Semiconductor device for generating internal voltage and memory system including the semiconductor device
A semiconductor device includes a comparator, an internal voltage generator, a control signal generator, and a selector. The comparator may compare a reference voltage to an internal voltage and output a comparison signal. The internal voltage generator may generate and output the internal voltage in response to the comparison signal. The control signal generator may generate a control signal. The selector may receive first and second target voltages, and select and output one of the first and second target voltages as the reference voltage in response to the control signal.
1. A semiconductor device, comprising:
a comparator adapted to compare a reference voltage to an internal voltage and to output a comparison signal;
an internal voltage generator adapted to generate and output the internal voltage in accordance with the comparison signal;
a control signal generator adapted to generate a control signal; and
a selector adapted to receive first and second target voltages, and to select and output one of the first and second target voltages as the reference voltage in accordance with the control signal,
wherein the selector is adapted to select the first target voltage as the reference voltage when performing an over-driving operation and to select the second target voltage as the reference voltage when performing a sensing operation.
2. The semiconductor device as claimed in claim 1 , wherein the selector is adapted to select the first target voltage as the reference voltage when performing the over-driving operation and during a predetermined period after starting the sensing operation, and to select the second target voltage as the reference voltage during the sensing operation not including the predetermined period.
3. The semiconductor device as claimed in claim 1 , wherein the comparator includes a current controller adapted to control a bias current of the comparator in accordance with the control signal.
4. The semiconductor device as claimed in claim 3 , wherein the comparator includes:
a first transistor having a first port connected to an output port of the comparator and a gate connected to the reference voltage;
a second transistor having a first port connected to a complementary output port of the output port, a second port connected to a second port of the first transistor, and a gate connected to an output of the internal voltage generator; and
a third transistor having a first port connected to the second ports of the first and second transistors, a second port connected to a ground voltage, and a gate connected to the reference voltage,
wherein the current controller includes a fourth transistor having a first port connected to the first port of the third transistor, a second port connected to the ground voltage, and a gate connected to the control signal.
5. A memory system, comprising:
a memory device as claimed in claim 1 ;
a controller adapted to control the memory device; and
a semiconductor device in the memory device, the semiconductor device adapted to output an internal voltage to the memory device.
6. A semiconductor device, comprising:
a comparator adapted to compare a reference voltage to a comparison voltage and to output a comparison signal;
an internal voltage generator adapted to generate and output an internal voltage in accordance with the comparison signal;
a control signal generator adapted to generate a control signal; and
a voltage divider adapted to output a voltage obtained by voltage dividing the internal voltage as the comparison voltage in accordance with the control signal in a first logic state, and to output the internal voltage as the comparison voltage in accordance with the control signal in a second logic state,
wherein the control signal generator generates the control signal in the first logic state during an over-driving operation and at a predetermined period after a sensing operation starts, and in the second logic state in a period for performing the sensing operation not including the predetermined period.
7. The semiconductor device as claimed in claim 6 , wherein the control signal generator is adapted to generate the control signal in the first logic state from a time when a predetermined command is received until a time when the internal voltage becomes the same as or less than the reference voltage after the sensing operation starts.
8. The semiconductor device as claimed in claim 6 , wherein the comparator includes a current controller adapted to control a bias current of the comparator in accordance with the control signal.
9. The semiconductor device as claimed in claim 6 , wherein the voltage divider includes:
a first resistive element connected between the internal voltage and a second an output port of the voltage divider;
a second resistive element connected between the output port of the voltage divider and a transistor; and
the transistor having a first port connected to the second resistive element, a second port connected to a ground voltage, and a gate connected to the control signal,
wherein at least one of the first and second resistive elements is a resistive element having a fixed resistance or a resistive element having a variable resistance.
10. The semiconductor device as claimed in claim 6 , wherein the control signal generator includes:
a delayer adapted to delay a received predetermined command, the delayer being adapted to output the delayed predetermined command as an output signal;
an inverter adapted to invert and output the output signal of the delayer; and
an AND gate adapted to perform an AND operation on the received predetermined command and the output signal of the inverter, an output of the AND gate being output as the control signal.
11. A memory system, comprising:
a memory device including the semiconductor device as claimed in claim 6 ; and
a controller adapted to control the memory device, the semiconductor device being adapted to output the internal voltage to the memory device.
12. A semiconductor device, comprising:
a comparator adapted to compare a reference voltage to a comparison voltage and to output a comparison signal;
an internal voltage generator adapted to generate and output an internal voltage in accordance with the comparison signal;
a control signal generator adapted to generate a control signal in a first logic state when performing an over-driving operation and a control signal in a second logic state when performing a sensing operation; and
a voltage divider adapted to output a voltage obtained by voltage dividing the internal voltage as the comparison voltage in response to the control signal in the first logic state, and to output the internal voltage as the comparison voltage in response to the control signal in the second logic state,
wherein the comparator includes a current controller adapted to control a bias current of the comparator in accordance with the control signal.
13. The semiconductor device as claimed in claim 12 , wherein the voltage divider includes:
a first resistive element connected between an output of the internal voltage generator and an output of the voltage divider;
a second resistive element connected to the output of the voltage divider; and
a transistor having a first port connected to a second port of the second resistive element, a second port connected to a ground voltage, and a gate connected to the control signal, and
wherein at least one of the first and second resistive elements is a resistive element having a fixed resistance or a resistive element having a variable resistance.
14. The semiconductor device as claimed in claim 12 , wherein the control signal generator generates the control signal in the first logic state during the over-driving operation and at a predetermined period after the sensing operation starts, and in the second logic state in a period for performing the sensing operation not including the predetermined period.