Reference current source
View Patent ↗Systems, methods, and apparatus for generating a reference current. A reference current source can include a current generator circuit; a first resistance circuit that has a positive temperature dependence; and a second resistance circuit that has a negative temperature dependence. The first resistance circuit and the second resistance circuit can be connected in parallel to the current generator circuit.
1. A reference current source, comprising:
a current generator circuit; and
a resistance circuit connected to the current generator circuit, wherein the resistance circuit comprises a current controlled resistance circuit and a voltage controlled resistance circuit that is connected in parallel with the current controlled resistance circuit, wherein the voltage controlled resistance circuit comprises a first plurality of MOSFETs, and wherein the first plurality of MOSFETs comprise:
a first MOSFET having a drain connected to an emitter of a bipolar transistor of the current generator, and having a source connected to ground;
a second MOSFET having a drain connected to a voltage source of the current generator and a gate connected to a first current control voltage source; and
a third MOSFET having a source connected to ground and a gate connected to a second current control voltage source, wherein a drain of the third MOSFET is connected to each of a drain of the second MOSFET and a gate of the first MOSFET.
2. The reference current source of claim 1 , wherein the current controlled resistance circuit comprises a second plurality of MOSFETs.
3. The reference current source of claim 2 , wherein the second plurality of MOSFETs comprise:
a fourth MOSFET having a drain connected to each of the drain of the first MOSFET and the emitter of the bipolar transistor, and having a source connected to the ground;
a fifth MOSFET having a source connected to the voltage source of the current generator and a gate connected to the current generator; and
a sixth MOSFET having a source connected to ground and a gate connected to each of a gate of the fourth MOSFET, a drain of the fifth MOSFET, and a drain of the sixth MOSFET.
4. The reference current source of claim 1 , wherein the current controlled resistance circuit has a positive temperature dependency.
5. The reference current source of claim 4 , wherein the voltage controlled resistance circuit has a negative temperature dependency.
6. The reference current source of claim 5 , wherein the current controlled resistance circuit and the voltage controlled resistance circuit are respectively configured so that a combination of the positive temperature dependency and the negative temperature dependency configure the reference current source to be temperature independent.
7. The reference current source of claim 5 , wherein the current controlled resistance circuit and the voltage controlled resistance circuit are respectively configured so that a combination of the positive temperature dependency and the negative temperature dependency configure the reference current source to have a positive temperature dependence.
8. The reference current source of claim 5 , wherein the current controlled resistance circuit and the voltage controlled resistance circuit are respectively configured so that a combination of the positive temperature dependency and the negative temperature dependency configure the reference current source to have a negative temperature dependence.
9. The reference current source of claim 1 , wherein the current generator circuit comprises a PTAT current generator circuit.
10. A reference current source comprising:
a current generator circuit;
a current controlled resistance circuit that has a positive temperature dependence; and
a voltage controlled resistance circuit that has a negative temperature dependence, wherein the current controlled resistance circuit and the voltage controlled resistance circuit are connected in parallel to the current generator circuit, and wherein an L2/L1 ratio and a p value for MOSFETs of the reference current source are selected to provide a zero current slope at a given temperature.
11. A reference current source, comprising:
a current generator circuit; and
a resistance circuit connected to the current generator circuit, wherein the resistance circuit comprises a current controlled resistance circuit and a voltage controlled resistance circuit, the current controlled resistance circuit connected to a voltage source of the current generator circuit, the voltage controlled resistance circuit connected to the voltage source of the current generator circuit, a first current control voltage source, and a second current control voltage source.