LED backlight boost switches cut power losses

Fairchild Semiconductor's has rolled out its FAN7340 and FAN73402 single-channel boost controllers with integrated high-voltage dimming MOSFETs. According to the company, the devices address the challenges of power losses and sub-harmonic oscillations by helping designers achieve greater efficiency, performance and better reliability in high-power lighting applications such as LED backlighting for 3D TVs and monitors.

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

The FAN7340 features R_DS(ON) = 3.4Ω at V_GS = 10V, BV_DSS = 400V while the FAN73402 touts an R_DS(ON) = 1.0Ω at V_GS = 10V, BV_DSS = 200V. The devices also deliver wide-supply voltage range from 10-35V and supports cycle-by-cycle current limiting. In addition, the controllers offer internal soft-start that prevents in-rush current flowing into output capacitor at start-up and have programmable switching frequency.

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