Self Regulating Charge Pump Noise Reduction
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Solution Overview
Problem
Charge pumps used in image sensors are noisy circuits that amplify noise from the reference supply, requiring high current overhead to regulate and provide stable voltage, which is inefficient and power-intensive, especially in mobile applications with low power supplies.
Innovation Solution
A charge pump design incorporating a charging transistor with a modulated gate voltage and a bulk regulated voltage, along with p-type and n-type transistors, reduces noise by regulating the voltage during charging, eliminating the need for a high current regulator and optimizing the voltage swing, thereby enhancing efficiency and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a regulator is used to reduce noise from the reference supply, then noise is reduced, but high current overhead is required
Solution Approach 1:
The patent divides the voltage regulation function into two separate stages: a bulk regulator that handles large current demands with lower precision, and a second regulator that provides fine noise reduction with minimal current overhead. This segmentation allows each regulator to be optimized for its specific function, reducing the total current overhead while maintaining noise reduction performance.
Solution Approach 2:
The patent employs dynamic switching between different regulator configurations based on operating conditions. The bulk regulator is activated during high current demand periods, while the second regulator takes over during low current periods for noise-sensitive operations. This dynamic approach optimizes the balance between current overhead and noise reduction.
2Stability of the object's composition
If voltage is regulated to provide stable supply, then stability is improved, but power consumption increases
Solution Approach 1:
The voltage regulation is segmented into bulk regulation and fine regulation stages. The bulk regulator provides coarse voltage stabilization with high efficiency, while the second regulator provides fine-tuned stability only when needed. This segmentation maintains voltage stability while minimizing continuous power consumption.
Solution Approach 2:
The patent implements periodic switching between regulation modes based on operational requirements. The second regulator is activated periodically during phases requiring high noise immunity, rather than operating continuously, thereby maintaining voltage stability when needed while reducing overall power consumption.
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 provides a more efficient and quieter voltage supply with lower current overhead, improving the power efficiency of charge pumps and reducing noise amplification, suitable for mobile devices like image sensors and optical pointing devices.
Implementation Method 1
The charging transistor may regulate the first voltage to substantially reduce noise from the first voltage when charging the pump capacitor and subsequently at the voltage output. The charging transistor may comprise a gate input to which a modulated voltage is applied and a bulk or body input to which a first regulated voltage is applied.
Implementation Method 2
Charge pumps are noisy circuits. They work by doubling a reference supply, and so noise on this reference is effectively sampled, and doubled. The charge pump may comprise a pump capacitor
Data Source
AI summary
A charge pump includes a transistor of the charge pump modified to regulate a supply voltage to substantially reduce noise from the supply voltage when charging the capacitor of the charge pump and subsequently reduces noise at the voltage output. The charge pump may have a regulating transistor for charging or for pumping or for both. The regulating transistor requires a regulated bulk voltage and a modulated gate voltage to enable regulation of the supply voltage. The regulated bulk voltage may be supplied by a small regulator.