US 6,959,066 B2Granted

Device for programmable frequency divider

AssigneeElan Microelectronics Corporation

InventorsJung-Chih Wang, Chao-Yu Hu

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Abstract

The present invention relates to a programmable frequency divider having one n-bit adder and one n-bit D Flip Flop. These are used to transform the import clock to the target clock. The adder takes one adjustment parameter and one return signal as a basis to create the first output signal, with the possibility to program the adjustment parameter. The D Flip Flop and the adder create a cycle, which is used to receive the first output signal and its import clock to create the second output signal. The second output signal is separated into a return signal and the target signal. The D Flip Flop sends the return signal back to the adder, which will make addition calculations under the adjustment parameter, finally giving out the target clock with the target signal as a calculation basis.

Claims10

Dependent claims

A programmable frequency divider used to transform one import clock to one target clock with an import clock having a frequency 2m times as high as that of the target clock wherein m is an integer larger than zero, comprising:

a) a NOR Gate using remaining bits after the elimination of the most significant bit of an adjustment parameter as a input signal to form one output signal wherein the adjustment parameter contains n bits, n is an integer larger than zero, and m≦n, said adjustment parameter is controlled by program command;
b) a n-bit adder (n-bit ADD) using a first signal and one return signal to create one first output signal wherein said first signal comprises the one output signal of the NOR Gate and the remaining bits after elimination of the most significant bit of the adjustment parameter, and said output signal is a most significant bit of the first signal;
c) a n-bit D Flip Flop connected to said n-bit adder to form a cyclic circuit receiving the first output signal and the import clock and generating a second output signal wherein said second output signal comprises a second signal comprising the most significant bit of said second output signal and a return signal comprising n-bits from said second output signal, and said return signal is sent back to said n-bit adder to make addition calculations with said first signal;
d) a NAND Gate using a first import and a second import to create a fourth output signal wherein said first import receives said output signal, and said second import from a inverse import for receiving the most significant bit of said adjustment parameter;
e) a second D Flip Flop receiving the fourth output signal and the import clock to create a third signal;
f) an AND Gate using a third import and a fourth import to create a fifth output signal wherein a third import receives said second signal and said fourth import form the inverse import for receiving said third signal;
g) a third D Flip Flop receiving the fifth output signal and an inverse import clock to create the fourth signal, said inverse import clock making use of an inverter to inverse output the import clock;
and
h) a XOR Gate using said second signal and said fourth signal to create a target signal wherein said target signal is the basis for the output of the target clock.

6 more elements

a) a NOR Gate using the remaining bits after the elimination of the most significant bit of an adjustment parameter as a input signal to form output signal wherein the adjustment parameter contains n bits, n is an integer larger than zero, and m≦n, said adjustment parameter is controlled by program command;
b) a n-bit adder (n-bit ADD) using first signal and one return signal to create one first output signal wherein said first signal comprises output signal of the NOR Gate and the remaining bits after elimination of the most significant bit of said adjustment parameter and said output signal is a most significant bit of the first signal;
c) a n-bit first temporary data storage unit said n-bit adder to form a cycle for receiving the first output signal and the import clock and generating a second output signal wherein said second output signal comprises a return signal comprising n-bits from said second output signal and a second signal comprising the most significant bit of said second output signal, and said return signal is sent back to said n-bit adder to make addition calculations with said first signal;
d) the a NAND Gate using the first import and the second import to create a fourth output signal wherein said first import receives said output signal and said second import form inverse import for receiving the most significant bit of the adjustment parameter;
e) a second temporary data storage unit receiving the fourth output signal and the import clock to create a third signal;
f) a AND Gate using the third import and the fourth import to create a fifth output signal wherein said third import receives the second signal and said fourth import form the inverse import for receiving the third signal;
g) a third D Flip Flop using the fifth output signal and the inverse import clock to create the fourth signal wherein the said inverse import clock make use of an inverter to inverse output the import clock;
and
hf) a XOR Gate using said second signal and said fourth signal to create a target signal wherein said target signal is the basis for the output of the target clock.

6 more elements

Dependencies are inferred from the claim text.