Digital Camera Step-Up Power Supply

The MAX1800 provides a complete power-supply solution for digital still cameras and video cameras. The device integrates a high-efficiency main step-up DC-DC converter, three auxiliary step-up controllers, and an uncommitted gain block that drives an external P-channel MOSFET for a linear regulator. The MAX1800 is targeted for applications that use either two or three primary cells or a single lithium-ion (Li+) battery.

The main DC-DC converter accepts inputs from +0.7V to +5.5V and regulates a resistor-adjustable output from 2.7V to 5.5V. It uses an internal synchronous rectifier to regulate the output with 95% efficiency. An adjustable operating frequency facilitates designs for optimum size, cost, and efficiency.

The auxiliary step-up controllers can be used to power a digital camera's CCD, LCD, and backlight. The MAX1800 also features expandability by supplying power, oscillator signal, and reference to the MAX1801, a low-cost slave DC-DC controller that supports step-up, SEPIC, and fly-back configurations.

The MAX1800 is available in a space-saving 32-pin TQFP package (5mm x 5mm body), and the MAX1801 is available in an 8-pin SOT package. An evaluation kit (MAX1800EVKIT) featuring both devices is available to expedite designs.

Applications

* Digital Still Cameras * Digital Video Cameras * DVD Players * Handheld Devices * Internet Access Tablets * PDAs

* +0.7V to +5.5V Input Voltage Range

* Main DC-DC Converter

* 95% Efficiency

* +2.7V to +5.5V Adjustable Output Voltage

* 1.5A Load Current

* Uncommitted Gain Block for Linear Regulator

* Three Independent Auxiliary Step-Up Controllers

* Adjustable Maximum Duty Cycle

* Oscillator and Reference Outputs to Drive External Slave Controllers (MAX1801)

* Power-Ready Output

* Up to 1MHz Switching Frequency

* 1µA Supply Current in Shutdown Mode

* Internal Soft-Start Control

* Overload Protection for all DC-DC Converters

* Compact 32-Pin TQFP Package (5mm x 5mm body)