MOS Switch Circuit With Voltage-Controlled Low-Current Conduction
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Solution Overview
Problem
Conventional semiconductor switch circuits experience high current consumption due to the need for a current flow to establish conduction, leading to excess leakage current and increased power consumption.
Innovation Solution
A semiconductor switch circuit configuration featuring first and second MOS transistors sharing a source and connected in series between input/output terminals, with third and fifth MOS transistors having drains connected to the gate of the first MOS transistor and fourth and sixth MOS transistors having drains connected to the gate of the second MOS transistor, along with a control terminal connected to the gates of these MOS transistors, where the sources and back gates of the third and fourth MOS transistors are connected to the sources of the first and second MOS transistors, allowing for voltage-controlled switching between conduction and non-conduction states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor switch circuit uses a current mirror circuit to control conduction state, then the switching control function is achieved, but current consumption increases due to necessary current flow through the control path
Solution Approach 1:
The patent replaces the conventional current mirror circuit (which requires continuous current flow) with a voltage-controlled switching mechanism using MOS transistors. The control signal applied to the gate terminal creates an electric field that controls the conduction state without requiring continuous current flow through the control path, thus substituting a current-based control system with a voltage-based control system that consumes less power.
Solution Approach 2:
The patent changes the control parameter from current (in conventional current mirror circuits) to voltage (in the MOS transistor gate control). By applying a voltage signal to the gate terminal, the transistor's conduction state is controlled through electric field effects rather than current flow, fundamentally changing the control mechanism to reduce power consumption while maintaining reliable switching function.
2Reliability
If resistance is added between gate and source to stabilize non-conduction state, then switching reliability improves, but voltage drop occurs and current consumption increases
Solution Approach 1:
The patent removes the resistance element (R24) from between the gate and source terminals that was present in conventional circuits. Instead of using resistance to stabilize the non-conduction state, the invention relies on the inherent properties of the MOS transistor structure and the control signal application method to achieve stable switching without the energy loss associated with resistive elements.
Solution Approach 2:
The MOS transistor structure inherently provides stable non-conduction state when the gate voltage is appropriate, without requiring external resistance elements. The transistor's own characteristics and the control signal work together to maintain the off state, making the circuit self-sufficient and eliminating the need for additional components that would cause voltage drop and power loss.
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 configuration reduces power consumption by eliminating unnecessary current flow during conduction and maintains a stable non-conduction state without a control signal, achieving low current consumption and reliable switching.
Implementation Method 1
third and fifth MOS transistors having drains connected to the gate of the first MOS transistor; fourth and sixth MOS transistors having drains connected to the gate of the second MOS transistor; and a control terminal connected to the gates of these MOS transistors
Data Source
AI summary
A semiconductor switch circuit is provided that enables current consumption to be reduced even in a conduction state. A semiconductor switch circuit 100 has P-type MOS transistors Q101 and Q102 for conduction that share a source and are connected in series between an input/output terminal 101 and input/output terminal 102, a P-type MOS transistor Q103 and N-type MOS transistor Q105 having drains connected to the gate of Q101, a P-type MOS transistor Q104 and N-type MOS transistor Q106 having drains connected to the gate of Q102, and a control terminal 103 connected to the gates of the transistors. Further semiconductor switch circuit 100 is configured with the sources and back gates of Q103 and Q104 connected to the sources of Q101 and Q102. Therefore, it is possible to switch the path between input/output terminal 101 and input/output terminal 102 between a conduction state and non-conduction state by means of voltage control by voltage value Vcont of a control signal applied to control terminal 103.