Voltage Generating Circuit Dynamic Reference Control
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Solution Overview
Problem
Existing voltage-generating circuits in NAND type flash memory face challenges in accurately controlling the rising speed of generated high voltages, which affects performance and reliability due to variations in process, voltage, temperature, and operating conditions, leading to inefficiencies and complexity in controlling the charge pump's output voltage.
Innovation Solution
A voltage-generating circuit with a dynamic reference voltage, generated using an RC time constant, is introduced to control the rising speed of the output voltage with high accuracy by incorporating a comparator circuit and a generating circuit that delays the reference voltage, allowing the circuit to mimic the charge pump's behavior and adjust the resistance voltage divider accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a charge pump is used to generate high voltage in flash memory, then the voltage can be boosted to required levels, but the rising speed of the generated voltage cannot be accurately controlled due to variations in process, voltage, temperature, and operating conditions
Solution Approach 1:
The patent implements a feedback mechanism where the rising speed of the charge pump output voltage is detected and compared against a target rising speed. Based on this comparison, the control circuit adjusts the charge pump operation to achieve accurate rising speed control despite PVT variations, thereby improving both measurement precision and reliability
Solution Approach 2:
The patent changes operating parameters dynamically by adjusting the reference voltage level based on detected rising speed. When the rising speed deviates from the target, the reference voltage is modified to correct the deviation, enabling accurate control under varying process, voltage, and temperature conditions
2Device complexity
If the charge pump output voltage is controlled using conventional methods, then voltage levels can be adjusted, but the circuit configuration becomes complex and the charge pump's pumping ability is compromised
Solution Approach 1:
The patent introduces an intermediary element - a controllable reference voltage source - that mediates between the charge pump output and the control circuit. This reference voltage acts as a mediator to regulate the charge pump operation without requiring complex direct control mechanisms, thereby simplifying the overall circuit configuration while maintaining pumping efficiency
Solution Approach 2:
The patent implements a multi-functional control approach where the same control circuitry serves both to regulate voltage levels and to control rising speed. By making the control system universal in its functionality, the patent avoids adding separate dedicated circuits for different control tasks, thus reducing overall circuit complexity while preserving charge pump efficiency
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 solution simplifies the circuit configuration, enables precise control of the rising speed of the generated voltage, and allows for flexible setting of target levels without compromising the charge pump's pumping ability, thereby improving the reliability and efficiency of voltage generation.
Implementation Method 1
a generating circuit, delaying a reference voltage according to an RC time constant, and generating the controlled reference voltage
Data Source
AI summary
What is provided is a voltage-generating circuit that uses dynamic reference voltage to accurately control the step-up of a generated voltage. A voltage-generating circuit 100 of the invention includes a charge pump 110 outputting voltage Vpump, a regulator 120, and a controlling circuit 140. The regulator 120 includes a comparator 122 and a comparator 132. The comparator 122 compares voltage Vdivide generated by the charge pump 110 with a reference voltage Vref, and outputs a comparison result CMP_OUT. The comparator 132 compares voltage Vdivide2 generated by the charge pump 110 with a reference voltage VrefRRC with a controlled rising speed, and outputs a comparison result CMP2_OUT. The controlling circuit 140 controls the charge pump 110 based on CMP_OUT and CMP2_OUT.