Fairchild Semiconductor’s LED Backlight Boost Switches Reduce Power Losses, Minimize Sub-Harmonic Oscillation In High-Power LED Applications

Designers of high-power LEDs are challenged with preventing power losses and sub-harmonic oscillations associated with inefficient discontinuous conduction mode (DCM) boost converters. Fairchild Semiconductor’s (NYSE: FCS) FAN7340 and FAN73402 single-channel boost controllers with integrated high-voltage dimming MOSFETs address these challenges by helping designers achieve greater efficiency, performance and better reliability in high-power lighting applications such as LED backlighting for 3D televisions and monitors.

These backlight driving boost switches use a current-mode control topology with programmable slope compensation to prevent sub-harmonic oscillation. Designed with an internal dimming and analog pulse-width modulation (PWM), these devices overcome the short falls of a DCM boost converter by achieving a fast PWM dimming response.

Both devices offer integrated protection features such as under-voltage lockout, open LED protection, and over-voltage protection that help to minimize component count. Additionally, these devices provide error prevention by generating a FAULT signal with delay if an abnormal LED string condition occurs.

Features and Benefits:

• FAN7340: R _DS(ON) = 3.4Ω at V _GS = 10V, BV _DSS = 400V
• FAN73402: R _{DS(ON) =} 1.0Ω at V _GS = 10V, BV _DSS = 200V
• Wide-supply voltage range: 10V to 35V
• Cycle-by-cycle current limiting
• Internal soft-start prevents in-rush current flowing into output capacitor at startup
• Programmable switching frequency

Packaging and Pricing Information (in US 1,000 quantity pieces)

Samples available upon request - Delivery 8-12 weeks ARO

• Both available in a 16-lead SOIC package the FAN7340 is priced at $0.85 and the FAN73402 is priced at $1.06

Fairchild enables engineers to drive innovation in their designs by developing solutions like the FAN7340 and FAN73402. The company offers a broad portfolio of full range power semiconductor devices that cover high-, mid-, and low-power ranges to help designers maximize energy savings in virtually every power-sensitive application.

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