Gate Driver for Battery Pack Using Boosted Charge Enable Transistor
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Solution Overview
Problem
Conventional battery packs with Li-ion cells face safety issues due to potential overheating, fires, or explosions when exposed to improper conditions, and existing fail-safe circuitry is not always effective in preventing damage or ensuring safe charging and discharging.
Innovation Solution
A battery management system that fully enables or disables charge and discharge transistors by boosting the drive signal to a level greater than the battery cell potential, using high-side NFET transistors integrated in a cost-effective high-voltage CMOS process, ensuring complete control and safety through a one-chip solution with integrated gate drivers, microcontrollers, and memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fail-safe circuitry is used to detect unsafe conditions, then safety monitoring is provided, but the circuitry is not always effective in preventing damage or ensuring safe charging and discharging
Solution Approach 1:
The gate driver circuit performs preliminary action by fully enabling the charge enable transistor before charging begins, driving the gate terminal to a potential substantially greater than the battery cell potential. This ensures the transistor is completely turned on in advance, establishing a low-impedance path that prevents voltage drops and instability during charging operation, thereby improving safety monitoring effectiveness.
Solution Approach 2:
The invention changes the voltage parameter of the gate driver output by boosting it to a level substantially greater than the battery cell potential (e.g., Vcc + 2Vreg). This parameter change ensures the charge enable transistor operates in its optimal conduction region, maintaining stable voltage and current during charging, and preventing conditions that could lead to overheating or failure.
2Ease of operation
If the charge enable transistor is substantially fully enabled by driving the gate terminal at a potential greater than the battery cell potential, then stable and flexible control is achieved, but the circuit complexity increases
Solution Approach 1:
The gate driver circuit merges multiple functions into a single integrated circuit. It combines the charge pump circuitry, voltage regulation, and transistor driving functions in one unit. The circuit integrates the ability to boost voltage above the battery potential while maintaining regulation, eliminating the need for separate voltage multiplication stages and simplifying the overall battery management architecture.
Solution Approach 2:
The gate driver circuit is designed with universality to handle multiple functions: it can drive the charge enable transistor fully on, provide voltage boosting above battery potential, maintain regulated output, and potentially drive other battery management transistors. This multi-functional design reduces the total number of components needed in the battery management system.
3Productivity
If high-side NFET transistors are used with boosted drive signals, then rapid charging is enabled, but the manufacturing cost may increase
Solution Approach 1:
The invention changes the voltage parameter by boosting the gate drive signal to substantially greater than the battery cell potential. This enables high-side NFET transistors to operate in their optimal region with low on-resistance, allowing rapid charging currents to flow. The parameter change from standard logic levels to boosted levels above battery potential is what enables the high-speed charging capability.
Solution Approach 2:
The gate driver circuit provides self-service by generating its own boosted voltage from the existing battery voltage and regulator output. The charge pump circuitry within the gate driver uses the battery voltage itself as the input to generate the higher voltage needed for driving the NFET gates, eliminating the need for external voltage multiplication circuits or additional power supply rails.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides stable and flexible control over charge and discharge operations, ensuring safe battery management by preventing dangerous conditions and allowing for rapid charging, while being more cost-effective and efficient than conventional low-side solutions.
Implementation Method 1
Pumping up the drive signal can include capacitively coupling a boost signal to the drive signal at the potential of the cells
Data Source
AI summary
Apparatus, method and computer program product are provided for battery management. In one implementation, a method is provided. The method includes enabling determining if a charger is coupled to a battery system. The battery system includes one more cells and a charge enable transistor. The method also includes substantially fully enabling the charge enable transistor including driving a charge enable transistor gate terminal at a potential that is substantially greater than a potential of the cells.