Constant Voltage Circuit Temperature Stabilization
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Solution Overview
Problem
Existing constant voltage circuits in semiconductor devices face issues with temperature-dependent output voltage variations, leading to either sudden voltage drops at high temperatures or overvoltage applications at low temperatures, which can cause operational failures.
Innovation Solution
A constant voltage circuit design incorporating a Zener diode and series diodes, where the output voltage is set based on dropped voltages of the diodes at high temperatures and clamped by the Zener diode at low temperatures, reducing voltage variation across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a simple constant voltage circuit is used in the sub-power supply circuit, then power consumption is reduced, but output voltage varies significantly with temperature
Solution Approach 1:
The patent uses a Zener diode to change the voltage regulation mechanism. The Zener diode operates in reverse breakdown region, utilizing the Zener effect to maintain a stable reference voltage that is less sensitive to temperature variations compared to simple diode voltage drops. This parameter change in the voltage regulation approach resolves the contradiction between low power consumption and voltage stability.
Solution Approach 2:
The constant voltage circuit employs a composite structure combining multiple diodes in series with a Zener diode. This composite configuration leverages the temperature compensation characteristics where the combined voltage drop of regular diodes and the Zener voltage work together to stabilize the output voltage across temperature ranges, addressing the reliability issue while maintaining simplicity.
2Device complexity
If diode voltage drops are used to set output voltage, then circuit complexity is reduced, but output voltage plummets suddenly at high temperatures
Solution Approach 1:
The Zener diode acts as an intermediary element between the power supply and the output. It provides a stable voltage reference that mediates the temperature-dependent voltage drops of the series diodes, preventing sudden voltage plummets at high temperatures while keeping the circuit configuration relatively simple.
Solution Approach 2:
The patent converts the harmful effect of temperature-induced voltage variations into a benefit by using the Zener diode's reverse breakdown characteristic. The Zener diode's voltage remains relatively stable over temperature ranges, and when combined with the series diodes, it compensates for their temperature sensitivity, turning the temperature dependency from a problem into a solution.
3Reliability
If Zener diode is used to clamp output voltage, then overvoltage at low temperatures is prevented, but circuit complexity increases
Solution Approach 1:
The Zener diode performs multiple functions: it provides a stable voltage reference, clamps the output voltage to prevent overvoltage at low temperatures, and compensates for temperature-induced voltage variations. This multi-functionality reduces the need for additional circuit elements, thereby limiting the increase in circuit complexity while achieving reliable voltage stabilization.
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 design stabilizes the output voltage across temperature fluctuations, preventing voltage plummets at high temperatures and overvoltage issues at low temperatures, ensuring reliable operation of logic circuits.
Implementation Method 1
a Zener diode, and a second transistor of a second conductivity type, which differs from the first conductivity type, coupled in series between the first node and a second voltage terminal
Implementation Method 2
a first diode coupled in series between the first node and a second voltage terminal
Data Source
AI summary
According to one embodiment, a constant voltage circuit includes a first resistance including a first terminal coupled to a first voltage terminal, and a second terminal coupled to a first node; a first transistor including a first terminal coupled to the first voltage terminal, a second terminal coupled to a second node, and a control terminal coupled to the first node; a first diode coupled in series between the first node and a second voltage terminal; a Zener diode, and a second transistor coupled in series between the first node and the second voltage terminal; a second resistance, and a third transistor coupled in series between the first node and the second voltage terminal; and third and fourth resistances coupled in series between the second node and the second voltage terminal.