Patent ID: 7719494

Claim:
A brightness adjustment circuit for providing a feedback voltage and for use in an electroluminescent display having an electroluminescent panel and a power supply unit, the power supply unit providing a working voltage to the electroluminescent panel in response to the feedback voltage, the brightness adjustment circuit comprising: an integrated circuit module, having a variable resistor, electrically coupled to the electroluminescent panel, including: an internal circuit unit electrically coupled to the power supply unit; and an external circuit unit having one end applied with a common potential; and a switch for changing the resistance of the integrated circuit module in response to a control signal so as to adjust the feedback voltage, wherein the internal circuit unit includes a first resistor and a second resistor connected in series, the external circuit unit has a plurality of resistors of different resistance connected in parallel, and the second resistor and at least one of the resistors of the external circuit unit are connected via the switch.