Interface circuit and input buffer integrated circuit including the same
AssigneeNEC Corporation
InventorYasunori Sawai
Life of this patent
Estimating the term…
Abstract
An interface circuit effectively prevents ringing of signal waveform. In a buffer integrated circuit, a level of an input signal to an input buffer and a reference level are compared by a comparator. A transistor is operated to be turned ON and OFF depending upon the comparison result to control level of the input signal. Even when the ringing of the waveform from the output buffer is large, ringing may not be recognized as “H” level signal so as not to cause malfunction.
Claims15
An interface circuit for reducing ringing provided in a second device receiving as an input an output signal of a first device wherein an output impedance of said first device and an input impedance of said second device are unmatched, said interface circuit controlling an input signal level to an input buffer receiving said output signal, comprising control means for clamping said input signal level depending upon a result of comparison of a level of said output signal and a predetermined reference level to reduce ringing due to one of under-shooting and overshooting of said input signal.
An interface circuit provided in a second device inputting an output signal of a first device, controlling an input signal level to an input buffer inputting said output signal, comprising control means for controlling said input signal level depending upon a result of comparison of a level of said output signal and a predetermined reference level,
- wherein said control means includes a comparator circuit comparing said output signal level and said reference level and a switching element turning ON and OFF depending upon the result or comparison of said comparator circuit for controlling said input signal level,
- wherein said switching element is a pull-down transistor connected between a signal line transmitting said output signal and the ground and controls state of electrical connection between said signal line and said ground depending upon said comparison result.
An input buffer integrated circuit for reducing ringing comprising:
- an input buffer provided in a second device receiving as an input an output signal of a first device, said first device and said second device having unmatched input and output impedances;
- an interface circuit provided in said second device, integrated with said input buffer on a single chip for forming an integrated circuit, and including control means for clamping a level of said input signal depending upon a result of comparison of a level of said output signal and a predetermined reference level to reduce ringing due to one of under-shooting and overshooting of said input signal.
An input buffer integrated circuit comprising:
- an input buffer provided in a second device inputting an output signal of a first device and inputting said output signal;
- an interface circuit provided in said second device, integrated with said input buffer on a single chip for forming an integrated circuit, and including control means for controlling a level of said input signal depending upon a result of comparison of a level of said output signal and a predetermined reference level,
- wherein said control means includes a comparator circuit comparing said output signal level and said reference level and a switching element turning ON and OFF depending upon the result of comparison of said comparator circuit f or controlling said input signal level,
- wherein said switching element is a pull-down transistor connected between a signal line transmitting said output signal and the ground and controls state of electrical connection between said signal line and said ground depending upon said comparison result.
Dependencies are inferred from the claim text.