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Nie W.,Jiangnan University | Nie W.,Wuxi Crystal Source Electronics Co | Yu Z.,Jiangnan University | Wang H.,Wuxi Crystal Source Electronics Co | And 3 more authors.
Journal of Semiconductors | Year: 2014

A single-stage flyback driving integrated circuit (IC) for light-emitting diodes (LEDs) is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the boundary conduction mode (BCM), while the output current can be derived and regulated precisely. By means of a simple external resistor divider, a compensation voltage is produced on the ISEN pin during the turn-on period of the primary MOSFET to improve the line regulation performance. On the other hand, since the delay time between the time that the secondary diode current reaches zero and the turn-on time of the MOSFET can be automatically adjusted, the MOSFET can always turn on at the valley voltage even if the inductance of the primary winding varies with the output power, resulting in quasi-resonant switching for different primary inductances. The driving IC is fabricated in a Dongbu HiTek's 0.35 μm bipolar-CMOS-DMOS process. An 18 W LED driver is finally built and tested. Results show that the driver has an average efficiency larger than 86%, a power factor larger than 0.97, and works under the universal input voltage (85-265 V) with the LED current variation within ±0.5%. © 2014 Chinese Institute of Electronics.


Nie W.,Jiangnan University | Nie W.,Wuxi Crystal Source Electronics Co. | Zhu W.,Wuxi Crystal Source Electronics Co. | Ma X.,Wuxi Crystal Source Electronics Co. | Yu Z.,Jiangnan University
Proceedings - 2014 IEEE 12th International Conference on Solid-State and Integrated Circuit Technology, ICSICT 2014 | Year: 2014

For the primary-side-regulation (PSR) single-stage flyback LED driver operating in critical conduction mode (CRM), the input line current is notably distorted around the zero-crossing of the line voltage, especially in the conditions of high input voltage and light load. This paper derives the expression of the line current, and the reason of line current zero-crossing distortion (LCZCD) is investigated. After that, a simple method to reduce LCZCD is proposed by duty cycle limitation (DCL). The driving integrated circuits (ICs) with and without DCL are fabricated and the experimental results from LED drivers verify the effectiveness of the proposed method. © 2014 IEEE.


Nie W.,Jiangnan University | Nie W.,Wuxi Crystal Source Electronics Co. | Yi F.,Wuxi Crystal Source Electronics Co. | Yu Z.,Jiangnan University
Journal of Semiconductors | Year: 2013

For 20 V planar active-gap lateral double-diffused MOSFET (LDMOS), the sectional channel is utilized to decrease the electric field in the n-drift region below the poly gate edge in the off-state, compared with the conventional single channel. Then the n-drift concentration can be increased to decrease the Kirk effect, while keeping off-state breakdown voltage Vbd unchanged. Meanwhile the influence of the n-drift concentration and the n-drift length Ldrift (the drain n+ diffusion to gate spacing) which are related to the Kirk effect is discussed. The trade-offs between R dson·Area, breakdown voltage Vbd and the electrical safe operating area (e-SOA) performance of LDMOS are considered also. Finally the proposed planar active-gap LDMOS devices with varied values of L drift are experimentally demonstrated. The experimental results show that the Kirk effect can be greatly suppressed with slight increase in the Rdson·Area parameter. © 2013 Chinese Institute of Electronics.


Nie W.,Jiangnan University | Nie W.,Wuxi Crystal Source Electronics Co. | Wu J.,Wuxi Branch of Southeast University | Ma X.,Wuxi Crystal Source Electronics Co. | And 2 more authors.
Journal of Semiconductors | Year: 2012

Isolated extended drain NMOS (EDNMOS) transistors are widely used in power signal processing. The hole current induced by a high electric field can result in a serious reliability problem due to a parasitic NPN effect. By optimizing p-type epitaxial (p-epi) thickness, n-type buried layer (BLN) and nwell doping distribution, the peak electric field is decreased by 30% and the peak hole current is decreased by 60%, which obviously suppress the parasitic NPN effect. Measured I-V characteristics and transmission line pulsing (TLP) results show that the on-state breakdown voltage is increased from 28 to 37 V when 6 V V gs is applied and the energy capability is improved by about 30%, while the on-state resistance remains unchanged. © 2012 Chinese Institute of Electronics.

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