CN114071835A - Power failure detection circuit and LED lamp - Google Patents
Power failure detection circuit and LED lamp Download PDFInfo
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- CN114071835A CN114071835A CN202010761879.7A CN202010761879A CN114071835A CN 114071835 A CN114071835 A CN 114071835A CN 202010761879 A CN202010761879 A CN 202010761879A CN 114071835 A CN114071835 A CN 114071835A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- H—ELECTRICITY
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- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
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- H05B45/10—Controlling the intensity of the light
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Abstract
The application belongs to the technical field of lighting, and relates to a power failure detection circuit and an LED lamp, wherein a power supply signal adjusted by a silicon controlled light modulation switch circuit is rectified by a rectifying circuit to generate a rectified power supply signal; the constant current driving circuit generates a constant current driving signal and a power supply signal according to the rectified power supply signal and adjusts the constant current driving signal according to the driving control signal; the voltage sampling circuit detects the sampling power supply signal to generate a voltage sampling signal; the control circuit compares the voltage sampling signal with a preset reference signal to generate a driving control signal; the power failure detection point is changed from the front of the rectifying circuit or the back of the rectifying circuit or a driven post-stage circuit into the auxiliary power supply end of the constant-current driving circuit, so that power supply signals are detected and sampled, short-time low power failure caused by a low conduction angle during phase-cut dimming of the silicon controlled rectifier can be compensated, power failure misdetection of the silicon controlled rectifier during the low conduction angle is avoided, and the stability and reliability of the lighting load compatible with silicon controlled rectifier dimming are improved.
Description
Technical Field
The application belongs to the technical field of lighting, and particularly relates to a power failure detection circuit and an LED lamp.
Background
Thyristors, also called thyristors (thyristors), are active switching elements which are normally kept in a non-conducting state until triggered by a small control signal or "fired" to make them conductive, and once fired they are kept in a conducting state even if the trigger signal is removed, a reverse voltage is applied between their anodes and cathodes or the current through the Thyristor diode is reduced below a certain value to make it non-conductive. Because the silicon controlled rectifier has the functions of current transformation/rectification, voltage regulation, frequency conversion, switching and the like, the silicon controlled rectifier has wide application in the aspects of automatic control, the electromechanical field, industrial electricity, household appliances and the like, and particularly, the used light modulator is a silicon controlled rectifier light modulator in European and American areas. The silicon controlled rectifier dimming is also the most extensive dimming mode currently applied to LED dimming, and has the advantages of high adjusting precision and efficiency, small volume, light weight, easy remote control and the like. The silicon controlled rectifier dimming realizes voltage regulation or dimming through a phase control method, belongs to one of alternating current trigger circuits, utilizes an RC (resistance-capacitance) loop in a silicon controlled rectifier dimming circuit to control the phase of a silicon controlled rectifier trigger signal, and when the R value is smaller, the RC time constant is smaller, the phase shift of the trigger signal is smaller, the conduction angle of the corresponding silicon controlled rectifier is larger, and the electric power obtained by a load is larger; when the R value is larger, the RC time constant is larger, the phase shift of the trigger signal is larger, the conduction angle of the corresponding silicon controlled rectifier is smaller, and the electric power obtained by the load is smaller. In the lighting power supply scheme, when the power failure of a circuit needs to be detected, the traditional power failure detection scheme is to detect and acquire a power failure signal in a front circuit, a rear circuit or a secondary circuit of a rectifier bridge, and perform corresponding power failure actions after logic processing in a chip. For the compatible silicon controlled dimming lighting circuit, the power failure detection scheme is easy to cause power failure false detection when the silicon controlled rectifier is in a small conduction angle state, namely the conduction angle of the silicon controlled rectifier is smaller than or equal to a certain value.
Therefore, the problem that power failure detection logic is abnormal when the controlled silicon is in a low-power state with a small conduction angle exists in the traditional technical scheme.
Disclosure of Invention
The application aims to provide a power failure detection circuit and an LED lamp, and aims to solve the problem that in the traditional technical scheme, when a thyristor is in a low-power state with a small conduction angle, power failure detection logic is abnormal.
The first aspect of the embodiment of the application provides a power failure detection circuit, is connected with silicon controlled rectifier dimmer switch circuit and lighting load, silicon controlled rectifier dimmer switch circuit is connected with power supply, power failure detection circuit includes:
the rectifying circuit is connected with the silicon controlled rectifier dimming switch circuit and is configured to rectify the power supply signal regulated by the silicon controlled rectifier dimming switch circuit to generate a rectified power supply signal;
the constant current driving circuit is connected with the rectifying circuit and the lighting load, is configured to generate a constant current driving signal and a power supply signal according to the rectifying power supply signal, and regulates the constant current driving signal according to a driving control signal;
the voltage sampling circuit is connected with the constant current driving circuit and is configured to detect and sample the power supply signal to generate the voltage sampling signal;
and the control circuit is connected with the voltage sampling circuit and the constant current driving circuit, is configured to compare the voltage sampling signal with a preset reference signal, and generates the driving control signal according to a comparison result.
