Power gating circuit and a semiconductor chip including the same
A power gating circuit including: a power gating transistor; a gate bias generating circuit configured to provide a gate bias control signal to the gate of the power gating transistor; and a body bias generating circuit configured to provide a body bias control signal to the body of the power gating transistor, wherein when the power gating transistor is turned on, the gate bias generating circuit provides the gate bias control signal having a positive voltage level and the body bias generating circuit provides the body bias control signal having the positive voltage level, and when the power gating transistor is turned off, the gate bias generating circuit provides the gate bias control signal having a ground voltage level or a negative voltage level, and the body bias generating circuit provides the body bias control signal having the ground voltage level or the negative voltage level.
1 . A power gating circuit comprising:
a power gating transistor;
a gate bias generating circuit connected to a gate of the power gating transistor and configured to provide a gate bias control signal to the gate of the power gating transistor to control a level of a voltage applied to the gate based on On/Off state of the power gating transistor; and
a body bias generating circuit connected to a body of the power gating transistor and configured to provide a body bias control signal to the body of the power gating transistor,
wherein the level of the voltage applied to the gate includes a positive voltage level, a ground voltage level and a negative voltage level, and
wherein:
after the power gating transistor is turned on, the gate bias generating circuit provides the gate bias control signal having the positive voltage level to the gate of the power gating transistor and the body bias generating circuit provides the body bias control signal having the positive voltage level to the body of the power gating transistor, and
after the power gating transistor is turned off, the gate bias generating circuit provides the gate bias control signal having the ground voltage level or the negative voltage level to the gate of the power gating transistor, and the body bias generating circuit provides the body bias control signal having the ground voltage level or the negative voltage level to the body of the power gating transistor.
2 . The power gating circuit of claim 1 , wherein the body bias generating circuit sets a voltage level of the body bias control signal based on a size of the power gating transistor.
3 . The power gating circuit of claim 2 , wherein the body bias generating circuit generates the body bias control signal having a lower negative voltage level as the size of the power gating transistor is increased.
4 . The power gating circuit of claim 3 , wherein the power gating transistor is an NMOS transistor.
5 . The power gating circuit of claim 1 , wherein the body bias generating circuit sets a voltage level of the body bias control signal based on a type of an internal circuit to which the power gating transistor is connected.
6 . The power gating circuit of claim 1 , wherein the body bias generating circuit sets a voltage level of the body bias control signal based on an amount of current consumed by an internal circuit to which the power gating transistor is connected.
7 . The power gating circuit of claim 6 , wherein the body bias generating circuit generates the body bias control signal having a higher positive voltage level as the amount of the current consumed by the internal circuit is increased.
8 . The power gating circuit of claim 7 , wherein the power gating transistor is a PMOS transistor.
9 . The power gating circuit of claim 1 , further comprising:
an additional power gating transistor,
wherein the power gating transistor is connected to an internal circuit and a ground voltage,
wherein the additional power gating transistor is connected to a power supply voltage and the internal circuit.
10 . The power gating circuit of claim 9 , further comprising:
a first inverter connected to the gate of the power gating transistor and a gate of the additional power gating transistor; and
a second inverter connected to the body of the power gating transistor and a body of the additional power gating transistor.
11 . The power gating circuit of claim 10 , wherein the power gating transistor and the additional power gating transistor are simultaneously turned on or turned off in response to the gate bias control signal and the body bias control signal.
12 . The power gating circuit of claim 11 , wherein the power gating transistor is an NMOS transistor, and the additional power gating transistor is a PMOS transistor.
13 . A semiconductor chip comprising:
a first power gating transistor connected to a first internal circuit and configured to provide a first power supply voltage to the first internal circuit;
a second power gating transistor connected to a second internal circuit, different from the first internal circuit, and configured to provide a second power supply voltage to the second internal circuit; and
a control circuit configured to control a switching operation of the first power gating transistor and the second power gating transistor,
wherein a level of a voltage, provided to a body of the first power gating transistor, is different from a level of a voltage provided to a body of the second power gating transistor.
14 . The semiconductor chip of claim 13 , further comprising:
a first gate bias generating circuit configured to provide a first gate bias control signal to a gate of the first power gating transistor;
a first body bias generating circuit configured to provide a first body bias control signal to the body of the first power gating transistor;
a second gate bias generating circuit configured to provide a second gate bias control signal to a gate of the second power gating transistor; and
a second body bias generating circuit configured to provide a second body bias control signal to the body of the second power gating transistor.
15 . The semiconductor chip of claim 14 , wherein a voltage level of the first gate bias control signal is higher than a voltage level of the second gate bias control signal.
16 . The semiconductor chip of claim 14 , wherein a voltage level of the first body bias control signal is higher than a voltage level of the second body bias control signal.
17 . The semiconductor chip of claim 13 , wherein a time required for the first internal circuit to reach a stable voltage is longer than a time required for the second internal circuit to reach a stable voltage.
18 . A power gating circuit comprising:
a first power gating transistor disposed between an internal circuit and a ground voltage;
a second power gating transistor disposed between the internal circuit and a power supply voltage;
a gate bias generating circuit configured to provide a gate bias control signal to a gate of the first power gating transistor; and
a body bias generating circuit configured to provide a body bias control signal to a body of the first power gating transistor,
wherein
when the first and second power gating transistors are turned on, the gate bias generating circuit and the body bias generating circuit provide the gate bias control signal having a positive voltage level and the body bias control signal having the positive voltage level, respectively, to the first power gating transistor, and
when the first and power gating transistors are turned off, the gate bias generating circuit provides the gate bias control signal, having a ground voltage level or a negative voltage level, and the body bias generating circuit provides the body bias control signal, having the ground voltage level or the negative voltage level, respectively, to the first power gating transistor.
19 . The power gating circuit of claim 18 , further comprising:
a first inverter disposed between the gate of the first power gating transistor and a gate of the second power gating transistor; and
a second inverter disposed between the body of the first power gating transistor and a body of the second power gating transistor.
20 . The power gating circuit of claim 19 , wherein
the first inverter inverts the gate bias control signal and provides an inverted version of the gate bias control signal to the gate of the second power gating transistor, and
the second inverter inverts the body bias control signal and provides an inverted version of the body bias control signal to the body of the second power gating transistor.