Low-Voltage Charge Pump Using Segmented Stages
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Solution Overview
Problem
Existing charge pumps fail to generate sufficient drive voltage for power switching devices when the input supply voltage is low, particularly below 1V, and require complex structures or suffer from reduced pump-stage voltage due to regulation, especially under heavy loading conditions.
Innovation Solution
A low-supply-voltage charge pump system with a simple design, utilizing N stages connected in cascade, each comprising two transistors and a capacitor, where the transistors are controlled by non-overlapping phase signals to charge and discharge the capacitor, allowing the system to generate an output voltage greater than the input voltage even at low supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional charge pump designs are used, then the structure can be simple, but the drive voltage is insufficient when input supply voltage is low (below 1V)
Solution Approach 1:
The charge pump is divided into multiple stages (first charge pump stage, second charge pump stage, etc.), where each stage independently generates voltage boost. This segmentation allows the system to achieve sufficient drive voltage even when input voltage is below 1V, while keeping each individual stage relatively simple in structure.
2Stability of the object's composition
If regulation is applied to maintain fixed output voltage, then output stability is improved, but the voltage across each pump stage is reduced below the open-loop value
Solution Approach 1:
By dividing the charge pump into multiple stages, the voltage boosting function is distributed across stages. This allows the system to maintain sufficient pump-stage voltage for gate drive while still providing regulated output, as each stage operates with adequate voltage headroom.
3Use of energy by moving object
If the supply voltage is particularly low (e.g., 1V), then power consumption is reduced, but charge pumps either fail to provide requisite driving voltage or require complex structure
Solution Approach 1:
The multi-stage architecture enables the charge pump to operate effectively at low supply voltages (e.g., 1V or below) by distributing the voltage multiplication across stages, avoiding the need for complex single-stage designs while maintaining low power consumption.
4Power
If loading conditions increase current demand (heavy loads), then power delivery capability is improved, but the problem of low input voltage is compounded
Solution Approach 1:
The multi-stage design provides sufficient drive voltage even under heavy loading conditions by ensuring each stage operates with adequate voltage headroom, preventing the compounding effect of low input voltage that plagues single-stage designs under load.
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 system effectively generates a higher output voltage than the input voltage, even at low supply voltages, with reduced circuitry complexity and improved performance by augmenting gate drive voltage through successive stages, enabling efficient operation in power converter applications.
Implementation Method 1
The first capacitor is coupled at one end to the node between the first and second transistors, and coupled at another end to receive one of two non-overlapping phase signals. At one value for one of the two non-overlapping phase signals, the first capacitor of the stage is charged by a respective stage input voltage. At another value for one of the two non-overlapping phase signals, the first capacitor of the stage is discharged to provide a respective stage output voltage.
Data Source
AI summary
In an embodiment, a charge pump of relatively simple design is provided which can generate sufficient drive voltage for a power switching device from a low-supply-voltage (e.g., 1V). In some embodiments, this charge pump performs better at lower input voltages when there are loading conditions (i.e., when the charge-pump output powers other circuit blocks such as amplifiers and LDO's).