High-speed, low-power input buffer for integrated circuit devices
View Patent ↗A high-speed, low-power input buffer for an integrated circuit device in which the input voltage (VIN) is coupled to both a pull-up and a pull-down transistor. In accordance with a specific embodiment, the input buffer utilizes a reference voltage input (VREF) during a calibration phase of operation but not when in an active operational mode. A maximum level of through current is supplied when VIN=VREF with lower levels of through current at all other VIN voltages. In an integrated circuit device incorporating an input buffer as disclosed, two (or more) input buffers may be utilized per device input pin.
1. An integrated circuit device including at least one input buffer comprising:
a pull-up device operatively coupled to a first voltage node;
a pull-down device operatively coupled between said pull-up device and a second voltage node, said pull-up and pull-down devices being capacitively coupled to an input voltage signal;
means for inducing a voltage offset between said input voltage signal and said pull-up device;
means for inducing a voltage offset between said input voltage signal and said pull-down device; and
an output node intermediate said pull-up and pull-down devices.
2. The integrated circuit device of claim 1 wherein said pull-up and pull-down devices comprise MOS transistors.
3. The integrated circuit device of claim 2 wherein said pull-up device comprises a P-channel transistor and said pull-down device comprises an N-channel transistor.
4. The integrated circuit device of claim 1 wherein said first voltage node comprises a supply voltage source and said second voltage node comprises circuit ground.
5. The integrated circuit device of claim 1 wherein said pull-down device is operatively coupled to said second voltage node through a first switching device in response to a first calibration signal.
6. The integrated circuit device of claim 5 further comprising:
a second switching device for selectively applying said input voltage signal to said pull-up and pull-down devices in response to a second calibration signal.
7. The integrated circuit device of claim 6 further comprising:
a third switching device for selectively applying a reference voltage signal to said pull-up and pull-down devices in response to a third calibration signal.
8. The integrated circuit device of claim 7 further comprising:
a fourth switching device for selectively coupling said output node to said second voltage node in response to a fourth calibration signal.
9. The integrated circuit device of claim 8 further comprising:
a resistive element coupling said fourth switching device to said second voltage node.
10. The integrated circuit device of claim 8 further comprising:
fifth and sixth switching devices for selectively coupling said reference voltage signal to said output node in response to respective fifth and sixth calibration signals.
11. The integrated circuit device of claim 7 wherein said second and third calibration signals are complementary.
12. The integrated circuit device of claim 8 wherein said first and fourth calibration signals are complementary.
13. The integrated circuit device of claim 10 wherein said fifth and sixth calibration signals are complementary.
14. The integrated circuit device of claim 1 further comprising:
an inverter for coupling said output node to an output terminal of said input buffer.
15. The integrated circuit device of claim 1 comprising at least two of said input buffers associated with at least one pin of said integrated circuit device.
16. The integrated circuit device of claim 15 wherein said at least two of said input buffers are alternatively coupled to receive said input voltage signal and to provide an output voltage signal during a respective operational phase thereof.