal to drive the light emitting element to emit light; The current detection circuit is electrically connected to the light emitting element, detects the current of the light emitting element and outputs a current signal; The control unit is electrically connected to the driving circuit and the current detection circuit, receives the current signal and controls the operation of the driving circuit. During the dimming detection period, the control unit controls the driving circuit to gradually reduce the periodic average voltage of the driving signal to adjust the light of the light-emitting device from bright to dark, and records the critical dimming information at this time when the current signal corresponds to the light-emitting device starting to flicker or turn off. The control unit reduces the dimming range according to the critical dimming information and obtains the dimming lower limit information corresponding to before the light-emitting device starts to flicker or turns off. During normal operation, the control unit controls the driving circuit to output the driving signal of the dimming range not lower than the dimming lower limit information.

2. The lamp dimming control system according to claim 1, characterized in that: The driving circuit includes a driving switch controlled by the control unit to output the driving signal. The control unit controls the on-time of the driving switch so that the driving signal starts to be output after the on-time after zero and continues until the next zero. During the dimming detection period, the control unit controls the driving switch so that the on-time is gradually delayed so that the periodic average voltage of the driving signal gradually decreases.

3. The lamp dimming control system according to claim 2, characterized in that: The critical dimming information is related to the on-time of the driving switch or to the turn-on time.

4. The lamp dimming control system according to claim 2, characterized in that: During the dimming detection period, the control unit records the turn-on time when the light-emitting element starts to flash or turn off as the critical dimming information, and subtracts the adjustment value from the recorded turn-on time as the dimming lower limit information, and then uses the period corresponding to the calculated turn-on time as the usable dimming range. During the normal operation period, the control unit controls the driving circuit to output the driving signal corresponding to the usable dimming range.

5. The lamp dimming control system according to claim 1, characterized in that: The control unit determines that the light-emitting element is turned off when the current corresponding to the current signal is lower than a low current value, and determines that the light-emitting element starts to flash when the current corresponding to the current signal starts to oscillate up and down.

6. A method for automatically determining a dimming range of a lamp, applied to a lamp dimming control system, the lamp dimming control system comprising a control unit, a drive circuit and a light-emitting element, the control unit being used to control the drive circuit to output a drive signal to make the light-emitting element emit light, characterized in that: The method for automatically determining the dimming range of a lamp comprises the following steps: (A) During the dimming detection period, the control unit controls the driving circuit to gradually reduce the periodic average voltage of the driving signal to adjust the light of the light-emitting element from bright to dark; (B) during the dimming detection period, the control unit detects the current of the light-emitting element, and records the critical dimming information when the current of the light-emitting element corresponds to the light-emitting element starting to flicker or turn off; (C) the control unit reduces the dimming range according to the critical dimming information to obtain dimming lower limit information corresponding to before the light emitting element starts to flicker or turn off; and (D) During normal operation, the control unit controls the driving circuit to output the driving signal that is not lower than the dimming range corresponding to the dimming lower limit information.

7. The method for automatically determining dimming range of a lamp according to claim 6, characterized in that: The driving circuit includes a driving switch controlled by the control unit to output the driving signal. The control unit controls the on-time of the driving switch so that the driving signal starts to be output after the on-time after zero and continues until the next zero. In step (A), the control unit controls the on-time of the driving switch so that the on-time is gradually delayed so that the periodic average voltage of the driving signal gradually decreases.

8. The method for automatically determining the dimming range of a lamp according to claim 7, characterized in that: The critical dimming information is related to the on-time of the driving switch or to the turn-on time.

9. The method for automatically determining dimming range of a lamp according to claim 7, characterized in that: In step (B), the control unit records the turn-on time when the light-emitting element starts to flash or turn off as the critical dimming information. In step (C), the control unit subtracts the adjustment value from the recorded turn-on time as the dimming lower limit information, and then uses the period corresponding to the calculated turn-on time as the usable dimming range. In step (D), the control unit controls the driving circuit to output the driving signal corresponding to the usable dimming range.

10. The method for automatically determining dimming range of a lamp according to claim 6, characterized in that: In step (B), the control unit determines that the light-emitting element is turned off when the current corresponding to the current signal is lower than a low current value, and determines that the light-emitting element starts to flash when the current corresponding to the current signal starts to oscillate up and down.

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