Cross-Coupled Charge Pump Voltage Drop Reduction
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Solution Overview
Problem
Pumping circuits that generate high voltage using capacitors and transistors face issues with voltage reduction due to changes in transistor resistance when the gate voltage changes during voltage transfer.
Innovation Solution
A cross-coupled charge pump circuit with first and second capacitors and transistors, along with a switching voltage supply circuit to stabilize switching voltages at the transistors, ensuring efficient transfer of input and pumping voltages without significant resistance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gate voltage of the transistor changes during the generation and transfer of the relatively high voltage, then the transistor can switch states, but the resistance of the transistor changes and the level of the relatively high voltage being transferred is reduced
Solution Approach 1:
The patent applies preliminary action by pre-charging the first and second capacitors to a voltage higher than the input voltage before the actual voltage transfer operation. This pre-charging ensures that when the transistors switch during voltage transfer, the capacitors can maintain stable voltage levels without significant drops, as the higher initial voltage compensates for transient resistance changes during switching.
Solution Approach 2:
The patent introduces capacitors as intermediary energy storage elements between the input voltage source and the output. These capacitors act as buffers that decouple the input and output sides, allowing the transistors to switch without directly affecting the output voltage stability. The capacitors absorb and release energy during switching transitions, maintaining voltage levels despite transient resistance changes.
2Reliability
If larger capacitance sizes are used for the pumping capacitors, then voltage stability is improved, but the device size and complexity increase
Solution Approach 1:
The patent changes the voltage parameter of the capacitors by charging them to a voltage higher than the input voltage. This parameter change allows the capacitors to store more energy at smaller physical sizes, as energy storage capacity is proportional to the square of the voltage (E = 0.5 * C * V^2). By increasing the operating voltage of the capacitors, the patent achieves better voltage stability without requiring proportionally larger capacitance values.
Solution Approach 2:
The pre-charging operation performed in advance stores energy in the capacitors at higher voltage levels. This preliminary energy storage reduces the burden on capacitor size during the actual voltage transfer phase, as the pre-stored energy can be quickly released to maintain output voltage stability during switching operations.
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 maintains stable voltage transfer and reduces the turn-on resistances of transistors, allowing for improved operating characteristics and reduced voltage drop, enabling smaller capacitance sizes for the pumping capacitors.
Implementation Method 1
first and second capacitors configured to pump an input voltage in response to a first clock signal and an inverted first clock signal
Implementation Method 2
If a gate voltage of the transistor changes during the generation and transfer of the relatively high voltage the resistance of the transistor may change
Data Source
AI summary
A pumping circuit includes a cross-coupled charge pump circuit including first and second capacitors configured to pump an input voltage in response to a first clock signal and to an inverted first clock signal and a plurality of transistors configured to one of transfer the input voltage to the first and second capacitors and to transfer a pumping voltage to an output node, and a switching voltage supply circuit configured to supply switching voltages to gates of the plurality of transistors to enable the transfer of the input voltage and the pumping voltage.