Generator for supplying reference voltage and reference current of stable level regardless of temperature variation
View Patent ↗A reference voltage and reference current generator supplies a reference voltage and a reference current, both having stable levels regardless of temperature variation. The reference voltage and reference current generator includes a reference voltage generating unit, a first current mirror, a temperature compensation MOS transistor and a second current mirror. The reference voltage generating unit outputs a reference voltage having a stable level regardless of temperature variation and process variation by using junction voltage characteristic and thermal voltage characteristic of a bipolar transistor, and supplies an inner current corresponding to the thermal voltage characteristic. The first current mirror supplies a first current by mirroring the inner current. The temperature compensation MOS transistor supplies a second current corresponding to the reference voltage through the source-drain stage. The second current mirror supplies a reference current corresponding to the sum of the first current and the second current.
1. A reference voltage and reference current generator comprising:
a reference voltage generating means for outputting a reference voltage having a stable level regardless of temperature variation and process variation by using junction voltage characteristic and thermal voltage characteristic of bipolar transistors, and supplying an inner current corresponding to the thermal voltage characteristic;
a first current mirror for mirroring the inner current to supply a first current;
a temperature compensation MOS transistor for supplying a second current corresponding to the reference voltage through a source-drain stage; and
a second current mirror for supplying a reference current corresponding to the first current and the second current.
2. The reference voltage and reference current generator as recited in claim 1 , wherein the first current mirror includes:
a first MOS transistor diode-coupled for receiving the inner current at one end; and
a second MOS transistor having a gate coupled commonly to the gate of the first MOS transistor for mirroring the inner current to supply the first current.
3. The reference voltage and reference current generator as recited in claim 2 , wherein the second current mirror includes:
a third MOS transistor diode-coupled for providing an operation current corresponding to the sum of the first current and the second current to supply the second MOS transistor and the temperature compensation MOS transistor with the first current and the second current, respectively, through a source-drain stage; and
a fourth MOS transistor having a gate coupled commonly to the gate of the third MOS transistor for mirroring the operation current to supply the reference current.
4. The reference voltage and reference current generator as recited in claim 1 , wherein the reference voltage generating means includes:
a first to a third bipolar transistors, each being diode-coupled;
a second resistor having one end coupled to the emitter of the second bipolar transistor;
a third resistor having one end coupled to the emitter of the third bipolar transistor;
an operational amplifier having a positive input coupled to the emitter of the first bipolar transistor and a negative input coupled to the other end of the first resistor;
a first to a third PMOS transistors having gates receiving the output of the operational amplifier, one ends commonly coupled to a power supply voltage and the other ends coupled to the emitter of the first bipolar transistor, the other end of the first resistor and the other end of the second resistor, respectively; and
a fourth PMOS transistor having a gate receiving the output of the operational amplifier, one end coupled to the power supply voltage, and other end for supplying the inner current.