Logic Control Circuit With Transistor Voltage Limiting
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Solution Overview
Problem
Existing logic control circuits for power amplifiers in mobile devices face challenges in reducing leakage current while minimizing die/chip area, as large resistors used to reduce leakage increase the chip area, and existing transistors may not effectively limit voltage and current.
Innovation Solution
A logic control circuit comprising a first inverter and a voltage limiter, where the inverter includes transistors with specific configurations such as depletion mode pHEMT and HBT, and the voltage limiter uses transistors connected in series to limit input current and voltage, replacing large resistors with transistors to reduce area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a relatively large resistor is used to reduce leakage current, then power consumption of the power amplifier is reduced, but die/chip area increases
Solution Approach 1:
The patent changes the physical state and operating parameters of the transistor by applying specific voltages to the gate terminal. By adjusting the gate voltage, the transistor's channel conductivity is controlled, enabling it to operate in different modes (linear, saturation, cutoff) to dynamically control leakage current without requiring large resistors
Solution Approach 2:
The patent replaces the passive mechanical resistor-based current limiting approach with an active transistor-based control mechanism. The transistor acts as a voltage-controlled current regulator, substituting the need for large physical resistors and enabling more compact circuit design
2Device complexity
If existing transistors are used to limit current, then device complexity is reduced, but voltage and current limiting effectiveness is insufficient
Solution Approach 1:
The patent introduces a specifically configured transistor as an intermediary element between the power amplifier and ground. This intermediary transistor actively mediates and controls the current flow, providing effective voltage and current limiting that protects the power amplifier while maintaining circuit simplicity
Solution Approach 2:
The patent optimizes the transistor's operating parameters including gate voltage, drain-source voltage, and channel dimensions to achieve effective current limiting. By carefully controlling these parameters, the transistor provides reliable protection without requiring complex additional circuitry
Data Source
AI summary
The present disclosure relates to a logic control circuit including a first inverter and a voltage limiter. The first inverter is connected to a first input voltage. The first inverter includes a first transistor having a first terminal and a second terminal. The second terminal of the first transistor is connected to a ground. The voltage limiter includes a second transistor. The second transistor has a gate connected to a ground, a source connected to the first terminal of the first transistor and a drain connected to a second input voltage.