Voltage Pre-Regulator Bias Circuit for Stable Mid-Voltage Drop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage regulators face challenges in protecting low voltage devices from high input voltages, requiring specialized transistors and struggling to maintain precision and stability across a wide range of input voltages and temperatures.
Innovation Solution
A voltage pre-regulator using a bias circuit with balanced positive and negative feedback to amplify leakage current, coupled with a laterally diffused metal oxide semiconductor (LDMOS) transistor, generates a regulated voltage drop, allowing for efficient conversion of middle voltage ranges to safe operating areas for low voltage devices without requiring uncommon transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized transistors (JFET or DM-LDMOS) are used to protect low voltage devices from high input voltages, then device protection is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces a pre-regulator circuit as an intermediary component between the high voltage input and the low voltage regulator. This pre-regulator drops the input voltage to a safe level before it reaches the low voltage devices, protecting them without requiring specialized transistors. The pre-regulator acts as a mediator that handles the voltage compatibility issue, allowing standard CMOS transistors to be used throughout the circuit.
2Reliability
If a pre-regulator is used to drop voltage from high input to safe operating area, then low voltage device protection is improved, but power consumption increases
Solution Approach 1:
The pre-regulator uses dynamic feedback control to adjust its operation. The bias circuit monitors the input voltage and dynamically adjusts the bias current to the LDMOS transistor accordingly. When input voltage is high, the pre-regulator drops more voltage; when input voltage decreases, the pre-regulator reduces its voltage drop. This dynamic operation minimizes power consumption while maintaining device protection across varying input conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the bias circuit monitors the input voltage and adjusts the bias current to the LDMOS transistor based on the actual voltage conditions. This feedback control ensures the pre-regulator operates efficiently, dropping only the necessary voltage amount and minimizing power loss as heat, thereby reducing overall power consumption while maintaining protection.
3Loss of time
If feedback loop amplifies leakage current to enable rapid startup, then startup time is improved, but stability control becomes more difficult
Solution Approach 1:
The patent uses feedback in two opposing ways: positive feedback through the bias circuit that amplifies leakage current to enable rapid startup, and negative feedback through the main regulator loop that stabilizes the output voltage. The positive feedback accelerates the startup by quickly establishing bias currents, while the negative feedback ensures the output remains stable once regulation begins, resolving the contradiction between fast startup and voltage stability.
4Measurement precision
If balanced positive and negative feedback is used to control bias current, then regulation precision is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the bias control function and the voltage regulation function into a unified feedback system. The same feedback loop that controls the LDMOS transistor for voltage regulation also controls the bias current to the transistor. By combining these functions, the circuit achieves precise voltage regulation without requiring separate complex bias control circuits, thereby improving precision while minimizing the increase in overall circuit complexity.
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 enables lower power consumption, better noise performance, and higher precision in voltage regulation, maintaining stability within 5% over a wide temperature range and rapid startup time, without the need for specialized transistors like JFET or DM-LDMOS.
Implementation Method 1
a feedback loop that is configured to amplify a leakage current created by an input voltage so that the leakage current increases according to positive feedback to become an amplified leakage current
Implementation Method 2
a current source that is coupled to the feedback loop. The current source is configured to limit the increase of the amplified leakage current by applying negative feedback to the feedback loop
Implementation Method 3
a laterally diffused metal oxide semiconductor (LDMOS) transistor that is configured to generate a voltage drop from an input of the voltage pre-regulator to an output of the voltage pre-regulator based on the bias current and the bias voltage
Data Source
AI summary
A voltage pre-regulator can receive a variable voltage in a middle voltage range (e.g., dozens of volts) and provide a regulated voltage in a safe operating region of a low voltage device. The use of the voltage pre-regulator can allow circuits to use low voltage devices to perform additional regulation/conversion without fear of damage. The voltage pre-regulator disclosed herein can perform the voltage reduction and regulation functions of pre-regulation with commonly used transistor types because the disclosed circuits and method use a bias circuit. The bias circuit uses positive feedback so that no additional start-up circuitry is required. The positive feedback is controlled by negative feedback so that the pre-regulator is able to provide a regulated voltage that is stable over a range of input voltages and temperatures.