Charge Pump Battery Charging Circuit for Dead Multi-Cell Precharge
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Solution Overview
Problem
Existing battery charging systems face inefficiencies and potential damage when attempting to fast charge a dead multi-cell-in-series battery, particularly due to high current demands that can shorten battery life.
Innovation Solution
A battery charging circuit utilizing a charge pump with an arbiter to select between multiple power supply rails, eliminating the need for a trickle charger and battery switch, allowing for efficient trickle charging by using a third power supply voltage to power the driver circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast charging is attempted on a dead multi-cell-in-series battery, then charging speed is improved, but battery life is shortened due to high current demands
Solution Approach 1:
The patent applies partial action by implementing a two-stage charging process: first performing trickle charging at low current to partially recharge the battery, then transitioning to fast charging only when the battery reaches a sufficient voltage level. This resolves the contradiction by allowing fast charging to occur only partially (when safe) rather than attempting it from a dead state, thus maintaining battery life while still achieving high charging speed when appropriate
2Reliability
If a trickle charger and battery switch are included in the charging circuit, then reliable trickle charging is achieved, but device complexity increases
Solution Approach 1:
The patent merges the functions of the battery switch and trickle charger into the existing charge pump circuit by utilizing the same switching elements (first and second switches) and control logic to perform both battery protection switching and trickle charging operations. This eliminates the need for separate dedicated components, thereby maintaining reliable trickle charging functionality while significantly reducing device complexity
Solution Approach 2:
The charge pump circuit is designed with multi-functionality to serve both as a fast charging circuit and a trickle charging circuit. The same charge pump, switches, and control circuitry dynamically switch between fast charging mode (when battery voltage is sufficient) and trickle charging mode (when battery voltage is low), eliminating the need for separate dedicated trickle charging components and reducing overall system complexity
3Area of stationary object
If a charge pump is used for trickle charging, then area consumption is reduced, but the need for additional power supply rails increases complexity
Solution Approach 1:
The charge pump circuit performs self-service by using its own internal capacitors and switching elements to generate the necessary voltage multiplication for trickle charging. The first capacitor is charged from the battery and then used to provide the elevated voltage needed for charge pump operation during trickle charging, eliminating the need for external additional power supply rails while maintaining compact area consumption
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 approach reduces area consumption, power loss, and complexity by eliminating the battery switch and trickle charger, providing a simpler and more efficient trickle charging process for dead multi-cell batteries.
Implementation Method 1
a charge pump circuit (206) comprising a plurality of switches and a capacitive element, being coupled to a first power supply node and a second power supply node, and being configured to at least one of: multiply a first voltage at the first power supply node to generate a second voltage at the second power supply node; or divide the second voltage at the second power supply node to generate the first voltage at the first power supply node
Data Source
AI summary
Methods and apparatus for trickle charging and precharging a dead multi-cell-in-series battery. One example battery charging circuit generally includes a charge pump circuit comprising a plurality of switches, being coupled to first and second power supply nodes, and being configured to multiply (or divide) a first voltage at the first power supply node to generate a second voltage at the second power supply node; a driver circuit configured to drive the plurality of switches in the charge pump circuit; and an arbiter having a first input coupled to the first power supply node, a second input coupled to the second power supply node, a third input coupled to a third power supply node having a third voltage, and an output coupled to a power supply terminal of the driver circuit. The arbiter is configured to select between the first, second, and third voltages to power the driver circuit.