Capacitor chargers work alone to power flashes

A new family of stand-alone high-efficiency ultrafast photoflash capacitor chargers eliminate the MPU loading and the software development traditionally required.

New from Linear Technology is the LT3484 family of high-efficiency ultrafast photoflash capacitor (typically 320V) chargers.

These ICs designed as stand-alone devices, eliminating microprocessor loading and the extensive software development normally associated with other photoflash charger solutions.

This family of photoflash capacitor charger ICs is designed for use in digital camera and mobile phone applications where space is at a premium.

The LT3484's patented control technique allows it to use extremely small transformers and the onboard NPN power switch requires no external Schottky diode clamp, reducing solution size.

Output voltage detection needs no external circuitry as the transformer turns ratio determines final charge voltage.

These devices have an input voltage range of 1.8 to 16V, making them ideal for applications powered by two AA alkaline cells or single cell Li-ion batteries.

The LT3484-0, -2 and -1 have primary current limits of 1.4, 1 and 0.7A, respectively, resulting in tightly controlled average input current of 500, 350 and 225mA, respectively.

The three versions are otherwise identical.

The charge pin gives full control of the part to the user.

Driving the charge pin low puts the part in shutdown.

The done pin indicates when the part has completed charging.

The LT3484 series of is offered in a tiny low profile 2 x 3mm DFN package.

The LT3484-0, -1 and -2 are available from stock and priced at $2.10 each in 1000-piece quantities.

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