Reference Voltage Switching for Stable Constant-Voltage Circuits
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Solution Overview
Problem
Existing constant voltage devices are dependent on the power source voltage, causing instability in the output voltage, which is undesirable for applications requiring a constant voltage source.
Innovation Solution
A constant voltage device is designed with a diode, switch, voltage generation circuit, and differential amplifier, where the switch controls the reference voltage supply to reduce dependency on the power source voltage, and an NMOS transistor is used as a diode to enhance efficiency, with electrical insulation from other elements to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reference voltage is generated from a voltage dependent on the power source voltage, then the device complexity is reduced, but the output voltage becomes dependent on the power source voltage
Solution Approach 1:
The patent introduces a switching element as an intermediary between the power source voltage and the reference voltage generation circuit. This switching element selectively connects or disconnects the reference voltage supply path based on the power source voltage level, thereby mediating the dependency relationship and preventing the output voltage from following power source voltage variations.
Solution Approach 2:
The patent applies preliminary action by proactively switching off the reference voltage supply path when the power source voltage exceeds a predetermined threshold before the output voltage can become dependent on the power source voltage variations. This preventive measure ensures that the output voltage remains stable and independent of power source fluctuations.
2Loss of energy
If an NMOS transistor is used as a diode, then the power loss is reduced and efficiency is improved, but electrical insulation from other elements must be ensured to prevent interference
Solution Approach 1:
The patent extracts the diode function from a separate discrete component and integrates it into the NMOS transistor structure by utilizing the transistor's inherent diode connection (drain to gate). This integration reduces the number of external components and minimizes electrical interference while maintaining the rectifying function needed for low power loss.
Solution Approach 2:
The patent merges the diode function with the NMOS transistor structure, combining two functions (transistor switching and diode rectification) into a single integrated component. This merging reduces the number of discrete components, minimizes electrical interference between separate elements, and improves overall efficiency by reducing power loss at component interfaces.
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 output voltage is stabilized and less dependent on the power source voltage, achieving a more stable and efficient constant voltage supply, even with variations in the power source voltage.
Implementation Method 1
the diode is configured by a p-n junction between a back gate terminal and a drain terminal of an NMOS transistor
Data Source
AI summary
A constant voltage device include a diode; a switch including one terminal connected to a ground potential and another terminal connected both to an anode terminal of the diode and to a drain of a PMOS transistor having a source applied with a power source voltage; a voltage generation circuit configured to generate a voltage of a predetermined magnitude; and a differential amplifier that includes a non-inverting input terminal to which both a cathode terminal of the diode and an output terminal of the voltage generation circuit are connected, and that is configured to change a supply route of a reference voltage applied to the non-inverting input terminal according to a state of the switch. The voltage generation circuit is configured to employ an output voltage based on the reference voltage and amplified by the differential amplifier to generate the reference voltage.