Power Supply Circuit Layout for Fast Transistor Gate Switching
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Solution Overview
Problem
Existing power source supply circuits for communication devices, particularly in TDD schemes, face challenges in achieving high-speed ON/OFF switching of transistors without increasing circuit scale, as previous solutions either fail to provide sufficient speed or require large circuit configurations.
Innovation Solution
A power source supply circuit with multiple first power sources, a switch circuit, an RF choke circuit, and a second capacitor with larger capacitance than the first capacitor, allowing for efficient switching of power source voltages and reducing the time constant of the RC delay circuit, thereby enabling faster transistor switching without increasing the circuit scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a decoupling capacitor with μF-class capacitance is connected near the gate terminal of the amplifying transistor, then voltage stabilization is improved, but the switching speed of the transistor is reduced due to long charge and discharge time
Solution Approach 1:
The patent divides the capacitor system into two separate capacitors: a first capacitor (small capacitance, e.g., 100 pF) connected near the gate terminal for fast switching, and a second capacitor (large capacitance, e.g., 10 μF) connected near the power source for voltage stabilization. This segmentation allows each capacitor to specialize in one function, resolving the contradiction between fast switching and voltage stability.
Solution Approach 2:
The patent introduces a switch circuit as an intermediary component between the power source and the amplifying transistor. This switch circuit enables controlled connection and disconnection of the power source, allowing the system to achieve fast switching by isolating the transistor from the large decoupling capacitor during switching operations while maintaining voltage stability when the switch is closed.
2Device complexity
If a discharging resistor with several kΩ resistance is connected in parallel with the decoupling capacitor, then the circuit complexity is reduced, but the charge and discharge time becomes excessively long
Solution Approach 1:
The patent changes the capacitance parameter by using two capacitors with vastly different capacitance values (small first capacitor and large second capacitor) instead of a single capacitor. This parameter change allows the system to achieve fast discharge through the small capacitor while the large capacitor maintains voltage stability, eliminating the need for a discharging resistor and its associated time delays.
3Speed
If multiple switch circuits are used to expand discharge current capability, then the switching speed is improved, but the circuit scale increases significantly
Solution Approach 1:
The patent segments the capacitor functions into two distinct capacitors with different capacitance values and locations, eliminating the need for multiple switch circuits. The first capacitor handles fast switching requirements near the transistor, while the second capacitor handles voltage stabilization near the power source, achieving fast switching without increasing circuit scale.
Solution Approach 2:
By changing the capacitance parameter distribution from a single large capacitor to two capacitors with different capacitance values, the system achieves fast discharge capability through the small first capacitor without requiring multiple switch circuits to expand discharge current capability.
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 achieves further increase in speed of ON/OFF switching of transistors, reducing switching times significantly while maintaining a compact circuit design, as demonstrated by comparisons with previous technologies.
Implementation Method 1
an RF choke circuit provided between the switch circuit and the voltage output terminal, the RF choke circuit including a first capacitor
Implementation Method 2
a second capacitor provided between the plurality of first power sources and the switch circuit, the second capacitor having a larger capacitance than the first capacitor
Data Source
AI summary
A power source supply circuit includes: a plurality of power sources (11-1, 11-2) that generate power source voltages different from each other; a switch circuit (14) that switches and outputs the power source voltages generated in the plurality of power sources (11-1, 11-2); a voltage output terminal (16) that outputs outside the power source voltages output from the switch circuit (14); an RF choke circuit (15) provided between the switch circuit (14) and the voltage output terminal (16), the RF choke circuit (15) including a first capacitor; and a second capacitor (12-1, 12-2) provided between the plurality of power sources (11-1, 11-2) and the switch circuit (14), the second capacitor (12-1, 12-2) having a larger capacitance than the first capacitor.