Sensing circuit
View Patent ↗A sensing circuit ( 120 ) for sensing currents, including: a measure circuit branch ( 132 i ), having a measure node for receiving an input current (Ic) to be sensed, for converting the input current into a corresponding input voltage (V−); at least one comparison circuit branch ( 132 o ), having a comparison node for receiving a comparison current (Igs), for converting the comparison current into a corresponding comparison voltage (V+); and at least one voltage comparator ( 140 ) for comparing the input and comparison voltages, and a comparison current generating circuit (N 3 s, 135 ; N 3 s, 135′ ; N 3 s, 135 ″) for generating the comparison current based on a reference current (Ir). The comparison current generating circuit includes at least one voltage generator ( 135; 135′; 135″ ). A memory device using the sensing circuit and a method are also provided.
1. A sensing circuit for sensing currents, comprising:
a measure circuit branch, having a measure node for receiving an input current to be sensed, for converting the input current into a corresponding input voltage;
at least one comparison circuit branch, having a comparison node for receiving a comparison current, for converting the comparison current into a corresponding comparison voltage;
at least one voltage comparator for comparing the input and comparison voltages; and
means for generating the comparison current based on a reference current, the means comprising:
at least one voltage generator for receiving the reference current and for generating a corresponding sense amplifier biasing voltage; and
means for converting the sense amplifier biasing voltage into the comparison current,
wherein
the at least one voltage generator includes:
a first circuit branch, having a first node for receiving the reference current, for converting the reference current into a corresponding reference voltage;
a second circuit branch, having a second node for receiving a regulation current, in current mirror configuration with the first circuit branch for mirroring a current corresponding to the reference current, the second circuit branch generating by conversion a non-regulated voltage corresponding to the mirrored current and to the regulation current; and
voltage regulator means receiving the reference voltage and the non-regulated voltage for regulating the sense amplifier biasing voltage by controlling the non-regulated voltage through the regulation current.
2. The sensing circuit according to claim 1 , wherein the voltage regulator means includes a differential amplifier for amplifying a voltage difference between the non-regulated and reference voltages, and a feedback network for converting the amplified voltage difference into the regulation current.
3. The sensing circuit according to claim 2 , wherein the feedback network comprises at least one transistor having a current delivery terminal connected to the second node and a control terminal receiving the amplified voltage difference.
4. The sensing circuit according to claim 2 , wherein the differential amplifier is an operational amplifier.
5. The sensing circuit according to claim 4 , wherein the feedback network comprises at least one transistor having a current delivery terminal connected to the second node and a control terminal receiving the amplified voltage difference.
6. The sensing circuit according to claim 1 , wherein the measure circuit branch and the at least one comparison circuit branch are in current mirror configuration, for mirroring the input current into the at least one comparison circuit branch.
7. The sensing circuit according to claim 1 , wherein the at least one voltage generator further includes at least one additional voltage generator comprising:
an additional circuit branch, having an additional node for receiving the regulation current, in current mirror configuration with the first circuit branch for mirroring the current corresponding to the reference current, the additional circuit branch generating by conversion an additional non-regulated voltage corresponding to the mirrored current and to the regulation current; and
additional voltage regulator means receiving the reference voltage and the additional non-regulated voltage for regulating the sense amplifier biasing voltage by controlling the additional non-regulated voltage through the regulation current.
8. The sensing circuit according to claim 7 , further including enabling means for selectively switching on or switching off the at least one additional voltage generator.
9. A memory device including at least one memory cell and one sensing circuit for sensing a current supplied by the at least one memory cell, wherein the sensing circuit comprising:
a measure circuit branch, having a measure node for receiving an input current to be sensed, for converting the input current into a corresponding input voltage;
at least one comparison circuit branch, having a comparison node for receiving a comparison current, for converting the comparison current into a corresponding comparison voltage; and
at least one voltage comparator for comparing the input and comparison voltages; and
means for generating the comparison current based on a reference current, the means comprising:
at least one voltage generator for receiving the reference current and for generating a corresponding sense amplifier biasing voltage; and
means for converting the sense amplifier biasing voltage into the comparison current,
wherein
the at least one voltage generator includes:
a first circuit branch, having a first node for receiving the reference current, for converting the reference current into a corresponding reference voltage;
a second circuit branch, having a second node for receiving a regulation current, in current mirror configuration with the first circuit branch for mirroring a current corresponding to the reference current, the second circuit branch generating by conversion a non-regulated voltage corresponding to the mirrored current and to the regulation current; and
voltage regulator means receiving the reference voltage and the non-regulated voltage for regulating the sense amplifier biasing voltage by controlling the non-regulated voltage through the regulation current.
