Светлый угол - светодиоды

ivdor писал(а):Что на 6-ногой детальке написано ?

За это сообщение автора Invisible_Light поблагодарил:

jml 2999 (16 июл 2015, 08:47)

большой писал(а):Скотч алюминиевый бывает до 200микрон, самый ходовой 45микрон

jml 2999 писал(а):

ivdor писал(а):Что на 6-ногой детальке написано ?

LEDA
1410

Preliminary

Outline
QX9920 is a high efficiency, stable and reliable high power LED lamp driver control IC, built-in high-precision comparator, off-time control circuit, the current driving control circuit, particularly suitable for high power, high brightness multiple LED strings constant-current drive.
QX9920 uses a fixed off-time control work, the operating frequency up to 2.5MHz, allows external inductors and filter capacitors, size reduction, efficiency.
In addition PWM signal EN pin adjustable LED light brightness.
By adjusting the external resistor to control high-brightness LED Lamp drive current, the LED lamp brightness to achieve the desired constant light level, through the high brightness LED lamp current from a few milliamperes to 1 Ampere.
• Property programmable LED drive current programmed range of 10mA to 1A
• High efficiency: 90%
• Input voltage range: 2.5V ~ 24V
• Operating frequency is adjustable: 500KHz ~ 2.5MHz
• driven LED lights feature strong:
LED light string can be from 1 to hundreds of high-brightness LED lights
• PWM adjustable brightness: adjust LED lamp brightness through EN pin,
• SOT-23-6 package
Applications
• 12V / 24V car power LED lights cup
• RGB large display screen high-brightness LED lights
• flat panel display LED backlight
• traffic warning LED lights
• common constant current source

Internal Block Diagram
LED driver control IC QX9920

Circuit work

QX9920 uses peak current control mode and fixed off-time detection circuit in the switch turns on and off the two states:
1. Conducting state: see block circuit diagram, MOS switch is in an ON state, the input voltage Vin through the inductor L, LEDs, MOS switch, the inductor current sense resistor Rcs charges inductor L. charging current increases with time, when the inductor current reaches 250mV / Rcs, QX9920 comparator output high and triggers the RS flip-flop thereby turning off the MOS switch.
2. Off state: MOS switch is in the off state, the inductor through the loop by the LEDs, diode D and inductor L itself composed of LEDs discharge, MOS switch after a fixed time Toff, turns back to the conduction state and repeatedly turns on and off course.
Fixed off-time Toff can be calculated from Roff and Coff setting:
    Roff•100KOhm
Toff = ──────── • 0.51 • (Coff+12pF)
    Roff+100KOhm

If you do not add Roff and Coff, QX9920 inside the off-time is set to:
Toff=612ns

LEDs current is set by the Rcs:
   250mV
Iled = ───
   Rcs

За это сообщение автора mnashe поблагодарил:

jml 2999 (16 июл 2015, 08:47)

За это сообщение автора ivdor поблагодарили: 2

jml 2999 (16 июл 2015, 08:47) • mnashe (16 июл 2015, 11:09)

ivdor писал(а):и нет речи про ШИМ. Рулиться-то будет, но вот частота шим-диммирования под вопросом.

За это сообщение автора ivdor поблагодарил:

mnashe (17 июл 2015, 04:13)