Product category: Power Supply ICs and Controllers
News Release from: Maxim Integrated Products | Subject: DS3991
Edited by the Electronicstalk Editorial Team on 03 April 2008
CCFL controller makes backlighting
simple
Supporting both push-pull and half-bridge drive schemes, the DS3991 converts a low-voltage DC supply to the high-voltage AC waveform required to power CCFLs.
The DS3991 from Maxim Integrated Products is a low-cost single-channel controller for CCFLs used to backlight liquid-crystal displays Supporting both push-pull and half-bridge drive schemes, this device converts a DC voltage (5 to 24V) to the high-voltage (300 to 1400V RMS) AC waveform that is required to power CCFLs
This article was originally published on Electronicstalk on 27 Aug 2002 at 8.00am (UK)
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These drive schemes use only a minimal number of external components, thus reducing component and assembly cost and making the design easy to implement.
Additionally, the push-pull drive scheme provides an efficient DC/AC conversion and produces near-sinusoidal waveforms.
Supporting both single- and multiple-lamp configurations, the DS3991 is ideal for backlighting LCD PC monitors and TVs.
The DS3991 drives two logic-level N-channel MOSFETs that are tied between a step-up transformer and a ground.
The transformer has a centre tap on the primary side that is connected to the DC supply.
The DS3991 alternately turns on the two MOSFETs to create the high-voltage AC waveform on the secondary side.
By varying the duration of the MOSFET turn-on times, the controller is able to accurately control the amount of current flowing through the CCFL lamp.
The DS3991 operates from a single, 4.5 to 5.5V supply voltage and is available in a 16-pin SO package.
Prices start at US $0.45 (1000-up).
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