Constant current generation circuit, constant voltage generation circuit, constant voltage/constant current generation circuit, and amplification circuit

Claim 2

A constant current generation circuit comprising: a first field effect transistor having a threshold voltage Vt; and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said first field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, and the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts.

Claim 3

The constant current generation circuit according to claim 1 , further comprising a first current mirror circuit for respectively causing currents which are equal or proportional to each other to flow through said first field effect transistor and said first resistor.

Claim 4

The constant current generation circuit according to claim 1 , further comprising a second field effect transistor, said first current mirror circuit comprising third and fourth field effect transistors, said first field effect transistor having its gate electrically connected to one end of said resistor, having its source electrically connected to the other end of said resistor, and having its drain electrically connected to the drain of said third field effect transistor, said second field effect transistor having its gate electrically connected to the drain of said first field effect transistor, having its source electrically connected to said one end of said resistor, and having its drain electrically connected to the drain of said fourth field effect transistor, said third field effect transistor having its source electrically connected to a predetermined potential, and having its gate electrically connected to the gate and the drain of said fourth field effect transistor, and said fourth field effect transistor having its source electrically connected to said predetermined potential.

Claim 5

The constant current generation circuit according to claim 3 , wherein said first, second, third and fourth field effect transistors are metal oxide semiconductor field effect transistors.

Claim 6

The constant current generation circuit according to claim 3 , further comprising potential holding means for holding the drain of said first field effect transistor at a predetermined potential.

Claim 7

The constant current generation circuit according to claim 1 , wherein the resistance value of said first resistor is adjustable at the time of at least the fabrication.

Claim 8

The constant current generation circuit according to claim 1 , wherein said first resistor is composed of polycrystalline silicon.

Claim 9

The constant current generation circuit according to claim 1 , wherein the gate length and the gate width of said first field effect transistor are set such that a voltage applied across both ends of said first resistor at a first temperature and a voltage applied across both ends of said first resistor at a second temperature different from the first temperature are equal to each other.

Claim 10

The constant current generation circuit according to claim 1 , wherein said first resistor is constructed using a plurality of resistors and a switch, and has a programmable function by switching said plurality of resistors using said switch.

Claim 11

A constant voltage generation circuit comprising a constant current generation circuit; and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, and said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to a current flowing through said first resistor in the constant current generation circuit.

Claim 12

A constant voltage generation circuit comprising a constant current generation circuit; and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, and said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to a current flowing through said first resistor in the constant current generation circuit.

Claim 13

The constant voltage generation circuit according to claim 10 , wherein the resistance value of said second resistor is adjustable at the time of at least the fabrication.

Claim 14

The constant voltage generation circuit according to claim 10 , wherein said constant current generation circuit further comprises a first current mirror circuit for respectively causing currents which are equal or proportional to each other to flow through said first field effect transistor and said first resistor.

Claim 15

The constant current generation circuit according to claim 10 , further comprising a second field effect transistor, said first current mirror circuit comprising third and fourth field effect transistors, said first field effect transistor having its gate electrically connected to one end of said resistor, having its source electrically connected to the other end of said resistor, and having its drain electrically connected to said third field effect transistor, said second field effect transistor having its gate electrically connected to the drain of said first field effect transistor, having its source electrically connected to said one end of said resistor, and having its drain electrically connected to the drain of said fourth field effect transistor, said third field effect transistor having its source electrically connected to a predetermined potential, and having its gate electrically connected to the gate and the drain of said fourth field effect transistor, and said fourth field effect transistor having its source electrically connected to the predetermined potential.

Claim 16

The constant current generation circuit according to claim 13 , wherein said first, second, third and fourth field effect transistors are metal oxide semiconductor field effect transistors.

Claim 17

The constant current generation circuit according to claim 10 , wherein said constant current generation circuit further comprises potential holding means for holding the drain of said first field effect transistor at a predetermined potential.

