Variable High Voltage Charge Pump with Cascaded Regulation
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Solution Overview
Problem
Existing high voltage generation circuits for electronic systems, such as MEMS, consume significant current due to the need for charge pumps and amplifiers to achieve accurate regulation, especially when the required voltage exceeds the supply voltage, leading to inefficiencies and increased current consumption.
Innovation Solution
A variable high voltage charge pump system with cascaded MOS switching stages and a feedback mechanism using regulated and unregulated switching stages, along with a bypass capacitor, to control pumping voltage and reduce current consumption by minimizing leakage currents and process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charge pumps and amplifiers are used to generate accurate high voltage above supply voltage, then voltage accuracy is improved, but current consumption increases significantly
Solution Approach 1:
The charge pump is divided into multiple cascaded stages (first charge pump stage, second charge pump stage, etc.), each contributing to the overall voltage multiplication. This segmentation allows for better control and regulation at each stage, improving voltage accuracy while distributing the current consumption across multiple manageable units rather than a single high-power stage
Solution Approach 2:
A feedback mechanism is implemented where a portion of the generated high voltage is fed back through a voltage divider to an error amplifier, which compares it against a reference voltage and adjusts the charge pump operation accordingly. This closed-loop feedback system maintains voltage accuracy while optimizing current consumption by only pumping when necessary to maintain the target voltage
2Power
If more charge pump stages are cascaded to achieve higher voltage, then output voltage is improved, but leakage currents and process variations have greater impact
Solution Approach 1:
The feedback loop continuously monitors the output voltage and compensates for leakage currents and process variations by adjusting the pumping action. The error amplifier detects voltage deviations caused by leakage or process variations and modulates the charge pump stages to maintain the desired output voltage, thereby improving reliability
Solution Approach 2:
The charge pump operates dynamically with clocked switching stages that can be independently controlled. The pumping action is activated only when voltage compensation is needed, rather than continuous operation, allowing the system to adapt to changing conditions and reduce the impact of leakage currents and process variations
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
The solution effectively reduces current consumption and stabilizes the output voltage, extending bandwidth and improving loop dynamics, thereby enhancing the efficiency of high voltage generation while minimizing the impact of process variations and load current fluctuations.
Implementation Method 1
charge pumps are necessary to pump up an on-chip reference
Implementation Method 2
cascaded MOS switching stages
Implementation Method 3
an amplifier is also required to ensure accurate regulation
Data Source
AI summary
A variable high voltage charge-pump system includes a plurality of unregulated switching stages and a plurality of regulated switching stages arranged in a cascaded configuration. The unregulated switching stages receive unregulated voltage input signals, and the regulated switching stages receive regulated voltage input signals. An amplifier generates the regulated voltage input signals to bring the output voltage to a desired value.