Small, High-Efficiency, Five-Channel Digital Still Camera Power Supply

The MAX1565 provides a complete power-supply solution for digital still and video cameras through the integration of ultra-high-efficiency step-up/step-down DC-to-DC converters along with three auxiliary step-up controllers. The MAX1565 is targeted for applications that use either 2 or 3 alkaline or NiMH batteries as well as those using a single lithium-ion (Li+) battery.

The step-up DC-to-DC converter accepts inputs from 0.7V to 5.5V and regulates a resistor-adjustable output from 2.7V to 5.5V. It uses internal MOSFETs to achieve 95% efficiency. Adjustable operating frequency facilitates design for optimum size, cost, and efficiency.

The step-down DC-to-DC converter can produce output voltages as low as 1.25V and also utilizes internal MOSFETs to achieve 95% efficiency. An internal soft-start ramp minimizes surge current from the battery. The converter can operate from the step-up output providing buck-boost capability with up to 90% compound efficiency, or it can run directly from the battery if buck- boost operation is not needed.

The MAX1565 features auxiliary step-up controllers that power CCD, LCD, motor actuator, and backlight circuits. The device also features low-cost expandability by supplying power, an oscillator signal, and a reference to the MAX1801 SOT23 slave controller that supports step-up, SEPIC, and flyback configurations. The MAX1565 is available in a space-saving 32-pin thin QFN package.

Applications

* Digital Still Cameras * Digital Video Cameras * PDAs

* Step-Up DC-to-DC Converter

* 95% Efficient

* 3.3V (Fixed) or 2.7V to 5.5V (Adjustable) Output Voltage

* Step-Down DC-to-DC Converter

* Operate from Battery for 95% Efficient Buck

* Combine with Step-Up for 90% Efficient Buck-

Boost

* Adjustable Output Down to 1.25V

* Three Auxiliary PWM Controllers

* Up to 1MHz Operating Frequency

* 1µA Shutdown Mode

* Internal Soft-Start Control

* Overload Protection

* Compact 32-Pin, 5mm x 5mm Thin QFN Package