| 摘要 |
PURPOSE:To decrease the number of resistances and switches and to keep the output impedance at a low level, by realizing the common use between a D/A converter main body and a comparison amplifier and then extracting plural D/A conversion outputs with time division. CONSTITUTION:The reference power supply VR is connected to an end of a series circuit M of resistances 4R, and the other end of the circuit M is connected to a series circuit L of resistance R. The voltage is selected by switches SW1-SW6 for the circuit M. Then switches SW7-SW12 are used to select the voltage of the circuit L. These selected voltages VH and VL are applied to a capacitor C1 of a comparison amplifier 11 via a joint between switches SW13 and SW14. An inverter 12 is connected to the capacitor C1, and the output of the inverter 12 is applied to AND circuits 13 and 15 which supply a timing signal T via an inverter 14. Then the outputs of the 13 and 15 are applied to a capacitor C3 connected to an output terminal. The main body of a D/A converter and the amplifier 11 are used in common with each other, and plural D/A conversion outputs are extracted. Thus the number of component parts is decreased for a D/A converter. |
