IMP Intros IMP528 EL Driver IC

IMP Inc. (San Jose, CA) introduced the IMP528 electroluminescent (EL) lamp driver integrated circuit. The IMP528 features a 220V peak-to-peak ac drive signal derived from dc or battery sources as low as 2V, allowing pager and cellular phone display screens to be easily backlit by EL lamps without bulky transformers, according to IMP."The IMP528 targets applications where maximum display brightness is needed over a wide operating voltage range," stated Vice President of Marketing, Sales and Applications Barry Wiley. "By working with key customers early in the design process, these new devices are expected to rapidly become the standard EL lamp driver in wireless communications devices."The IC integrates four EL lamp driving functions on-chip, including boost switch-mode power supply, high-frequency oscillator, high-voltage H-bridge lamp driver and low-frequency oscillator. The 220V ac peak-to-peak drive signal is developed from a 2.0Vdc to 6.5Vdc input voltage. For EL lamps commonly used in battery powered handheld communication and computing devices, the IMP528 output will be held constant by an internal regulator, maximizing brightness over the full battery life. The only external components required are one inductor, one diode, one capacitor and two resistors. The resistors allow independent adjustment of boost converter frequency and of EL lamp drive frequency. Adjustable lamp drive frequency allows control over lamp color and power dissipation; no external resistor is needed in series with the EL lamp for protection.The IC can be disabled when it is not needed to drive the EL backlight, reducing the current to 420uA. Available in 8-pin MicroSO and SO packages, the IMP528 is priced at $1.09 each in 1,000-piece quantities.