Abstract In this paper, a low power current protection circuit implemented in LDOs is presented. ... more Abstract In this paper, a low power current protection circuit implemented in LDOs is presented. The proposed circuit, designed in 0.35 mum CMOS process, provides a precise limiting current as well as holding current with low dependency on both supply voltage ...
In this work, we propose a quick response circuit to improve the load transient response of fully... more In this work, we propose a quick response circuit to improve the load transient response of fully low dropout voltage linear regulator (LDO) which is operable with a very low power consumption. Simulating by HSPICE with 0.35 mum CMOS technology shows that we can achieve the transient responses with less transient overshoot or undershoot when driving large current loads. Comparing to the generic LDO, for example, in case of 1 muF decoupling capacitor, about 95% output drop and 27% settling time for 0.1 mA to 100 mA load current and 88% output overshoot and 63% settling time for 100 mA to 0.1 mA load current have been together improved. The proposed circuit only dissipates low static power, so we could achieve the above LDO with only 3.3 muA consuming current at V out + 1 V and 150 mA load current. V out is the output voltage of the regulator.
In this work, we propose a design technique of low power fully CMOS low-dropout voltage regulator... more In this work, we propose a design technique of low power fully CMOS low-dropout voltage regulator (LDO) based on quick response (QR) circuit to improve the load transient response. Implemented in 0.18 mum CMOS technology, the LDO with proposed QR circuit can achieve a fast load transient responses with less transient overshoot or undershoot when driving a large load current. For 1 muF decoupling capacitor and 0.1 mA-150 mA load current change, the output undershoot and overshoot are 196 mV and 172 mV while the settling time is approximately 60 mus and 65 mus respectively . The proposed circuit dissipates a very low static power, with only 8.5 muA for light load and 35 muA for heavy load for output voltage VOUT = 1.2 V and input voltage VDD = VOUT + 1.0 V . This includes the reference circuit, the over current protection circuit as well as the feedback network.
In this work, the bulk-gate controlled circuit to improve the power supply ripple ratio (PSRR) of... more In this work, the bulk-gate controlled circuit to improve the power supply ripple ratio (PSRR) of a Low Dropout Regulator (LDO) which deteriorates due to lowering power consumption is proposed. Designing with 0.25 mum CMOS process, the simulation results by HSPICE shown that the proposed circuit provides a high performance of PSRR even though 1/10 of the power consumption is reduced compare to the conventional circuit. It is confirmed that about 40[dB] at 10[Hz] frequency and 20[dB] at 1[kHz] frequency of PSRR are together improved.
In this work, a Bulk-Gate Controlled Circuit, for improving power supply rejection ratio (PSRR) o... more In this work, a Bulk-Gate Controlled Circuit, for improving power supply rejection ratio (PSRR) of a Low Dropout Voltage Regulator (LDO) which deteriorates due to lowering of power consumption is proposed. A test chip was fabricated using 0.18-mum CMOS process. Experimental results of the test chip demonstrate that the proposed circuit provides a high performance of PSRR which is up to 77 dB at 10 Hz, and 64.3 dB at 1 KHz, while the consumption current of the whole LDO which includes currents of all component circuits such as a reference circuit, an over current protection circuit, etc., is reduced to 8.5 muA without load, and 35 muA with full load. Comparing to the basic type of conventional LDOs, PSRR of the proposed bulk-gate controlled LDO achieves an improvement of 16 dB for 10 Hz and 27.8 dB for 1 KHz .
In the recent years, laser dicing had emerged as an feasible alternative to blade dicing, with it... more In the recent years, laser dicing had emerged as an feasible alternative to blade dicing, with its parametric effect yet to be understood completely. This paper focuses on the parametric study of the laser dicing and had established a parameter prediction graph on the cutting depth to Kerf width ratio with respective to the specific laser influence. By comparison to conventional diamond blade dicing, the quality and processability of the laser diced wafers are assessed, indicating its advantages and limitations. The result shows that laser is capable of reaching 2.5 times faster feed speed with comparable sawing quality to blade dicing, for thin wafers(<70 mum) application and less competitive in thick wafers(>175 mum).
Studies were conducted as part of Asian Pacific Regional Aerosol Characterization Experiment (ACE... more Studies were conducted as part of Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) to characterize the major ion and elemental composition of aerosol particle samples collected at Gosan, an ACE-Asia supersite (GOS, Korea, total suspended particle or TSP samples) and at Zhenbeitai (ZBT, China, TSP and particles < 2.5 μm diameter or PM2.5 samples), a site closer to the sources for Asia dust. The concentrations of 24 elements in the ZBT PM2.5 samples were correlated with Al (an indicator of mineral dust), and the ratios of these elements to Al were similar to those in a loess certified reference material, but a second group of elements was enriched over crustal proportions most likely as a result of pollution emissions. The concentrations of various water-soluble (WS) cations (Na+, K+, Ca2+, Mg2+) also were generally well correlated with Al in both the ZBT and GOS samples, with the exception being WS K+ at ZBT, where biomass burning may have had an effect. The percentage of calcium that was soluble approached 100% at ZBT versus ˜60% at GOS, and the ratio WS Ca2+/Al also was higher at ZBT. The molar ratio of sulfate to WS Ca2+ was ˜0.1 at ZBT but increased to near unity at GOS, where the aerosol nitrate/WS Ca2+ ratio was tenfold to hundredfold higher compared with ZBT, presumably because of anthropogenic influences. The observed differences in aerosol characteristics between sites can only be explained as the end product of different source contributions combined with complex processes involving gas-particle conversion, size-dependent fractionation, and aerosol mixing.
