Reference Voltage Circuit With Dynamic Zener Current Control
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Solution Overview
Problem
Conventional reference voltage circuits face challenges in maintaining linearity of the voltage applied to the Zener diode with respect to temperature changes, leading to increased power consumption due to the need for high constant current flow through the Zener diode.
Innovation Solution
A reference voltage circuit incorporating a current mirror circuit, a current control circuit, and resistors, which generates a control current to adjust the current through the Zener diode, maintaining linearity without increasing the current from the constant current source, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the constant current source supplies a large current to the Zener diode to maintain linearity of the voltage with respect to temperature, then the linearity of the voltage Vz is improved, but the power consumption of the reference voltage circuit increases
Solution Approach 1:
The patent applies dynamics by replacing the static constant current source with a dynamic current source that adjusts its output based on temperature. The current control circuit generates a control current proportional to the anode voltage of the first diode, which varies with temperature, thereby dynamically adjusting the current through the Zener diode to maintain voltage linearity across temperature ranges without requiring excessive current at all times.
Solution Approach 2:
The patent changes the parameter of current magnitude from a fixed high value to a variable value that adapts to temperature conditions. By using a current control circuit that generates control current proportional to the diode's anode voltage, the system optimizes the current level at each temperature point, ensuring sufficient current for linearity only when necessary while reducing current (and thus power consumption) when high current is not needed for maintaining voltage characteristics.
2Reliability
If the constant current source supplies a large current to reduce the influence of the negative temperature coefficient of the diode voltage, then the temperature coefficient of the output voltage can be brought to 0, but the power consumption increases
Solution Approach 1:
The patent implements feedback by using the anode voltage of the first diode as a sensing parameter that reflects temperature conditions. The current control circuit uses this voltage to generate a control current that is fed back to adjust the current through the Zener diode and the first diode, creating a closed-loop system that automatically compensates for temperature effects and maintains optimal operating conditions without requiring manual intervention or excessive current.
Solution Approach 2:
The patent changes the current parameter from a static high value to a dynamic value that adapts to temperature. The control current generated by the current control circuit is proportional to the anode voltage, which varies with temperature, allowing the system to optimize the current level at each temperature point to maintain zero temperature coefficient while minimizing power consumption.
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 solution effectively maintains the linearity of the voltage applied to the Zener diode's cathode while minimizing the current from the constant current source, resulting in reduced power consumption and improved temperature stability.
Implementation Method 1
a Zener diode 104 and a series circuit of resistors 107 and 106 and a diode 105 are connected in parallel in which the Zener diode 104 is connected in a reverse direction
Implementation Method 2
the diode 105 is connected in a forward direction
Implementation Method 3
Vout=(R106·Vz+R107·VD)/(R106+R107)
Data Source
AI summary
Provided is a reference voltage circuit including a Zener diode having a cathode connected to a current source via a first node, and an anode connected to a ground point; a first resistor having one end connected to the first node; a second resistor having one end connected to another end of the first resistor; a first diode having an anode connected to another end of the second resistor via a second node, and a cathode connected to the ground point; and a current control circuit configured to generate a control current corresponding to an anode voltage of the first diode so that the current source supplies a reference current corresponding to the control current to the first diode.