Two-Phase Charge Pump Circuit Body Effect Control
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Solution Overview
Problem
Existing charge pump circuits are unable to effectively control the body effect in NMOS and PMOS transistors, leading to increased voltage requirements due to unmanaged body effects.
Innovation Solution
A two-phase charge pump circuit design that uses a mixed structure of NMOS and PMOS transistors, where the bodies of NMOS transistors are switched to a lower voltage level and PMOS transistors to a higher voltage level, utilizing a set of first and second input signals with opposite phases to control switches connected to the transistors, thereby preventing the body effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the body of each NMOS transistor is connected to ground without further processing, then the circuit structure is simple, but the body effect occurs causing higher voltage requirements for conduction
Solution Approach 1:
The patent applies the dynamics principle by making the body connection of NMOS transistors dynamic rather than static. Switches controlled by control signals connect the bodies to either ground or higher voltage levels based on operational phases, allowing the circuit to adapt voltage requirements dynamically and eliminate the body effect during conduction.
Solution Approach 2:
The patent changes the voltage parameter of the transistor body by using switches to dynamically alter the body connection point. The body voltage is changed from a fixed ground connection to a dynamic connection that can be at ground or higher voltage levels, thereby changing the electrical parameters to eliminate the body effect.
2Reliability
If switches are added to control the body voltage of transistors, then the body effect is prevented, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing switches that serve multiple functions: they control both the conduction path of the transistor and the body connection simultaneously. The same control signals that drive the main transistor gates also control the body switches, making the control system multi-functional and reducing overall complexity.
Solution Approach 2:
The patent merges the control of transistor conduction and body voltage by using the same control signals for both functions. The control signals that activate the main transistors also activate the body switches, combining two control functions into a unified control mechanism.
3Reliability
If higher voltage is applied to overcome the body effect, then conduction is achieved, but energy consumption increases
Solution Approach 1:
The patent changes the body voltage parameter dynamically to match the conduction requirements. By adjusting the body voltage to the appropriate level (ground or higher) based on the operational phase, the transistor can conduct at lower gate-source voltages, reducing the energy required for conduction compared to always applying high voltage.
Solution Approach 2:
The patent uses periodic control signals that alternate between different voltage levels in sync with the charge pump operation phases. This periodic switching of body voltage ensures that the transistor only requires higher voltage temporarily when needed, rather than continuously, thereby reducing overall energy consumption.
Data Source
AI summary
A two-phase charge pump circuit without the body effect includes a voltage boost stage, an input stage connected to the voltage boost stage, and a high-voltage generator connected to the input stage. Each of the circuits can consist of NMOS or PMOS transistors. The body of each NMOS transistor is connected to an NMOS switch. The body of each PMOS transistor is connected to a PMOS switch. By providing an appropriate driving signal to each NMOS or PMOS switch, the body of each NMOS transistor can be switched to a lower voltage level and the body of each PMOS transistor is switched to a higher voltage level. This can prevent the body effect from occurring.