| 摘要 |
PURPOSE: An automatic white balance adjusting circuit of a color image display is provided to optimize a cutoff or drive gain by eliminating an affect of a leakage current of a cathode using the less number of capacitors. CONSTITUTION: An automatic white balance adjusting circuit of a color image display comprises a switch circuit(1), a drive gain adjusting circuit(4), a cutoff adjusting circuit(7), a drive circuit(10), a fly back erase circuit(51), a current detection resistor(17) and a transistor(13) which are configured so as to correspond to each of cathodes of a cathode ray tube(CRT)(16). The switch(1) receives a color signal and first and second reference signals(1,2), and the drive gain adjusting circuit(4) adjusts an AC amplitude of an output signal. The cutoff adjusting circuit(7) adjusts a DC level of an output signal from the drive gain adjusting circuit(4). An output signal of the cutoff adjusting circuit(7) is provided to a base of the transistor(13) through the fly back erase circuit(51) and the drive circuit(10). The fly back erase circuit(51) sets a corresponding cathode electrode to a no-signal state on the basis of a corresponding fly back erase signal(R.BLK). The drive gain adjusting circuit(4) and the cutoff adjusting circuit(7) are controlled by corresponding control circuits(55,54) which commonly receive a voltage converted by the resistor(17).
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