Power Supply Device for Vehicle ECU with Dual Linear Regulators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power supply devices for electronic control units in vehicles face issues with high minimum operating voltage, leading to potential power disruption to microcomputers during battery voltage drops, especially during cranking periods.
Innovation Solution
A power supply device comprising a first linear regulator, a switching regulator of a step-down type, and a second linear regulator, where the first linear regulator operates during off-periods with low current consumption and the second linear regulator supports during on-periods with a lower minimum operating voltage, ensuring continuous power supply while managing current consumption effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a linear regulator using N-channel type MOS transistors is used for small current consumption, then current consumption is reduced, but the minimum operating voltage becomes high
Solution Approach 1:
The power supply device is divided into two separate linear regulators: a first linear regulator optimized for low current consumption during off-periods, and a second linear regulator with lower minimum operating voltage during on-periods. This segmentation allows each regulator to be independently optimized for its specific operational requirements, resolving the contradiction between current consumption and minimum operating voltage.
2Use of energy by moving object
If the power supply switch is turned off during off-periods to save power, then current consumption is reduced, but power supply to the computer may be disabled when battery voltage falls
Solution Approach 1:
The first linear regulator is prepared in advance and remains operational during off-periods to provide a backup power supply path. When the power supply switch is turned off, the first linear regulator is already positioned to immediately supply power to the computer if battery voltage drops, preventing power disruption without requiring active monitoring or switching decisions.
3Reliability
If the main switching component of the switching regulator is driven to turn on at all times, then the minimum operating voltage is lowered, but current consumption increases during off-periods
Solution Approach 1:
The system dynamically switches between different regulator configurations based on operational state. During on-periods, the second linear regulator operates with the switching component fully on to provide lower minimum operating voltage. During off-periods, the system transitions to the first linear regulator configuration optimized for low current consumption, allowing the system to adapt its characteristics to current operational requirements.
Data Source
AI summary
A power supply device comprises: a first linear regulator, which receives a voltage from a direct-current power supply at all times and outputs a first voltage; a step-down switching regulator, which receives the voltage from the direct-current power supply through a path via a power supply switch and outputs an intermediate voltage, and a second linear regulator, which receives the intermediate voltage and outputs a second voltage. The power supply device outputs a higher one of the first voltage and the second voltage. The first linear regulator has a smaller current consumption and a higher minimum operating voltage than the second linear regulator. When the voltage supplied from the direct-current power supply is lower than or equal to a predetermined threshold value, the switching regulator drives a main switching component interposed in series with a voltage input-output path to turn on at all times. The second linear regulator executes an output operation of the second voltage during a full-on period, during which the main switching component is driven to turn on at all times.