Light sensing driving circuit and lamp

Abstract

The present invention belongs to the field of lighting technology, and provides a light sensing driving circuit and a lamp. The light sensing driving circuit is connected to an LED module, and includes a filter and rectifier module, a power module, a light sensing module, a sampling module, a main control module, and a driving module. The filter and rectifier module generates a rectified voltage according to the mains; the power module generates a power supply voltage according to the rectified voltage; the light sensing module generates a light sensing signal according to the ambient light intensity and the power supply voltage; the sampling module generates a sampling signal according to the rectified voltage; the main control module generates a control signal with a preset duty cycle according to the light sensing signal and the sampling signal when the control signal turns off the driving module; the driving module generates a driving voltage according to the control signal and the rectified voltage to drive the internal LED module to emit light.

Description

Technical Field

[0001] The present invention belongs to the field of lighting technology, and in particular relates to a light sensing driving circuit and a lamp. Background Art

[0002] At present, the mainstream market solution for visible light photosensitive lamps is to connect MOS tubes in series with the output light source. When the ambient light is bright, the MOS tube is turned off. At this time, the output voltage is OVP (Over Votage Protect) voltage, which is higher than the normal working voltage. When the environment becomes darker, the MOS tube is turned on. At this time, there will be a large impact current in the entire output circuit, and the circuit reliability is poor. In addition, visible light photosensitive lamps are easily affected by their own light source, and the light intensity detection is inaccurate.

[0003] Therefore, conventional visible light photosensitive lamps are easily affected by their own light emission and have poor circuit reliability. Summary of the invention

[0004] The object of the present invention is to provide a light-sensing driving circuit and a lamp, aiming to solve the problem that traditional visible light light-sensing lamps are easily affected by their own light emission and have poor circuit reliability.

[0005] A light sensing driving circuit is connected to an LED module, and the light sensing driving circuit comprises:

[0006] A filter and rectifier module for connecting to the mains and generating a rectified voltage according to the mains;

[0007] A power supply module connected to the filtering and rectifying module and used for generating a power supply voltage according to the rectified voltage;

[0008] A light sensing module connected to the power module and detecting the ambient light intensity according to the power supply voltage to generate a light sensing signal;

[0009] A sampling module connected to the filtering and rectifying module and used to generate a sampling signal according to the rectified voltage;

[0010] A main control module connected to the light sensing module and the sampling module, and used to generate a control signal with a preset duty cycle according to the light sensing signal and the sampling signal when the control signal turns off the driving module;

[0011] A driving module connected to the main control module and the filtering and rectifying module, and used for generating a driving voltage according to the control signal and the rectified voltage to drive the internal LED module to emit light.

[0012] In one embodiment, the driving module includes:

[0013] A first driving module connected to the main control module and the filtering and rectifying module, and configured to generate a driving voltage according to the control signal and the rectified voltage;

[0014] The LED module is connected to the first driving module and is used to emit light according to the driving voltage.

[0015] In one embodiment, the driving module includes:

[0016] The LED module connected to the filter and rectifier module and configured to emit light according to the rectified voltage;

[0017] A first switch module is connected to the LED module and is used to turn on or off the loop from the rectified voltage to the power ground according to a preset duty cycle based on the control signal.

[0018] In one embodiment, the driving module includes:

[0019] A second driving module connected to the main control module and the filtering and rectifying module, and configured to generate a driving voltage according to the control signal and the rectified voltage;

[0020] The LED module connected to the second driving module and configured to emit light according to the driving voltage;

[0021] A second switch module connected to the LED module and the control module, and configured to switch on or off the drive voltage according to a preset duty cycle based on the control signal.

[0022] In one embodiment, the first driving module includes: a first driving chip, a first inductor, a first diode and a first capacitor;

[0023] The drain end of the driving chip is connected to the first end of the first inductor, the second end of the first inductor is connected to the filtering and rectifying module through the first capacitor, the control end of the driving chip is the control signal input end of the driving module, the anode of the first diode is connected to the first end of the first inductor, the cathode of the first diode is the rectifier voltage input end of the driving module, the second end of the first inductor is connected to the cathode of the LED module, and the first inductor is connected to the anode of the LED module through the first capacitor.

