Voltage Regulator Current Limiter for Fast Startup Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional voltage regulators require separate sets of circuitry for startup and current regulation, leading to longer startup times and susceptibility to current overshoot when battery voltage increases slowly or irregularly.
Innovation Solution
A single set of current limiter circuitry is used in the voltage regulator, configuring the current limiting transistor as a diode-connected transistor during startup and transitioning it into a current control loop for current regulation, eliminating the need for comparator activation and enabling faster startup and current limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate sets of circuitry are used for startup and current regulation, then current regulation reliability is improved, but startup time increases and device complexity increases
Solution Approach 1:
The patent combines separate startup circuitry and current regulation circuitry into a single integrated current limiter circuit that performs both functions. The circuit uses a unified structure with transistors and switches that can operate in different modes (startup mode and current regulation mode) depending on the operational state, eliminating the need for separate dedicated circuits for each function.
2Reliability
If separate sets of circuitry are used for startup and current regulation, then current regulation reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single current limiter circuit structure, reducing the total number of components. The circuit uses shared transistors, switches, and control logic that can serve both startup and current regulation purposes, thereby simplifying the overall device architecture while maintaining reliable current regulation.
Solution Approach 2:
The current limiter circuit is designed as a universal structure that can perform multiple functions: startup current limiting, ongoing current regulation, and protection against current overshoot. The circuit elements (transistors, switches, comparators) are configured to adapt their behavior based on the operational phase, making the circuit multi-functional rather than requiring separate dedicated circuits.
3Device complexity
If conventional voltage regulators are used, then circuit design is simplified, but current overshoot susceptibility increases when battery voltage increases slowly or irregularly
Solution Approach 1:
The patent implements feedback control through a comparator that continuously monitors the voltage across the output capacitor and compares it to a reference voltage. Based on this feedback, the control logic adjusts the switching state of the current limiter circuit to prevent current overshoot. The feedback mechanism ensures that current limiting is dynamically adapted to the actual charging state, improving reliability under varying battery voltage conditions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A voltage regulation circuit and method of operation are described, where the voltage regulation circuit includes an error amplifier configured to provide an error signal based on a comparison of a reference voltage and a voltage at a first voltage divider coupled to an output node of the voltage regulation circuit, a pass transistor configured to selectively pass current from an input node to the output node based, at least in part, on the error signal, current limiter circuitry including a current limiting transistor that is configured to limit electrical current through the pass transistor, and logic circuitry configured to configure the current limiting transistor as a diode-connected transistor in a first state and configure the current limiting transistor as part of a current control loop in a second state.