Abstract: A detector circuit detects a voltage corresponding to the leakage current that flows through the cathode electrode of a color display during a vertical blanking period of a video signal. The voltage detected is held in a first sample-and-hold circuit. Meanwhile, a reference signal corresponding to the reference black level is input during a part of the vertical blanking period of the video signal. A voltage corresponding to the leakage current that flows through the cathode electrode of the color display during the part of the vertical blanking period is detected by the detector circuit and then held in a second sample-and-hold circuit. The voltage held in the first sample-and-hold is subtracted from the voltage held in the second sample-and-hold circuit. A comparator circuit compares the difference between these voltages with a reference voltage. The result of the comparison controls a cutoff adjustment circuit for adjusting a DC level of the video signal.

Abstract: A detector circuit detects a voltage corresponding to the leakage current that flows through the cathode electrode of a color display during a vertical blanking period of a video signal. The voltage detected is held in a first sample-and-hold circuit. Meanwhile, a reference signal corresponding to the reference black level is input during a part of the vertical blanking period of the video signal. A voltage corresponding to the leakage current that flows through the cathode electrode of the color display during the part of the vertical blanking period is detected by the detector circuit and then held in a second sample-and-hold circuit. The voltage held in the first sample-and-hold is subtracted from the voltage held in the second sample-and-hold circuit. A comparator circuit compares the difference between these voltages with a reference voltage. The result of the comparison controls a cutoff adjustment circuit for adjusting a DC level of the video signal.

Abstract: A detector circuit detects a voltage corresponding to the leakage current that flows through the cathode electrode of a color display during a vertical blanking period of a video signal. The voltage detected is held in a first sample-and-hold circuit. Meanwhile, a reference signal corresponding to the reference black level is input during a part of the vertical blanking period of the video signal. A voltage corresponding to the leakage current that flows through the cathode electrode of the color display during the part of the vertical blanking period is detected by the detector circuit and then held in a second sample-and-hold circuit. The voltage held in the first sample-and-hold is subtracted from the voltage held in the second sample-and-hold circuit. A comparator circuit compares the difference between these voltages with a reference voltage. The result of the comparison controls a cutoff adjustment circuit for adjusting a DC level of the video signal.

Abstract: An analog IC includes analog circuit components and digital circuit components formed from plural I2L circuits. The analog IC is supplied with first and second voltages from first and second direct current sources. The analog circuit components are driven by the first voltage and the I2L circuits are driven by the second voltage. At least one I2L circuit is activated before the analog IC receives the first voltage while the remaining at least one I2L circuit is activated after the analog IC receives the first voltage, a switching circuit switching on and off the transmission of the second voltage to the remaining at least one I2L circuit according to a voltage level of the first voltage.

Abstract: A volume controlire include a volume regulating circuit having an input terminal connected to an audio signal source and a control terminal to which a volume regulating voltage is supplied. a circuit for supplying parallel data in multiple bits. a Df/A conversion circuit having including multiple current circuits formed in parallel corresponding to every bit of the parallel data, for ON/OFF controlling the current circuits according to respective bit data and for supplying total sun current flowing through these current circuits, a control circuit for controlling output current from the D/A conversion circuit to non-linear current by switching current volumes of respective current circuits corresponding to the most significant bit data out of the parallel data, and a circuit for generating the volume regulating voltage by converting the output current from the D/A conversion circuit into voltage.