Dual-Drive Shunt Regulator for Faster Low-Voltage Stabilization
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Solution Overview
Problem
Conventional shunt regulators experience increased time to reach a desired low output voltage due to the operating voltage being based on the output voltage, which decreases when the output voltage drops, leading to slower stabilization.
Innovation Solution
A shunt regulator design incorporating a first drive circuit with high accuracy and stability, a second drive circuit with shorter activation time, and an activation control circuit that switches between the two to rapidly stabilize the output voltage, utilizing a voltage divider circuit and NMOS transistors to control the output transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a single drive circuit is used to control the output transistor, then the circuit structure is simple, but the time required for low output voltage to reach a desired value increases
Solution Approach 1:
The drive circuit is divided into two separate drive circuits: a first drive circuit for normal operation and a second drive circuit for rapid activation. Each circuit is optimized for its specific function, allowing the system to achieve fast activation times while maintaining operational stability through segmentation of control functions.
Solution Approach 2:
The system dynamically switches between the first drive circuit and the second drive circuit based on operating conditions. The activation control circuit monitors the output voltage and selectively activates the appropriate drive circuit, enabling the system to adapt its behavior to achieve optimal performance across different operating states.
2Measurement precision
If the operating voltage is based on the output voltage, then the circuit operates with high accuracy, but when the output voltage decreases, the stabilization time increases
Solution Approach 1:
A dummy reference voltage circuit is introduced as an intermediary element that provides a stable reference voltage independent of the output voltage. This dummy reference voltage serves as a mediator that allows the second drive circuit to rapidly stabilize the output voltage during activation without being constrained by the output voltage level, thereby reducing stabilization time while maintaining accuracy through the activation control circuit's selective operation.
3Productivity
If a second drive circuit with shorter activation time is added, then the time to reach desired output voltage is reduced, but the circuit complexity increases
Solution Approach 1:
The activation control circuit serves multiple functions: it monitors the output voltage, determines when rapid activation is needed, switches between the two drive circuits, and manages the transition between activation and normal operation modes. This multi-functional approach consolidates control logic into a single circuit, reducing overall system complexity despite adding a second drive circuit.
Data Source
AI summary
Provided is a shunt regulator including: multiple resistors, connected in series between an output terminal and a ground terminal and constituting a voltage divider circuit; an output transistor, connected between the output terminal and the ground terminal; a first drive circuit, including a first reference voltage circuit which outputs a first reference voltage and an error amplifier, and controlling the output transistor based on a voltage of a first output terminal of the voltage divider circuit; a second drive circuit, controlling the output transistor based on a voltage of a second output terminal of the voltage divider circuit; and an activation control circuit, switching operation of the first drive circuit and the second drive circuit based on the first reference voltage. The second drive circuit has a shorter activation time than the first drive circuit.