In one embodiment, the power down detection circuit further includes:
and the alternating current-direct current voltage conversion circuit is connected with the rectifying circuit and the control circuit and is configured to perform voltage conversion processing on the rectified power supply signal so as to generate a first direct current.
In one embodiment, the power down detection circuit further includes:
the first photoelectric isolation circuit is connected with the voltage sampling circuit and the control circuit and is configured to perform photoelectric isolation processing on the voltage sampling signal to generate an isolated sampling signal;
the control circuit is specifically configured to compare the isolated sampling signal with the preset reference signal and generate the driving control signal according to a comparison result;
the second photoelectric isolation circuit is connected with the control circuit and the constant current driving circuit and is configured to carry out photoelectric isolation processing on the driving control signal so as to generate an isolated driving control signal;
the constant current drive circuit is specifically configured to regulate the constant current drive signal according to the power supply signal and the isolation drive control signal.
In one embodiment, the power-down detection circuit comprises a plurality of constant current driving circuits; each constant current driving circuit correspondingly drives one path of the lighting load.
In one embodiment, the power down detection circuit comprises a plurality of the voltage sampling circuits; the plurality of constant current driving circuits are connected with the plurality of voltage sampling circuits in a one-to-one correspondence mode.
In one embodiment, the driving control signal is one of a voltage signal and a pulse width modulation signal.
In one embodiment, the constant current driving circuit:
the voltage transformation unit is connected with the rectifying circuit and the lighting load and is configured to generate the constant current driving signal and the power supply signal according to the rectifying power supply signal;
and the constant current driving unit is connected with the rectifying circuit, the voltage transformation unit, the voltage sampling circuit and the control circuit and is configured to regulate the constant current driving signal according to the driving control signal.
In one embodiment, the constant current driving unit includes: the constant current driving circuit comprises a constant current driving chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first diode and a first capacitor; the enable end of the constant current driving chip is connected with the first end of the first resistor, the dimming configuration end of the constant current driving chip is connected with the first end of the second resistor, the real-time clock end of the constant current driving chip is connected with the first end of the third resistor, the second end of the first resistor, the two ends of the second resistor and the second end of the third resistor are connected with a power ground, the drain end of the constant current driving chip and the anode of the first diode are connected with the voltage transformation unit, the cathode of the first diode is connected with the first end of the sixth resistor, the second end of the sixth resistor is connected with the anode of the first diode, the first end of the fourth resistor and the first end of the first capacitor, the first end of the first capacitor is further connected with the voltage sampling circuit, and the second end of the fourth resistor, The first end of the fifth resistor and the overvoltage detection end of the constant current driving chip are connected with the second photoelectric isolation circuit, the cathode of the first diode and the high-voltage end of the constant current driving chip are connected with the rectifying circuit, and the second end of the fifth resistor, the second end of the first capacitor and the negative voltage end of the constant current driving chip are connected with a power ground.
In one embodiment, the control circuit comprises: a microprocessor; the first data input and output end of the microprocessor is connected with the first photoelectric isolation circuit, the second data input and output end of the microprocessor is connected with the second photoelectric isolation circuit, the power supply end of the microprocessor is connected with the first power supply end, and the grounding end of the microprocessor is connected with the power ground.
A second aspect of embodiments of the present application provides an LED lamp, which includes the power down detection circuit as described in any one of the above.
Compared with the prior art, the embodiment of the invention has the following beneficial effects: in the power failure detection circuit and the LED lamp, the power supply signal adjusted by the thyristor dimming switch circuit is rectified by the rectifier circuit to generate a rectified power supply signal; the constant current driving circuit generates a constant current driving signal and a power supply signal according to the rectified power supply signal and adjusts the constant current driving signal according to the driving control signal; the voltage sampling circuit detects the sampling power supply signal to generate a voltage sampling signal; the control circuit compares the voltage sampling signal with a preset reference signal and generates a driving control signal according to a comparison result; the power failure detection point is newly designed from the front of the rectifying circuit or the back of the rectifying circuit or a driven post-stage circuit to be an auxiliary power supply end, namely a power supply signal end, of the constant-current driving circuit, and the transient power failure caused by the low conduction angle of the silicon controlled rectifier when the silicon controlled rectifier is switched to be in phase for dimming is compensated by utilizing the energy storage discharge characteristic of the constant-current driving circuit, so that the power failure misdetection of the silicon controlled rectifier when the conduction angle is low is avoided, and the stability and reliability of driving lighting load to emit light in the lighting driving circuit compatible with silicon controlled rectifier dimming are improved.
