Self-Refresh Period Measurement Circuit for Semiconductor Devices
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Solution Overview
Problem
Conventional self-refresh period measurement circuits in semiconductor devices are unstable and unable to accurately measure the self-refresh period, leading to inappropriate auto TCSR circuit performance due to the oscillator's instability during the first self-refresh cycle.
Innovation Solution
A self-refresh period measurement circuit that measures the period of a second or subsequent self-refresh cycle using a delay device, period measurement start signal generator, and refresh period output unit to generate a refresh period output signal, ensuring more stable and accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional self-refresh period measurement circuit measures the first self-refresh cycle, then the measurement process is simple, but the measurement accuracy is poor due to oscillator instability
Solution Approach 1:
The measurement circuit skips the first unstable self-refresh cycle and waits for the oscillator to stabilize before beginning measurement. The circuit uses a cycle counter to detect when the oscillator has stabilized and then starts measuring from the second cycle onward, ensuring accurate measurements while maintaining reasonable circuit complexity
Solution Approach 2:
The patent introduces a cycle counter and control logic as intermediary components between the oscillation signal and the period measurement function. These intermediaries filter out the unstable first cycle and enable stable measurement cycles, resolving the contradiction between measurement accuracy and circuit simplicity
2Reliability
If the measurement circuit uses the first self-refresh cycle, then the measurement time is short, but the reliability of measurement is poor
Solution Approach 1:
The circuit performs preliminary detection of oscillator stability before committing to measurement. By using a cycle counter to monitor the first cycle and determine stability, the circuit ensures reliable measurements are taken only when conditions are appropriate, accepting a small time delay for the sake of measurement reliability
Solution Approach 2:
The measurement circuit skips the unstable first cycle quickly using simple counter logic, then proceeds to measure stable subsequent cycles. This approach minimizes the time loss while ensuring that only reliable measurement data is collected from stabilized oscillator operation
Data Source
AI summary
A self-refresh period measurement circuit of a semiconductor device is disclosed, herein which includes a period measurement start signal generator configured to receive a self-refresh signal and an oscillation signal, to allow a self-refresh operation to be performed, and generate a period measurement start signal, to set the time that the oscillation signal is enabled, and a refresh period output unit configured to receive the period measurement start signal and the oscillation signal, and generate a refresh period output signal that is enabled for a period from the time that the period measurement start signal is enabled to a time that the oscillation signal is enabled.