Dual LDO Voltage Tracking With Overvoltage Isolation
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Solution Overview
Problem
Conventional low dropout (LDO) voltage regulators in automotive applications often require external ICs for voltage tracking, which increases cost and space, and lack effective solutions for avoiding negative impacts during overvoltage events.
Innovation Solution
A dual LDO voltage regulator with independent output voltage selection and the capability to selectively enable or disable voltage tracking, allowing the auxiliary regulator to operate independently if an overvoltage event is detected, thereby avoiding negative impacts on the auxiliary voltage regulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage tracking is enabled in dual LDO regulators, then output accuracy and signal integrity are improved, but the system becomes vulnerable to overvoltage events affecting the auxiliary regulator
Solution Approach 1:
The patent applies preliminary anti-action by detecting overvoltage conditions before they can propagate to the auxiliary regulator. The control circuit monitors the main regulator output and proactively disables tracking mode when overvoltage is detected, preventing the harmful effect from occurring in the first place
Solution Approach 2:
The control circuit acts as an intermediary between the main and auxiliary regulators. It mediates the tracking function by selectively enabling or disabling the tracking path based on overvoltage detection, thus protecting the auxiliary regulator while maintaining output accuracy under normal conditions
2Adaptability or versatility
If external ICs are used for voltage tracking in conventional LDO regulators, then voltage tracking functionality is achieved, but cost and device space increase
Solution Approach 1:
The patent merges the voltage tracking functionality directly into the dual LDO regulator chip, combining what were previously separate functions (main regulator, auxiliary regulator, and external tracking IC) into a single integrated device. This eliminates the need for external tracking ICs, reducing both cost and device space while maintaining full voltage tracking capability
Solution Approach 2:
The dual LDO regulator is designed with multi-functionality, serving as both the main voltage regulator and the auxiliary voltage regulator with built-in tracking capability. This universal design eliminates the need for separate external tracking components, achieving versatility without increasing device complexity
Data Source
AI summary
A voltage regulator circuit includes a first voltage regulator having a first output voltage selection pin set and producing a first output voltage based on a first digital signal received at the first output voltage selection pin set, and a second voltage regulator having a second output voltage selection pin set and producing a second output voltage based on a second digital signal received at the second output voltage selection pin set. The first and second voltage regulators are operable in a voltage tracking mode with the output voltage of the second voltage regulator tracking the output voltage of the first voltage regulator when digital signals received at the selection pin sets have a same value. An overvoltage sensor detects overvoltage events at the first voltage regulator. Control circuitry selectively avoids operation in voltage tracking mode as a result of an overvoltage event detected at the first voltage regulator.