1, LED drive power supply is to convert the power supply into a specific voltage and current to drive LED light power converter, usually LED drive power input includes high voltage frequency AC (i.e. mains), low voltage DC, high voltage DC, low voltage high frequency AC (such as electronic transformer output).
2, LED to constant current power supply, otherwise easy to aging damage. You can use LM317, the principle is to use 317 probe control voltage unchanged, and then divide the resistance, is the constant current value. circuitAs shown below. Lights can be connected as many as needed. Change R1 to change the current, current =25/R1. Let me know if you need more.
3, the constant current drive power supply through the current feedback circuit, control the size of the output current, to ensure that the brightness of the LED lamp is stable. The current adjustment module is used to adjust the brightness of the LED lamp. The brightness of the LED lamp is related to the size of the current, so the current adjustment module can adjust the brightness of the LED lamp by changing the size of the output current.
4. Non-isolated constant current power supply: Non-isolated means that there is a direct connection between the load end and the input end, so the touch is negativeMeasures such as conventional transformers, simple resistance-capacitance buck and other methods will reduce the high voltage to the low voltage you need.
4, the most widely used non-isolated direct step-down power supply. That is, after the AC is rectified, the DC high voltage is obtained, and then the Buck circuit is directly used for buck and constant current control.
1, LED driver power supply is to convert the power supply into a specific voltage and current to drive LED light power converter, usuallyThe input of the LED driver power supply includes high-voltage power frequency AC (i.e. mains), low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as the output of electronic transformers).
2,. Non-isolated constant current power supply: Non-isolated means that there is a direct connection between the load and the input end, so there is a risk of electric shock when touching the load. At present, the most used non-isolated direct step-down power supply. That is, after the AC is rectified, the DC high voltage is obtained, and then the Buck circuit is directly used for buck and constant current control.
3, usually, the typical working current of 1W high-power LED is 350mA, if the RFB is equal to 1 ohms, the power consumption of the RFB is: PRFB=I2*R=0.352*1=0.12W (4) Considering the power consumption of the operational amplifier itself, the power consumption of the RFB and its affiliated circuits is about 12% of the power of the 1W LED.
4, LED is the light source, the normal working voltage is generally 3V, 30mA, the current limiting resistor each LED, and LED in series, used to limit the LED current, so that the maximum current of the LED is 30mA, the switch is generally three, the first gear is stopped, the second gear is the general light, the third gear is full bright.
5, mainly the role of lightning protection. L1 is a common mode inductor, EMI element. Figure 2 is a simple PFC correction circuit that can increase the PF value of the power supply and is also part of the EMI circuit, the rectifier filter circuit! From the design of this circuit, it may be an export product, and the domestic LED power supply rarely has such a good treatment.
6, before replacing the power supply, first confirm whether the LED light board is common positive, if it is also common, you can use a multimeter resistance to measure whether the positive input of the two groups of LED light source is connected (red circle position in the figure below). Such asIf the result is similar, it can be replaced.
1, multimeter 3 is the DC voltage after resistance and capacitance step-down rectification, Table 2 is the reference voltage of TL431, Table 1 is the current flowing through the LED.
2, this is a simple amplifier circuit, parts according to the drawing on the line. 2K is for resistanceThat is, there are three resistors with resistance values of 2 thousand ohm and 1 thousand ohm respectively. The * indicates that the resistance value is determined during debugging, and a 470K fine tuning resistor is available.
3, so V2 base is approximately grounded, so V2 is cut off. At this time, LED1 is on and LED2 is off. When C1 is charged, the base of V2 is flat, so it is on, the LED is lit, and the charge on C1 is discharged, V1 is cut off, and LED1 is extinguished. C2 is charged through R2, V1 is charged, and then the power line is so cycled, all two leds flash alternately.
4. U31 is the switching power management chip.Functions are divided into voltage sampling, RC shock, overcurrent detection protection, PWM drive and other functions. T41 for you N channel power switch MOSFET, it will drive transformer B.
5, because the negative electrode of the 12V power supply is not directly grounded, but through a diode D6 into the ground. So the blue part of the line is more negative than the ground. Figure: The red arrow is the circuit when charging. The green arrows are AC powered circuits. Orange is the battery-operated circuit.
1, LED drive power supply is to convert the power supply into a specific voltage and current to drive LED light power converter, usually LED drive power input includes high voltage frequency AC (i.e. mains), low voltage DC, high voltage DC, low voltage high frequency AC (such as electronic transformer output).
2, if you are directly in parallel, the voltage at both ends of each diode is the same, it is likely that some led current will be larger than other led, and even a led will burn due to too much current. R1 in the circuit diagram, according toYour current choice, but not too small, R7 can be directly connected to the jumper.
3, using mains power to drive high-power LED also needs to solve the problem of buck, isolation, PFC (power factor correction) and constant current, but also need to have a high conversion efficiency.
4, this paper will introduce the production method of LED driver circuit, including LED brightness and current calculation, PNP triode driver, chip signal connection, MCU board purchase and other content.
5, PWM dimming circuit by changing the PWM signal duty cycle to change the size of the output current, fromThe dimming function of LED lamp is realized. The protection module is used to protect the LED street driver circuit and the safe operation of the LED lamp. Common protection modules include overvoltage protection, overcurrent protection and short circuit protection.