New Industry Products

Analog DC-DC Controller Features Dynamic Temperature-Compensated Current Sensing

October 20, 2013 by Jeff Shepard

Texas Instruments, Inc. (TI) has introduced an analog dc-dc step-down controller with remote bipolar junction transistor (BJT) temperature-compensated inductor current sensing that minimizes total solution footprint in high-power POL conversion. The 20-V LM27403 dc-dc synchronous buck controller provides greater than 95-percent efficiency from a 12-V input at 25 A of output current to optimize solution size and deliver fast transient response in communications infrastructure, industrial, medical and power module applications.

The temperature-compensated inductor dc resistance sensing improves the current limit accuracy to 10 percent over temperature by using a low-cost BJT to measure real-time temperature shifts, allowing the LM27403 to maintain a consistent current limit threshold across the operating temperature range. The current limit accuracy over temperature results in a smaller dc-dc converter footprint and reduces inductor over-design and allows for the use of smaller and lower-cost inductors.

Additional features and benefits include: Wide 3-V to 20-V input voltage range converts 3.3-V, 5-V and 12-V input. Voltage rails to point-of-load (POL) as low as 0.6 V with one-percent accuracy. 30-ns minimum on-time allows higher switching frequencies at lower duty cycles, providing greater scalability and smaller solution size. 15-ns adaptive dead-time control provides higher efficiency in high frequency operation, reducing power consumption. Output voltage remote sensing gives improved load regulation in high current applications.

The LM27403 synchronous buck controller is available in volume now from TI and its authorized distributors. Offered in a 4-mm by 4-mm by 0.8-mm, 24-pin PowerPadâ„¢ WQFN package, the controller is priced at US$1.20 in 1,000-unit quantities.