Voltage Regulator Overcurrent Protection Circuit Single Resistor Adjustment
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Solution Overview
Problem
Existing voltage regulators with overcurrent protection circuits require separate adjustment of limited and short-circuited currents, leading to increased chip size due to the need for multiple resistive elements.
Innovation Solution
A voltage regulator design that includes an output transistor, error amplifier circuit, and overcurrent protection circuit with a current mirror and voltage control mechanism, allowing for collective adjustment of both currents by varying the size ratio of transistors and a single resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate adjustment resistors are used for limited current and short-circuited current, then each current can be adjusted independently, but chip size increases
Solution Approach 1:
The patent combines the adjustment functions for limited current and short-circuited current into a single resistor. By using one resistor to adjust both currents simultaneously, the chip area is reduced while maintaining the ability to precisely set both current parameters. The resistor is configured to be effective in both the drooping characteristic circuit and the fold-back characteristic circuit, eliminating the need for separate adjustment components.
Solution Approach 2:
The single resistor serves multiple functions: it adjusts the limited current in the drooping characteristic mode and simultaneously adjusts the short-circuited current in the fold-back characteristic mode. This multi-functional component replaces what would traditionally require two separate adjustment resistors, reducing chip size while maintaining adjustment precision for both current parameters.
2Manufacturing precision
If multiple adjustable resistors are configured, then limited current and short-circuited current can be set to desired values, but device complexity increases
Solution Approach 1:
The patent merges the adjustment mechanisms for limited current and short-circuited current into a single resistor component. This reduces the total number of components and simplifies the circuit structure while maintaining the capability to accurately set both current parameters. The single resistor is strategically positioned and configured to influence both current characteristics simultaneously.
Solution Approach 2:
The single resistor performs multiple adjustment functions: it controls the limited current during normal operation and controls the short-circuited current during fault conditions. This universal adjustment component eliminates the need for separate resistors and adjustment circuits, thereby reducing device complexity while preserving manufacturing precision for current setting.
Data Source
AI summary
To provide a voltage regulator equipped with an overcurrent protection circuit which needs not to separately adjust a limited current and a short-circuited current and is capable of collectively adjusting them. There is provided an overcurrent protection circuit equipped with an output current limitation circuit which distributes a current supplied from a transistor sensing an output current of an output transistor and controls a gate voltage of the output transistor by the distributed current to limit the output current. The overcurrent protection circuit is configured in such a manner that the current distributed from the transistor sensing the output current is varied according to the voltage outputted from the output transistor, and its distribution ratio is determined by a size ratio between elements.