Spinning off a semiconductor company from University premises -The story of Camsemi

The spinning off of Cambridge Semiconductor Ltd (Camsemi) from the High Voltage Microelectronics Lab at Cambridge University is discussed. The technology originated from Cambridge University and was subsequently developed and commercialized as PowerBrane by Camsemi. The paper also discusses the business model and the enabling financial factors that led to the formation of Camsemi as a fables IC company, including access to seed funding from University and the subsequent investments of venture capital in several rounds. © 2011 IEEE.

Low-carbon off-grid electrification for rural areas in the United Kingdom: Lessons from the developing world

Low-carbon off-grid electrification for rural areas is becoming increasingly popular in the United Kingdom. However, many developing countries have been electrifying their rural areas in this way for decades. Case study fieldwork in Nepal and findings from United Kingdom based research will be used to examine how developed nations can learn from the experience of developing countries with regard to the institutional environment and delivery approach adopted in renewable energy off-grid rural electrification. A clearer institutional framework and more direct external assistance during project development are advised. External coordinators should also engage the community in a mobilization process a priori to help alleviate internal conflicts of interest that could later impede a project. © 2011 Elsevier Ltd.

Turn-off failure mechanism in large area IGCTs

The destruction mechanism in large area IGCTs (Integrated Gate Commutated Thyristors) under inductive switching conditions is analyzed in detail. The three-dimensional nature of the turn-off process in a 91mm diameter wafer is simulated with a two-dimensional representation. Simulation results show that the final destruction is caused by the uneven dynamic avalanche current distribution across the wafer. © 2011 IEEE.

Parameters influencing the performance of an IGBT gate drive

This paper presents an improvement of an IGBT gate drive implementing Active Voltage Control (AVC), and investigates the impact of various parameters affecting its performance. The effects of the bandwidths of various elements and the gains of AVC are shown in simulation and experimentally. Also, the paper proposes connecting a small Active Snubber between the IGBT collector and its gate integrated within the AVC. The effect of this snubber on enhancing the stability of the gate drive is demonstrated. It will be shown that using a wide bandwidth operational amplifier and integrating the Active Snubber within the gate drive reduces the minimum gate resistor required to achieve stability of the controller. Consequently, the response time of the IGBT to control signals is significantly reduced, the switching losses then can be minimised and, hence, the performance of gate drive as whole is improved. This reflects positively on turn-off and turn-on transitions achieving voltage sharing between the IGBTs connected in series to construct a higher voltage switch, making series IGBTs a feasible practice. ©2008 IEEE.

Active-passive 44 SOA-based switch with integrated power monitoring

The first monolithically integrated 44 switch with power monitoring function using on-chip PIN photodiodes is reported. Using 10Gb/s signals, under active power control an IPDR of 12dB for a 1dB power penalty is achieved. © 2012 OSA.