Negative Charge Pump Regulation Circuit Topology
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Solution Overview
Problem
Existing charge pump regulation techniques fail to simultaneously achieve continuous time average sampling and high frequency response for negative charge pumps, leading to ripple issues and the need for large decoupling capacitors.
Innovation Solution
The implementation of a negative charge pump with a voltage controlled current source, a comparator to measure IR drop across a resistor and capacitor, and a pump controller to adjust the resistance and capacitance of these components to improve high frequency response and reduce ripple, while maintaining continuous time domain regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional regulation techniques are used for negative charge pumps, then the circuit is simpler, but the high frequency response is poor and ripple is large
Solution Approach 1:
The regulation circuit is segmented into two independent paths: a continuous time domain path using a resistor for average sampling, and a high frequency sampling path using a capacitor. This segmentation allows each path to specialize in one frequency range, resolving the contradiction between simplicity and high frequency response capability.
Solution Approach 2:
A switch is introduced as an intermediary component that selectively connects either the resistor or capacitor to the comparator based on the pump enable signal state. This intermediary enables the circuit to dynamically switch between continuous time domain regulation and high frequency sampling, achieving both goals without permanent complexity.
2Object-generated harmful factors
If large decoupling capacitors are used to reduce ripple, then ripple is reduced, but the charge pump module size increases
Solution Approach 1:
The high frequency sampling function is extracted from the traditional continuous time domain regulation path and implemented separately using a capacitor connected through a switch. This extraction allows the circuit to handle high frequency ripple components without requiring large decoupling capacitors, thus reducing the charge pump module size while still achieving ripple reduction.
Solution Approach 2:
The circuit dynamically changes the sampling parameters by switching between resistor-based continuous time domain sampling and capacitor-based high frequency sampling. This parameter change allows the system to adapt to different frequency requirements, reducing ripple effectively without the need for large fixed decoupling capacitors.
3Measurement precision
If continuous time domain regulation is implemented, then average sampling is achieved, but high frequency response is limited
Solution Approach 1:
The regulation circuit is made dynamic by introducing a switch that can change the sampling mechanism based on the pump enable signal. During pump operation, the switch connects the capacitor for high frequency sampling; during idle periods, it connects the resistor for continuous time domain average sampling. This dynamic adaptation allows the circuit to maintain measurement precision while achieving high frequency response when needed.
Solution Approach 2:
The circuit employs periodic switching between two sampling modes synchronized with the pump enable signal. The high frequency sampling path is activated periodically during pump operation to capture high frequency components, while the continuous time domain path operates during idle periods. This periodic action allows the system to achieve both average sampling accuracy and high frequency response capability.
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 approach enhances the high frequency response of the regulation circuit, reduces ripple, and minimizes the size of the charge pump module by eliminating the need for large decoupling capacitors, thereby improving the stability and efficiency of negative voltage generation for applications like flash memory and tunable floating batteries.
Implementation Method 1
A voltage controlled current source generates a current proportional to an input voltage
Implementation Method 2
The comparator measures an IR drop across the resistor and the capacitor
Data Source
AI summary
A negative charge pump is responsive to a pump enable signal. A voltage controlled current source provides a current. A resistor is coupled between a node from the voltage controlled current source and a negative charge output from the negative charge pump. A capacitor is placed in parallel with the resistor. A comparator generates the pump enable signal to control the negative charge pump. The comparator is coupled to the resistor and the capacitor and measures an IR drop thereacross and compares this measurement against a reference threshold. A level of the pump enable signal can be variable by tuning an amount of resistance of the resistor or capacitor or adjusting the reference threshold. A memory can be driven by a method of the negative charge pump.