Booster circuit
A boosting circuit comprises a first boosting cell row and a second boosting cell row. The boosting circuit further comprises an analog comparison circuit for comparing the potential of boosting cells on the same stage, and selecting and outputting the lower or higher of the potentials. The potential of an N well is controlled using the output potential of the analog comparison circuit. Thereby, the amplitude of an N well potential can be suppressed, and a single N well region can be shared.
1. A booster circuit comprising:
boosting cells each having a first-conductivity type first well region on a substrate, a second-conductivity type second well region in the first well region, and at least one switching element in either or both of the first well region and the second well region, wherein the at least one switching clement switches to transfer charges from a first terminal to a second terminal;
a first boosting cell row including N stages (N≧1) of the boosting cells;
a second boosting cell row including M stages (M≧1) of the boosting cells; and
at least one analog comparison circuit for outputting a well bias potential generated by an output potential of the boosting cell on the i-th stage (1≦i≦N) of the first boosting cell row and an output potential of the boosting cell on the i-th stage (1≧i≧M) of the second boosting cell row,
wherein the well bias potential of the at least one analog comparison circuit is applied to the first well region of the switching element included in the at least one boosting cell of the first and second boosting cell rows.
2. The booster circuit of claim 1 , wherein;
the first boosting cell row includes N stages (N≧1) of the boosting cells and at least one backflow preventing circuit;
the second boosting cell row includes M stages (M≧1) of the boosting cells and at least one backflow preventing circuit; and
the well bias potential of the at least one analog comparison circuit is applied to the first well region of the switching element included in the at least one backflow preventing circuit of the first and second boosting cell rows.
3. The booster circuit of claim 1 , wherein the well bias potential is the higher potential out of the output potential of the boosting cell on the i-th stage (1 ≦i≦N) of the first boosting cell row and the output potential of the boosting cell on the i-th stage (1≦i≦M) of the second boosting cell row.
4. The booster circuit of claim 1 , wherein the well bias potential is the lower potential out of the output potential of the boosting cell on the i-th stage; (1 ≦i≦N) of the first-boosting cell row and the output potential of the boosting cell on the i-th stage (1≦i≦M) of the second boosting cell row.
5. The booster circuit of claim 1 , wherein the second well region and the first terminal are connected to each other so that the second well region and the first terminal have the same potential.
6. The booster circuit of claim 1 , wherein the second well region and the first well region are connected to each Other so that the second well region and the first well region have the same potential.
7. The booster circuit of claim 1 , wherein
the at least one analog comparison circuit has a first-conductivity type first well region on the substrate, a second-conductivity type second well region in the first well region, and at least one switching element in the first well region or the second well region, and
the at least one analog comparison circuit is provided one for each boosting cell stage.
8. The booster circuit of claim 1 , wherein
the at least one analog comparison circuit has a first-conductivity type first well region on the substrate, a second-conductivity type second well region in the first well region, and at least one switching element in the first well region or the second well region, and at least one analog comparison circuit is provided for the first and second boosting cell rows, and
the at least one analog comparison circuit is provided one every arbitrary number of boosting cell stages.
9. The booster circuit of claim 1 , wherein a diode element is provided between the first terminal and the first well region of the boosting cell.
10. The booster circuit of claim 1 , wherein the at least one switching elements having the same potential of the first well region of the first and second boosting cell rows share a common first well region.
11. The booster circuit of claim 1 , wherein the at least one switching elements having the same potential of the first well region of the first and second boosting cell rows and the at least one analog comparison circuit share a common first well region.
12. The booster circuit of claim 1 , wherein
the at least one switching circuit of the boosting cell on the i-th stage of the first boosting cell row and a first element of the at least one analog comparison circuit share a common first well region, and
the at least one switching circuit of the boosting cell on the i-th stage of the second boosting cell row and a second element of the at least one analog comparison circuit share a common first well region.
13. A booster circuit comprising:
boosting cells and backflow preventing circuits each having a first-conductivity type first well region on a substrate, a second-conductivity type second well region in the first well region, and at least one switching element in either or both of the first well region and the second well region, wherein the at least one switching element switches to transfer charges from a first terminal to a second terminal;
a first boosting cell row including N stages (N≧1) of the boosting cells and the backflow preventing circuit;
a second boosting cell row including M stages (M≧1) of the boosting cells and the backflow preventing circuit; and
at least one analog comparison circuit for outputting the well bias potential generated by an intermediate potential of the backflow preventing circuit of the first boosting cell row and an intermediate potential of the backflow preventing circuit of the second boosting cell row,
wherein the well bias potential of the at least one analog comparison circuit is applied to the first well region of the switching element included in the at Least one backflow preventing circuit, the boosting cell on the (i+1)-th stage, the boosting cell on the i-th stage, or at least one of the boosting cells on less than i-th stages of the first and second boosting cell rows.
14. A booster circuit comprising:
boosting cells each having a first-conductivity type first well region on a substrate, a second-conductivity type second well region in the first well region, and at least one switching element in either or both of the first well region and the second well region, wherein the at least one switching element switches ON/OFF a connection between a first terminal and a second terminal so as to transfer charges from the first terminal to the second terminal;
a first boosting cell row including N stages (N≧1) of the boosting cells; and
a second boosting cell row including M stages (M≧1) of the boosting cells;
wherein a potential of the first well region of the at least one switching element included in the boosting cells in the first and second boosting cell rows is controlled according to an output potential of the boosting cells of the first boosting cell row and an output potential of the boosting cells of the second boosting cell row.
15. The booster circuit of claim 1 , wherein an output potential of the analog comparison circuit is applied to the first well region of the at least one switching element included in a boosting cell of a boosting cell row different from the first and second boosting cell rows.