High PFC THD ODM Dimmable 4KV Anti-surge Linear LED Driver
Solutions Satisfied Certification Requirements
Features
Made of 500V high pressure process
External power MOS output current up to 350mA
Input AC voltage 110V/220V
With line voltage compensation
Support analog voltage dimming function
With VS pin is energy control
Support multiple sets of parallel use to increase output power
Support multi-segment series operation mode to improve PFC/THD
With temperature foldback -10% / °C function
Overvoltage (adjustable) protection
Support multi-segment series operation mode to improve PFC/THD
Each harmonic complies with IEC6100-3-2
Anti-surge 4KV or more
Start current protection
Low voltage start function
Package form SOP-8, SOT-89, TO-252
High-power downlights, bulbs, floodlights, LED lamps for
certification requirements
F Linear Series Chip Matching Selection Table
| NO. | P/N | Function&Features | MOSFET | I(mA) | LED VF value | Package |
| 1 | 3*F7112 | Full voltage lamps less than 15W, constant power, temperature
reentry | Internal | 60-100 | 126/126 | ESOP-8 |
| 2 | 3*F7110 | High power full voltage constant power high voltage linear scheme | External | 350 | 126/126 | ESOP-8 |
| 3 | F7110+F5111/2 | High-power linear solution that meets certification requirements | External | 350 | 252 | SOP-8+TO-252 |
| 4 | F7111/2+F2552 | Full voltage lamps less than 10W, no constant power, temperature
reentry | Internal | 60-100 | 126/126 | PDFN+ESOP+8 |
Product Specification
What is the Constant Power Design of LED Driver?
Driving LED by constant power mode has recently been a popular
topic. Why do LEDs must be driven by the constant current? Why not
with a constant power source?
Before discussing the above issue, we must understand why the LED
must be driven by a constant current. As shown in Figure (a) LED
I-V curve, when the LED forward voltage changed about 2.5%, the
current through the LED will correspondingly change about 16%, and
forward voltage of the LED is easily affected by junction
temperature. The change of high and low temperature may even make
the voltage change as high as 20% or more. The brightness of the
LED is proportional to the forward current of the LED. If the
current varies in big scale, so is the brightness. Therefore, LED
must be driven by a constant current source. However, can the LED
be driven by constant power? To further discuss this topic, first,
we should neglect whether constant power is equivalent to constant
brightness or not. Via I-V and temperature curve of LED, the design
of a constant power driver seems workable. If the answer is yes,
why do LED driver manufacturers not develop the constant power LED
driver? It is not difficult to design a driver with constant power
design as long as the implementation of the MCU ( Micro Controller
Unit ) is carried out in LED driver, which control output power
refers to the PWM ( Pulse Width Modulation )duty cycle.
In order to control PWM duty cycle, the microcontroller is in
charge of the calculation between feedback signals of the output
voltage and current and drives the output to refer to constant
power curve in blue of Figure (b), so that the constant power
output can be achieved. However, to manufacture a constant power
led driver not only cost a certain amount of money but also causing
another issue that the output current will increase due to the
damage of LED, which can further make the situation even worse. As
the LED is a negative temperature coefficient component, reducing
the output current to maintain the high life performance of the LED
is expected when the temperature is higher. Nevertheless, the
constant power method is in conflict with this consideration. The
constant power design LED driver will increase the output current
refer to lower output voltage for high-temperature application. In
sum, considering various factors, providing “ resemble constant
power” led driver with a wide range of output voltage and current
is the most effective solution.
The constant power LED drivers made by MEAN WELL are specially
designed, providing customers with a wide range of voltage and
current. To avoid unnecessary cost due to over-design, the misusage
because of LED’s characteristic, and causing damage to the lamps,
offering a wide range, resemble constant power is currently the
most sufficient solution.
