A linear power supply is a circuit architecture directly driven by AC. Multiple high-voltage LEDs (light-emitting diodes) are connected in series to withstand the input voltage. The LEDs are divided into multiple segm...A linear power supply is a circuit architecture directly driven by AC. Multiple high-voltage LEDs (light-emitting diodes) are connected in series to withstand the input voltage. The LEDs are divided into multiple segments through a segment switching mechanism to adapt to the pulsating DC changes after bridge rectification. Due to imperfect switching between control signals, there may be signal overlap or misalignment, which reduces circuit performance and component lifespan. Firstly, signal overlap occurs when the next segment opens before the previous segment is about to close. This state causes overlapping intervals where two segments of current combine, resulting in a high combined current that can lead to significant power losses and generate heat, potentially reducing the lifespan of the components. Secondly, signal misalignment occurs when the next segment prepares to open after the previous segment has completely closed. In this state, there is a time gap with no current flow, resulting in reduced output power and exacerbating LED flickering. Both of these undesirable phenomena introduce ripple into the LED output current. In this paper, a digitalized design is proposed to precisely compensate for the timing between alternating signals, significantly reducing output current ripple. This approach helps enhance power supply performance, extend component lifespan, and reduce LED index flicker.展开更多
The automated detection and lighting control system is proposed in this paper.It is used to reduce the investment of human resources and reduce the incidence of misjudgment or disoperation caused by human fatigue,whic...The automated detection and lighting control system is proposed in this paper.It is used to reduce the investment of human resources and reduce the incidence of misjudgment or disoperation caused by human fatigue,which will greatly help the investment cost and efficiency.This paper used NI LabVIEW’s program control interface with microcontroller(MCU)and oscilloscope kit(GentryUSB)to develop an oscilloscope and logical analysis functions with automatic detection of LED lamps.The proposed system has data detection,logic analysis,waveform photo capture,lamp control,RS232 packet transmission.Its characteristic is to complete the complicated control/detection process through automation by one click to reduce the error rate and labor cost.In addition,the software and firmware are designed independently,which has extremely high function expansion flexibility and can also accept customized functions and interface custom design.It is expected to bring a lot of benefits and convenience to the laboratory or factory in the future.展开更多
The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum pass...The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum passivation. By optimizing the thickness of passivation layer and annealing condition, the minority carrier lifetime of p-type single crystalline Czochralski wafer could be improved from 10 μs to 190 μs. The formation and variation of hillock defect on passivation layer was founded to be affected by the thermal annealing temperature. For the purpose of obtaining high minority carrier lifetime and low hillock defect density simultaneously, using a lower heating and cooling speed in thermal annealing process is suggested.展开更多
文摘A linear power supply is a circuit architecture directly driven by AC. Multiple high-voltage LEDs (light-emitting diodes) are connected in series to withstand the input voltage. The LEDs are divided into multiple segments through a segment switching mechanism to adapt to the pulsating DC changes after bridge rectification. Due to imperfect switching between control signals, there may be signal overlap or misalignment, which reduces circuit performance and component lifespan. Firstly, signal overlap occurs when the next segment opens before the previous segment is about to close. This state causes overlapping intervals where two segments of current combine, resulting in a high combined current that can lead to significant power losses and generate heat, potentially reducing the lifespan of the components. Secondly, signal misalignment occurs when the next segment prepares to open after the previous segment has completely closed. In this state, there is a time gap with no current flow, resulting in reduced output power and exacerbating LED flickering. Both of these undesirable phenomena introduce ripple into the LED output current. In this paper, a digitalized design is proposed to precisely compensate for the timing between alternating signals, significantly reducing output current ripple. This approach helps enhance power supply performance, extend component lifespan, and reduce LED index flicker.
文摘The automated detection and lighting control system is proposed in this paper.It is used to reduce the investment of human resources and reduce the incidence of misjudgment or disoperation caused by human fatigue,which will greatly help the investment cost and efficiency.This paper used NI LabVIEW’s program control interface with microcontroller(MCU)and oscilloscope kit(GentryUSB)to develop an oscilloscope and logical analysis functions with automatic detection of LED lamps.The proposed system has data detection,logic analysis,waveform photo capture,lamp control,RS232 packet transmission.Its characteristic is to complete the complicated control/detection process through automation by one click to reduce the error rate and labor cost.In addition,the software and firmware are designed independently,which has extremely high function expansion flexibility and can also accept customized functions and interface custom design.It is expected to bring a lot of benefits and convenience to the laboratory or factory in the future.
文摘The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum passivation. By optimizing the thickness of passivation layer and annealing condition, the minority carrier lifetime of p-type single crystalline Czochralski wafer could be improved from 10 μs to 190 μs. The formation and variation of hillock defect on passivation layer was founded to be affected by the thermal annealing temperature. For the purpose of obtaining high minority carrier lifetime and low hillock defect density simultaneously, using a lower heating and cooling speed in thermal annealing process is suggested.
