MOS-Gated Charge Transfer Circuit for Fast Low-Power Operation
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Solution Overview
Problem
Existing charge transfer circuits are power hungry due to the need for operational amplifiers with high driving capability to enable fast charge transfer, which consumes excessive power.
Innovation Solution
A charge transfer circuit that utilizes a MOS transistor to transfer charge between capacitors, where the gate voltage of the MOS transistor is controlled by an amplified voltage from the operational amplifier, allowing the MOS transistor to handle the charge transfer with reduced operational amplifier driving requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an operational amplifier with high driving capability is used to enable fast charge transfer, then the charge transfer speed is improved, but the power consumption increases
Solution Approach 1:
A MOS transistor is introduced as an intermediary component between the operational amplifier and the capacitors. The operational amplifier only needs to drive the gate of the MOS transistor, while the MOS transistor handles the main charge transfer current between capacitors. This mediator approach allows the operational amplifier to operate at low power while achieving fast charge transfer through the MOS transistor's channel.
Solution Approach 2:
The charge transfer function is segmented into two parts: (1) the operational amplifier generates and amplifies the control voltage to drive the MOS transistor gate, and (2) the MOS transistor executes the actual charge transfer between capacitors. This segmentation allows each component to operate in its optimal efficiency range, with the operational amplifier consuming minimal power and the MOS transistor providing fast charge transfer.
2Power
If an operational amplifier with high driving capability is used, then the output current is increased, but the power consumption increases
Solution Approach 1:
The MOS transistor serves as an intermediary that amplifies the current capability. The operational amplifier only needs to provide sufficient current to charge/discharge the MOS transistor gate capacitance, which is minimal. The MOS transistor then provides the high current output needed for fast charge transfer, effectively decoupling the operational amplifier's current output requirement from the overall system power consumption.
3Productivity
If the operational amplifier directly transfers charge between capacitors, then the charge transfer is achieved, but the operational amplifier becomes power hungry
Solution Approach 1:
The direct charge transfer mechanism using operational amplifier output current is replaced by a voltage-controlled mechanism using MOS transistor. The operational amplifier outputs a voltage signal that controls the MOS transistor's conductive channel, which then facilitates the charge transfer. This substitution changes the control mechanism from direct current control to voltage-controlled current flow, significantly reducing operational amplifier power consumption.
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
This approach results in a more power-efficient charge transfer circuit by reducing the capacitive load on the operational amplifier, enabling fast charge transfer with lower power consumption.
Implementation Method 1
an operational amplifier, wherein: the first capacitor is configured to couple to the second capacitor via the MOS transistor; the operational amplifier is configured to receive a voltage at the first capacitor and output a control voltage
Data Source
AI summary
A circuit comprises: a first capacitor; a second capacitor; a MOS (metal oxide semiconductor) transistor; and an operational amplifier, wherein the first capacitor is configured to couple to the second capacitor via the MOS transistor; the operational amplifier is configured to receive a voltage at the first capacitor and output a control voltage; and the MOS transistor is configured to be controlled by the control voltage.