Switching circuit having an output voltage varying between a reference voltage and a negative voltage

• US 6,031,761 A
• Filed: 03/24/1999
• Issued: 02/29/2000
• Est. Priority Date: 03/27/1998
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Maccarrone, Marco, Ghezzi, Stefano, Commodaro, Stefano, Ghilardelli, Andrea
• Primary Examiner(s): Tran, Andrew Q.
• Application Number:
  US09/275,255
• Time in Patent Office: 342 Days
• Field of Search: 365/185.23, 365/185.29, 365/189.11, 365/185.27, 365/189.09
• US Class Current: 365/185.23
• CPC Class Codes: G11C 16/14 Circuits for erasing electrically, e.g. erase voltage switching circuits

Abstract

Switching circuit that receives a supply voltage, a reference voltage, a line adapted to carry a negative voltage and a control signal, the switching circuit capable of providing at an output a voltage alternatively equal to the reference voltage or to the voltage of the line in response to the control signal. The circuit includes a first MOSFET with a first electrode operationally connected to the line, a second electrode operationally connected to the output, and a control electrode, a second MOSFET with a first electrode operationally connected to the reference voltage, a second electrode operationally connected to the output, and a control electrode, and driving circuitry adapted to bring the control electrodes of the first and second MOSFETs respectively to the supply voltage and to the voltage of the line or, alternatively, to the voltage of the line and to the supply voltage, in response to the control signal.

Claims

1. A switching circuit receiving a supply voltage, a reference voltage, a line carrying a negative voltage, and a control signal, the switching circuit capable of providing at an output a voltage alternatively equal to said reference voltage or to the voltage of said line in response to said control signal, comprising:

a first MOSFET with a first electrode operationally connected to said line, a second electrode operationally connected to said output, and a control electrode;

a second MOSFET with a first electrode operationally connected to said reference voltage, a second electrode operationally connected to said output, and a control electrode; and

driving means for driving the control electrodes of said first and second MOSFETs respectively to the supply voltage and to the voltage of said line or, alternatively, to the voltage of said line and to the supply voltage, in response to said control signal.

2. Circuit according to claim 1, wherein said driving means comprises first circuit means driven by said control signal adapted to bring the control electrode of said first MOSFET alternatively to said supply voltage, to provide at the output the voltage of said line, or to the voltage of said line when said reference voltage is to be provided at the output, and seconds circuit means driven by said control signal adapted to connect the control electrode of said second MOSFET alternatively to the output, when the voltage of said line is to be provided at the output, or to the supply voltage to provide at the output said reference voltage.

3. Circuit according to claim 2, wherein said first circuit means comprises a voltage level translator that receives in input said control signal varying among said reference voltage and said supply voltage, and provides at an output node a varying signal respectively varying between the voltage of said line and said supply voltage.

4. Circuit according to claim 3, wherein said level translator comprises first switch means, second switch means, third switch means, fourth switch means, said first and third switch means on one side and said second and fourth switch means on the other side, connected in series between said supply voltage and said line, and said output mode corresponding to the node in common between said first switch means and said third switch means, said control signal driving said first switch means and second switch means in such way that when said first switch means are open, also said fourth switch means are open while said second switch means and third switch means are closed, connecting the output mode to said line, and vice versa when said first switch means are closed, also said fourth switch means are closed while said second switch means and third switch means are open, connecting the output mode to said supply voltage.

5. Circuit according to claim 4, wherein:

said first switch means includes a third P-channel MOSFETs, with a first electrode connected to said supply voltage, a second electrode connected to a first node and the control electrode driven by a logic complement of said control signal, a fourth P-channel MOSFET, with a first electrode connected to said first node, a second electrode connected to the output mode and the control electrode connected to said reference voltage, a fifth N-channel MOSFET, with a first electrode connected to said first node, a second electrode connected to said reference voltage and the control electrode driven by said logic complement of said control signal;

said second switch means includes a sixth P-channel MOSFETs, with a first electrode connected to said supply voltage, a second electrode connected to a second node and the control electrode driven by said control signal;

a seventh P-channel MOSFET, with a first electrode connected to said second node, a second electrode connected to said fourth switch means and the control electrode connected to said reference voltage;

an eighth N-channel MOSFET, with a first electrode connected to said second node, a second electrode connected to said reference voltage and the control electrode driven by said control signal;

said third switch means includes a ninth N-channel MOSFETs, in triple well technology, with a first electrode connected to the output mode, a second electrode connected to said line and the control electrode connected to the node in common to said seventh P-channel MOSFET and said fourth switch means;

said fourth switch means includes a tenth N-channel MOSFET, in triple well technology, with a first electrode connected to the control electrode of said ninth MOSFET, a second electrode connected to said line and the control electrode connected to the output mode.

6. Circuit according to claim 5, wherein said second circuit means includes an eleventh MOSFETs having a first electrode driven by said logic complement of said control signal, a second electrode connected to the control electrode of said second MOSFET, and a control electrode connected to said reference voltage, and a twelfth MOSFET having a first electrode connected to the control electrode of the second MOSFET, a second electrode connected to the output and a control electrode driven by said control signal.

7. Circuit according to claim 6, wherein said first, second and twelfth MOSFETs are N-channel and are realized in triple well technology, while said eleventh MOSFETs is P-channel.

8. A semiconductor electrically programmable and erasable non-volatile memory comprising at least an individually erasable memory sector, said memory sector comprising a set of memory cells arranged in rows and columns, driving means of the rows, said driving means of the rows being fed by a first positive voltage and by a second voltage which takes a value equal to the reference voltage of the memory during the reading and the programming of the memory, while in erasing the second voltage takes a negative value, and comprising a switching circuit according to claim 1 to supply said second voltage to said driving means of the rows.