Drawings
Fig. 1 is a schematic structural diagram of a power down detection circuit according to an embodiment of the present application;
fig. 2 is another schematic structural diagram of a power down detection circuit according to an embodiment of the present application;
fig. 3 is another schematic structural diagram of a power down detection circuit according to an embodiment of the present application;
fig. 4 is another schematic structural diagram of a power down detection circuit according to an embodiment of the present application;
fig. 5 is another schematic structural diagram of a power down detection circuit according to an embodiment of the present application;
fig. 6 is a schematic diagram of an example circuit of a power down detection circuit according to an embodiment of the present application.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
Fig. 1 shows a schematic structural diagram of a power down detection circuit provided in a first embodiment of the present application, and for convenience of description, only the parts related to this embodiment are shown, and details are as follows:
the utility model provides a power failure detection circuit, is connected with silicon controlled rectifier dimmer switch circuit 02 and lighting load 100, and silicon controlled rectifier dimmer switch circuit 02 is connected with power supply 01, and power failure detection circuit includes: a rectifier circuit 11, a constant current drive circuit 12, a voltage sampling circuit 13, and a control circuit 14.
A rectifier circuit 11 connected to the thyristor dimmer switch circuit 02 and configured to rectify the power supply signal adjusted by the thyristor dimmer switch circuit 02 to generate a rectified power supply signal; a constant current driving circuit 12 connected to the rectifying circuit 11 and the lighting load 100, configured to generate a constant current driving signal and a power supply signal according to the rectified power supply signal, and to adjust the constant current driving signal according to the driving control signal; a voltage sampling circuit 13 connected to the constant current driving circuit 12 and configured to detect the sampled power supply signal to generate a voltage sampling signal; and the control circuit 14 is connected with the voltage sampling circuit 13 and the constant current driving circuit 12, and is configured to compare the voltage sampling signal with a preset reference signal and generate a driving control signal according to the comparison result.
In a specific implementation, the power supply 01 may be an ac power supply, which provides ac power, for example, 220V or 110V ac power, and the triac dimmer circuit 02 is connected to the ac power supply, so as to adjust the current output to the subsequent circuit by adjusting the conduction angle of the triac. The rectifier circuit 11 rectifies the power supply signal adjusted by the thyristor dimmer switch circuit 02 to generate a rectified power supply signal, thereby converting the sine-wave power supply signal into a rectified power supply signal having a waveform without a negative half cycle. The constant current driving circuit 12 transforms the rectified power signal to generate a constant current driving signal and a power supply signal, the constant current driving signal is used for driving the lighting load 100 to emit light; the power supply signal is used for auxiliary power supply of the constant current driving circuit 12, and is also used for voltage detection and sampling of the voltage sampling circuit 13 to generate a voltage sampling signal. The control circuit 14 compares the voltage sampling signal with a preset reference signal and generates a driving control signal according to the comparison result, and the constant current driving circuit 12 further adjusts the constant current driving signal according to the driving control signal, thereby adjusting the constant current driving signal output to the lighting load 100.
Optionally, the preset reference signal is a preset voltage signal or a preset voltage change rate or a preset duration, for example, when the preset reference signal is the preset voltage signal, the control circuit 14 compares the voltage sampling signal with the preset voltage signal, and if the comparison result is consistent, the driving control signal is generated; if not, no driving control signal is generated, or a driving control signal of another level is generated, so as to correspondingly control the constant current driving circuit 12 to adjust the constant current driving signal. The power failure detection mode of judging whether power failure occurs or not by detecting the voltage of the power supply signal output by the power supply signal end of the constant current driving circuit 12 replaces the mode of detecting the power failure of the rectified power supply signal output after rectification or the power supply signal before rectification or the driving signal in the driving rear-stage circuit, and the energy storage discharge characteristic of the constant current driving circuit 12 is utilized, so that the short-time power failure (such as 0-2 s power failure) caused by false triggering of a switch or a low conduction angle of the silicon controlled rectifier can be effectively compensated, the problem of abnormal logic of power failure detection caused by false triggering of the silicon controlled rectifier or the switch is avoided, a stable and reliable constant current driving signal is output to drive the lighting load 100 to emit light, and the stable reliability of driving the lighting load to emit light in the lighting driving circuit compatible with silicon controlled rectifier dimming is improved.
Optionally, the constant current driving circuit 12 may be one or more of a voltage reduction circuit, a voltage boost circuit, and a flyback circuit, and may generate a constant current driving signal according to the rectified power signal to drive the lighting load 100 to emit light, and generate a power supply signal to assist in supplying power to the constant current driving circuit 12, where the power supply signal is used as a detection sampling object of the voltage sampling circuit 13.
