TI Announces New Family of High-Frequency DC/DC Converters That Extends Battery Life in Portable Applications
At 2.5 MHz, New Synchronous Buck Converters Offer Highest Operating Frequency in the Industry, Making them Ideal for Handheld Electronic Devices
DALLAS (Jan. 17, 2001) -- Designers of portable applications can increase the operating time of their system by using a new low-power, high-frequency DC/DC buck converter announced today from Texas Instruments Incorporated (TI) (NYSE: TXN). This device is part of a new family of synchronous buck converters that offer up to 94 percent efficiency, a maximum operating frequency of 2.5 megahertz (MHz) and a multi-mode programmability feature that allows designers to optimize the converters. These buck converters are ideal for handheld electronics devices powered by one or two-cell Li-ion battery packs, such as Internet Audio players, digital still cameras, cellular and satellite phones, and personal digital assistants (PDAs). (see www.ti.com/sc/aap5537u)
The new devices, the TPS6210x family of low-power buck converters with integrated FETs, allow designers to configure an optimized power management solution that reduces both board space and system costs by using smaller inductors and capacitors as well as eliminating the need for an external Schottky rectifier. The TPS6210x devices also give designers a complete power supply solution that takes full advantage of the lifespan of a battery cell. The devices even provide reliable operation when the battery voltage is at 2.5 Volts (V) - the end of a useful charge voltage for a single Li-Ion cell.
The purpose of these devices is to facilitate the construction of low-cost, small, high-frequency and fast-response DC/DC converters. The family is available in four operating frequencies ranging from 300 kHz to 2 MHz. To further reduce board space, designers are able to synchronize the TPS62103 to an external clock signal and achieve an operating frequency of 2.5 MHz.
"In the past, designers were limited in using buck regulators in portable applications due to their size and efficiency. Since the TPS6210x devices offer high frequency with high efficiency, designers are now able to implement smaller filtering devices, inductors and capacitors and still maintain the same efficiency as seen with other buck converters found on the market today," said Guenter Sporer, system engineering manager for DC/DC converters, TI. "At the same time, though, the devices have the ability to automatically switch operating modes on the fly to further prolong the operating time of a battery."
The TPS6210x devices offer a wide input range from 2.5 to 9 V and function well with one- or two-cell Lithium-ion (Li-ion) batteries, as well as Nickel Metal Hydride (NiMH) or Alkaline batteries. The family also includes an adjustable output range from 0.8 to 8V, which makes the TPS6210x devices particularly well suited to new, next-generation microprocessors and digital signal processors (DSPs) that have low core voltage requirements.
Multi-Mode Programmability Allows Designers to Optimize Converters
All of the devices in the TPS6210x family can be programmed to operate in any of three modes. For noise-sensitive environments, designers are able to use the fixed-frequency mode and maintain the device's characterized operating frequency at all times, overcoming any difficulties in environments that may be subject to high levels of extraneous electrical noise. When building low output current applications, designers can use the variable frequency mode (PFM - pulse frequency modulation) to optimize the power consumption in the converter. This mode monitors the output voltage and maintains it between +/- 2.5 percent of nominal by either charging the output filter capacitor when the voltage falls below this range or ceasing to charge it when the output voltage rises above it. In the third operating mode, the automatic mode, the TPS6210x devices can switch back and forth between the fixed-frequency and variable frequency modes, depending on the processing load on the system and the characteristics of the environment.
The TPS6210x devices also include a shutdown mode that can be used to deploy an active power management subsystem. By sending a control signal to the power converter, the device can enable or disable portions of the host system to lengthen battery life. When it is in shutdown mode, a TPS6210x device disconnects its output from the input and draws a current of one micro-Ampere (uA).
A 100 percent duty cycle allows a TPS6210x synchronous buck converter to continue to operate and the system to function until the battery is completely discharged. The TPS6210x family also features three methods of overload protection, one thermal shutdown method and two over-current protection schemes.
Pricing and Availability
The TPS6210x devices come in an eight-pin small outline integrated circuit (SOIC) package. The devices are scheduled to be available in February from TI and its authorized distributors. Suggested resale pricing in quantities of 1,000 is $2.81.
# # #
| 
