Circuit for generating reference voltage of semiconductor memory apparatus
A reference voltage generating circuit in a semiconductor memory apparatus comprises a driving control signal generating unit configured to generate a driving control signal according to a temperature variation, wherein the driving control signal generating unit is enabled in response to a power-up signal, a driving unit configured to control a voltage level, which is applied to a voltage transfer node, in response to the power-up signal and the driving control signal, and a reference voltage generating unit configured to generate a reference voltage when a voltage level on the voltage transfer node is higher than a predetermined voltage level.
1. A reference voltage generating circuit in a semiconductor memory apparatus comprising:
a driving control signal generating unit configured to detect a temperature variation and generate a driving control signal according to the temperature variation, and to be enabled in response to a power-up signal;
a driving unit configured to control a voltage level applied to a voltage transfer node in response to the power-up signal and the driving control signal; and
a reference voltage generating unit configured to generate a reference voltage when a voltage level on the voltage transfer node is higher than a predetermined voltage level.
2. The reference voltage generating circuit of claim 1 , wherein the driving control signal generating unit is further configured to generate the driving control signal by comparing a detection voltage, generated according to a temperature variation, with a divided voltage, generated by dividing an external power supply voltage.
3. The reference voltage generating circuit of claim 2 , wherein the driving control signal generating unit includes:
a temperature detecting unit configured to generate the detection voltage of which voltage level is varied according to the temperature variation;
a voltage divider configured to generate the divided voltage by dividing the external power supply voltage; and
a comparison unit configured to compare the detection voltage with the divided voltage in order to generate the driving control signal.
4. The reference voltage generating circuit of claim 3 , wherein the temperature detecting unit includes a temperature sensor of which the resistance is increased when a temperature goes up.
5. The reference voltage generating circuit of claim 4 , wherein the temperature sensor is a transistor configured as a diode.
6. The reference voltage generating circuit of claim 3 , wherein the voltage divider is further configured to output the divided voltage from a connection node between a plurality of resistors connected in series.
7. The reference voltage generating circuit of claim 3 , wherein the comparison unit is further configured to activate the driving control signal when the detection voltage is higher than the divided voltage.
8. The reference voltage generating circuit of claim 3 , wherein the comparison unit is further configured to deactivate the driving control signal when the detection voltage is lower than the divided voltage.
9. The reference voltage generating circuit of claim 1 , wherein the driving unit includes:
a start-voltage applying unit configured to apply a voltage of a predetermined level to a start node;
a driving acceleration unit configured to apply an external power supply voltage to the start node in response to the driving control signal and connect the start node to the voltage transfer node; and
a switching unit configured to connect the start node to the voltage transfer node in response to the power-up signal.
10. The reference voltage generating circuit of claim 9 , wherein the start-voltage applying unit includes:
a first transistor having a gate connected to a ground voltage terminal, a source to which the external power supply voltage is applied, and a drain connected to the start node; and
a second transistor having a gate and a drain which are connected to the start node, and a source connected to the ground voltage terminal.
11. The reference voltage generating circuit of claim 9 , wherein the driving acceleration unit is further configured to apply the external power supply voltage to the start node and connect the start node to the voltage transfer node when the driving control signal is activated.
12. The reference voltage generating circuit of claim 11 , wherein the driving acceleration unit includes:
a first transistors configured to apply the external power supply voltage to the start node in response to the driving control signal; and
a second transistor configured to connect the start node to the voltage transfer node in response to the driving control signal.
13. The reference voltage generating circuit of claim 9 , wherein the switching unit includes a transistor to connect the start node to the voltage transfer node in response to the power-up signal.