Claim 18

The constant current generation circuit according to claim 10 , wherein the resistance value of said first resistor is adjustable at the time of at least the fabrication.

Claim 19

The constant current generation circuit according to claim 10 , wherein said first resistor is composed of polycrystalline silicon.

Claim 20

The constant current generation circuit according to claim 10 , wherein the gate length and the gate width of said first field effect transistor are set such that a voltage applied across both ends of said first resistor at a first temperature and a voltage applied across both ends of said first resistor at second temperature different from the first temperature are equal to each other.

Claim 21

The constant current generation circuit according to claim 10 , wherein said second resistor is constructed using a plurality of resistors and a switch, and has a programmable function by switching said plurality of resistors using said switch.

Claim 22

The constant current generation circuit according to claim 10 , wherein said first resistor is constructed using a plurality of resistors and a switch, and has a programmable function by switching said plurality of resistors using said switch.

Claim 23

A constant voltage/constant current generation circuit comprising a constant voltage generation circuit, said constant voltage generation circuit comprising a constant current generation circuit, and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said first field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to the current flowing through said first resistor in said constant current generation circuit to flow through said second resistor, and said constant voltage/constant current generation circuit further comprising a third current mirror circuit for generating a current which is equal or proportion to the current flowing through said first resistor in said constant current generation circuit in said constant voltage generation circuit.

Claim 24

A constant voltage/constant current generation circuit comprising a constant voltage generation circuit, said constant voltage generation circuit comprising a constant current generation circuit, and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said first field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to the current flowing through said first resistor in said constant current generation circuit to flow through said second resistor, and said constant voltage/constant current generation circuit further comprising a third current mirror circuit for generating a current which is equal or proportion to the current flowing through said first resistor in said constant current generation circuit in said constant voltage generation circuit.

Claim 25

An amplification circuit comprising: a plurality of operational amplifiers; and a constant voltage/constant current generation circuit for applying a constant voltage as a reference voltage to an input terminal of at least one of the plurality of operational amplifiers as well as supplying a constant current as a bias current, said constant voltage/constant current generation circuit comprising a constant voltage generation circuit, said constant voltage generation circuit comprising a constant current generation circuit, and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said first field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to the current flowing through said first resistor in the constant current generation circuit to flow through said second resistor, and said constant voltage/constant current generation circuit further comprising a third current mirror circuit for generating a current which is equal or proportion to the current flowing through said first resistor in said constant current generation circuit in said constant voltage generation circuit.

Claim 26

An amplification circuit comprising: a plurality of operational amplifiers; and a constant voltage/constant current generation circuit for applying a constant voltage as a reference voltage to an input terminal of at least one of the plurality of operational amplifiers as well as supplying a constant current as a bias current, said constant voltage/constant current generation circuit comprising a constant voltage generation circuit, said constant voltage generation circuit comprising a constant current generation circuit, and a current/voltage conversion circuit for converting a current flowing through said constant current generation circuit into a voltage, said constant current generation circuit comprising a first field effect transistor having a threshold voltage Vt, and a first resistor, said first field effect transistor and said first resistor being connected to each other such that said first field effect transistor operates in a saturation region, a voltage applied across both ends of said first resistor is uniquely determined by a voltage between the gate and the source of said first field effect transistor, and a current flowing through said first field effect transistor and a current flowing through said first resistor are equal or proportional to each other, the voltage between the gate and the source of said first field effect transistor being set within a range of not less than (Vt+0.1) volts nor more than (Vt+0.4) volts, said current/voltage conversion circuit comprising a second resistor composed of the same material as that for said first resistor in said constant current generation circuit, and a second current mirror circuit for causing a current which is equal or proportional to the current flowing through said first resistor in the constant current generation circuit to flow through said second resistor, and said constant voltage/constant current generation circuit further comprising a third current mirror circuit for generating a current which is equal or proportion to the current flowing through said first resistor in said constant current generation circuit in said constant voltage generation circuit.