| 摘要 |
<p>A D/A converter of the type provided with an amplifier (A3) to produce the analog output signal and formed as an IC chip. The chip includes a power voltage monitor (30) to sense when the applied DC voltage is above a preset lower level and below a preset upper level. When that condition is sensed, the monitor activates a control circuit (34) which in turn opens a transmission gate (G1) between the amplifier output circuit and the converter output terminal, and closes a transmission gate (G2) between the output terminal and ground. When the DC voltage goes above the preset upper level, and a valid digital word is loaded into the converter register (20) and presented for conversion, the condition of the transmission gates is reversed to provide for normal operation of the converter.</p> |
