Level-Shifting Charge Pump for Wide-Range Low-Noise Control Voltage
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Solution Overview
Problem
Conventional charge pumps face challenges in generating a control voltage with a large range and low noise, especially in low-voltage applications where the narrow headroom worsens their functionality and noise performance.
Innovation Solution
A charge pump design incorporating a pull-up circuit with a P-type transistor, a switched-capacitor circuit, and a pull-down circuit with a current source, utilizing level-shifting techniques to boost voltages and reduce noise, allowing for a larger control voltage range and zero headroom in charge generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If larger drain-to-source voltages are used for the P-type transistor or N-type transistor, then noise is reduced, but the control voltage range becomes narrow
Solution Approach 1:
The charge pump is divided into separate pull-up and pull-down circuits with independent current sources and switched-capacitor circuits. This segmentation allows each circuit to be optimized independently - the pull-up circuit can use larger drain-to-source voltages for lower noise while the pull-down circuit operates separately, thereby expanding the overall control voltage range.
Solution Approach 2:
Switched-capacitor circuits are introduced as intermediary elements between the current sources and the output node. These switched-capacitor circuits enable voltage boosting and level-shifting, allowing the charge pump to achieve larger control voltage range without requiring the transistors to operate with compromised drain-to-source voltages, thus maintaining low noise performance.
2Use of energy by moving object
If the charge pump is applied in low-voltage applications, then power consumption is reduced, but the headroom becomes narrow worsening functionality and noise
Solution Approach 1:
The invention changes the operating parameters of the charge pump by introducing switched-capacitor circuits that enable voltage boosting. This allows the charge pump to maintain adequate voltage headroom for proper transistor operation and low noise performance even when supplied with lower supply voltages, thus improving reliability without increasing power consumption.
Solution Approach 2:
The switched-capacitor circuits introduce an additional voltage dimension through capacitive coupling and charge redistribution. This allows the charge pump to achieve effective voltage amplification and level-shifting, providing sufficient voltage headroom for reliable operation and low noise even in low-voltage applications where traditional charge pump topologies would fail.
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 charge pump with a larger control voltage range and reduced noise, effectively addressing the limitations of conventional charge pumps by employing switched-capacitor circuits and current-mirror-like topology to enhance voltage control and reduce noise.
Implementation Method 1
a first capacitor, coupled to a first electrode of the first transistor; and a switched-capacitor circuit, coupled between a supply voltage and a second electrode of the transistor, for boosting a voltage of the second electrode of the first transistor to charge the first capacitor via the first transistor
Implementation Method 2
the first capacitor and the output terminal of the charge pump are electrically connected such that under a charge distribution operation charges at the first capacitor flow to an output capacitor of the output terminal of the charge pump until voltages at the first capacitor and the output capacitor are equal
Data Source
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AI summary
The present invention provides a charge pump including a pull-up circuit for selectively providing charges to an output terminal of the charge pump, and the pull-up circuit comprises a transistor, a capacitor and a switched-capacitor circuit, wherein the capacitor is coupled to an electrode of the transistor, and the switched-capacitor circuit is coupled between a supply voltage and another electrode of the transistor. The switched-capacitor circuit is configured to boost a voltage of the other electrode of the transistor to charge the capacitor via the transistor, then the capacitor and the output terminal of the charge pump are under a charge distribution operation.