Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Amplitude control
Reexamination Certificate
1999-03-18
2001-03-13
Lam, Tuan T. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Amplitude control
C327S331000
Reexamination Certificate
active
06201428
ABSTRACT:
BACKGROUND
The present specification generally relates to integrated circuits. More particularly, the present specification describes a buffer/driver system.
Technology advances in integrated circuit fabrication have led to more compact chip designs. Lower voltage processes come with the smaller size. CMOS devices can use low voltage power supplies to prevent damage to devices having small feature sizes, and to reduce the overall power consumption. For example, power supplies for CMOS devices are being reduced from 3.3 volts to 2.5 volts and lower. However, low voltage CMOS devices often interface with transistor—transistor logic (TTL) devices that operate at higher supply voltages, e.g., 5 volts.
The Peripheral Component Interconnect (PCI) bus standard, PCI Compliance Checklist, Revision 2.1, published Jan. 1, 1997, requires a minimum of 2.4 volts on the bus to identify a high transition. Typically, there are a large number of buffers and drivers tied to the bus, any of which can be a TTL device. Therefore, each device must be capable of driving at least 2.4 volts, and be able to withstand voltage levels as high as 6.5 volts.
Another issue with multiple supply voltages is that the different voltages have different characteristics. Some voltages may be stable before others. In a worst case scenario, the highest voltage, e.g., 5 volts, may stabilize first, and already be at its highest level while the other voltages, e.g., 3.3 volts and 1.8 volts, are still at ground or low level. Such an initial condition at power-up could expose low voltage CMOS devices to the full 5 volts. This can cause damage to the device or a shortened life. For example, this could damage the gate oxide in the transistors that form the devices. This situation can be exacerbated by the PCI specification, which requires some of the PIN's to power up at 5 volts.
SUMMARY
The present disclosure describes a buffer/driver system that operates on an input signal to provide an output signal with a sufficient capability at an output terminal to drive a particular interface. The input signal is operated on to produce the output signal that has wider voltage swing than the input signal. Therefore, the devices in a circuit that is producing the input signal can operate with low voltages, while the output signal can drive other circuits with sufficient voltage levels.
Other embodiments and advantages will become apparent from the following description and from the claims.
REFERENCES:
patent: 5568062 (1996-10-01), Kaplinsky
patent: 6054888 (2000-04-01), Maley
Fish & Richardson P.C.
Intel Corporation
Lam Tuan T.
Nguyen Hiep
LandOfFree
5-volt tolerant 3-volt drive push-pull buffer/driver does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with 5-volt tolerant 3-volt drive push-pull buffer/driver, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 5-volt tolerant 3-volt drive push-pull buffer/driver will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504072