Power IC's move ink jet printers to new performance levels

Ink jet printer performance is rapidly growing and color capability, as well as resolution and productivity increases all push printheads to higher numbers of ink jet drop ejectors. A silicon power IC at the heart of these printheads contains multiple on-chip heater elements and associated power switches, each addressed through low-voltage logic circuitry, to provide thermal energy required for nucleation and ink drop ejection. Performance requirements make the lateral power n-channel MOSFET an ideal power switch for this application. A compact chip is achieved because the switches are on printing resolution pitch and they function in the thermal gradient caused by heater element proximity. Specific power switch design issues are discussed through the use of two-dimensional numerical modeling and electrical data from fabricated devices.