10. The memory device according to claim 9 , including at least one reference cell for supplying the reference current.
11. The memory device according to claim 9 , wherein the voltage regulator means includes a differential amplifier for amplifying a voltage difference between the non-regulated and reference voltages, and a feedback network for converting the amplified voltage difference into the regulation current.
12. The memory device according to claim 11 , wherein the feedback network comprises at least one transistor having a current delivery terminal connected to the second node and a control terminal receiving the amplified voltage difference.
13. The memory device according to claim 11 , wherein the differential amplifier is an operational amplifier.
14. The memory device according to claim 13 , wherein the feedback network comprises at least one transistor having a current delivery terminal connected to the second node and a control terminal receiving the amplified voltage difference.
15. The memory device according to claim 9 , wherein the measure circuit branch and the at least one comparison circuit branch are in current mirror configuration, for mirroring the input current into the at least one comparison circuit branch.
16. The memory device according to claim 9 , wherein the at least one voltage generator further includes at least one additional voltage generator comprising:
an additional circuit branch, having an additional node for receiving the regulation current, in current mirror configuration with the first circuit branch for mirroring the current corresponding to the reference current, the additional circuit branch generating by conversion an additional non-regulated voltage corresponding to the mirrored current and to the regulation current; and
additional voltage regulator means receiving the reference voltage and the additional non-regulated voltage for regulating the sense amplifier biasing voltage by controlling the additional non-regulated voltage through the regulation current.
17. The memory device according to claim 16 , further including enabling means for selectively switching on or switching off the at least one additional voltage generator.
18. A method of sensing an input current, including:
receiving the input current at a measure node of a measure branch of a sense amplifier;
converting the input current into a corresponding input voltage;
receiving a reference current;
generating a sense amplifier biasing voltage corresponding to the reference current;
converting the sense amplifier biasing voltage into a comparison current;
receiving the comparison current at a comparison node of at least one comparison circuit branch of the sense amplifier;
converting the comparison current into a corresponding comparison voltage; and
comparing the input and comparison voltages,
wherein
generating the sense amplifier biasing voltage includes receiving the reference current at a first node of a first circuit branch of at least one voltage generator;
converting the reference current into a corresponding reference voltage;
mirroring a current corresponding to the reference current into a second circuit branch of the at least one voltage generator in current mirror configuration with the first circuit branch;
receiving a regulation current at a second node of the second circuit branch; generating by conversion a non-regulated voltage corresponding-to the mirrored current and to the regulation current;
providing the reference and non-regulated voltages to voltage regulator means; and
regulating the sense amplifier biasing voltage by controlling the non-regulated voltage through the regulation current.
19. A sensing circuit for sensing currents, comprising:
a measure circuit branch, having a measure node for receiving an input current to be sensed, for converting the input current into a corresponding input voltage;
at least one comparison circuit branch, having a comparison node for receiving a comparison current, for converting the comparison current into a corresponding comparison voltage, wherein the at least one comparison circuit branch is arranged to be crossed by a current related to the input current to be sensed and to the comparison current;
at least one voltage comparator for comparing the input and comparison voltages; and
means for generating the comparison current based on a reference current, the means comprising:
at least one voltage generator for receiving the reference current and for generating a corresponding sense amplifier biasing voltage; and
means for converting the sense amplifier biasing voltage into the comparison current,
wherein
the at least one voltage generator includes:
a first circuit branch, having a first node for receiving the reference current, for converting the reference current into a corresponding reference voltage;
a second circuit branch, having a second node for receiving a regulation current, in current mirror configuration with the first circuit branch for mirroring a current corresponding to the reference current, the second circuit branch generating by conversion a non-regulated voltage corresponding to the mirrored current and to the regulation current; and
voltage regulator means receiving the reference voltage and the non-regulated voltage for regulating the sense amplifier biasing voltage by controlling the non-regulated voltage through the regulation current.