Parallel Power Supply Current Sharing for Fuse Trip Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vehicle infotainment systems experience high input currents during battery transients, leading to fuse tripping and electrical issues due to sudden drops in input voltage, which existing current limiters increase system cost and complexity, or require power reduction methods that are inefficient.
Innovation Solution
Implementing parallel power supply circuits with current sensing circuits that adjust their operation to reduce current draw when exceeding a specified limit, using high-side high-bandwidth current sensing amplifiers and shared resistors to manage total current across channels, allowing efficient power delivery without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current limiter circuit is used to reduce input current during transients, then fuse tripping is prevented, but system cost and complexity increase
Solution Approach 1:
The patent combines multiple current sensing functions into a single shared resistor that is common to both parallel power supply circuits. This single resistor serves dual purposes: sensing current for each individual circuit and sensing the total combined current, eliminating the need for separate current limiters and reducing overall system complexity while maintaining reliable over-current protection
Solution Approach 2:
The shared resistor performs multiple functions simultaneously: it acts as a current sense element for the first power supply circuit, a current sense element for the second power supply circuit, and a total current limit element for the combined parallel output. This multi-functionality reduces component count and system complexity while ensuring reliable current limiting protection
2Reliability
If power delivery is reduced during transients to limit input current, then current limits are maintained, but power delivery efficiency decreases
Solution Approach 1:
The patent implements dynamic current sharing between parallel power supply circuits based on real-time operating conditions. Each circuit dynamically adjusts its current contribution based on its efficiency characteristics and the total current requirements, allowing the system to maintain current limits while optimizing power delivery efficiency by utilizing the most efficient circuit at any given moment
Solution Approach 2:
The system dynamically changes operating parameters (current distribution ratios) between parallel power supply circuits based on efficiency characteristics and transient conditions. During normal operation, the system optimizes for efficiency by selecting the most efficient circuit. During transients, parameters are adjusted to limit total current while still maintaining acceptable power delivery, avoiding excessive power reduction
Data Source
AI summary
The present subject matter relates to an electronic system including multiple power supply circuits connected in parallel. A first power supply circuit includes a current sensing circuit configured to measure current to the first power supply circuit and total current drawn by the multiple power supply circuits. A second power supply circuit is connected in parallel to the first power supply circuit and includes a current sensing circuit configured to measure current to the second power supply circuit and the total current drawn by the multiple power supply circuits. Each of the first and second power supply circuits are configured to change operation of the power supply circuit to reduce current drawn by the power supply circuit when either the current to the power supply circuit or the total current drawn by the multiple power supply circuits exceeds a specified current limit level.