Linear Power Supply Parallel Transistor Mode Switching
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Solution Overview
Problem
Conventional linear power supplies face challenges in achieving low voltage drive with a small-scale circuit structure, particularly when using N-channel transistors, and require complex feedback control when using P-channel transistors, leading to increased circuit complexity.
Innovation Solution
A linear power supply design that includes a P-channel or PNP first output transistor and an N-channel or NPN second output transistor connected in parallel, with a control circuit that switches between modes based on input voltage, using a P-channel transistor for low voltage drive and an N-channel transistor for stable drive, thereby reducing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an N-channel output transistor is used, then the circuit structure is simple and stable driving is achieved, but low voltage drive cannot be realized
Solution Approach 1:
The patent segments the power supply operation into two distinct modes: a first mode using a P-channel transistor for low voltage drive, and a second mode using an N-channel transistor for stable driving. The control circuit switches between these modes based on input voltage conditions, allowing the system to benefit from both transistor types without requiring both to be present simultaneously in the same configuration.
Solution Approach 2:
The patent implements dynamic switching between different output transistors based on input voltage conditions. The control circuit monitors the input voltage and dynamically selects which transistor to use, transitioning from the P-channel transistor at low voltages to the N-channel transistor at higher voltages, optimizing performance across the entire operating range.
2Use of energy by moving object
If a P-channel output transistor is used, then low voltage drive is achieved, but circuit complexity increases due to dependency on input voltage
Solution Approach 1:
The patent separates the functions of voltage dependency management from the P-channel transistor by introducing a control circuit that monitors input voltage and switches between transistors. This segmentation allows the P-channel transistor to operate in its optimal low-voltage range without bearing the burden of complex voltage dependency compensation.
Solution Approach 2:
The control circuit acts as an intermediary between the input voltage source and the output transistors. It monitors the input voltage and mediates the selection of appropriate transistors, thereby simplifying the overall circuit structure by centralizing the voltage dependency management function.
3Device complexity
If only one type of transistor is used, then the circuit scale is reduced, but both low voltage drive and stable drive cannot be achieved simultaneously
Solution Approach 1:
The patent creates a universal power supply circuit that can adapt to both low voltage and stable driving conditions by incorporating two transistors with complementary characteristics. The control circuit enables the system to function effectively across diverse operating conditions, making the power supply versatile without requiring separate dedicated circuits for each mode.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A linear power supply (1) includes a P-channel (or PNP) first output transistor (10) connected between an input terminal of an input voltage (Vin) and an output terminal of an output voltage (Vout), an N-channel (or NPN) second output transistor (20) connected in parallel to the first output transistor (10), and a control circuit (30) that switches between a first mode and a second mode according to the input voltage (Vin), in which the first mode uses the first output transistor (10) while the second mode uses the second output transistor (20) as an output transistor that generates the output voltage (Vout) from the input voltage (Vin).