Method for smoothing a current consumed by an integrated circuit and corresponding device
A method for smoothing current consumed by an electronic device is based on a series of current copying operations and on a current source delivering a reference current. The reference current is delivered in such a manner that current consumed as seen from the power supply depends on the reference current.
1. A method comprising:
providing a main current to an electronic device from a power supply; and
generating a smoothing current from the power supply, wherein a sum of the main current and the smoothing current is proportional to a reference current irrespective of variations of the main current, and wherein generating the smoothing current comprises:
generating a first current proportional to the main current;
generating a second current proportional to the reference current; and
generating a third current proportional to a difference between the reference current and the main current.
2. The method of claim 1 , wherein
the first current is equal to the main current divided by a first factor; and
the second current is equal to the reference current divided by the first factor.
3. The method of claim 2 , wherein the first factor is equal to 100.
4. The method of claim 1 , further comprising generating an independent current from the power supply.
5. A method comprising:
providing a main current to an electronic device from a power supply; and
generating a smoothing current from the power supply, wherein a sum of the main current and the smoothing current is proportional to a reference current irrespective of variations of the main current, wherein the reference current is higher than a maximum value of the main current.
6. A circuit comprising:
an electronic device configured to consume a main current from a power supply; and
a smoothing current generator circuit configured to consume a smoothing current from the power supply, wherein a sum of the main current and the smoothing current is proportional to a reference current irrespective of variations of the main current, wherein the smoothing current generator circuit comprises:
a first current generation circuit configured to generate a first current proportional to the main current;
a second current generation circuit configured to generate a second current proportional to the reference current; and
a third current generation circuit configured to generate a third current proportional to a difference between the reference current and the main current.
7. The circuit of claim 6 , wherein
the first current generation circuit comprises a first current mirror;
the second current generation circuit comprises a second current mirror; and
the third current generation circuit comprises a third current mirror.
8. The circuit of claim 7 , wherein
the first current mirror comprises transistors of a p-type;
the second current mirror comprises transistors an n-type; and
the third current mirror comprises transistors of the n-type.
9. The circuit of claim 8 , wherein the smoothing current generator circuit further comprises a noise generator coupled to the second current mirror.
10. The circuit of claim 7 , wherein
the first current mirror is coupled to the second current mirror; and
the second current mirror is coupled to the third current mirror.
11. The circuit of claim 10 , wherein the smoothing current generator circuit further comprises a first operation amplifier coupled between the second current mirror and the third current mirror.
12. The circuit of claim 11 , wherein the smoothing current generator circuit further comprises
a first cascode stage coupled between the first current mirror and the second current mirror; and
a second cascode stage coupled between the power supply and the third current mirror.
13. The circuit of claim 6 , wherein the electronic device comprises a microprocessor.
14. A circuit comprising:
an electronic device configured to consume a main current from a power supply; and
a smoothing current generator circuit configured to consume a smoothing current from the power supply, wherein a sum of the main current and the smoothing current is proportional to a reference current irrespective of variations of the main current, wherein the reference current is higher than a maximum value of the main current.
15. A smartcard comprising:
a microprocessor configured to consume a main current from a power supply; and
a smoothing current generator circuit configured to consume a smoothing current from the power supply, wherein a sum of the main current and the smoothing current is proportional to a reference current irrespective of variations of the main current, wherein the smoothing current generator circuit comprises:
a first current generation circuit configured to generate a first current proportional to the main current;
a second current generation circuit configured to generate a second current proportional to the reference current; and
a third current generation circuit configured to generate a third current proportional to a difference between the reference current and the main current.
16. The smartcard of claim 15 , wherein the smoothing current generator circuit further comprises a noise generator coupled to the second current generation circuit.
17. The smartcard of claim 15 , wherein the reference current is higher than a maximum value of the main current.
18. The circuit of claim 14 , wherein the smoothing current generator circuit comprises:
a first current generation circuit configured to generate a first current proportional to the main current;
a second current generation circuit configured to generate a second current proportional to the reference current; and
a third current generation circuit configured to generate a third current proportional to a difference between the reference current and the main current.
19. The circuit of claim 18 , wherein
the first current generation circuit comprises a first current mirror;
the second current generation circuit comprises a second current mirror; and
the third current generation circuit comprises a third current mirror.
20. The circuit of claim 19 , wherein
the first current mirror is coupled to the second current mirror;
the second current mirror is coupled to the third current mirror; and
the smoothing current generator circuit further comprises:
a first operation amplifier coupled between the second current mirror and the third current mirror,
a first cascode stage coupled between the first current mirror and the second current mirror, and
a second cascode stage coupled between the power supply and the third current mirror.