The embodiment of the application is through will fall the power consumption check point from rectifier circuit front or behind the rectifier circuit or the later stage circuit innovation design of driven for constant current drive circuit's auxiliary power supply end (promptly power supply signal end), utilize constant current drive circuit's energy storage discharge characteristic, the short-term power consumption that the low conduction angle that the compensation silicon controlled rectifier cut phase dimming leads to, avoid the silicon controlled rectifier to fall the power consumption false detection when low conduction angle, the accurate reliability of falling the power consumption detection has been improved, the luminous stable reliability of drive lighting load among the lighting drive circuit of compatible silicon controlled rectifier dimming has been improved simultaneously.
Referring to fig. 2, in one embodiment, the constant current driving circuit 12 includes: a voltage transforming unit 121 and a constant current driving unit 122.
A voltage transformation unit 121 connected to the rectifying circuit 11 and the lighting load 100, and configured to generate a constant current driving signal and a power supply signal from the rectified power supply signal; the constant current driving unit 122 is connected to the rectifier circuit 11, the transformer unit 121, the voltage sampling circuit 13, and the control circuit 14, and is configured to adjust the constant current driving signal according to the driving control signal.
In specific implementation, optionally, the voltage transformation unit 121 includes a transformer, and performs voltage conversion on the rectified power supply signal through a primary winding and a secondary winding of the transformer to generate a constant current driving signal; the rectified power signal is voltage-converted by a primary winding and an auxiliary winding of the transformer to generate a power supply signal. The constant current driving unit 122 includes a constant current driving chip, and is capable of adjusting a rectified power signal on the primary winding of the transformer according to the driving control signal, so as to adjust a constant current driving signal output by the secondary winding of the transformer, so as to output a stable constant current driving signal, and stably and reliably drive the lighting load 100 to emit light.
Alternatively, the driving control signal is one of a voltage signal and a pulse width modulation signal (i.e., a PWM signal). The control circuit 14 generates a drive control signal according to the voltage sampling signal to control the constant current driving unit 122 to adjust the constant current drive signal output to the lighting load 100.
When the thyristor is in a low conduction angle state or the switch is triggered by mistake so that a short power failure (low power state) occurs, the energy storage and discharge characteristics of a primary winding and an auxiliary winding of the transformer are utilized, when the short power failure occurs, a power supply signal generated by electromagnetic induction of the auxiliary winding of the transformer does not disappear immediately, the voltage sampling circuit 13 detects a sampling power supply signal to generate a voltage sampling signal, the control circuit 14 performs operation, analysis, comparison and other processing on the voltage sampling signal to generate a driving control signal, namely, the voltage sampling signal is compared with a preset reference signal, and a driving control signal is generated according to a comparison result, so that the constant current driving unit 122 is controlled to adjust the constant current driving signal, and then a stable constant current driving signal is output to drive the lighting load 100 to emit light instead of stopping outputting the constant current driving signal; when the power failure time exceeds the time of releasing electric energy of the transformer winding, the voltage sampling circuit 13 cannot detect a power supply signal, so that the control circuit 14 can generate a driving control signal to enable the constant current driving unit 122 to control the voltage transformation unit 121 to stop outputting the constant current driving signal, when the short power failure occurs due to the fact that the controlled silicon is in a low conduction angle or the switch is triggered by mistake, a power failure instruction is started without judging that the circuit is powered down, the power failure detection and processing logic abnormality of the controlled silicon in the low conduction angle is avoided, and the accurate reliability of the power failure detection circuit is improved.
Referring to fig. 3, in one embodiment, the power down detection circuit includes a plurality of constant current driving circuits 12; each constant current driving circuit 12 drives one path of lighting load 100 correspondingly.
In a specific implementation, the number of the constant current driving circuits 12 in the optional power-down detection circuit is multiple. In specific application, according to lighting requirements, the output end of the rectifying circuit 11 is connected in parallel with a plurality of constant current driving circuits 12, for example, when there are two paths of lighting loads 100 including a main lighting load and an auxiliary small night light lighting load, two constant current driving circuits 12 are correspondingly connected in parallel, and constant current driving signals are respectively output to drive the main lighting load and the auxiliary small night light lighting load to emit light.
Optionally, the power-down detection circuit includes a plurality of voltage sampling circuits 13; the plurality of constant current driving circuits 12 are connected to the plurality of voltage sampling circuits 13 in a one-to-one correspondence.