[0024] In one embodiment, the first switch module includes: a first MOS tube;

[0025] The gate of the first MOS tube is the control signal input terminal of the first switch module, the drain of the first MOS tube is connected to the cathode of the LED module, and the source of the first MOS tube is grounded.

[0026] In one embodiment, the second driving module includes: a second driving chip, a second inductor, a second diode and a second capacitor;

[0027] The drain terminal of the second driving chip is connected to the first terminal of the second inductor, the second terminal of the second inductor is connected to the filtering and rectifying module through the second capacitor, the control terminal of the second driving chip is the control signal input terminal of the second driving module, the anode of the second diode is connected to the first terminal of the second inductor, the cathode of the second diode is the rectifier voltage input terminal of the second driving module, the second terminal of the second inductor is connected to the second switch module, and the second inductor is connected to the anode of the LED module through the second capacitor.

[0028] In one embodiment, the second switch module includes: a photoelectric isolation tube and a second MOS tube;

[0029] The positive electrode of the light emitter of the photoisolator is the control signal input end of the second switch module, the negative electrode of the light emitter of the photoisolator is grounded, the first end of the light receiver of the photoisolator is connected to a DC power supply, the second end of the light receiver of the photoisolator is connected to the gate of the second MOS tube, the drain of the second MOS tube is connected to the negative electrode of the LED module, and the negative electrode of the second MOS tube is grounded.

[0030] In one of the embodiments, the main control module includes: a main control chip;

[0031] The first input and output end of the main control chip is the sampling signal input end of the main control module, the second input and output end of the main control chip is the light sensing signal input end of the main control module, and the third input and output end of the main control chip is the control signal output end of the main control module.

[0032] In addition, a lamp is provided, which includes the above-mentioned light sensing driving circuit.

[0033] The above-mentioned light-sensing driving circuit converts the input mains into a rectified voltage through a filtering and rectifying module, and samples the rectified voltage through a sampling module, senses the ambient light intensity through the light-sensing module, and generates a light-sensing signal according to the ambient light intensity and the power supply voltage, and the main control module generates a control signal according to the light-sensing signal and the sampling signal, and controls the driving module to drive the LED module. When the environment becomes darker, the driving module adjusts the driving voltage according to the preset duty cycle of the control module. At this time, there will be no large impact current in the entire output circuit, thereby improving the circuit reliability; the sampling module ensures that each chopping point is at the same voltage point of the rectified voltage, so that the current waveform of each cycle will remain consistent, and there will be no visible flicker to the human eye, and when the control signal turns off the driving module, a control signal with a preset duty cycle is generated according to the light-sensing signal and the sampling signal, that is, the light-sensing signal is sampled and obtained when the LED module is off, eliminating the influence of its own light emission on ambient light detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a light sensing driving circuit provided by an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the structure of a light sensing driving circuit provided by another embodiment of the present invention;

[0036] Figure 3 A schematic diagram of the structure of a light sensing driving circuit provided by yet another embodiment of the present invention;

[0037] Figure 4 A schematic diagram of the structure of a light sensing driving circuit provided by another embodiment of the present invention;

[0038] Figure 5 for Figure 2 An example circuit schematic diagram of a light sensing driving circuit is shown;

[0039] Figure 6 for Figure 3 An example circuit schematic diagram of a light sensing driving circuit is shown;

[0040] Figure 7 for Figure 4 An example circuit schematic diagram of a light sensing driving circuit is shown. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] like Figure 1 and Figure 2As shown, the light sensing driving circuit includes: a filter and rectifier module 10, a power module 20, a light sensing module 30, a sampling module 40, a main control module 50 and a driving module 60. Among them, the filter and rectifier module 10 is used to connect to the mains and generate a rectified voltage according to the mains; the power module 20 is connected to the filter and rectifier module 10 and is used to generate a power supply voltage according to the rectified voltage; the light sensing module 30 is connected to the power module 20 and detects the ambient light intensity according to the power supply voltage to generate a light sensing signal; the sampling module 40 is connected to the filter and rectifier module 10 and is used to generate a sampling signal according to the rectified voltage; the main control module 50 is connected to the light sensing module 30 and the sampling module 40 and is used to generate a control signal with a preset duty cycle according to the light sensing signal and the sampling signal when the control signal turns off the driving module 60; the driving module 60 is connected to the main control module 50 and the filter and rectifier module 10 and is used to generate a driving voltage according to the control signal and the rectified voltage to drive the internal LED module 61 to emit light.

