Resistor string digital/analog converter with resetting switches

A digital/analog (D/A) converter comprising:

• first and second power supply voltage means;
• an output terminal;
• a plurality of first resistors connected in series between, said first and second power supply voltage means, each of said first resistors including a pair of second resistors in series;
• a plurality of switches arranged in a tree configuration between first nodes of said first resistors and said output terminal, said switches being turned ON and OFF in response to input bits;
• and
• a plurality of reset switches, each connected between one second node of said pair of second resistors and one node of one of said switches on a side of said output terminal.

An analog/digital (A/D) converter apparatus comprising:

• at least first and second A/D converters, said first A/D converter performing an A/D conversion upon an analog input voltage;
• and
• at least one digital/analog (D/A) converter, connected to said first A/D converter, for performing a D/A conversion upon output bits of said first A/D converter,
• said second A/D converter performing an A/D conversion upon a difference between said analog input voltage and an analog output voltage of said D/A converter,
• said D/A converter comprising:
• first and second power supply voltage means;
• an output terminal;
• a plurality of resistors connected in series between said first and second power supply voltage means;
• a plurality of switches arranged in a tree configuration between first nodes of said resistors and said output terminal, said switches being turned ON and OFF in response to the output bits of said first A/D converter;
• and
• at least one reset switch, connected to a second node of at least one of said switches on a side of said output terminal, for resetting said second node to a predetermined voltage.

An analog/digital (A/D) converter apparatus comprising:

• first and second A/D converters for performing A/D conversions upon an analog input voltage;
• and
• a digital/analog (D/A) converter, connected to said first and second A/D converters, for applying first and second comparison reference voltages to said first and second A/D converters, respectively,
• said D/A converter comprising:
• first and second power supply voltage means;
• a plurality of output terminals for generating said second comparison reference voltages;
• a plurality of first resistors, connected in series between said first and second power supply voltage means, for generating said first comparison reference voltages, each of said first resistors including a plurality of second resistors in series;
• a plurality of switches arranged in a tree configuration between first nodes of said second resistors and said output terminals, said switches being turned ON and OFF in response to output bits of said first A/D converter;
• and
• a plurality of reset switches, each connected to one second node of one of said switches on a side of said output terminals.