| 摘要 |
PURPOSE: An electro luminescence display apparatus is provided to escape a concentration of a consumption current and to realize a secure gradation display. CONSTITUTION: An electro luminescence display apparatus comprises an n-bit counter(12),an adder(20), first to third correspondence detecting circuits(21,22,23), a NOR gate(24), an AND gates(25,26) and an OR gate(27). The adder(20) adds n-bit fixing data (m-1) generated in a pulse width modulation circuit of each column and n-bit gradation data (M DATA) of a m-th column. The first correspondence detecting circuit(21) compares n-bit lower data (nP) of (n+1)-bit add data from the adder(20) with a count value(nT) of the counter(12), and outputs a result signal(A). The result signal(A) has a 'H' level from a point of time when the count value(nT) becomes '1' and has a 'L' level at a point of time when the data (nP) is less than the value(nT). The second correspondence detecting circuit(22) compares the fixing data (m-1) with the count value(nT), and outputs a result signal(B). The result signal(B) has a 'H' level from a point of time when the count value(nT) becomes '1' and has a 'L' level at a point of time when the value(nT) is more than the data (m-1). The third correspondence detecting circuit(23) compares the fixing data (m-1) with the count value(nT), and outputs a result signal(C). The result signal(C) has a 'H' level only when the value(nT) is equal or more than the data (m-1). The NOR gate(24) receives an inverted version of the signal(B) and the most significant bit(Q) of the add data, and the AND gate(25) receives an inverted version of an output signal of the NOR gate(24) and the signal(A). The AND gate(26) receives the most significant bit(Q) of the add data and the signal(C), and the OR gate(27) receives output signals of the AND gates(25,26).
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