A high performance white light emitter diode (LED) driver based on boost converter with novel single-wire serial-pulse digital dimming (SWSP) is proposed. The driver uses external serial programmed pulses and internal clock to simplify brightness control. By embedding a 5-bit digital analog converter (DAC) into the driver, wide dimming range is achieved. Moreover, a new dynamic slope compensation circuit is presented and other key circuits of the driver are optimized to get higher efficiency and fast transition response. A practical circuit is implemented with 0.6 um bipolar complementary-metal-oxide-semiconductor double-diffused-metal-oxide-semiconductor (BCD) technology. The simulation results show that the driver can provide both wide output current from 1.3 mA to 42 mA with 32-level digital dimming and higher efficiency up to 83% while it works at 1 MHz switching frequency with the input voltage variation from 2.7 V to 5.5 V.
This paper presents a security strategy for resisting a physical attack utilizing data remanence in poweredoff static random access memory(SRAM).Based on the mechanism of physical attack to data remanence,the strategy intends to erase data remanence in memory cells once the power supply is removed,which disturbs attackers trying to steal the right information.Novel on-chip secure circuits including secure power supply and erase transistor are integrated into conventional SRAM to realize erase operation.Implemented in 0.25μm Huahong-NEC CMOS technology,an SRAM exploiting the proposed security strategy shows the erase operation is accomplished within 0.2μs and data remanence is successfully eliminated.Compared with conventional SRAM,the retentive time of data remanence is reduced by 82% while the operation power consumption only increases by 7%.