In specific implementation, during power failure detection, a plurality of voltage sampling circuits 13 can be correspondingly arranged according to a plurality of constant current driving circuits, a plurality of voltage sampling signals are correspondingly generated by respectively detecting signals (namely power supply signals) of auxiliary power supply ends of a plurality of constant current driving control circuits 12 through the plurality of voltage sampling circuits 13, a plurality of driving control signals are correspondingly generated by processing the plurality of voltage sampling signals, such as operation, analysis, comparison and the like, so as to respectively and correspondingly control the plurality of constant current driving circuits 12 to regulate and output the constant current driving signals to a plurality of lighting loads 100, thereby realizing power failure detection of the whole lighting driving circuit, avoiding power failure misdetection caused by short power failure when a thyristor is at a low conduction angle or a switch is mistriggered, and improving the stability of lighting by driving the lighting loads.
Referring to fig. 4, in one embodiment, the power down detection circuit further includes: and an ac/dc voltage conversion circuit 15.
The ac/dc voltage conversion circuit 15 is connected to the rectifier circuit 11 and the control circuit 14, and configured to perform voltage conversion processing on the rectified power supply signal to generate a first dc power.
In specific implementation, the ac/dc voltage conversion circuit 15 performs ac/dc voltage conversion and voltage stabilization on the rectified power signal output after rectification, and outputs a first dc voltage with a constant voltage to power the control circuit 14, so as to meet the power demand of the control circuit 14.
Optionally, the first direct current may also be output by a direct current power supply, for example, the first direct current may be provided by a battery power supply; or the voltage conversion circuit performs voltage conversion, voltage stabilization and other processing on the power supply signal to generate the power supply signal.
Referring to fig. 5, in one embodiment, the power down detection circuit further includes: a first opto-isolation circuit 16 and a second opto-isolation circuit 17.
The first photoelectric isolation circuit 16 is connected with the voltage sampling circuit 13 and the control circuit 14 and is configured to perform photoelectric isolation processing on the voltage sampling signal to generate an isolated sampling signal; a second photoelectric isolation circuit 17 connected to the control circuit 14 and the constant current driving circuit 12, and configured to perform photoelectric isolation processing on the driving control signal to generate an isolated driving control signal; the control circuit 14 is specifically configured to compare the isolated sampling signal with a preset reference signal, and generate a driving control signal according to the comparison result; the constant current drive circuit 12 is specifically configured to regulate the constant current drive signal according to the isolation drive control signal.
In specific implementation, the voltage sampling signal can be subjected to photoelectric coupling isolation processing through the first photoelectric isolation circuit 16, the driving control signal can be subjected to photoelectric isolation processing through the second photoelectric isolation circuit 17, and in the driving circuit of the lighting load 100, the optical signal and the electric signal are not interfered with each other and work respectively, so that respective normal work of a power supply and a light source is ensured, the electric insulation capacity and the interference prevention capacity of the circuit are improved, the circuit and a wire are effectively protected, and the safety and reliability of a power failure detection circuit are improved.
Optionally, when the power down detection circuit includes a plurality of constant current driving circuits 12 and a plurality of voltage sampling circuits 13, the power down detection circuit further includes a plurality of first photoelectric isolation circuits 16 and a plurality of second photoelectric isolation circuits 17. The plurality of first photoelectric isolation circuits 16 are connected with the plurality of voltage sampling circuits 13 in a one-to-one correspondence manner and are all connected with the control circuit 14; the plurality of second photoelectric isolation circuits 17 are all connected with the control circuit 14 and are connected with the plurality of constant current driving circuits 12 in a one-to-one correspondence manner; therefore, the photoelectric isolation processing is respectively carried out on the plurality of voltage sampling signals and the plurality of driving control signals, the electromagnetic interference in the power failure detection circuit is reduced, the safety and reliability of the power failure detection circuit are improved, and meanwhile, the anti-interference capability and the safety and reliability of the lighting and lighting driving circuit are also improved.
Referring to fig. 6, in one embodiment, the constant current driving unit 122 includes: the constant current driving circuit comprises a constant current driving chip U1, a first resistor R3, a second resistor R4, a third resistor R5, a fourth resistor R9, a fifth resistor R10, a first diode D9 and a first capacitor C5; wherein, the enable terminal CS of the constant current driving chip U1 is connected to the first terminal of the first resistor R3, the dimming configuration terminal Tonmax of the constant current driving chip U1 is connected to the first terminal of the second resistor R4, the real-time clock terminal RTC of the constant current driving chip U1 is connected to the first terminal of the third resistor R5, the second terminal of the first resistor R3, the two terminals of the second resistor R4 and the second terminal of the third resistor R5 are connected to the power ground, the DRAIN terminal DRAIN of the constant current driving chip U1 is connected to the transforming unit 121, the anode of the first diode D9, the first terminal of the fourth resistor R9 and the first terminal of the first capacitor C5 are connected to the transforming unit 121, the first terminal of the first capacitor C5 is further connected to the voltage sampling circuit 13, the second terminal of the fourth resistor R9, the first terminal of the fifth resistor R10 and the overvoltage detection terminal of the constant current driving chip U1 are connected to the second photoelectric isolation circuit 17, the cathode of the first diode HV rectifying circuit HV driving chip 68611, the second terminal of the fifth resistor R10, the second terminal of the first capacitor C5, and the negative voltage terminal VS of the constant current driver U1 are connected to ground.
