480 MHz 10-tap Clock Generator Using Edge-Combiner DLL for USB 2.0 Applications
A clock generator with an edge-combiner DLL (ECDLL) has been developed for USB 2.0 applications. The clock generator generates 480 MHz 10-tap output signals from a 12 MHz reference signal and consists of three DLLs to shrink the design area so that it is smaller than a conventional one based on a PL...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2012-01-01
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| Series: | Journal of Electrical and Computer Engineering |
| Online Access: | http://dx.doi.org/10.1155/2012/267247 |
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| Summary: | A clock generator with an edge-combiner DLL (ECDLL) has been developed for USB 2.0 applications. The clock generator generates 480 MHz 10-tap output signals from a 12 MHz reference signal and consists of three DLLs to shrink the design area so that it is smaller than a conventional one based on a PLL. Each DLL is applied to our proposed shot pulse reset technique to prevent from a harmonic lock and is applied to a voltage-controlled delay line (VCDL) with a trimming function to operate against any process voltage temperature (PVT) variations. A 90 nm CMOS process was used to fabricate our proposed clock generator. The 480 MHz 10-tap output signals satisfy the USB 2.0 specifications. A power consumption is less than 1.3 mW and a locking time is less than 3.5 μs, which are far less than a conventional one, 10.0 μs. The design area is 200×225 μm, which is half that of the conventional one. |
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| ISSN: | 2090-0147 2090-0155 |