Phoenix, Arizona -- July 27, 1999 -- A new half bridge driver introduced by Semiconductor Components Group (SCG) today offers state-of-the-art high frequency stability for fluorescent lamp ballasts and includes an ICO pin which allows use of sophisticated frequency control techniques. The device is designed primarily for fluorescent lamp ballasts and is ideal for specific switching power supply topologies where switching frequency stability or control is critical.
The unit, type MC33157, is a high voltage, high side/low side driver designed specifically for European style electronic ballasts. It is a highly integrated circuit that includes all the functions necessary to control fluorescent lamps powered by either AC or DC mains in industrial applications.
Housed in a wide body SOIC 16 pin package, this multichip device contains an application specific frequency control circuitry for fluorescent lamp ballasts and a high side driver compatible with any high voltage MOSFET or IGBT half bridge. The switching performance of any design is enhanced because the stray capacitance between the high side and low side drivers is greatly reduced.
The device features an onboard current controlled oscillator (ICO) which determines the frequency of the driver and makes dimming and remote control possible when used in the regulation mode. It automatically manages the preheating of the tube filaments and offers a sophisticated frequency sweep sequence combined with a "strike" detect input to manage the tube.
This reliable high voltage insulation multichip is capable of sustaining 600V and includes an accurate built-in voltage bandgap reference which, when combined with the ICO, provides outstanding frequency stability across temperature and external component variation. This very high frequency stability allows designers to use less expensive, passive, standard components yet maintaining a stable output. As a result, the time, effort and cost of designing a frequency-stable tube are significantly minimized.
To control the fluorescent lamp ballasts fault condition; a specific pin is provided to handle extremely fast RESET action. Pin 13 is omitted to provide high isolation between the high side and low side drivers. The large sink and source output current capability allow the MC33157 to drive any high voltage MOSFET used in the power system and in addition, the adjustable dead time makes the product suitable for any snubber capacitor and size of MOSFET used as power switches.
"The performance and reliability of the MC33157 allows industrial designers to design electronic lamp ballast schemes as simple or as sophisticated as they choose," comments Scott Delaney, Director of Marketing for SCG. " SCG has once again addressed the need of designers for 'more features' by providing the industry's first highly integrated high voltage multichip driver."
The MC33157 is available in a SOIC 16-pin wide body package. Samples and production quantities are now available with pricing of $0.80 in 10K quantities.
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