In specific implementation, the high-voltage terminal HV of the constant current driving chip U1 is connected in series with the resistor R6 and then connected to the rectified power signal output by the rectifying circuit 11. The anode of the first diode D9, the first end of the fourth resistor R9, and the first end of the first capacitor C5 together constitute a power supply signal terminal of the constant current driving unit 122, and output a power supply signal (VCC1) to the voltage sampling circuit 13, so as to provide the voltage sampling circuit 13 with voltage detection sampling. The overvoltage detection end OVP of the constant current driving chip U1 inputs an isolation driving control signal (OVP1) output after the optoelectronic coupling isolation processing, so that the constant current driving chip U1 adjusts the constant current driving signal output by the voltage transformation unit 121. Optionally, the isolated drive control signal (OVP1) is a voltage signal.
In one embodiment, the isolation driving control signal may also be a PWM signal, and the constant current driving chip U1 adjusts the constant current driving signal output by the voltage transforming unit 121 to the lighting load 100 according to the isolation driving control signal or the driving control signal in the form of the PWM signal.
In one embodiment, referring to fig. 6, the transforming unit 121 includes a transformer T1, the transformer T1 includes a primary winding Na1, a secondary winding Nb1, and an auxiliary winding Nc1, a constant current driving signal is generated and output from the secondary winding Nb1 of the transformer T1, and a power supply signal is generated and output from the auxiliary winding Nc1 of the transformer T1. The DRAIN terminal DRAIN of the constant current driving chip U1 is connected to the second terminal of the primary winding Na1 of the transformer T1, and the second terminal of the primary winding Na1 of the transformer T1 is the rectified power supply signal input terminal of the transforming unit 121.
In a specific implementation, the power supply signal generated from the auxiliary winding Nc1 of the transformer T1 may be output to the constant current driving unit 122 after reverse connection protection and current limiting protection are performed through the diode D8 and the resistor R11. The constant current driving chip U1 in the constant current driving unit 122 adjusts the voltage of the primary winding Na1 of the transformer T1 according to the driving control signal or the isolation driving control signal (OVP1), thereby adjusting the constant current driving signal output from the secondary winding Nb1 of the transformer T1.
The embodiment of the application changes the power-fail detection point from the front of the rectifier bridge or the rear-stage circuit of the drive into the auxiliary power supply end for detecting the constant-current drive chip U1, detects and samples power supply signals (such as VCC1 and VCC2), utilizes the energy storage discharge characteristic of the winding of the transformer T1, compensates the short power-fail caused by the low conduction angle when the thyristor is phase-cut and modulated, and can effectively avoid the power-fail misdetection of the thyristor when the conduction angle is low.
Referring to fig. 6, in one embodiment, the control circuit 14 includes: a microprocessor U3; the first data input/output end P1.3 of the microprocessor U3 is connected to the first optoelectronic isolation circuit 16, the second data input/output end P1.4 of the microprocessor U3 is connected to the second optoelectronic isolation circuit 17, the power supply end VDD of the microprocessor U3 is connected to the first power supply end, and the ground end GND of the microprocessor U3 is connected to the power ground.
In a specific implementation, the first power supply terminal outputs a first direct current VDD. The microprocessor U3 may be a Micro Controller Unit (MCU) or a single chip microcomputer with computing, analyzing and judging capabilities, and can perform processing such as computing, analyzing and comparing on the voltage sampling signal to generate the driving control signal.
In one embodiment, the lighting circuit includes two paths of lighting loads 100, where the first path of lighting load 100 is a main lighting LED (S1+ and S1-), and corresponds to the first constant current driving circuit 12; the second path of lighting load 100 is a small night light lighting LED (S2+ and S2-), and corresponds to the second constant current driving circuit 12, and the two constant current driving circuits 12 have the same structure and the same working principle. The voltage sampling circuit 13 includes sampling resistors, for example, the first voltage sampling circuit 13 employs a first sampling resistor R01, the second voltage sampling circuit 13 employs a second sampling resistor R02, the first voltage sampling circuit 12 outputs a power supply signal (VCC1) and the second voltage sampling circuit 12 outputs a power supply signal (VCC2) to be detected and sampled, the first voltage sampling signal and the second voltage sampling signal are generated correspondingly and respectively, and the first voltage sampling signal and the second voltage sampling signal are output to the first data input/output terminal P1.3 of the microprocessor U3 and the third data input/output terminal P1.2 of the microprocessor U3 through the first photoelectric isolation circuit 16 connected thereto. The microprocessor U3 generates a first driving control signal and a second driving control signal according to the first voltage sampling signal and the second voltage sampling signal, and outputs the first driving control signal and the second driving control signal to the corresponding second photoelectric isolation circuit 17 through a second data input/output end P1.4 of the microprocessor U3 and a fourth data input/output end P1.5 of the microprocessor U3, respectively, to perform photoelectric isolation processing, so as to output isolation driving control signals (OVP1 and OVP2) to the first constant current driving circuit 12 and the second constant current driving circuit 12, respectively, to adjust constant current driving signals output to the main illumination LEDs (S1+ and S1-) and the small night illumination LEDs (S2+ and S2-).
