Capacitance Selectable Charge Pump for Image Sensor Power
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Solution Overview
Problem
Conventional charge pumps in image sensors exhibit unpredictable spiking and inefficiencies due to asynchronous operation, leading to high noise and reduced efficiency in power supply, necessitating complex filtering circuits and inefficient voltage regulation.
Innovation Solution
A capacitance selectable charge pump (CSCP) system with a control module that dynamically selects and activates capacitance charge pump modules based on current consumption, maintaining a consistent pumping frequency and reducing ripple voltage by only using the minimal necessary capacitance, thereby improving power supply stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional charge pumps operate asynchronously to meet varying current demands, then adaptability is improved, but noise and ripple voltage increase
Solution Approach 1:
The charge pump system dynamically adjusts the capacitance value by selectively activating individual pump modules based on current consumption levels. The control module monitors current demand and reconfigures the active capacitance in real-time, allowing the system to adapt to varying loads while maintaining optimal noise performance at each operating point.
Solution Approach 2:
The system changes the operational parameter of capacitance by selecting different combinations of pump modules. Each module contributes a specific capacitance value, and by adjusting which modules are active, the total capacitance parameter is optimized for the current demand, thereby reducing ripple voltage and noise while maintaining adaptability.
2Stability of the object's composition
If larger capacitance is used in charge pump to reduce ripple voltage, then power supply stability is improved, but device complexity and power consumption increase
Solution Approach 1:
The charge pump is divided into multiple independent pump modules, each with its own capacitance element. Instead of using a single large capacitor that would increase complexity, the system segments the capacitance into smaller units that can be selectively activated. This segmentation allows the system to achieve the required power supply stability with minimal necessary capacitance, reducing overall device complexity.
Solution Approach 2:
The system dynamically configures which pump modules are active based on current consumption requirements. The control module adjusts the capacitance in real-time by enabling or disabling specific modules, allowing the system to maintain power supply stability without permanently incorporating excessive capacitance that would increase device complexity and power consumption.
3Device complexity
If conventional charge pumps use fixed capacitance, then device complexity is reduced, but efficiency decreases under varying load conditions
Solution Approach 1:
The charge pump system transitions from fixed capacitance to dynamic capacitance selection. The control module monitors current consumption and adjusts which pump modules are active, thereby optimizing the capacitance for each operating condition. This dynamic adjustment improves power supply efficiency by matching capacitance to actual load requirements without significantly increasing device complexity.
Solution Approach 2:
Instead of always using maximum capacitance, the system applies partial action by activating only the necessary number of pump modules based on current demand. This avoids the energy losses associated with excessive capacitance while maintaining sufficient power supply stability, thereby improving overall efficiency with minimal increase in control complexity.
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 CSCP system provides a stable and efficient power supply with reduced ripple voltage, allowing for lower noise and improved dynamic range, reducing the burden on filtering circuits and enhancing battery life in mobile devices.
Implementation Method 1
A capacitance charge pump may include a first capacitance charge pump module, a second capacitance charge pump module, and a third capacitance charge pump module.
Data Source
AI summary
A step-up converter includes an input coupled to receive a first voltage potential and an output coupled to output a second voltage potential higher than the first voltage potential. The step-up converter also includes an array of capacitance charge pumps. Each of the capacitance charge pumps in the array includes switches to be modulated to individually run each of the capacitance charge pumps by selectively connecting each of the capacitance charge pumps to the input and the output. The step-up converter further includes a control module coupled to the switches of each of the capacitance charge pumps and configured to modulate the switches at a substantially fixed frequency. The control module modulates the switches of selected capacitance charge pumps in the array in response to a current draw on the output. The step-up converter may be included in an image sensor.