[0043] In this embodiment, the input mains is converted into a rectified voltage by the filter rectifier module 10, and the rectified voltage is sampled by the sampling module 40, the ambient light intensity is sensed by the light sensing module 30, and a light sensing signal is generated according to the ambient light intensity and the power supply voltage, and a control signal with a preset duty cycle is generated according to the light sensing signal and the sampling signal when the control signal turns off the driving module 60, that is, the light sensing signal is sampled and obtained when the LED module 61 is off, eliminating the influence of the self-luminescence on the ambient light detection. And when the environment becomes dark, the driving module 60 adjusts the driving voltage according to the preset duty cycle of the control module, and at this time, there will be no large impact current in the entire output circuit, thereby improving the circuit reliability. In a specific implementation, the control signal and the sampling signal are in phase. The sampling module 40 ensures that each chopping point is at the same voltage point of the rectified voltage, and the control signal and the sampling signal are in phase, so that the current waveform of each cycle will remain consistent, and no visible stroboscopic light will occur.

[0044] In one embodiment, the driving module 60 includes: a first driving module 62 and an LED module 61; the first driving module 62 is connected to the main control module 50 and the filter rectifier module 10, and is used to generate a driving voltage according to the control signal and the rectified voltage; the LED module 61 is connected to the first driving module 62, and is used to emit light according to the driving voltage.

[0045] In one embodiment, the first driving module 62 includes: a first driving chip U1, a first inductor L1, a first diode D1 and a first capacitor C1; the drain end of the first driving chip U1 is connected to the first end of the first inductor L1, the second end of the first inductor L1 is connected to the filtering and rectifying module 10 through the first capacitor C1, the control end of the first driving chip U1 is the control signal input end of the first driving module 62, the anode of the first diode D1 is connected to the first end of the first inductor L1, the cathode of the first diode D1 is the rectified voltage input end of the first driving module 62, the second end of the first inductor L1 is connected to the cathode of the LED module 61, and the first inductor L1 is connected to the anode of the LED module 61 through the first capacitor C1.

[0046] The following circuit principle is combined with the attached Figure 3 For further explanation:

[0047] Step 1: The sampling module 40 is used to detect the rectified voltage, and generates a sampling signal TS1 by sampling through the first voltage-dividing resistor R2 and the second voltage-dividing resistor R3. When the sampling signal input terminal of the main control chip U2 detects that the voltage of the sampling signal TS1 drops to the first preset value (1.5V), the control signal output terminal of the main control chip U2 first outputs a low-level control signal for the first preset time of 2ms, at which time the LED module 61 is turned off, and then the control signal output terminal of the main control chip U2 outputs a high-level control signal, and the LED module 61 lights up. When the sampling signal input terminal of the main control chip U2 detects that the voltage of the sampling signal TS1 drops to 1.5V again, the control signal output terminal of the main control chip U2 outputs a low level for the first preset time of 2ms again, and the detection cycle is repeated.

[0048] Step 2: The light sensing module 30 is an ambient light brightness detection circuit. When the environment is brighter, the resistance of the photosensitive diode CDS1 is smaller, and the voltage at the second end of the photosensitive diode CDS1 is higher. When the voltage of TS2 at the light sensing signal input end of the main control chip U2 increases to be greater than the second preset voltage 3V, the control signal output end of the main control chip U2 outputs a low-level control signal, and the LED module 61 is turned off; when the environment is darker, the resistance of the photosensitive diode CDS1 is larger, and the voltage at the second end of the photosensitive diode is higher. When the voltage of TS2 at the light sensing signal input end of the main control chip U2 decreases to be less than the third preset voltage 0.7V, the control signal output end of the main control chip U2 outputs a high-level control signal, and the LED module 61 is turned on.

[0049] Step 3: When the voltage of TS2 at the light sensing signal input terminal of the main control chip U2 drops to less than the third preset voltage 0.7V, execute step 1;

[0050] Step 4: When the voltage of the light sensing signal input terminal TS2 of the main control chip U2 rises to the second preset voltage 3V, the control signal output terminal of the main control chip U2 outputs a low-level control signal, and the LED module 61 is turned off.

