In-Vehicle USB PD Power Supply with Mode-Based Output Limits

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Solution Overview

Problem

Conventional in-vehicle USB chargers, when replaced with high-capacity power supply devices like USB PD standard, increase the likelihood of battery depletion due to consistent high power consumption, compromising user convenience.

Innovation Solution

A power supply unit with a control unit that switches between two upper limit power modes based on the state of a main control signal, providing reduced power in accessory mode to prevent battery drain and increased power in on mode to support user devices, while maintaining or reducing the risk of battery depletion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a high-capacity power supply device conforming to the USB PD standard is used as an in-vehicle USB charger, then user convenience is improved and devices can be quickly charged, but the possibility that the battery runs out increases

Engineering Contradiction:
Improveuser convenienceVSAvoidbattery depletion risk
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The power supply unit dynamically changes its maximum output power based on the operating mode detected from the main control signal. In accessory mode, it limits output to a first upper limit value, while in on mode, it allows a second upper limit value that is higher. This dynamic adjustment resolves the contradiction by providing high power when needed (improving convenience) while limiting power in accessory mode (reducing battery depletion risk).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the power output parameter based on the operating mode. The control unit detects the main control signal state and adjusts the maximum output power accordingly - setting it to a lower first upper limit in accessory mode and a higher second upper limit in on mode. This parameter change strategy allows the system to optimize between user convenience and battery safety under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If power supply capacity is limited in accessory mode to prevent battery drain, then battery life is maintained, but user convenience is reduced

Engineering Contradiction:
Improvebattery lifeVSAvoiduser convenience
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The system dynamically adjusts power supply capacity based on the detected operating mode. When accessory mode is detected, it applies a first upper limit to maintain battery life. When on mode is detected, it switches to a second upper limit for higher power delivery. This dynamic behavior resolves the contradiction by adapting power capacity to the actual operational context.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention implements parameter changes by setting different maximum output power values based on the main control signal state. The control unit modifies the power output parameter from the first upper limit value in accessory mode to the second upper limit value in on mode, thereby balancing battery preservation with user convenience requirements.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If power supply capacity is increased to support high-power devices, then charging speed is improved, but the risk of battery depletion increases

Engineering Contradiction:
Improvecharging speedVSAvoidbattery depletion risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The power supply unit employs dynamic control of output power based on the operating mode detected from the main control signal. In accessory mode, it limits power to prevent battery depletion. In on mode, it enables higher power output for fast charging. This dynamic power adjustment resolves the contradiction between charging speed and battery safety.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the maximum output power parameter according to the operating mode. When in accessory mode, it sets a lower first upper limit to reduce battery depletion risk. When in on mode, it sets a higher second upper limit to enable fast charging. This parameter adaptation strategy effectively balances charging performance with battery protection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4674695A1Power supply unit and mobile body
Publication Date: 2026.01.07 JAPAN AVIATION ELECTRONICS IND LTD
  • EP4674695A1 patent drawingFigure 1~2
  • EP4674695A1 patent drawingFigure 3
  • EP4674695A1 patent drawing

AI summary

A power supply unit (10) has a first input terminal (101) to which a main control signal is input, a power supply input terminal (103) connected to a battery, a power supply output terminal (105), and a control unit (12). The control unit (12) applies a voltage to the power supply input terminal (103) and supplies output power, for which the maximum value is controlled, from the power supply output terminal (105) to an external device. The control unit (12) has at least a first upper limit power mode and a second upper limit power mode. The control unit (12) operates in the first upper limit power mode when the main control signal is in an ON state, and operates in the second upper limit power mode when the main control signal is in an OFF state. The maximum value of the output power in the second upper limit power mode is lower than the maximum value of the output power in the first upper limit power mode.