Level shifter

A column selector for selecting bit lines of a semiconductor memory device in response to a received address code, the column selector comprising:

• a plurality of switches associated respectively with bit lines and configured to be selectively controlled through corresponding switch control signals, respectively, for selecting the respective bit lines;
• a plurality of level shifters associated respectively with switches and configured to generate the corresponding switch control signals according to respective selection signals based on the address code, wherein each level shifter includes:
• first and second supply inputs for receiving a first supply voltage and a second supply voltage, respectively;
• a shifting circuit configured to receive a corresponding one of the selection signals and set the switch control signal to a selected one of the first supply voltage and the second supply voltage according to a value of the corresponding selection signal, the shifting circuit including a circuit branch connected between the first supply input and the second supply input, said circuit branch including a plurality of series-connected electronic devices and a voltage dropper device connected in series with the plurality of electronic devices and configured to introduce a voltage drop;
• and
• a bias generator configured to generate a bias voltage for the voltage dropper device according to values of the first supply voltage and the second supply voltage, said voltage drop depending on the bias voltage.

A semiconductor memory device, comprising:

• a plurality of memory cells arranged in rows and columns;
• a plurality of bit lines associated respectively with the columns of memory cells;
• and
• a column selector configured to select at least one bit line of the bit lines in response to a received address code, the column selector including:
• a plurality of switches associated respectively with the bit lines and configured to be selectively controlled through corresponding switch control signals, respectively, for selecting the respective bit lines;
• a plurality of level shifters associated respectively with the switches and configured to generate the corresponding switch control signals, respectively, based on respective selection signals based on the address code, wherein each level shifter includes:
• first and second supply inputs for receiving a first supply voltage and a second supply voltage, respectively;
• a shifting circuit configured to receive a corresponding one of the selection signals and set the corresponding switch control signal to a selected one of the first supply voltage and the second supply voltage according to a value of the corresponding selection signal, the shifting circuit including a circuit branch connected between the first supply input and the second supply input, said circuit branch including a plurality of series-connected electronic devices, and a voltage dropper device connected in series with the plurality of electronic devices and configured to introduce a voltage drop;
• and
• a bias generator configured to generate a bias voltage for the voltage dropper device according to values of the first supply voltage and the second supply voltage, said voltage drop depending on the bias voltage.

A method, comprising:

• providing a first supply voltage and a second supply voltage to a first supply input and to a second supply input of a level shifter circuit, respectively;
• providing an input voltage to a shifting circuit included in the level shifter circuit;
• at the shifting circuit, outputting a selected one of the first supply voltage and the second supply voltage according to a value of the input voltage, the shifting circuit including a circuit branch connected between the first supply input and the second supply input, said circuit branch including a plurality of series-connected electronic devices, the step of outputting including:
• generating a bias voltage according to values of the first supply voltage and the second supply voltage;
• providing said bias voltage to a voltage dropper device connected in series with the plurality of electronic devices for introducing a voltage drop, wherein said voltage drop depends on the bias voltage.

An electronic system, comprising:

• a processor;
• input/output units for receiving and providing data;
• and
• a memory coupled to said processor, said memory including:
• a plurality of memory cells arranged in rows and columns;
• a plurality of bit lines associated respectively with the columns of memory cells;
• and
• a column selector configured to select at least one of the bit lines in response to a received address code, the column selector including:
• a plurality of switches associated respectively with the bit lines and configured to be selectively controlled through corresponding switch control signals, respectively, for selecting the respective bit lines;
• a plurality of level shifters associated respectively with the switches and configured to generate the corresponding switch control signals, respectively, based on respective selection signals based on the address code, wherein each level shifter includes:
• first and second supply inputs for receiving a first supply voltage and a second supply voltage, respectively;
• a shifting circuit configured to receive a corresponding one of the selection signals and set the corresponding switch control signals to a selected one of the first supply voltage and the second supply voltage according to a value of the corresponding selection signal, the shifting circuit including a circuit branch connected between the first supply input and the second supply input, said circuit branch including a plurality of series-connected electronic devices, and a voltage dropper device connected in series with the plurality of electronic devices and configured to introduce a voltage drop;
• and
• a bias generator configured to generate a bias voltage for the voltage dropper device according to values of the first supply voltage and the second supply voltage, said voltage drop depending on the bias voltage.