1999-01-25 , E/DS-1013/13
Product News From Philips Semiconductors

With over 25 percent of the world's generated electricity used to power lighting systems, it is vital that these systems are made as efficient as possible to conserve valuable energy resources. A new range of high-voltage silicon bipolar fast switching transistors from Philips Semiconductors, the largest European semiconductor manufacturer, contributes to energy savings by dramatically reducing power dissipation in electronic lighting ballasts.

Fabricated using a planar-passivated ion-implantation process at Philips Semiconductors' bipolar PowerFAB in Hazel Grove, UK, BUJ-Series transistors feature very fast fall times (tf) as short as 30 ns when switching inductive loads of several amps. This, combined with tightly controlled storage times, very short turn-on times, and extremely low V_CE saturation voltages, can yield 40 percent reductions in the transistor's power dissipation in electronic lighting ballast applications. In addition to saving energy, their low power dissipation translates into lower junction temperatures, reduced heatsinking requirements and improved device reliability. For a given junction temperature rise, it also means that BUJ-Series transistors can drive higher power loads than has been possible with any other glass mesa or planar design.

Available with collector-emitter voltage (V_CES) ratings between 700 V and 1200 V and collector current (I_Csat) ratings between 0.5 A and 6 A, these new transistors provide optimum solutions for all line supply voltage, load powers and switching frequencies. They also feature narrowly defined gain spreads, making it easier for designers to predict circuit performance under worst-case operating conditions.

High Safe Operating Areas which exceed the capabilities of equivalent transistors available today, ensure that the BUJ series transistors can withstand abnormal and stressful operating conditions. Fast and consistently smooth collector current fall waveforms at transistor switch off prevent the excitation of "ringing" in the circuit and prevent the generation of excess RF Interference. This has been achieved by the revolutionary transistor design which is able to remove the stored charge carriers in a fast and extremely uniform manner.

"In conjunction with our existing range of power switching MOSFETs and wide range of power rectifiers, the introduction of these new low-loss bipolar switching transistors means Philips Semiconductors becomes a one-stop-shop for all power semiconductors used in electronic lighting ballasts," commented product marketing manager Nigel Stott. 'They are also suitable for use in other high-voltage applications such as off-line switchmode power supplies and motor drives," he added.

Philips Semiconductors, a division of Royal Philips Electronics, headquartered in Eindhoven, The Netherlands, is the eighth largest semiconductor supplier in the world (according to Dataquest's preliminary 1998 ranking by sales). Discrete semiconductors are central to the company's operations and it is the third largest discretes supplier in the world, with the target of becoming the world's largest. It has a very broad and deep product range grouped into three specific competences: Power, RF and General Application products which cover all application areas. Philips Semiconductors is supported by a worldwide network of systems laboratories and product application groups to develop complete, dedicated solutions to specific customer requirements.