Maxim introduced the MAX1583 , a high-efficiency, step-up DC-DC converter that drives up to five white LEDs in series with a high constant current to provide camera flash/strobe power in cell phones, PDAs, and other handheld devices.
The MAX1583 integrates a 1MHz, 24V, step-up DC-DC converter and a high-voltage, low-dropout (LDO) current regulator. It operates from input voltages of 2.6V to 5.5V. Two logic inputs control four modes of operation: shutdown mode (0.5µA max); movie mode (programmable up to 100mA); precharge mode for charging a reservoir capacitor up to 24V while the LEDs are off; and strobe mode for firing the flash with a regulated current (programmable up to 300mA) during an exposure. The MAX1583 also features overvoltage and thermal shutdown protection.
The circuit is available in a space-saving 3 x 3mm, 10-pin TDFN package screened for the extended temperature range (-40°C to +85°C). It is available with three preset input-current limits, AX1583X (1A), MAX1583Y (500mA), and MAX1583Z (250mA). Prices start at $1.70 (1000-up, FOB USA). An evaluation kit is available to speed designs.
Maxim Integrated Products Ltd , Theale, Berks RG7 4XX, UK.