Current Mirror Charging Circuit for Stable CC-CV Switching
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Solution Overview
Problem
Conventional charging devices face challenges in maintaining stable output of current and voltage, leading to reduced charging efficiency and shorter battery service life.
Innovation Solution
A constant current charging device is designed with a reference current source, current mirror, current adjustment control unit, and current compensation unit, utilizing transistors with adjustable channel width-to-length ratios to provide stable charging current and voltage, and reduce conversion time between charging modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional charging devices use simple current and voltage control circuits, then device complexity is reduced, but current and voltage stability deteriorates
Solution Approach 1:
The patent implements feedback mechanisms through the current compensation unit that continuously monitors the charging current and adjusts the control transistor accordingly. The operational amplifier compares the actual charging current with the reference current and modifies the control signal to maintain current stability, eliminating the trade-off between simplicity and stability.
Solution Approach 2:
The patent employs dynamic adjustment of the control transistor's channel width-to-length ratio during charging operation. The control transistor's parameters are not fixed but are dynamically modified based on real-time charging conditions, allowing the system to maintain optimal performance across varying load conditions without requiring complex external control circuits.
2Manufacturing precision
If conventional charging devices use fixed transistor parameters, then manufacturing precision is improved, but charging efficiency deteriorates
Solution Approach 1:
The patent makes the transistor parameters dynamic by adjusting the control transistor's channel width-to-length ratio during operation. This allows the system to adapt to different charging stages and load conditions, achieving high charging efficiency while maintaining manufacturing simplicity through a single adjustable parameter approach.
Solution Approach 2:
The patent changes the electrical parameters of the control transistor dynamically during charging operation. The channel width-to-length ratio is adjusted as a key parameter to optimize charging efficiency at different stages, transforming a static manufacturing specification into a dynamic performance optimization mechanism.
3Device complexity
If conventional charging devices lack current compensation mechanisms, then device complexity is reduced, but current stability deteriorates
Solution Approach 1:
The current compensation unit implements a feedback loop that continuously monitors the charging current and adjusts the control transistor to maintain current stability. This feedback mechanism ensures reliable current control without requiring complex external regulation circuits, as the compensation is achieved through the intrinsic transistor parameter adjustments.
4Reliability
If conventional charging devices use gradual current reduction, then battery safety is improved, but conversion time between charging modes increases
Solution Approach 1:
The patent enables rapid and controlled transition between charging modes by dynamically adjusting the control transistor's channel width-to-length ratio. This dynamic parameter adjustment allows the system to switch between constant current and constant voltage modes quickly while maintaining battery safety, avoiding the prolonged gradual reduction period used in conventional approaches.
Solution Approach 2:
The patent prepares for mode transition in advance by continuously monitoring charging conditions and pre-adjusting the control transistor parameters. When switching between charging modes is anticipated, the control transistor is pre-configured to enable rapid transition, reducing the overall conversion time while ensuring battery safety through controlled parameter changes.
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
The device achieves stable and controllable charging current and voltage, extending battery life and improving charging efficiency by adjusting current and voltage through the control transistor and compensation unit.
Implementation Method 1
a current mirror electrically coupled to the reference current source and outputting a mirror current
Implementation Method 2
the current adjustment control unit includes a control transistor and a control contact connected to an output terminal of the current compensation unit and the control transistor, and wherein the current adjustment control unit adjusts the control transistor according to a charging voltage to reduce a current flowing through the control contact
Data Source
AI summary
A constant current charging device is configured to charge a device to be charged and includes: a reference current source; a current mirror electrically coupled to the reference current source and configured to output a mirror current; a current adjustment control unit electrically coupled to the current mirror and the device to be charged; and a current compensation unit electrically coupled to the current mirror and the current adjustment control unit. The current adjustment control unit includes a control transistor and a control contact connected to an output terminal of the current compensation unit and the control transistor, wherein the current adjustment control unit controls the control transistor according to a charging voltage to reduce current flows through the control contact.