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Digital Camera Step-Down Power Supply

Complete Power-Supply Solution for Digital Camera Delivers 5 Outputs from 2 Li+ or 4 AA Cells

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 2.5V to 11V Input Voltage Range
  • Main DC-DC Controller
    • 94% Efficiency
    • +2.7V to +5.5V Adjustable Output Voltage
    • Up to 100% Duty Cycle
    • Independent Shutdown
  • Core DC-DC Converter
    • 94% Efficiency
    • Up to 500mA Load Efficiency
    • Output Voltage Adjustable Down to 1.25V
    • Independent Shutdown
  • Three Auxiliary DC-DC Controllers
    • Adjustable Maximum Duty Cycle
    • Independent Shutdown
  • Power, Oscillator, and Reference Outputs to Drive External Slave Controllers (MAX1801)
  • Up to 1MHz Switching Frequency
  • 3µA Supply Current in Shutdown Mode
  • Internal Soft-Start
  • Overload Protection for All DC-DC Converters
  • Compact 32-Pin TQFP Package

Applications/Uses

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

Description

The MAX1802 provides a complete power-supply solution for digital still cameras and video cameras by integrating two high-efficiency step-down DC-DC converters and three auxiliary step-up controllers. This complete solution is targeted for applications that use either three to four alkaline cells or two lithium-ion (Li+) cells.

The main step-down DC-DC controller accepts inputs from 2.5V to 11V and regulates a resistor-adjustable output from 2.7V to 5.5V. It uses a synchronous rectifier to regulate the output with up to 94% efficiency. An adjustable operating frequency (up to 1MHz) facilitates designs for optimum size, cost, and efficiency.

The core step-down DC-DC converter accepts inputs from 2.7V to 5.5V and regulates a resistor-adjustable output from 1.25V to 5.5V. It delivers 500mA with up to 94% efficiency.

The three auxiliary step-up controllers can be used to power the digital camera's CCD, LCD, and backlight. The MAX1802 also features expandability by supplying power, an oscillator signal, and a reference to the MAX1801, a low-cost slave DC-DC controller that supports step-up, single-ended primary inductance converter (SEPIC), and fly-back configurations.

The MAX1802 is available in a space-saving 32-pin TQFP package (5mm x 5mm body), and the MAX1801 is available in an 8-pin SOT-23 package. An evaluation kit (MAX1802EVKIT) featuring both devices is available to expedite designs.

Simplified Block Diagram

MAX1802: Typical Operating Circuit MAX1802: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .