Charge Pump Circuit With Resistor Gate Control
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Solution Overview
Problem
Conventional charge pump circuits using MOSFETs as charge transfer elements suffer from reduced power efficiency due to increased threshold voltage, and the level shifting circuit increases current consumption and hindering boosting efficiency, making them unsuitable for mobile devices.
Innovation Solution
A charge pump circuit design that includes series-connected MOSFETs, first and second coupling capacitors with reversed phase clock pulses, and resistors connecting sources to gates and drains, eliminating the need for a level shifting circuit to achieve high boosting efficiency and rapid stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MOSFETs are used as charge transfer elements in a charge pump circuit, then adaptability to integrated circuit process is improved, but threshold voltage increases due to substrate effect, reducing power efficiency
Solution Approach 1:
The charge pump circuit is divided into multiple independent stages, each with its own MOSFET and coupling capacitor. This segmentation allows each stage to operate independently, reducing the cumulative threshold voltage effect and improving overall power efficiency while maintaining integrated circuit adaptability
Solution Approach 2:
Coupling capacitors are introduced as intermediary elements between MOSFET stages. These capacitors transfer charges between stages without requiring direct MOSFET-to-MOSFET connection, thereby reducing the impact of substrate effect on threshold voltage and improving power efficiency
2Power
If the number of charge pump stages is increased to achieve higher voltage, then voltage output is improved, but power efficiency reduces due to cumulative threshold voltage effect
Solution Approach 1:
The voltage generation process is divided into multiple discrete stages, each contributing a controlled voltage increment. By segmenting the voltage generation, the circuit achieves high voltage output while minimizing the cumulative threshold voltage penalty through independent stage operation
Solution Approach 2:
The charge pump operates in periodic cycles where MOSFETs are alternately switched on and off. This periodic action allows charges to be transferred in discrete packets through coupling capacitors, reducing continuous conduction losses and improving power efficiency at high voltage outputs
3Ease of operation
If a level shifting circuit is added to convert clock signals, then gate voltage control is improved, but current consumption increases and boosting efficiency is hindered
Solution Approach 1:
The level shifting function is extracted from a separate dedicated circuit and integrated directly into the clock signal distribution path through the coupling capacitors. This eliminates the need for a separate level shifting circuit, reducing current consumption while maintaining proper gate voltage control
Solution Approach 2:
The coupling capacitors serve multiple functions simultaneously: they transfer charges between stages, block DC voltage levels, and provide gate voltage control. This multi-functionality eliminates the need for separate level shifting circuits, reducing overall current consumption and improving boosting efficiency
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 proposed circuit achieves high boosting efficiency and short start time without the level shifting circuit, improving power efficiency and reducing the time to reach a stable state after power application.
Implementation Method 1
first coupling capacitors 110 to 115 in which first ends thereof are connected with respective connection points of the charge transfer MOSFETs and in which first clock pulses whose phases are reversed to each other are supplied to second ends of the first coupling capacitors
Implementation Method 2
a plurality of charge transfer MOSFETs 100 to 105 connected in series with gates thereof respectively connected with voltages different from a power source voltage Vdd
Data Source
AI summary
Provided is an electronic device including a charge pump circuit whose circuit structure is simple and boosting efficiency is high. The charge pump circuit uses MOSFETs as charge transfer elements and has a structure in which a voltage of a gate of a charge transfer MOSFET is controlled to a predetermined level based on a dividing voltage caused by a first resistor connected between a source and the gate thereof and a second resistor connected between a drain and the gate thereof and a clock pulse for on/off control of the charge transfer MOSFET is supplied to the gate through a capacitor.