Delay signal generator
A delay clock generator includes a plurality of delay element arrays arranged in parallel; a feed side transfer line and a return side transfer line provided in each of the delay elements which make up the delay element arrays, and that transfer a clock signal in a feed direction and a return direction; a selector selecting a first transfer route that couples the feed side transfer lines to each other along the preceding and succeeding delay elements and a third transfer route that couples the return side transfer lines to each other along the preceding and succeeding delay elements, and a second transfer route that couples the feed side transfer lines and the return side transfer lines of each of the delay elements; and a decoder causing the selector to select the second transfer route for one of the delay elements in the delay element array.
1. A delay signal generator comprising:
a delay element array which is divided into a plurality of blocks, and the plurality of blocks are arranged in parallel;
a decoder including a main decoder, a block decoder and a sub decoder, the block decoder to receive an input code and output a block decode signal, the main decoder to receive the input code and output a main decode signal based on the input code, the sub decoder to receive the main decode signal and the block decode signal and output a selection signal based on the main decode signal and the block decode signal; and
wherein each plurality of blocks includes a plurality of delay elements delay an input signal through a first transfer route or a second transfer route;
wherein each of the plurality of delay elements selects the first transfer route or the second transfer route in response to the selection signal.
2. The delay signal generator according to claim 1 ,
wherein the main decoder includes a first selector to select the input code and an inverted input code based on the block decode signal and decodes a selected signal.
3. The delay signal generator according to claim 2 , wherein the sub-decoder is provided for each of the plurality of delay elements.
4. The delay signal generator according to claim 2 , wherein the main decoder generates the main decode signal so as to control a number of the plurality of delay elements used in at least one of the plurality of blocks.
5. The delay signal generator according to claim 2 , wherein each of the plurality of delay elements includes a second selector for selecting either the first transfer route or the second transfer route based on the selection signal.
6. The delay signal generator according to claim 5 , wherein the second selector comprises:
a first NAND circuit and a second NAND circuit whose input terminals are coupled to the first transfer route;
a third NAND circuit whose input terminals are coupled to the second transfer route;
wherein, the selection signal including a complementary signal is input to the first NAND circuit and the second NAND circuit.
7. The delay clock generator according to claim 5 , wherein the selector comprises:
a first inverter circuit that is interposed in the feed side transfer line;
a second inverter circuit that is interposed in the feed side transfer line, and has a first transfer gate interposed between an input terminal and the return side transfer line; and
a second transfer gate that is interposed between an output terminal of the first inverter circuit and an input terminal of the second inverter circuit;
wherein either the first transfer gate or the second transfer gate is made conductive by the sub-decode signal.
8. The delay signal generator according to claim 1 , wherein the first transfer route for transferring an input signal to an adjacent block via at least one of a plurality of delay elements included in each plurality of blocks, the second transfer route for transferring the input signal back to an input-signal-supplying side via at least the other delay element of the plurality of delay elements.