In year 2007 and 2008, one of the most released IC among
power ICs is LED driver for high brightness LEDs. The LED
based lighting, which is set to overtake al the other lighting
options is driving this market. This short article is aimed
at helping you in selecting right LED driver.
The White light can be produced by either exclusive white
LEDs and through pair of RGB LEDs (getting white light by
mixing proportionally the Red, Green and Blue colors). A
RGB LED expands the range of visible light in comparison
to white LED.
Both white and other high-brightness RGB LEDs perform only
at a tightly regulated voltage and current, for any small
change in driving current the light output will suffer.
Also each LED vendor has different set of parameters prompting
design engineer to correct the circuit or change LED Driver.
The forward voltage and forward current are the key parameters
to be kept under control to get the max light output. Voltage
and current characters may vary even more differently when
LEDs are connected serially or parallel. The LED driver
should take care of such variations and drive constant voltage
and current to produce constant and maximum light. The temperature
will naturally change due to heat generated while producing
light. Keeping the relationship between voltage, current
and temperature for maximum light and enduring and ensuring
the life and safety of LED is the task of white LED lighting
system design engineer.
LED drivers can be buck type, boost type, buck/boost type,
and also charge-pump type.
Depending on the input voltage and output power the choice
can be made. For power line driven systems the buck type
is chosen, for single cell battery operated devices the
boost type is chosen, for the systems which run on both
powerline and battery the buck/boost is chosen. Charge pump
type is preferred when the output power is less and EMI
and other noise are issues.
Listed down below are the new LED drivers released recently
in the market for you to choose. Please note this list covers
leading vendors only and also not ranked by any parameter.
The latest technology feature trends in LED drivers are,
1. To drive LEDs both parallel and series configurations
and the capability to drive large number of LEDs
2. Built-in current matching
3. High power efficiencies > 90%
4. Multiple dimming interfaces
5. Low external component count
6. Extreme low current in shutdown mode of less than few
micro amps
7. Less space consuming packages such as MLP package, SC-70,
TSOT packages.
8. Wide input voltage range
9. Driven by multiple battery chemistries such as Li Ion,
NiMH, alkaline, and NiCd
10. Wide operating temperature range from -40°C to +125°C
11. Protection features such as over-temperature protection,
over-voltage protection, short circuit and open
circuit protection and detection (string and individual),
Under-voltage lockout (UVLO), Thermal shutdown.
12. The tight output voltage and current tolerance to keep
color and brightness of LED constant.
13. Automatically matching current to LEDs
14. Soft-start to reduce in-rush current
15. Wide current setting range - 31.25µA to 25mA
16. I2C interface to digitally control brightness and color
17. Inductor less feature in case of charge pumps
LED Driver IC list
| Vendor |
Part Number |
| Catalyst (merged with On Semi) |
CAT4201 |
| Fairchild |
FAN5606 |
| Micrel |
MIC2142 |
| Micrel |
MIC2287c |
| On Semi |
NCP3066 |
| On Semi |
NCP5623 |
| On Semi |
NCP5890 |
| On Semi |
NCP5008 |
| On Semi |
CAT4103 |
| On Semi |
CAT4109 |
| Semtech |
SC4538 |
| Semtech |
SC440 |
| Semtech |
SC619 |
| Semtech |
SC605 |
| Semtech |
SC620 |
| Maxim |
MAX6964 |
| Maxim |
MAX8822 |
| Advanced Analogic Tech |
AAT3104 |
| Advanced Analogic Tech |
AAT2830/31 |
| National Semiconductor |
LM340X |
| Advanced Analogic Tech |
AAT3195 |
| ROHM Electronics |
BD8113EFV-E2 |
| Catalyst (merged with On Semi) |
CAT3636 |
| Catalyst (merged with On Semi) |
CAT4134 |
| Linear Technology |
LTC3220/-1 |
| Intersil |
EL7630 |
| Intersil |
ISL97636 |
Few popular LED Manufacturers
1. Toshiba
2. American Bright
3. Cree, Inc.
4. Everlight
5. Lite-On, Inc.
6. Nichia Corporation
7. OSRAM Opto Semiconductors
8. Philips Lumileds
9. Seoul Semiconductor
10. Vishay
11. Avago Technologies
12. Panasonic
To read similiar article on HB white LEDs read "Brightest
White LEDs in the market".
