Charge-Discharge Control Circuit Cell Balancing Terminal Reduction
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Solution Overview
Problem
Conventional charge-discharge control circuits face cost reduction challenges while incorporating cell balancing circuits, which lead to characteristic deterioration of transistors due to current flow through protective resistors, applying voltages higher than a threshold to NMOS transistors.
Innovation Solution
Incorporating first and second cell balancing circuits with switches, and first and second cell balance detection circuits with complementary switches, the control circuit outputs control signals to manage voltage balancing without causing transistor deterioration, reducing the number of terminals and thus costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cell balancing circuits are incorporated into the charge-discharge control circuit to reduce the number of terminals, then device complexity and cost are reduced, but characteristic deterioration of transistors occurs due to voltage higher than threshold being applied to gates of NMOS transistors
Solution Approach 1:
The patent applies preliminary action by turning off the switches in cell balance detection circuits before cell balancing operation begins. This preventive measure ensures that when current flows through protective resistors during cell balancing, no voltage is applied to the gates of NMOS transistors in detection circuits, thereby preventing characteristic deterioration before it can occur.
Solution Approach 2:
The patent implements periodic action by operating switches in cell balancing circuits and cell balance detection circuits in alternating cycles. During cell balancing operation, balancing switches are turned on while detection switches are turned off; during detection periods, the opposite occurs. This periodic switching pattern allows both functions to share common terminals without causing transistor deterioration.
2Ease of manufacture
If cell balancing circuits are incorporated to eliminate separate output terminals, then manufacturing cost is reduced, but voltage higher than threshold is applied to gates of NMOS transistors during long-term use
Solution Approach 1:
The patent applies preliminary action by turning off the switches in cell balance detection circuits before cell balancing operation begins. This preventive measure ensures that when current flows through protective resistors during cell balancing, no voltage is applied to the gates of NMOS transistors in detection circuits, thereby preventing characteristic deterioration before it can occur.
Solution Approach 2:
The patent implements periodic action by operating switches in cell balancing circuits and cell balance detection circuits in alternating cycles. During cell balancing operation, balancing switches are turned on while detection switches are turned off; during detection periods, the opposite occurs. This periodic switching pattern allows both functions to share common terminals without causing transistor deterioration.
Data Source
AI summary
A charge-discharge control circuit includes a first cell balancing circuit having a first switch; a second cell balancing circuit having a second switch; a first cell balance detection circuit having a third switch; a second cell balance detection circuit having a fourth switch; and a control circuit which outputs a control signal to turn on the first switch in a prescribed cycle according to the voltage of a first battery which is higher than or equal to a cell balance detection voltage, or outputs a control signal to turn on the second switch in the prescribed cycle according to the voltage of a second battery which is higher than or equal to the cell balance detection voltage, and outputs a control signal to turn off the third switch and the fourth switch in the prescribed cycle during output of the control signal.