In a specific implementation, optionally, the voltage sampling circuit 13 further includes a diode, for example, the first voltage sampling circuit 13 further includes a diode D16, the second voltage sampling circuit 13 further includes a diode D17, and the diode D16 and the diode D17 can rectify, stabilize and prevent reverse connection of the power supply signals (VCC1 and VCC2), so that the stability and reliability of the power failure detection circuit are improved.
Referring to fig. 6, in one embodiment, the first photo-isolation circuit 16 includes a photo-coupler U5; the anode of the photocoupler U5 is connected with the voltage sampling circuit 13, the emitter of the photocoupler U5 is connected with the control circuit 14, and the cathode of the photocoupler U5 and the collector of the photocoupler U5 are connected with the power ground.
In specific implementation, a voltage sampling signal is input to an anode of the photoelectric coupler U5, and an isolated sampling signal is output from an emitter of the photoelectric coupler U5. Optionally, the circuit structure composition of the second photoelectric isolation circuit 17 is the same as the circuit structure composition of the first photoelectric isolation circuit 16.
In one embodiment, the power down detection circuit further includes: a filter circuit 18. And the filter circuit 18 is connected with the rectifying circuit 11 and the constant current driving circuit 12 and is configured to perform filtering and noise reduction processing on the rectified power supply signal so as to filter noise interference of the rectified power supply signal and improve the stability and reliability of the power failure detection circuit and the lighting load 100 for lighting.
In one embodiment, referring to fig. 6, the filter circuit 18 includes an inductor L1, a resistor R1, a capacitor C1, a capacitor C2, a capacitor C3, and a resistor R2; the first end of the inductor L1, the first end of the resistor R1, and the first end of the capacitor C1 are connected to the rectifying circuit 11, the second end of the inductor L1, the second end of the resistor R1, the first end of the capacitor C2, and the first end of the capacitor C3 are connected to the constant current driving circuit 12, the first end of the capacitor C1, the second end of the capacitor C2, and the second end of the resistor R2 are connected to the power ground, and the first end of the resistor R2 is connected to the second end of the capacitor C3. In a specific implementation, the rectifying circuit 11 is connected to the first end of the inductor L1, the first end of the resistor R1, and the first end of the capacitor C1 after being connected in series with the diode D4. The rectified power supply signal can be effectively filtered and denoised by the filter circuit 18, so that noise is suppressed and spike electromagnetic interference is prevented, and a smooth and stable rectified power supply signal is output to the constant current drive circuit 12. A diode D4 can be connected in series between the rectifying circuit 11 and the filter circuit 18 to prevent reverse connection or prevent the power components from being damaged due to reverse current flow.
A second aspect of the present application provides an LED lamp comprising a power down detection circuit as described above.
In specific implementation, the LED lamp can be applied to a lighting system with the thyristor light-adjusting switch circuit 02, and a user can perform on-off control and light adjustment on the LED lamp by adjusting the thyristor light-adjusting switch circuit 02.
The LED lamp can automatically compensate the short-time power failure (low-power state) caused by the low conduction angle during the phase-cut dimming of the silicon controlled rectifier, the problem of power failure misdetection of the silicon controlled rectifier during the low conduction angle is avoided, and the stability and the reliability of the LED lamp for illumination are high.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the functional units, modules and circuits described above are illustrated as being divided into different functional units, modules and circuits, and in practical applications, the functions may be divided into different functional units, modules and circuits according to different requirements, that is, the internal structure of the device may be divided into different functional units, modules or circuits to complete all or part of the functions described above. In the embodiments, each functional unit, module, and circuit may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units, modules and circuits are only used for distinguishing one from another, and are not used for limiting the protection scope of the present application.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. The utility model provides a power failure detection circuit, is connected with silicon controlled rectifier dimmer switch circuit and lighting load, silicon controlled rectifier dimmer switch circuit is connected with power supply, its characterized in that, power failure detection circuit includes:
the rectifying circuit is connected with the silicon controlled rectifier dimming switch circuit and is configured to rectify the power supply signal regulated by the silicon controlled rectifier dimming switch circuit to generate a rectified power supply signal;
the constant current driving circuit is connected with the rectifying circuit and the lighting load, is configured to generate a constant current driving signal and a power supply signal according to the rectifying power supply signal, and regulates the constant current driving signal according to a driving control signal;
the voltage sampling circuit is connected with the constant current driving circuit and is configured to detect and sample the power supply signal to generate a voltage sampling signal;
and the control circuit is connected with the voltage sampling circuit and the constant current driving circuit, is configured to compare the voltage sampling signal with a preset reference signal, and generates the driving control signal according to a comparison result.
