Semiconductor Device ODT Circuit Signal Integrity Self-Refresh
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining signal integrity during self-refresh operations due to variations in the chip select signal level, which can lead to malfunctions and increased power consumption.
Innovation Solution
A semiconductor device is designed with an ODT circuit that includes a termination resistor, adjustable via a resistor value change signal, allowing the device to adjust the termination resistor's value based on the chip select signal transitions, thereby stabilizing the signal level and reducing power consumption during self-refresh operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the termination resistor value is kept fixed during self-refresh operation, then the circuit structure is simple, but signal integrity deteriorates due to signal level variations
Solution Approach 1:
The patent applies the dynamics principle by making the termination resistor value adjustable rather than fixed. The ODT circuit includes a termination resistor whose resistance value can be dynamically changed based on the operation mode. During self-refresh operation, the termination resistor value is adjusted to match the impedance of the external circuit, thereby maintaining signal integrity and preventing signal level variations that would otherwise cause malfunctions.
Solution Approach 2:
The patent applies parameter changes by modifying the resistance value of the termination resistor according to different operation modes. The operation control circuit generates a resistor value change signal that adjusts the termination resistor value specifically during self-refresh operation. This parameter adjustment ensures that the termination resistor maintains proper impedance matching with external circuits during self-refresh, resolving the signal integrity issue without requiring complete circuit redesign.
2Reliability
If the termination resistor value is adjusted during self-refresh operation, then signal integrity is improved, but device complexity increases
Solution Approach 1:
The operation control circuit is designed to perform multiple functions: it controls both the termination resistor value adjustment and generates the self-refresh command signal. By integrating these functions into a single circuit block, the patent reduces overall device complexity while still achieving the goal of maintaining signal integrity during self-refresh operation. The multi-functionality approach avoids adding separate dedicated circuits for each function.
Solution Approach 2:
The operation control circuit automatically detects when the semiconductor device enters self-refresh mode and autonomously adjusts the termination resistor value without requiring external intervention. The circuit monitors the operation mode and self-regulates the termination resistor setting, thereby maintaining signal integrity through autonomous control rather than requiring complex external management circuits.
3Loss of energy
If a fixed termination resistor is used, then the device structure is simple, but power consumption increases during self-refresh
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the termination resistor value based on operation mode. During self-refresh operation, the termination resistor is adjusted to a specific value that optimizes power consumption while maintaining signal integrity. This dynamic adjustment allows the device to consume less power during self-refresh compared to using a fixed termination resistor that would continuously draw unnecessary current.
Solution Approach 2:
The patent changes the resistance parameter of the termination resistor according to operation mode. During self-refresh, the termination resistor value is modified to reduce power consumption while still providing adequate signal termination. This parameter change enables the device to adapt its power consumption characteristics to match the operational requirements, thereby reducing energy loss without requiring complete removal of the termination function.
Data Source
AI summary
A semiconductor device may include: a first receiver configured to receive a chip select signal from a receiving node to which a termination resistor is coupled and configured to generate a first internal chip select signal; a command pulse generation circuit configured to generate a command pulse for entering into a self-refresh operation based on an internal command address and the first internal chip select signal; and an operation control circuit configured to, when the semiconductor device enters the self-refresh operation based on the command pulse, generate a resistor value change signal that adjusts the value of the termination resistor.