[0051] Since the output current is chopped and has ripple, the TS1 detection in step 1 can ensure that each chopping point is at the same voltage point of the rectifier bridge BD1, so that the current waveform of each cycle will remain consistent and there will be no visible flicker to the human eye.

[0052] At the same time, in order to avoid detecting the self-light, the detection of the light sensing module 30 in step 2 is effective within the first preset time of 2ms, that is, after the LED module 61 is turned off, that is, when the control signal turns off the driving module 60, a control signal with a preset duty cycle is generated according to the light sensing signal and the sampling signal. The specific detection time is the first preset time 1.7-1.87ms. The detection starts at this time point, and the detection is not performed during the period of 0-1ms. In addition, the output first capacitor C1C1 in the driving module 60 uses a small-capacity film capacitor. When the control signal output end of the main control chip U2 outputs a low level of 2ms, the output current does not immediately drop to 0mA, but it can ensure that the current is reduced to 0mA within 1ms, and the detection is performed at the time point of 1.7-1.87ms, so that the detection of the self-light can be avoided and only the ambient light can be detected.

[0053] In one embodiment, the driving module 60 includes: an LED module 61 and a first switch module 63; the LED module 61 is connected to the filter and rectifier module 10, and is used to emit light according to the rectified voltage; the first switch module 63 is connected to the LED module 61, and is used to turn on or off the loop from the rectified voltage to the power ground according to a preset duty cycle according to a control signal.

[0054] In one embodiment, the first switch module 63 includes: a first MOS tube Q1; the gate of the first MOS tube Q1 is the control signal input terminal of the first switch module 63, the drain of the first MOS tube Q1 is connected to the cathode of the LED module 61, and the source of the first MOS tube Q1 is grounded. In this embodiment, since the LED module 61 in the driving module 60 is directly connected in series with the first MOS tube Q1, when the control signal output terminal of the main control chip U2 outputs a low-level control signal, the first MOS tube Q1 is turned off, the output current can be immediately reduced to 0mA, and the LED module 61 is immediately extinguished, so that the detection of self-light can be avoided and only the ambient light can be detected.

[0055] In one embodiment, the driving module 60 includes a second driving module 64, an LED module 61 and a second switch module 65; the second driving module 64 is connected to the main control module 50 and the filter rectifier module 10, and is used to generate a driving voltage according to the control signal and the rectified voltage; the LED module 61 is connected to the second driving module 64, and is used to emit light according to the driving voltage; the second switch module 65 is connected to the LED module 61 and the control module, and is used to turn on or off the driving voltage according to a preset duty cycle according to the control signal.

[0056] In one embodiment, the second driving module 64 includes a second driving chip U3, a second inductor L2, a second diode D2 and a second capacitor C2; the drain end of the second driving chip U3 is connected to the first end of the second inductor L2, the second end of the second inductor L2 is connected to the filtering and rectifying module 10 through the second capacitor C2, the control end of the second driving chip U3 is the control signal input end of the second driving module 64, the positive electrode of the second diode D2 is connected to the first end of the second inductor L2, the cathode of the second diode D2 is the rectifier voltage input end of the second driving module 64, the second end of the second inductor L2 is connected to the second switch module 65, and the second inductor L2 is connected to the positive electrode of the LED module 61 through the second capacitor C2.

[0057] In one embodiment, the second switch module 65 includes: a photoelectric isolator U4 and a second MOS tube Q2; the positive electrode of the light emitter of the photoelectric isolator U4 is the control signal input terminal of the second switch module 65, the negative electrode of the light emitter of the photoelectric isolator U4 is grounded, the first end of the light receiver of the photoelectric isolator U4 is connected to a DC power supply, the second end of the light receiver of the photoelectric isolator U4 is connected to the gate of the second MOS tube Q2, the drain of the second MOS tube Q2 is connected to the negative electrode of the LED module 61, and the negative electrode of the second MOS tube Q2 is grounded. In this embodiment, when the control signal output terminal of the main control chip U2 outputs a low-level control signal, the control signal is output through the photoelectric isolator U4, the second MOS tube Q2 is turned off, and the LED module 61 is immediately extinguished, so that the current can be immediately reduced to 0mA, so that the detection of self-light can be avoided, and only the ambient light can be detected, and there is no OVP problem in the output, and there will be no impact current.

