|Sanken Electric has recently developed the SED70N2, the world's smallest* 60W output AC adapter, optimal for mobile notebook PCs.
By employing Sanken's proprietary control IC dedicated for AC adapters and by completely revising a control circuit, a downsized adapter as small as 96 cc (88.5 mm width × 39.5 mm depth × 27.5 mm height) has been achieved, while supplying the rated output power of 60W (70W max.), where mobile notebook PCs require the output power of about 50 to 60W.
The SEC70N2 AC adapter will be launched into mass production this fall after shipping samples to certain customers.
*Based on researches by Sanken Electric in March 2007, covering the products with equivalent specifications form major manufacturers worldwide.
||Development Background and Product Overview
||The electric power required by the operation of notebook PCs, notably widespread recently, has been increasing more and more due to the enhanced graphics functions as well as the high-performance and multifunctional features. Especially, on the mobile notebook PCs, the electric power of around 50 to 60W is required and further downsizing is also required from the portability point of view.
Thus, Sanken Electric has employed a synchronous rectification system in the secondary side of a fly-back converter that uses Sanken's proprietary dedicated IC (SSC6210) for higher efficiency (90% maximum at 230 V input), and the temperature increase has successfully suppressed, otherwise resulting in a use of larger package. Furthermore, the total number of parts has been reduced by at least 30% by, in the control circuit, thoroughly revising the circuit while incorporating into the IC the various functions that consist of conventional discrete parts, and also by simplifying the noise filter part through employing a newly developed patented low-noise transformer. By the above means, Sanken Electric has successfully developed the SED70N2, the adapter such that can provide 60W output while it is about a half-size of Sanken's conventional 60W adapter and is downsized to a 40W-adapter equivalent size (96cc).
The SED70N2 is a compact energy-saving AC adapter which controls the input power to 0.4W or lower (conventional products: 1W) at no load and is ideal for portable uses.
Sanken's proprietary control IC that is dedicated for AC adapters and incorporates into one chip the versatile protection functions (for overcurrent, overvoltage, etc.) which are demanded by AC adapters.
<2>Synchronous rectification system
The system that uses a power MOSFET allowing both better efficiency and lower noise in the secondary side rectification circuit, instead of using diodes causing a larger power loss.
||Features ("conventional products" refers to Sanken's conventional 40W output adapters.)
|| Microminiaturized (96 cc) with 60W output (70W max.)
Attains microminiaturization with a volume of 96 cc (88.5 mm (width) × 39.5 mm (depth) × 27.5 mm (height), 200 g) and a power density of 1.6 cc/W, while keeping a rated power output of 60W (70W max.). The power density has improved by 50%, with a case size equivalent to the conventional products.
||High efficiency of up to 90%
Newly employing a synchronous rectification system in the secondary side rectifier, average efficiencies of 89% (at 115 V input), and 90% (at 230 V input) have been achieved. Thus, the case surface temperature is successfully controlled to about the same as that of the conventional products, while supplying a high output.
||Number of parts greatly reduced
<1>By incorporating the functions such as startup circuit, overload protection, etc. into an IC chip and by installing the IC into the primary-side circuit, discrete parts are greatly reduced (57% reduction over conventional products).
<2>By newly employing the synchronous rectification circuit and also by revising thoroughly the design of the secondary side rectification circuit, the number of discrete parts has been reduced (15% reduction over conventional products).
||Input power of 0.4W or lower at no load
Reactive power is suppressed by controlling the frequency at no load with a dedicated IC (SSC6210), allowing to suppress the input power at no load to 0.4W or lower (conventional products: 1W).
|| Low-noise design reduces a noise filter to two thirds
By combining Sanken's patented low-noise transformer with a dedicated IC (SSC6210) having a frequency modulation function, the noise filter circuit area has been reduced to tow thirds (parts have been reduced 10% over Sanken's conventional products), while achieving low noise.
||Complies with various safety standards, EMI (noise) standards, and environmental regulations
<1>Safety standards: Japanese Electrical Safety Code, UL, and C-UL (compliant with EU safety standards)
<2>EMI: VCCI Class B, FCC Class B, CISPR Class B
<3>Environmental regulations: RoHS directive compliant
Input voltage: 90 to 264 V AC (Universal input voltage range)
Output voltage: 16.0 V
Output current (power): 3.75 A (Rating: 60 W) to 4.38 A (70 W max.)