Point-of-load power modules boast fast transient response
By Margery Conner, Technical Editor -- EDN, November 8, 2005
Power systems for networking and communications systems must be able to respond to the transient power needs of powerful system processors such as DSPs, FPGAs, ASICs, and microprocessors. Texas Instruments' new T2 series of point-of-load dc/dc converter modules incorporates TurboTrans, a feature that allows designers to customize the modules for specific transient-load requirements.
"TurboTrans allows you to tune the feedback loop so that you get the maximum amount of transient response out of the module, which allows you to reduce the amount of capacitance that you have on the output to respond to the transients," said Don Matthiesen, marketing manager for TI's power-management product line. The end result is faster transient response with 40% less output-voltage deviation and a 5× to 8× reduction in output capacitance, according to the company.
"What we've been seeing lately is that [some IC manufacturers] have reduced the overall tolerance on the core voltage rail from 5% down to 3%," Matthiesen said. "These are typically 1 or 1.2V rails, so when you start talking about 3% of a 1V rail, you've only got 30 mV that you can let that voltage rail swing under transients. So designers really have to pay attention to how much of a transient they'll have and make sure that the core voltage rail stays within the specification."
The modules, which extend TI's line of PTH devices, also incorporate the SmartSync function, which allows the designer to synchronize the switching frequencies of multiple T2 devices, maximizing power efficiency and minimizing EMI, according to TI. SmartSync also allows the T2 modules to synchronize at different phase angles using external circuits to help balance source loading and minimize input capacitance. The synchronized modules also make EMI filtering easier by eliminating beat frequencies, the company said.
The series supports step-down dc/dc conversion from a wide 4.5 to 14V input, with adjustable output voltages down to 0.7V at output currents up to 50A, which is useful for IBA (intermediate bus architecture) applications. The power modules reduce the overall power footprint by as much as 50% compared with TI's previous generation devices, according to the company.
T2 power modules are available now in sample quantities. Pricing begins at $7.90 (1000). Evaluation modules of the T2 family, application notes, and TI's online selection tool for power-management products are available through power.ti.com.
