Bus Drive Circuit Control for Lower Current and Noise
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Solution Overview
Problem
The increasing number of data bits and transfer frequency in semiconductor integrated circuits leads to higher power consumption for bus driving, with unnecessary current consumption occurring when the signal level of the bus output signal remains the same, causing inefficiency and increased noise.
Innovation Solution
The semiconductor integrated circuit design includes a logic circuit that stops outputting the logical value when the signal level is the same as the previous cycle, reducing unnecessary current consumption and noise by eliminating unnecessary operations in bus drive circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bus drive circuit continuously outputs the logical value to the common bus, then the data transfer reliability is ensured, but the current consumption increases unnecessarily when the signal level remains the same as the previous cycle
Solution Approach 1:
The bus drive circuit is configured to output the logical value to the common bus only during specific periods when the signal level changes, rather than continuously. The control circuit determines whether to output based on comparing the current signal level with the previous cycle's level, enabling periodic action that eliminates unnecessary continuous output operations and reduces current consumption while maintaining data transfer reliability when changes occur
Solution Approach 2:
The bus drive circuit dynamically adjusts its output behavior based on real-time signal level comparisons. The control circuit actively monitors whether the signal level differs from the previous cycle and dynamically controls the output transistor accordingly, switching between active output and high-impedance states to optimize both reliability and energy efficiency under varying operating conditions
2Reliability
If the bus drive circuit outputs peak current continuously, then the signal integrity is maintained, but the noise level increases due to unnecessary operations
Solution Approach 1:
The bus drive circuit implements periodic action by outputting peak current only during specific periods when signal level changes are detected, rather than continuously. The control circuit compares the current signal level with the previous cycle's level and activates the output transistor only when a change is detected, thereby eliminating unnecessary peak current operations that generate noise while maintaining signal integrity during actual data transfers
Solution Approach 2:
The invention converts the potentially harmful effect of continuous peak current output (which generates noise) into a beneficial selective output mechanism. By using the control circuit to detect signal level changes and activate output only when necessary, the system transforms what would be a harmful continuous operation into a beneficial conditional operation that maintains signal integrity while minimizing noise generation
Data Source
AI summary
A semiconductor integrated circuit capable of reducing unnecessary current consumption includes a plurality of bus drive circuits for receiving data input, a common bus coupled to the bus drive circuits, and a bus holder coupled to the common bus. One of the bus drive circuits is selected as the selected bus drive circuit. When a logical value corresponding to the data input to be output is the same as a logical value that has been held by the bus holder and output to the common bus, the selected bus drive circuit stops outputting the logical value corresponding to the data input to the common bus. With this configuration, it is possible to eliminate the unnecessary output of the selected bus drive circuit, and to reduce unnecessary current consumption compared to the conventional semiconductor integrated circuit.