LED driver selection discussion
LED Spotlight 30W IC characteristics and selection
User question: LED driver must use a dedicated LED driver IC? What are the advantages and disadvantages compared with ordinary IC?
Re: the advantages of dedicated LED driver IC is Vin width, output current, high precision constant current, using the shaking frequency can effectively reduce the EMI.
The led power 50w with constant current source is to ensure that the light intensity of the LED in the light-emitting time, not blinking. Low-cost handsets LDO drive the LED backlight is also commonly used, but the utilization of power is not high, but fortunately most of mobile phone design lithium battery voltage drop caused by 3.3V shutdown. LED lighting drive is not a good way to use LDO, LDO not constant current.
User question: domestic and foreign LED driver IC and how should we choose?
Expert replies: LED driver IC, many, cost is not the same, the key to the design target price, such as seeking competitiveness and more profits, local IC products are also good.
LED drive power to select and design issues
User question: selection and design of the LED drive power to consider
Re: LED Light is the power supply is converted to a specific voltage and current to drive the LED light voltage converter is usually the case: the LED drive power input, including mains, low voltage DC high voltage direct current, low voltage high frequency AC. LED driver power supply output voltage can be changed with the change of the LED forward voltage drop value constant current source.
According to the rules of grid electricity and the characteristics of the LED drive power requirements, the selection and design of LED drive power to consider the following questions.
a high reliability, especially as the drive power of the LED lights installed in the high-altitude, inconvenient repairs and maintenance spend.
(b) the efficiency of high-efficiency power supply, the loss power, heat lamps, reduces the temperature rise of the lamps. Beneficial to delay the LED light failure.
c-driven approach is now common, there are two: one is a constant voltage source for the multiple constant current source, each constant current source separately to each LED power supply. Another is a direct constant current power supply, led driver 120w in series or parallel operation. How to select the startup mode according to actual needs. Multi-channel constant-current output power supply, in terms of cost and performance. May be a future direction of the mainstream.
(d) the ability of anti-surge surge protection LED is relatively poor, especially the anti-reverse voltage capability. Kai rejection grid load and the induction of lightning from the grid system will invade a variety of surge, some surge can cause damage to the LED. LED driver power supply have to inhibit the intrusion of the surge, the ability to protect the LED is not damaged.
(e) other elements, such as to improve the power factor; increase in the negative feedback function of LED Flood light 10W temperature; external protection aspects to be waterproof, moisture shell lightfast; drive power of life and the life of the LED adapter; to comply with safety regulations and electromagnetic compatibility requirements.