Internal voltage generating circuit and semiconductor integrated circuit device
View Patent ↗A voltage for reference at a voltage level higher than a target value is produced from a constant current provided from a constant current generating circuit, and is subjected to resistance division by a resistance division circuit to produce a reference voltage at the target level, and then a final reference voltage is produced by a voltage follower. An internal voltage generating circuit thus provided can generate the reference voltage having the desired voltage level with high accuracy as well as an internal voltage based on the reference voltage by controlling temperature characteristic even with a low power supply voltage.
1. An internal voltage generating circuit comprising:
a first reference voltage generating circuit generating a first reference voltage;
a voltage dividing circuit producing a second reference voltage by dividing said first reference voltage, wherein said voltage dividing circuit includes a voltage-follower-connected differential amplifier receiving said first reference voltage, and a divided voltage output circuit dividing an output voltage of said differential amplifier to produce and output said second reference voltage; and
a divided voltage producing circuit dividing said second reference voltage to produce a divided voltage,
wherein said divided voltage producing circuit includes:
a resistance division circuit effecting resistance division on said second reference voltage,
a first level shifter effecting level shift on an output voltage of said resistance division circuit,
a second level shifter effecting level shift on said divided voltage, and
a drive circuit making a comparison between an output voltage of said second level shifter and an output voltage of said first level shifter to produce said divided voltage according to a result of said comparison.
2. The internal voltage generating circuit according to claim 1 , wherein said first and second level shifters include insulated gate field-effect transistors having thick gate insulating films and operating in a source follower mode.
3. The internal voltage generating circuit according to claim 1 , wherein said drive circuit includes:
a comparing circuit having a differential stage receiving the output voltages of said first and second level shifters and allowing adjustment of a ratio,
a current supply coupled to said differential stage and determining a drive current of said differential stage, and
a drive element producing said divided voltage according to an output signal of said comparing circuit.