Digital Controlled Battery Charging System Loop Management
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Solution Overview
Problem
Conventional battery charging systems are complex due to the need for multiple error amplifiers with different compensation networks, making them difficult to design and transplant across different power stages, and transitions between control loops are challenging due to closely related error amplifier signals.
Innovation Solution
A battery charging system with a digital control unit that manages a plurality of analog control loops, each receiving reference and feedback signals along with a slope compensation signal to provide loop control signals, allowing the system to automatically switch between loops and simplify the circuit structure by replacing error amplifiers with comparison circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple error amplifiers with different compensation networks are used for each control loop, then each loop can be independently controlled, but the system complexity increases and transplantation across different power stages becomes difficult
Solution Approach 1:
The patent merges multiple error amplifiers into a single shared error amplifier that serves all control loops. The feedback signals from different loops (input voltage, input current, battery voltage, battery charging current) are combined through a summation circuit, allowing one error amplifier to process all feedback signals and generate control signals for multiple loops, thereby reducing component count and system complexity
Solution Approach 2:
The single error amplifier is designed to perform multiple functions by receiving different feedback signals from various control loops. The summation circuit enables the error amplifier to universally handle voltage and current feedback from different stages, making the same component adaptable to multiple control functions without requiring dedicated amplifiers for each loop
2Measurement precision
If each control loop has its own error amplifier with dedicated compensation network, then loop control precision is improved, but the transition between loops becomes difficult to design
Solution Approach 1:
The patent combines multiple feedback signals through a summation circuit that merges voltage and current feedback from different control loops into a single composite signal. This allows the error amplifier to process all loop information centrally, simplifying the transition logic between loops while maintaining precise control through the unified error signal generation
Data Source
AI summary
A battery charging system has a switching circuit and a control circuit. The switching circuit has a first switch, and the control circuit has a plurality of analog control loops and a digital control unit. Each of the analog control loops provides a loop control signal based on a corresponding feedback signal, a corresponding reference signal and a slope compensation signal. The digital control unit provides a switching control signal to control the first switch based on the plurality of analog control loops and a time period control signal, and the digital control unit turns ON or turns OFF the first switch automatically in response to one of the plurality of analog control loops.