Claims
- 1. A semiconductor integrated circuit device comprising:
- a reference voltage generating circuit outputting a reference voltage from a step-up voltage provided as a supply voltage to said reference voltage generating circuit;
- a step-up circuit, connected to said reference voltage generating circuit and an external power supply voltage, stepping up the reference voltage within a range lower than the external power supply voltage and thus outputting said step-up voltage as a supply voltage to said reference voltage generating circuit;
- a buffer amplifier circuit, connected to said reference voltage generating circuit, outputting a buffered voltage in accordance with said reference voltage; and
- an internal circuit, connected to said buffer amplifier circuit, receiving, as a power supply voltage thereof, the buffered voltage.
- 2. The semiconductor integrated circuit device as claimed in claim 1, further comprising a switching element selectively supplying, as a power supply voltage of said reference voltage generating circuit, the step-up voltage to the reference voltage generating circuit.
- 3. The semiconductor integrated circuit device as claimed in claim 2, wherein:
- said switching element has a control terminal receiving a control signal;
- the switching element applies the step-up voltage to the reference voltage generating circuit in a first mode of operation of the semiconductor integrated circuit device; and
- the switching element prevents the step-up voltage from being applied to the reference voltage generating circuit in a second mode of operation to thereby allow an external reference voltage to be applied to the buffer amplifier circuit in order to test the semiconductor integrated circuit device.
- 4. The semiconductor integrated circuit device as claimed in claim 2, further comprising a starter circuit supplying a predetermined voltage to the switching element when a power supply to the semiconductor integrated circuit device is turned on, so that the reference voltage generating circuit can be immediately initiated.
- 5. The semiconductor integrated circuit device as claimed in claim 2, wherein said switching element comprises:
- a field effect transistor having a first terminal receiving the step-up voltage, a second terminal applying the step-up voltage to the reference voltage generating circuit, and a third terminal receiving the control signal; and
- a resistor having a first end connected to the third terminal of the field effect transistor, and a second end connected to a predetermined potential.
- 6. The semiconductor integrated circuit device as claimed in claim 5, wherein:
- said first field effect transistor is a p-channel field effect transistor;
- the first, second and third terminals of the field effect transistor correspond to a source, a drain and a gate of said p-channel field effect transistor; and
- said predetermined potential corresponds to a ground level, and the external power supply voltage is higher than the ground level.
- 7. The semiconductor integrated circuit device as claimed in claim 4, wherein said starter circuit comprises:
- a first n-channel field effect transistor of a depletion type having a drain receiving the external power supply voltage, a source being grounded via a first resistor, and a gate grounded; and
- a second n-channel field effect transistor of a depletion type having a drain receiving the external power supply voltage, a source connected to the switching element and grounded via a second resistor, and a gate connected to the drain of the first n-channel field effect transistor.
- 8. The semiconductor integrated circuit device as claimed in claim 4, wherein said starter circuit comprises:
- a first n-channel field effect transistor of a depletion type having a drain receiving the external power supply voltage, a source being grounded via a first resistor, and a gate grounded; and
- a second n-channel field effect transistor of a depletion type having a drain receiving the external power supply voltage, a source connected to the source of a p-channel field effect transistor of the switching element and grounded via a second resistor, and a gate connected to the drain of the first n-channel field effect transistor.
- 9. The semiconductor Integrated circuit device as claimed in claim 7, wherein back bias voltages of the first and second n-channel field effect transistors are connected to source voltages thereof so as to be equal thereto.
- 10. The semiconductor integrated circuit device as claimed in claim 8, wherein back bias voltages of the first and second n-channel field effect transistors are equal to source voltages thereof.
- 11. The semiconductor integrated circuit device as claimed in claim 1, wherein said step-up circuit comprises:
- a first p-channel field effect transistor of an enhancement type having a drain being grounded, a source connected to a first resistor to which the external power supply voltage is applied, and a gate receiving the reference voltage; and
- a first n-channel field effect transistor of a depletion type having a drain receiving the external power supply voltage, a source connected to the switching element and grounded via a second resistor, and a gate connected to the source of the first p-channel field effect transistor.
- 12. The semiconductor integrated circuit device as claimed in claim 1, wherein:
- said step-up circuit comprises a plurality of field effect transistors cascaded;
- a first one of the plurality of field effect transistors located at a first stage has a gate receiving the reference voltage;
- a second one of the plurality of field effect transistors located at a final stage has a terminal via which the step-up voltage is output; and
- the step-up voltage is based on threshold voltages of the plurality of field effect transistors.
- 13. The semiconductor integrated circuit device as claimed in claim 1, further comprising a terminal receiving an external reference voltage, and further comprising an electrically shielded connector for connecting the external reference voltage to the step-up circuit and the buffer amplifier circuit.
- 14. The semiconductor integrated circuit device as claimed in claim 13, further comprising shield patterns which electrically shield said line and are set to a ground level.
Priority Claims (2)
Number |
Date |
Country |
Kind |
6-008542 |
Jan 1994 |
JPX |
|
6-086697 |
Apr 1994 |
JPX |
|
Parent Case Info
This application is a continuation application Ser. No. 08/377,229 filed Jan. 24, 1995, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
63-265524 |
Nov 1988 |
JPX |
Non-Patent Literature Citations (3)
Entry |
Concannon et al., IBM Technical Disclosure Bulletin--"Regulated On-Chip Supply Voltage Source For MOSFET Integrated Circuits", Feb. 1982, pp. 4668-4669. |
Hansen, IBM Technical Disclosure Bulletin--"Voltage Regulator", Sep. 1971, p. 1050. |
Dorler et al., IBM Technical Disclosure Bulletin--"Constant-Voltage Source", Sep. 1971, p. 1058. |
Continuations (1)
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Number |
Date |
Country |
Parent |
377229 |
Jan 1995 |
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