An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output d...An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.展开更多
The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on trad...The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.展开更多
A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a...A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.展开更多
A new type of intelligent recolser controller installed on the outdoor rod is developed, which is mainly composed of microcontroller of Intel 87C196KC 20 and CPLD devices. This controller integrates all the functions ...A new type of intelligent recolser controller installed on the outdoor rod is developed, which is mainly composed of microcontroller of Intel 87C196KC 20 and CPLD devices. This controller integrates all the functions of measuring, controlling, protection, fault diagnosis, communication, remote controlled operation and self power devices with infra red remote control devices as a unit. The controller applies the distributed structure, field concentration line and intelligent technology to seal up the synthetic servomechanisms such as the microcomputer based protection and measuring devices in the second stage of the mini out door transformer substation, which are distributed on the outdoor circuit switches on the spot and formed as a whole. Therefore, this technology can transform a large number of ordinary homemade SF 6 circuit beaker and vacuum circuit breaker into intelligent circuit recloser, thus replacing the expensive imported automatic circuit recolser.展开更多
基金supported by the High Efficacy Energy-Saving Project of Zhejiang Province China(No.2006C11007).
文摘An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.
文摘The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.
文摘A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.
文摘A new type of intelligent recolser controller installed on the outdoor rod is developed, which is mainly composed of microcontroller of Intel 87C196KC 20 and CPLD devices. This controller integrates all the functions of measuring, controlling, protection, fault diagnosis, communication, remote controlled operation and self power devices with infra red remote control devices as a unit. The controller applies the distributed structure, field concentration line and intelligent technology to seal up the synthetic servomechanisms such as the microcomputer based protection and measuring devices in the second stage of the mini out door transformer substation, which are distributed on the outdoor circuit switches on the spot and formed as a whole. Therefore, this technology can transform a large number of ordinary homemade SF 6 circuit beaker and vacuum circuit breaker into intelligent circuit recloser, thus replacing the expensive imported automatic circuit recolser.
