LIGHT EMITTING DIODE DRIVING DEVICE OF KEYPAD

摘要

PURPOSE: A keypad is provided to easily recognize a key with other key, user does not watch the liquid crystal display while user press the keypad by light emitting diode(LED) driving device. CONSTITUTION: The keypad comprises a LED for back-light, a LED for key selection display, and a controller. In the keypad, the LED for back-light to provide back-light to the keypad and makes a form of array. The LED for key selection display independently operates and indicates whether a key is pressed in response to each key. The controller generates a common control signal to drive the LED for back-light while an interrupt is generated. The controller generates a single control signal to drive the LED for key selection display while some key is pressed.