Patent ID: 7397449
Filing Date: 2008-07-08
Classification: G09G,H03M

Abstract:
1. A current generation circuit comprising: a current output section that has circuit systems in which driving elements having respective gain coefficients corresponding to respective weights of bits of input data and switching elements which are on-off controlled according to a content of said bits are connected in series, a number of the circuit systems corresponding to a number of the bits of said input data, respective gates of said driving elements being commonly connected to a predetermined node, and that outputs a data current such that electrical currents flowing through respective channels of said driving elements are merged in a state in which a voltage of said node is set to a driving voltage; and a gate voltage generation section for setting the voltage of said node to an offset voltage corresponding to a threshold voltage of said driving elements by diode-connecting at least one of said driving elements and for setting the voltage of said node to said driving voltage, in which said offset voltage is used as a reference, by varying a voltage supplied to a terminal of a capacitor, the capacitor having another terminal connected to said node; wherein said gate voltage generation section comprises a first transistor, provided between said node and one of the terminals of said at least one driving element, the first transistor being on-off controlled for diode-connecting said at least one driving element; and wherein said gate voltage generation section further comprises a second transistor provided between said node and a terminal to which an initial voltage having a voltage level higher than said threshold voltage is supplied, the second transistor being turned on before the voltage of said node is set to said offset voltage.