The tiny power circuit can operate with input voltages lower than 0.3-V with high efficiency, allowing designers to overcome the low-voltage design barrier of incorporating these alternative energy sources in applications, such as mobile phones, portable medical devices and media players.

The new TPS61200 step-up converter with integrated 1.5-A switch supports input voltages of 0.3-V to 5.5-V during normal operation, and continues to manage power down to 0.0-V if the under-voltage lockout pin is connected directly to the output voltage. The converter provides an extremely low 0.5-V start-up capability in any load condition, and can operate with more than 90 percent efficiency. In contrast, today's best step-up converters can only support an input voltage beginning at 0.7-V with start-up at 0.9-V - good for primary re-chargeable battery cells or main supplies, but not low enough to support new applications using energy harvesting power sources.

The TPS61200's ability to operate from a single solar cell eliminates the need for multiple solar cells in series, and eliminates the required protection circuitry associated with series connection. This opens the door to new potential innovative designs, such as a built-in solar-powered cell phone charger that uses indoor ambient lighting to help provide an infinite amount of standby time.

"Portable equipment designers, including those in the portable medical, wireless and portable audio fields, are continuing to look at how to apply solar and fuel cell technology into their devices to extend battery life and differentiate their products," said Uwe Mengelkamp, director of TI's DC/DC converter product line. "It's not certain what we will see first, but the ideas are endless. What is certain is that designers can use the TPS61200 to achieve low-voltage operation to connect these new low-power energy sources with the ICs in their system."

Protecting the System at Low Voltages

The TPS61200, which comes in a 10-pin, 3 mm x 3 mm QFN package, offers several features that are critical during low-voltage operation, including output short-circuit protection, programmable under-voltage lockout and a unique "down-conversion mode" that helps protect the device when an input voltage rises higher than the output voltage. In addition, the converter can be disabled to further minimize battery drain. While the end equipment shuts down, the TPS61200 protects the system from receiving any additional power from the battery.

Extends the Operating Range of Single-Cell Alkaline, NiCd and NiMH Batteries

The integrated circuit's extremely low operating voltage also eliminates many of the design challenges that occur when operating a single-cell Alkaline, nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries to power anything from toys to portable medical devices. The TPS61200 extends the operating time of many pulsed-load applications that experience pass-load conditions at low-voltage inputs - Texas Instruments.