DALLAS (Oct. 2, 2000) -- Designers of Internet audiosystems and other portable applications are able toimprove system performance and battery life bydesigning their power supply solution based on two newfamilies of highly-efficient, synchronous DC/DCconverters from Texas Instruments (TI) Incorporated(NYSE: TXN). These new converters are designed tosupport battery-operated systems being powered froma 1-cell Lithium Ion (Li-Ion) battery or from a 2- or3-cell nickel-cadmium (NiCd), nickel-metal-hydride(NiMH) or alkaline battery. In addition, they offer anexcellent power conversion efficiency of 96 percent atlow load currents, making them ideally suited forsupplying the low core voltages of low-power digitalsignal processors (DSPs) found in Internet audioplayers, digital cameras, cordless phones and portablemedical equipment.

These low-power devices, the TPS6101x family of boostconverters and the TPS6200x family of step-downconverters, provide a complete power supply solutionthat takes full advantage of the lifespan of a battery cellwith reliable operation even when the battery voltage isat 0.9 Volts (V).

"In today's portable market, battery life is one of thekey differentiators. With portable equipment OEMsproviding increased functionality with each new model,the power management design is becoming more criticalwhen identifying ways to help maximize the batteryperformance," said Bernd Krafthofer, product marketingengineer for TI's power management products. "With a96 percent power conversion efficiency, the ability tooperate below 1V and a low quiescent current, thesenew DC/DC converters enable manufacturers to designsmaller, more power-efficient portable applications whileincreasing their product run time." TPS6101x Boost Converters Offers High Efficiencyand Low Quiescent Current

The TPS6101x family, which consist of seven devices,operate at up to 96 percent efficiency and serve asboost converters for 1- and 2-cell NiCd, NiMH, andalkaline batteries. As a synchronous converter, theTPS6101x family helps reduce board space and systemcosts since the devices do not require a Schottkyrectifier and can start up to full load from a 0.9V inputvoltage; therefore, no external switch is needed to startup at such low voltages. To help minimize battery drain and extend battery life,the quiescent current for the TPS6101x family is lessthan 50 microAmperes (uA), and a shutdown modedraws less than 1 uA. In addition, a Power Save modekeeps efficiency high under low load conditions bychanging from PWM to PFM switching schemes. Anotherfeature, unique in the industry, is a programmableoutput discharge that speeds the discharge of theoutput capacitor, when needed. The family comprisessix fixed output voltage units and one programmableunit that generate from 1.5 V to 3.3 V, making thesedevices suitable to supply core voltage requirements ofDSP and other processors directly from one battery cell.The devices also have a minimum output current of 100mA with a 0.8-V supply. TPS6200x Step-Down DC/DC Converters OffersSmallest Solution Members of the second family, designated TPS6200x,include eight devices in all, and serve as buck convertersthat operate at efficiencies up to 95 percent. Byaccepting a minimum input voltage of 2 V, the family caneliminate the need for a boost converter since it canoperate directly from two battery cells. With a max inputvoltage of 5.5V, the devices can also operate from 1-cellLi-ion or 3-cells NiCd, NiMH, or alkaline batteries toproduce output voltages of 0.9V to 3.3V. Of the eightmembers, seven come with fixed outputs and one isadjustable.

A complete solution using the TPS6200x family takes aminimum of just three components: input and outputcapacitors and an inductor. In addition, a Power Goodindicator tells a second converter or the host processorwhen the converter is operating properly. To keepexternal components small, the TPS6101x features ahigh operating frequency (up to 750 kHz internal; 1 MHzfrom an external clock). For low noise operation, unitscan be operated in the PWM mode, and multiple unitscan be synchronized to the same clock. If used in thesame system, both families can be synchronized to eachother as well. An internal antiringing switch also helpsreduce electrical noise. Like the TPS6101x family,TPS6200x draws just 50 uA of quiescent current and 1uA in shut down mode. It also has a power saving modeto keep efficiency high at light loads.

New Converters Provide A Complete Power SupplySolution for TI's Audio DSP

The rapid growth in Telecom and Internet technologies has generated high demands for power converters to power the new wave of equipment and devices built to access and utilize the new information superhighways. With battery power being the prime source of energy for many portable electronics these days, DC/DC converters are widely used to either step-up or step-down the battery voltage to levels compatible with the electronic loads and circuitry within these devices. Insuring higher efficiency is critical to extending battery life and performance. TI is introducing a new family of step-up and step-down DC/DC converters for battery powered devices featuring efficiencies of up to 96% and operation at battery voltages as low as 0.9V thus allowing these converters to work off single cell batteries. Other features include synchronous rectification, PWM and PFM operation, and a programmable output discharge to speed up the discharge of the output capacitor if needed.