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On-chip Clock Controller: Enhancing Clock Control for Integrated Circuits

OCC refers to component or module that manages and controls the clock signals within an integrated circuit (IC) for the purpose of testing.The OCC is responsible for generating and distributing clock signals to different parts of the IC during test operations.An on-chip clock controller is an essential component in modern digital systems. It is responsible for generating the clock signals that synchronize the operations of different components of a system. It consists of a clock control chain and one or more clock generators.

Also Read What is Clock Tree Synthesis?

Working Mechanism for On-chip Clock Controller

The clock control chain is responsible for shifting clock control bits in series. It outputs clock control bits that correspond to at least one or more clock domains. This process is triggered by a clock control scan clock, provided from outside the chip.

In test mode, each domain clock generator selectively outputs a corresponding data scan clock and a corresponding function clock. The data scan clock is derived from at least one or more data scan clocks supplied from outside the chip. And the function clock is derived from at least one or more function clocks provided from inside the chip. The selection of the data scan clock and function clock is based on the clock control bits. Additionally, the domain clock generator generates the data scan clock and function clock as internal clocks. As a result, the clock control chain and the operating clocks of the clock generator are provided independently of one another, reducing needless power waste due to flip-flop toggling.

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In scan capture mode, the On-Chip Clock Controller (OCC) creates a launch and capture clock utilizing the slow scan clock from the external test equipment (ATE) and the high-speed clock on the internal PLL.

Functions and Uses of On-chip clock controller

The on-chip clock controller is a component that generates and distributes clock signals to the various components on a chip. The clock controller is typically implemented as a digital circuit on the same chip as the components it controls.

The on-chip clock controller typically receives an external clock signal and generates several internal clock signals that are distributed to the various components on the chip. The internal clock signals may have different frequencies and phases, depending on the requirements of the components they control.

The on-chip clock controller is usually designed to provide a stable clock signal with a low skew across the entire chip. Skew is a measure of the difference in time between two clock signals. High skew can lead to timing errors and affect the overall performance of the system. Therefore, the clock controller must be designed to minimize skew and ensure that the clock signals are as stable as possible.


Hence, we can conclude that the on-chip clock control generating circuit is critical for next-generation ASICs, SoCs with numerous IPs operating at various clock domains. And if you are interested in knowing more about the semiconductor industry in detail, get enrolled at Chipedge, which is one of the best training and placement institutes in Bangalore. Here you will discover a variety of VLSI courses including various job-oriented courses in Bangalore available both for the freshers as well as professionals. So hurry up and enroll now!

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