D/A converter with improved means to prevent output signal instability

In an IC chip including a DAC and an amplifier to be energized by a power-supply voltage with a nominal operating voltage range, said amplifier having an input circuit to receive the DAC output signal and an output circuit producing an amplified signal for an output terminal;

• that improvement for preventing harmful output signal fluctuations comprising:
• a voltage-monitoring device arranged to receive said power-supply voltage to detect its level;
• said voltage-monitoring device including means operable to de-activate said amplifier input and output circuits when said voltage is detected to be outside of said operating range;
• and
• means for restoring said amplifier input and output circuits to operating condition after said voltage level is in its operating range.

In an IC chip including a DAC and an amplifier to be energized by a power-supply voltage with a nominal operating voltage range, said amplifier having an input circuit to receive the DAC output signal and an output circuit producing an amplified signal for an output terminal;

• that improvement for preventing harmful output signal fluctuations comprising:
• a voltage-monitoring device arranged to receive said power-supply voltage to detect its level;
• said voltage-monitoring device including means operable to de-activate said amplifier output circuit when said voltage is detected to be outside of said operating range;
• means for re-activating said amplifier output circuit when said voltage level is in its operating range;
• said voltage-monitoring device comprising a band-gap voltage reference for establishing a reference voltage for determining when said supply voltage is out of said operating range.

In an IC chip including a DAC and an amplifier to be energized by a power-supply voltage with a nominal operating voltage range, said amplifier having an input circuit to receive the DAC output signal and an output circuit producing an amplified signal for an output terminal;

• that improvement for preventing harmful output signal fluctuations comprising:
• a voltage-monitoring device arranged to receive said power-supply voltage to detect its level;
• said voltage-monitoring device including means operable to produce a RESET signal to disable said amplifier after said voltage is detected to be outside of said operating range;
• means for enabling said amplifier after said voltage level reaches its operating range;
• and
• means to receive a RESET signal from a source external to said IC chip for disabling said amplifier.

In an IC chip including connection pins and formed with a DAC and an amplifier to be energized by a power-supply voltage with a nominal operating voltage range, said amplifier having an input circuit to receive the DAC output signal and an output circuit producing an amplified signal for an output terminal;

• that improvement for preventing harmful output signal fluctuations comprising:
• a voltage-monitoring device arranged to receive said power-supply voltage to detect its level and to produce a RESET signal when said voltage is out of its operating range;
• means responsive to said RESET signal to disable said amplifier after said voltage is detected to be outside of said operating range;
• means for enabling said amplifier after said voltage level is in its operating range;
• and
• means to produce said RESET signal on a pin of said chip to provide that said RESET signal can be directed to any other device in the system.