Single-cell charge pumps save board space, improve power efficiency

Designers are able to reduce board area by up to 25 percent while enhancing power efficiency in portable systems thanks to a new family of DC/DC converters.

Designers are able to reduce board area by up to 25 percent while enhancing power efficiency in portable systems that operate on a single-cell battery thanks to a new family of low-power DC/DC converters from Texas Instruments.

These new devices are claimed to be the first single cell charge pumps in the industry to feature a flexible conversion ratio that prolongs battery life. Applications that can benefit from the new charge pumps’ space savings and power efficiency include pagers, toys, medical and measurement instruments, metering equipment, and a variety of other battery-powered systems.

Suitable for use with low-power microcontrollers, the TPS6030x family of single-cell charge pumps provides a regulated 3.0- or 3.3-volt (V) output at up to 20 milliamps (mA) from a single NiMH, NiCd or alkaline battery.

The charge pumps convert input voltages ranging from 0.9- to 1.8-V at either a 3x or 4x rate, depending on the input level. This flexible conversion rate, compensates for the lower voltage level in a partially discharged battery, enabling more efficient power usage throughout the discharge life of the battery.

The devices include a newly developed LinSkip mode that enables the power supplies to achieve an efficiency of up to 90 percent over a wide load range. This patented technology also allows designers to use small 1-microfarad (uF) capacitors, and provides a typical output voltage ripple of 30mVpp at an output current of 20mA. This is a reduction of 40 percent at twice the output current when compared to similar devices found on the market today. Under light loads, the charge pump automatically switches from low-noise, constant-frequency linear regulation to a power-saving pulse-skip mode.

Load isolation disables current flow to the system during shutdown, providing longer shelf and standby times for the battery. Operating efficiency is increased with a low quiescent current of less than 35 microamps (uA) during operation and less than 500 nanoamps (nA) during shutdown.

Samples of the TPS6030x single-cell charge pumps are available now from TI with planned volume production scheduled for August this year.

The devices are packaged in a 10-pin MSOP package, and suggested resale pricing is $1.25 in quantities of 1000 units.

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