National Semiconductor Adds Flexibility and Higher Performance to SIMPLE SWITCHER Buck Switching Regulator Family
National Semiconductor Corp. announced the addition of six high-frequency buck regulators to its popular SIMPLE SWITCHER® product family along with a "dial-in" performance enhancement to its WEBENCH® design environment. The six new regulators feature a unique combination of high performance, flexibility and ease-of-use for dc-dc power supply designs.
National’s new buck regulators and enhanced WEBENCH suite of tools enable novice as well as seasoned power supply designers to easily "dial-in" their size and efficiency requirements while also realizing fast time to market. Design results are verified by WEBENCH online electrical and thermal simulations and created for 24-48 hour delivery using the BuildIt!™ custom prototype power supply kit.
The new regulators operate with an input voltage range up to 75V and deliver up to 3A of continuous output current. The patented emulated-current-mode technology provides impressive load transient response in low duty cycle applications that are not addressable by traditional current mode control. Operating frequency is adjustable from 50kHz to 1MHz, providing what the company claims is industry-leading dynamic range. To reduce EMI, a frequency synchronization pin allows multiple ICs from the family to self-synchronize or to synchronize to an external clock. The new regulators deliver robustness with cycle-by-cycle current limit, short-circuit protection and thermal shut-down.
Emulated-current-mode control overcomes traditional current-mode control’s noise susceptibility by emulating the buck switch current signal, which is then used for current-mode control. The emulated buck switch current signal is the sum of an emulation ramp current and the sampled diode current just before switching occurs. Avoiding direct buck switch current measurement minimizes the effect of switching noise, while maintaining the benefits of the current-mode control.
Six products are included in the new line of SIMPLE SWITCHER regulators. The 0.5A LM5574, 1.5A LM5575 and 3.0A LM5576 buck regulators feature a very wide input voltage range from 6 to 75V and adjustable switching frequency between 50 and 500kHz. The 0.5A LM25574, 1.5A LM25575 and 3.0A LM25576 buck regulators feature wide input voltage range from 6 to 42V and adjustable switching frequency between 50kHz and 1MHz.
All of the new SIMPLE SWITCHER regulators are available for simulation on National’s WEBENCH design tool via the company’s website. National’s six new SIMPLE SWITCHER regulators are available now. Prices for the products range from $1.35 to $2.90 in 1,000-unit quantities.
