Linear Voltage Regulator with Feedback Voltage Divider
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Solution Overview
Problem
Linear voltage regulators fail to produce a sufficient output voltage when the input voltage is lower than the desired output voltage, resulting in an excessive voltage drop and potentially no output voltage at all.
Innovation Solution
A linear voltage regulator design that includes a first transistor for series regulation, a reference voltage source, and a second transistor acting as a voltage-dependent resistor within a voltage divider, connected to a differential amplifier, which adjusts the forward resistance of the first transistor to minimize voltage drop and maintain output voltage when input voltage is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the input voltage is lower than the desired output voltage, then the voltage drop at the pass transistor increases, but the output voltage becomes too small or zero
Solution Approach 1:
The patent implements feedback by connecting a voltage divider (comprising first and second resistors) between the output voltage terminal and reference voltage terminal, with the tap connected to the inverting input of the differential amplifier. This feedback mechanism allows the system to detect output voltage changes and adjust the pass transistor accordingly, ensuring stable output voltage even when input voltage is insufficient.
Solution Approach 2:
The patent changes the operating parameters of the pass transistor by using a differential amplifier to dynamically adjust its gate voltage based on the voltage difference between the reference voltage (at the non-inverting input) and the feedback voltage (at the inverting input). This parameter adjustment allows the pass transistor to operate effectively across a wider input voltage range, including cases where input voltage is lower than the desired output voltage.
2Adaptability or versatility
If the input voltage range is extended to include values smaller than the desired output voltage, then the adaptability improves, but the voltage regulation capability deteriorates
Solution Approach 1:
The feedback voltage divider network continuously monitors the output voltage and feeds it back to the inverting input of the differential amplifier. This feedback mechanism enables the system to maintain precise output voltage regulation across an extended input voltage range, including cases where the input voltage is lower than the desired output voltage, by dynamically adjusting the pass transistor's resistance.
Solution Approach 2:
The patent introduces dynamic control by using a differential amplifier that continuously adjusts the pass transistor's gate voltage based on the real-time voltage difference between the reference voltage and feedback voltage. This dynamic adjustment allows the system to adapt to varying input voltage conditions while maintaining precise output voltage regulation.
3Loss of energy
If the pass transistor is used for series regulation, then the voltage drop is reduced, but the minimum input voltage requirement remains
Solution Approach 1:
The feedback mechanism using a voltage divider network connected to the differential amplifier allows the system to detect when the output voltage deviates from the reference voltage and adjust the pass transistor accordingly. This feedback control enables the system to maintain efficient series regulation with minimal voltage drop while adapting to a wider range of input voltages, including cases where the input voltage is lower than the desired output voltage.
Solution Approach 2:
The patent changes the control parameters of the pass transistor by using the differential amplifier to dynamically adjust its gate voltage based on the voltage difference between the reference voltage and feedback voltage. This parameter adjustment enables the pass transistor to operate with minimal voltage drop across a wider input voltage range, extending the minimum input voltage requirement below the desired output voltage.
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
The regulator delivers an output voltage approximately equal to the input voltage when it is insufficient to produce the desired output, extending the input voltage range and ensuring stable operation even below the normal operating limits.
Implementation Method 1
the forward resistance of the second transistor changes such that the voltage at the tap of the voltage divider decreases
Data Source
AI summary
A linear voltage regulator is provided having a first transistor connected between a terminal for an input voltage and a terminal for an output voltage, a reference voltage source for producing a reference voltage, a first resistor, a second resistor, a second transistor, wherein the first resistor, the second resistor, and the second transistor are series-connected between the terminal for the output voltage and a reference voltage, and constitute a voltage divider, wherein a divided output voltage is present at a tap of the voltage divider, and also having a differential amplifier with an inverting input and a non-inverting input, wherein the inverting input is connected to the reference voltage source, the non-inverting input is connected to the tap of the voltage divider, and an output terminal of the differential amplifier is connected to a control terminal of the first transistor.