Charge Controller with Deep Discharge Protection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional secondary battery charge controllers face inefficiencies in preventing power loss and quickly charging deeply discharged batteries, as they require complex charging sequences and cannot directly detect deep discharge states, leading to increased IC size and cost.
Innovation Solution
A charge controller with a protection circuit that sends a charge inhibit signal to prevent charging when the battery is deeply discharged, allowing for immediate constant-current charging without a pre-charge sequence, and using a protection IC and charge control IC integrated on a single semiconductor chip to manage charging and discharging efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-charge sequence is implemented to detect deep discharge state, then charging safety is improved, but charging time increases and charging efficiency decreases
Solution Approach 1:
The protection IC performs preliminary detection of the battery's discharge state before the charge control IC initiates charging. The protection IC detects whether the battery is in a deep discharge state (below threshold voltage) and sends a charge inhibit signal in advance, preventing the need for a pre-charge sequence and enabling immediate constant-current charging when safe.
2Reliability
If a pre-charge sequence is implemented to detect deep discharge state, then charging safety is improved, but device complexity increases
Solution Approach 1:
The charging control system is segmented into two independent ICs: a protection IC that handles safety detection and a charge control IC that handles charging control. The protection IC independently detects deep discharge state and sends inhibit signals, separating the detection function from the charging execution function and simplifying the overall system architecture.
Solution Approach 2:
The protection IC acts as an intermediary between the battery and the charge control IC. It monitors the battery's discharge state and communicates safety status to the charge control IC through charge inhibit signals, enabling safe charging without requiring the charge control IC to directly monitor battery voltage thresholds.
3Ease of operation
If substrate diode is used for preliminary charge, then charging capability is maintained, but power loss increases
Solution Approach 1:
The protection IC performs preliminary detection of the battery's discharge state before the charge control IC initiates charging. By detecting deep discharge state in advance and sending charge inhibit signals, the system avoids unnecessary pre-charge sequences through the substrate diode, enabling immediate constant-current charging when safe and reducing power loss.
Data Source
AI summary
A charge controller includes a charge control circuit that, when detecting that a charging power supply is connected, controls the charging transistor to apply the charge current; a first and second control switch element connected in series between one terminal of a secondary battery and an external terminal; and a protection circuit that, when the secondary battery is over-discharged, turns off the first control switch element to stop discharge current and when deeply discharged, turns off the second control switch element. The protection circuit sends a charge inhibit signal to the charge control circuit when the secondary battery is deeply discharged, and while receiving the charge inhibit signal, the charge control circuit keeps the charging transistor off to prevent the charge current from flowing even if detecting that the charging power supply is connected.