[0058] In one embodiment, the filter rectifier module 10 includes a rectifier bridge BD1, a rectifier diode D3, and a filter capacitor EC1; the first input end of the rectifier bridge BD1 is connected to the live wire of the mains, the first input end of the rectifier bridge BD1 is connected to the neutral wire of the mains, the first output end of the rectifier bridge BD1 is grounded, the second output end of the rectifier bridge BD1 is connected to the positive electrode of the rectifier diode D3, the negative electrode of the rectifier diode D3 is the rectified voltage output end of the filter rectifier module 10, and the filter capacitor EC1 is connected between the negative electrode of the rectifier diode D3 and the ground. Specifically, the filter rectifier module 10 can convert the input 50 / 60HZ sinusoidal wave voltage into a 100 / 120HZ voltage waveform without a negative half cycle through the rectifier bridge BD1.

[0059] In one embodiment, the light sensing module 30 includes a photosensitive diode CDS1 and a voltage divider resistor R1; the first end of the photosensitive diode CDS1 is connected to the power module 20, the second end of the photosensitive diode CDS1 is grounded through the voltage divider resistor R1, and the second end of the voltage divider resistor R1 is the light sensing signal output end of the light sensing module 30.

[0060] In one embodiment, the sampling module 40 includes a first voltage-dividing resistor R2 and a second voltage-dividing resistor R3; the first voltage-dividing resistor R2 and the second voltage-dividing resistor R3 are connected in series between the filtering and rectifying module 10 and the ground, and the common connection end of the first voltage-dividing resistor R2 and the second voltage-dividing resistor R3 is the sampling signal output end of the sampling module 40.

[0061] In addition, based on the above-mentioned light-sensing driving circuit, the present invention further provides a lamp, which includes the above-mentioned light-sensing driving circuit.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A light sensing driving circuit, characterized in that: The light sensing driving circuit comprises: A filter and rectifier module for connecting to the mains and generating a rectified voltage according to the mains; A power supply module connected to the filtering and rectifying module and used for generating a power supply voltage according to the rectified voltage; A light sensing module connected to the power module and configured to detect the ambient light intensity according to the power supply voltage to generate a light sensing signal; A sampling module connected to the filtering and rectifying module and used to generate a sampling signal according to the rectified voltage; A main control module connected to the light sensing module and the sampling module, and used to generate a control signal with a preset duty cycle according to the light sensing signal and the sampling signal when the control signal turns off the driving module; A driving module connected to the main control module and the filtering and rectifying module, and used to generate a driving voltage according to the control signal and the rectified voltage to drive the internal LED module to emit light; The driving module comprises: A second driving module connected to the main control module and the filtering and rectifying module, and configured to generate a driving voltage according to the control signal and the rectified voltage; The LED module connected to the second driving module and configured to emit light according to the driving voltage; A second switch module connected to the LED module and the main control module, and configured to switch on or off the driving voltage according to a preset duty cycle based on the control signal; The second driving module includes: a second driving chip, a second inductor, a second diode and a second capacitor; The drain terminal of the second driving chip is connected to the first terminal of the second inductor, the second terminal of the second inductor is connected to the filtering and rectifying module through the second capacitor, the control terminal of the second driving chip is the control signal input terminal of the second driving module, the anode of the second diode is connected to the first terminal of the second inductor, the cathode of the second diode is the rectifier voltage input terminal of the second driving module, the second terminal of the second inductor is connected to the second switch module, and the second inductor is connected to the anode of the LED module through the second capacitor; The second switch module includes: a photoelectric isolation tube and a second MOS tube; The positive electrode of the light emitter of the photoisolator is the control signal input end of the second switch module, the negative electrode of the light emitter of the photoisolator is grounded, the first end of the light receiver of the photoisolator is connected to a DC power supply, the second end of the light receiver of the photoisolator is connected to the gate of the second MOS tube, the drain of the second MOS tube is connected to the negative electrode of the LED module, and the negative electrode of the second MOS tube is grounded.

2. The light sensing driving circuit according to claim 1, characterized in that: The main control module includes: a main control chip; The first input and output end of the main control chip is the sampling signal input end of the main control module, the second input and output end of the main control chip is the light sensing signal input end of the main control module, and the third input and output end of the main control chip is the control signal output end of the main control module.

3. A lamp, characterized in that: The lamp comprises the light sensing driving circuit as claimed in any one of claims 1 to 2.

Images