EDNE September 2012 - (Page 27)

voltage on the load terminal determine the duty cycle of Q2. A PWM controller operates this type of synchronous dc-dc boost converter in continuous-conduction mode to maintain the voltage on the load terminal. Microhybrid exaMple For the battery switch, International Rectifier’s AUIRF1324S7P surface-mount MOSFET delivers a maximum on-state resistance as low as 1 mΩ and an output current up to 240A. For through-hole packaging requirements, the company offers the AUIRF1324L in a conventional TO-262 with a maximum onstate resistance of 1.65 mΩ. The wide-lead, TO-262-packaged AUIRF1324WL power MOSFET can reduce the maximum on-state resistance by roughly 20%. Wider-lead packages mean more areas fit the internal wirebonds at the MOSFET’s source terminal. The lower on-state resistance and the improved wirebonding inside the package collectively yield an approximately 30% increase in the maximum-drain-current rating. All MOSFETs in the 24V 1324 family are suitable candidates for battery-switch applications. IR also offers 40V automotivegrade MOSFETs with an on-state resistance as low as 1.25 mΩ. These products are suited for dc-dc-converter applications. The AUIR3240S, an automotive-grade high-side MOSFET driver, drives the battery power switch for start-stop applications (Figure 4). The highly integrated boost converter was designed specifically for start-stop systems, which require a board-net stabilizer that uses a power switch to disconnect the starter and main battery from the auxiliary electrical systems during engine start. The AUIR3240S can drive several MOSFETs in parallel to achieve very low on-state resistance, with current consumption of less than 50 μA. The device provides 15V on the output, with a wide input voltage of 4 to 36V. The AUIR3240S also features diagnostics on the output current and a thermal sensor interface for a robust design. Continued development of microhybrid start-stop systems requires solutions for reducing the cranking voltage drop, integrating more electronics into the starter and furthering the evolution of battery technologies. Power-electronics vendors and automakers are putting the components in place to make the necessary advancements.EDN authors’ biographies Masashi Sekine is an applications and technical marketing engineer in the Automotive Product business unit of International Rectifier (El Segundo, CA). He supports field activities related to MOSFET-based automotive applications as well as product specifications and definitions. Sekine holds a bachelor of science degree in electrical engineering from Tokyo Institute of Technology and has 10 years of experience in power electronics. Jifeng Qin is a product manager in the Automotive Product business unit of International Rectifier. He holds a bachelor of science degree in electrical engineering from Zhejiang University (Hangzhou, Zhejiang, China) and a master’s degree in electrical engineering from North Carolina State University. Qin has more than five years of experience in circuit design, application, and marketing, and he holds seven US patents. www.edn-europe.com SEPTEMBER 2012 | EDN EuropE 27 http://digikey.com/europe http://www.edn-europe.com

Table of Contents for the Digital Edition of EDNE September 2012

Cover
Contents
International Rectifier
Microchip
RS Components
Masthead
Microchip
EDN Comment
Pulse
Analog Devices
Altera
Baker's best
Messe München
Test & Measurement World
Agilent Techno
Digi-key
Bergquist
Advanced power switches boost microhybrid emissions gains
Digi-Key
Image sensors evolve to address Emerging embedded- vision needs
Renesas
Silicon Labs
Digi-Key
Vicor
Power becomes a software issue as smart phones become smarter
IAN
Power : a significant challenge in EDA design
Digi-Key
Mechatronics in Desin
Design Ideas
Product roundup
Tales from the Cube

EDNE September 2012