2. The power down detection circuit of claim 1, further comprising:
and the alternating current-direct current voltage conversion circuit is connected with the rectifying circuit and the control circuit and is configured to perform voltage conversion processing on the rectified power supply signal so as to generate a first direct current.
3. The power down detection circuit of claim 1, further comprising:
the first photoelectric isolation circuit is connected with the voltage sampling circuit and the control circuit and is configured to perform photoelectric isolation processing on the voltage sampling signal to generate an isolated sampling signal;
the control circuit is specifically configured to compare the isolated sampling signal with the preset reference signal and generate the driving control signal according to a comparison result;
the second photoelectric isolation circuit is connected with the control circuit and the constant current driving circuit and is configured to carry out photoelectric isolation processing on the driving control signal so as to generate an isolated driving control signal;
the constant current drive circuit is specifically configured to regulate the constant current drive signal according to the isolation drive control signal.
4. The power-down detection circuit according to claim 1, wherein the power-down detection circuit includes a plurality of the constant current drive circuits; each constant current driving circuit correspondingly drives one path of the lighting load.
5. The power down detection circuit of claim 4, wherein the power down detection circuit comprises a plurality of the voltage sampling circuits; the plurality of constant current driving circuits are connected with the plurality of voltage sampling circuits in a one-to-one correspondence mode.
6. The power down detection circuit of claim 1, wherein the drive control signal is one of a voltage signal and a pulse width modulated signal.
7. The power-down detection circuit of claim 1, wherein the constant current drive circuit:
the voltage transformation unit is connected with the rectifying circuit and the lighting load and is configured to generate the constant current driving signal and the power supply signal according to the rectifying power supply signal;
and the constant current driving unit is connected with the rectifying circuit, the voltage transformation unit, the voltage sampling circuit and the control circuit and is configured to regulate the constant current driving signal according to the driving control signal.
8. The power down detection circuit of claim 7, wherein the constant current driving unit comprises: the constant current driving circuit comprises a constant current driving chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode and a first capacitor; wherein, the enable end of the constant current driving chip is connected with the first end of the first resistor, the dimming configuration end of the constant current driving chip is connected with the first end of the second resistor, the real-time clock end of the constant current driving chip is connected with the first end of the third resistor, the second end of the first resistor, the two ends of the second resistor and the second end of the third resistor are connected with the power ground, the drain end of the constant current driving chip, the anode of the first diode, the first end of the fourth resistor and the first end of the first capacitor are connected with the voltage transformation unit, the first end of the first capacitor is further connected with the voltage sampling circuit, the second end of the fourth resistor, the first end of the fifth resistor and the overvoltage detection end of the constant current driving chip are connected with the second photoelectric isolation circuit, the cathode of the first diode and the high voltage end of the constant current driving chip are connected with the rectification circuit, and the second end of the fifth resistor, the second end of the first capacitor and the negative voltage end of the constant current driving chip are connected with a power ground.
9. The power down detection circuit of claim 1, wherein the control circuit comprises: a microprocessor; the first data input and output end of the microprocessor is connected with the first photoelectric isolation circuit, the second data input and output end of the microprocessor is connected with the second photoelectric isolation circuit, the power supply end of the microprocessor is connected with the first power supply end, and the grounding end of the microprocessor is connected with the power ground.
10. An LED lamp comprising the power down detection circuit of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010761879.7A CN114071835A (en) | 2020-07-31 | 2020-07-31 | Power failure detection circuit and LED lamp |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010761879.7A CN114071835A (en) | 2020-07-31 | 2020-07-31 | Power failure detection circuit and LED lamp |
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| CN114071835A true CN114071835A (en) | 2022-02-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010761879.7A Pending CN114071835A (en) | 2020-07-31 | 2020-07-31 | Power failure detection circuit and LED lamp |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116055955A (en) * | 2023-01-10 | 2023-05-02 | 富满微电子集团股份有限公司 | Silencing circuit and chip |
-
2020
- 2020-07-31 CN CN202010761879.7A patent/CN114071835A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116055955A (en) * | 2023-01-10 | 2023-05-02 | 富满微电子集团股份有限公司 | Silencing circuit and chip |
| CN116055955B (en) * | 2023-01-10 | 2023-10-27 | 富满微电子集团股份有限公司 | Silencing circuit and chip |
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