Abstract In this paper, a low power current protection circuit implemented in LDOs is presented. ... more Abstract In this paper, a low power current protection circuit implemented in LDOs is presented. The proposed circuit, designed in 0.35 mum CMOS process, provides a precise limiting current as well as holding current with low dependency on both supply voltage ...
In this work, we propose a quick response circuit to improve the load transient response of fully... more In this work, we propose a quick response circuit to improve the load transient response of fully low dropout voltage linear regulator (LDO) which is operable with a very low power consumption. Simulating by HSPICE with 0.35 mum CMOS technology shows that we can achieve the transient responses with less transient overshoot or undershoot when driving large current loads. Comparing to the generic LDO, for example, in case of 1 muF decoupling capacitor, about 95% output drop and 27% settling time for 0.1 mA to 100 mA load current and 88% output overshoot and 63% settling time for 100 mA to 0.1 mA load current have been together improved. The proposed circuit only dissipates low static power, so we could achieve the above LDO with only 3.3 muA consuming current at V out + 1 V and 150 mA load current. V out is the output voltage of the regulator.
In this work, we propose a design technique of low power fully CMOS low-dropout voltage regulator... more In this work, we propose a design technique of low power fully CMOS low-dropout voltage regulator (LDO) based on quick response (QR) circuit to improve the load transient response. Implemented in 0.18 mum CMOS technology, the LDO with proposed QR circuit can achieve a fast load transient responses with less transient overshoot or undershoot when driving a large load current. For 1 muF decoupling capacitor and 0.1 mA-150 mA load current change, the output undershoot and overshoot are 196 mV and 172 mV while the settling time is approximately 60 mus and 65 mus respectively . The proposed circuit dissipates a very low static power, with only 8.5 muA for light load and 35 muA for heavy load for output voltage VOUT = 1.2 V and input voltage VDD = VOUT + 1.0 V . This includes the reference circuit, the over current protection circuit as well as the feedback network.
In this work, the bulk-gate controlled circuit to improve the power supply ripple ratio (PSRR) of... more In this work, the bulk-gate controlled circuit to improve the power supply ripple ratio (PSRR) of a Low Dropout Regulator (LDO) which deteriorates due to lowering power consumption is proposed. Designing with 0.25 mum CMOS process, the simulation results by HSPICE shown that the proposed circuit provides a high performance of PSRR even though 1/10 of the power consumption is reduced compare to the conventional circuit. It is confirmed that about 40[dB] at 10[Hz] frequency and 20[dB] at 1[kHz] frequency of PSRR are together improved.
In this work, a Bulk-Gate Controlled Circuit, for improving power supply rejection ratio (PSRR) o... more In this work, a Bulk-Gate Controlled Circuit, for improving power supply rejection ratio (PSRR) of a Low Dropout Voltage Regulator (LDO) which deteriorates due to lowering of power consumption is proposed. A test chip was fabricated using 0.18-mum CMOS process. Experimental results of the test chip demonstrate that the proposed circuit provides a high performance of PSRR which is up to 77 dB at 10 Hz, and 64.3 dB at 1 KHz, while the consumption current of the whole LDO which includes currents of all component circuits such as a reference circuit, an over current protection circuit, etc., is reduced to 8.5 muA without load, and 35 muA with full load. Comparing to the basic type of conventional LDOs, PSRR of the proposed bulk-gate controlled LDO achieves an improvement of 16 dB for 10 Hz and 27.8 dB for 1 KHz .
In the recent years, laser dicing had emerged as an feasible alternative to blade dicing, with it... more In the recent years, laser dicing had emerged as an feasible alternative to blade dicing, with its parametric effect yet to be understood completely. This paper focuses on the parametric study of the laser dicing and had established a parameter prediction graph on the cutting depth to Kerf width ratio with respective to the specific laser influence. By comparison to conventional diamond blade dicing, the quality and processability of the laser diced wafers are assessed, indicating its advantages and limitations. The result shows that laser is capable of reaching 2.5 times faster feed speed with comparable sawing quality to blade dicing, for thin wafers(<70 mum) application and less competitive in thick wafers(>175 mum).
Studies were conducted as part of Asian Pacific Regional Aerosol Characterization Experiment (ACE... more Studies were conducted as part of Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) to characterize the major ion and elemental composition of aerosol particle samples collected at Gosan, an ACE-Asia supersite (GOS, Korea, total suspended particle or TSP samples) and at Zhenbeitai (ZBT, China, TSP and particles < 2.5 μm diameter or PM2.5 samples), a site closer to the sources for Asia dust. The concentrations of 24 elements in the ZBT PM2.5 samples were correlated with Al (an indicator of mineral dust), and the ratios of these elements to Al were similar to those in a loess certified reference material, but a second group of elements was enriched over crustal proportions most likely as a result of pollution emissions. The concentrations of various water-soluble (WS) cations (Na+, K+, Ca2+, Mg2+) also were generally well correlated with Al in both the ZBT and GOS samples, with the exception being WS K+ at ZBT, where biomass burning may have had an effect. The percentage of calcium that was soluble approached 100% at ZBT versus ˜60% at GOS, and the ratio WS Ca2+/Al also was higher at ZBT. The molar ratio of sulfate to WS Ca2+ was ˜0.1 at ZBT but increased to near unity at GOS, where the aerosol nitrate/WS Ca2+ ratio was tenfold to hundredfold higher compared with ZBT, presumably because of anthropogenic influences. The observed differences in aerosol characteristics between sites can only be explained as the end product of different source contributions combined with complex processes involving gas-particle conversion, size-dependent fractionation, and aerosol mixing.
Uploads
Papers by Kha Mum