HB-LED-driver chip set provides dimming, PFC
Bill Schweber, EETimes -- EDN, December 15, 2011
A chip-set pair from On Semiconductor provides high-efficiency, HB (high-brightness)-LED drive and dimming. The multistage, resonant, half-bridge NCL30051 LED driver delivers a constant voltage to a step-down dc/dc converter/LED driver, such as the NCL30160. The device, which combines a critical-conduction mode, a PFC controller, and a half-bridge resonant controller with a built-in 600V driver, targets use in offline power supplies.
The NCL30051’s half-bridge stage operates
at a fixed frequency. You achieve regulation
by adjusting the PFC-stage output voltage.
The device integrates open feedback-loop
protection, plus PFC overvoltage- and
undervoltage-detection mechanisms, as well
as an adjustable-frequency
oscillator, which can be set at
frequencies as high as 75 kHz.The dimmable, constant-current, step-down buck NCL30160 LED driver for high-power LEDs steps down the voltage from the NCL30051-enabled power supply to provide a constant current across the LED string. It provides as much as 98% efficiency using an internal, 55-mΩ-on-resistance MOSFET, and it can operate at a 100% duty cycle.
The device operates with an input voltage of 6.3 to 40V, which suits it for use in industrial and automotive applications. Switching frequencies as high as 1.4 MHz allow the use of small external components, helping to minimize board size and cost.
The hysteretic control of the NCL30160 provides fast response during load transients and eliminates the need for small-signal control-loop-compensation components. Protection features include resistor-programmed LED current, shorted-LED protection, undervoltage lockout, and thermal shutdown.
Both the NCL30051 and the NCL30160 have operating-junction-temperature ranges of −40 to +125°C. The NCL30160 comes in an SOIC-8 package, and the NCL30051 comes in an SOIC-16 package.
On Semiconductor
Talkback
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Has anybody out there used the NCL30160? I made a prototype to drive 6 in series leds at 350ma. I'm getting about 220ma using component values calculated from the data sheet. Tech support at ON Semiconductor hasnt come up with an answer yet.If you've had success with this device, let me know. Thank you.
Michael Wils - 2012-10-4 17:19:38 PDT -
A link to the data sheet... that'd be nice.
onsemi.com /pub_link/Collateral/NCL30051-D.PDF
Thank you.
JJ Walker - 2011-22-12 12:36:46 PST
