Clock Generator Startup Voltage Tracking for Stable NAND Read Timing
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Solution Overview
Problem
Existing clock-generating circuits in integrated circuits face challenges in maintaining accurate and stable clock signal frequencies, which affects the data read transfer time in NAND flash memory systems, leading to potential failures in meeting design specifications.
Innovation Solution
A clock-generating circuit comprising a voltage-reference circuit, a tracking-voltage-generating circuit, a voltage regulator, and a level shifter, where the tracking-voltage-generating circuit provides a temporary reference voltage to the voltage regulator, enabling a stable oscillation power-supply voltage for the oscillation generator, and a switch circuit controls the voltage level to ensure a sufficient and consistent clock signal output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional voltage regulator is used to generate the oscillation power-supply voltage, then the circuit structure is simple, but the clock signal frequency varies significantly during startup, failing to meet design specifications
Solution Approach 1:
The tracking-voltage-generating circuit generates a temporary reference voltage before the main voltage reference circuit is fully operational. This preliminary voltage tracking action ensures that the oscillation power-supply voltage starts at the correct level, preventing significant frequency variations during startup while maintaining overall circuit simplicity.
Solution Approach 2:
The tracking-voltage-generating circuit acts as an intermediary between the external voltage and the main voltage reference circuit. It provides a temporary reference voltage that bridges the startup gap, ensuring smooth transition and frequency stability without requiring complete redesign of the voltage regulation system.
2Reliability
If the oscillation power-supply voltage starts from 0V and increases gradually, then the circuit protects against voltage spikes, but the clock frequency varies significantly and data read transfer time increases
Solution Approach 1:
The tracking-voltage-generating circuit performs preliminary voltage establishment by generating a temporary reference voltage that matches the external voltage during startup. This allows the oscillation power-supply voltage to reach its target level quickly without gradual ramping, reducing data read transfer time while maintaining voltage stability through the tracking mechanism.
3Productivity
If the clock frequency is increased to meet data read transfer time specifications, then the transfer time is reduced, but the frequency variation becomes more significant and system reliability decreases
Solution Approach 1:
The voltage regulator uses feedback from the temporary reference voltage to adjust the oscillation power-supply voltage in real-time during startup. This feedback mechanism allows the circuit to maintain accurate frequency control even at higher operating frequencies, ensuring both fast data read transfer and frequency reliability.
Solution Approach 2:
The circuit dynamically changes the reference voltage parameter during startup by switching from the temporary reference voltage to the main reference voltage. This parameter transition enables the oscillation frequency to be accurately controlled at higher values needed for fast data transfer while maintaining frequency accuracy through precise voltage regulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures a more stable and quickly attainable clock frequency, reducing the data read transfer time in NAND flash memory systems to meet design specifications, thereby improving the reliability of data transfer operations.
Implementation Method 1
The voltage regulator receives the reference voltage and the temporary reference voltage, and it converts the reference voltage or the temporary reference voltage into an oscillation power-supply voltage
Implementation Method 2
The oscillation generator generates a first clock signal according to the oscillation power-supply voltage
Data Source
AI summary
A clock-generating circuit is provided, which includes a voltage-reference circuit, a tracking-voltage-generating circuit, a voltage regulator, an oscillation generator, and a level shifter. The voltage-reference circuit and the tracking-voltage-generating circuit respectively convert the external voltage into a reference voltage and a temporary reference voltage. The voltage regulator receives the reference voltage and the temporary reference voltage, and it converts the reference voltage or the temporary reference voltage into an oscillation power-supply voltage. The oscillation generator generates a first clock signal according to the oscillation power-supply voltage. The level shifter converts a voltage amplitude of the first clock signal to generate a second clock signal that is output by the clock-generating circuit. The voltage regulator includes a switch circuit for controlling whether to pull up the oscillation power-supply voltage, which is at an output terminal of the voltage regulator, to the external voltage according to an enable signal.