Ultra-small xenon photoflash driver ICs

Size and cost are minimised through a high level of integration within the confines of a tiny (2 x 2 mm) DFN package. Battery life is extended by using primary-side voltage sensing to remove the need for a secondary-side voltage divider and associated leakage current, and the devices also feature very low supply current in both shutdown and standby mode.

The A8732 and A8735 are optimised for use in mobile devices using single-cell lithium batteries, and achieve more than 75% efficiency using zero-voltage switching for lower losses. Capacitor charging is provided by an IGBT driver, while an integrated 50 V DMOS switch offers self-clamping protection.

The switch current limit in the A8732 can be programmed from 0.45 to 1.5 A in 16 steps via a single wire interface, while the current limit for the A8735 is fixed at the popular setting of 1 A. The integrated IGBT driver incorporates internal gate resistors for minimum external component count. The charge and trigger voltage logic thresholds are set at 1 VHI (min) to support mobile-phone applications implementing low-voltage control logic.