An adjustable brightness LED driver with high efficiency, high stability and low power consumption is proposed. In order to obtain high stability at different working conditions, a novel voltage loop adaptive frequency compensation circuit is constructed. Moreover, the high efficiency of this system is realized by using the LDO power supply derived from the systems output, which reduces the system's power consumption. The different light intensities are obtained by setting the maximum of the LED load current. The LED driver is designed on a 0.18μm process with an input voltage range of 5V- 35V. Meanwhile, the working frequency is adjustable and synchronized with the external clock. The simulation results demonstrate that the LED driver is a single polar system through the adaptive frequency compensation circuit and eliminating the effect of zero-pole pair.
A multi-band terahertz metamaterial absorber (MA) is proposed. The unit cell is formed by windmill-shaped elements in a square ring, a dielectric substrate and a metallic ground plane. The MA unit cell is investigated at normal and oblique incidence for both transverse electric (TE) and transverse magnetic (TM) polarizations. The simulated results show that the MA has three high absorption (greater than 99%) resonance narrow bands. The LC equivalent circuit is employed to analyze the origin of multi-band. The proposed MA is easy to fabricate, what’s more, the proposed MA has high absorption rate and insensitive to polarization, which is favorable for various applications, such as terahertz detecting, imaging, and so on.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.