Charge Pump with Voltage Equalization for Wide Current Range
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Solution Overview
Problem
Current charge pumps in memory systems face challenges in providing a wide range of output currents with stability, often requiring reconfiguration of op-amps to accommodate different current levels, which can be inefficient and complex.
Innovation Solution
A current steering charge pump with a voltage equalization circuit and a third branch, using configurable current sources to match the first and second branches, allowing the op-amp to operate at a fixed low current, enabling the charge pump to generate current at various levels without reconfiguring the op-amp.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the charge pump uses a single branch configuration with configurable current sources, then it can provide a wide range of output currents, but the voltage stability between nodes deteriorates
Solution Approach 1:
The charge pump is divided into multiple parallel branches (first branch with first current source, second branch with second current source, third branch with third current source) instead of using a single branch. This segmentation allows each branch to contribute to the total output current while maintaining voltage stability through the parallel structure and voltage equalization circuit.
Solution Approach 2:
A voltage equalization circuit is introduced as an intermediary component connected between the first node and second node. This equalization circuit actively balances the voltages at different nodes, compensating for the instability that would otherwise occur when using multiple current sources with different current levels.
2Adaptability or versatility
If the op-amp is reconfigured to accommodate different current levels, then the charge pump can adapt to various current outputs, but the device complexity increases
Solution Approach 1:
The op-amp is designed with a universal structure that can handle multiple current levels without requiring reconfiguration. By using multiple parallel current sources that can be independently controlled, the same op-amp circuitry serves multiple functions across different current ranges, eliminating the need for complex reconfiguration mechanisms.
Solution Approach 2:
The charge pump uses dynamically controllable current sources where the current magnitude can be adjusted by controlling the switching of transistor pairs in each branch. This dynamic control allows the system to adapt to different current requirements by simply adjusting control signals rather than physically reconfiguring the op-amp circuit.
3Adaptability or versatility
If the charge pump uses multiple branches with different current sources, then it can generate a wide range of currents, but the circuit complexity increases
Solution Approach 1:
The circuit is segmented into three parallel branches, each with its own current source and transistor pairs. This segmentation allows independent control of each branch's current contribution, enabling fine-grained adjustment of the total output current while maintaining a modular and manageable circuit structure.
Solution Approach 2:
Multiple current sources are merged in parallel configuration rather than series, allowing their currents to add together at the output node. This merging strategy enables the charge pump to achieve a wide current range by combining smaller current sources, rather than requiring one large current source that would be difficult to control precisely.
Data Source
AI summary
A charge pump has a first branch that includes a first node connected between a first pull-up switch and a first pull-down switch and a second branch that includes a second node connected between a second pull-up switch and a second pull-down switch. The second branch is connected in parallel with the first branch. The charge pump has a voltage equalization circuit to equalize a first voltage at the first node and a second voltage at the second node. A third branch includes a third node that is connected between a third pull-up switch and a third pull-down switch. The third node is connected to the second node. The third pull-up switch and the first pull-up switch are controlled by a common pull-up signal. The third pull-down switch and the first pull-down switch are controlled by a common pull-down signal.