Charge Control Circuit Using Battery Voltage Tracking
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Solution Overview
Problem
Wearable devices face challenges in size reduction due to the inclusion of step-down switching DC-DC converters, which increase the size of charging devices and lower battery charging efficiency due to the voltage difference between input and output voltages.
Innovation Solution
A charge control circuit that includes a charge current control circuit, comparator, current mirror, and amplifier to manage the power transistor and control signals, allowing the input voltage to track the charging voltage without the need for additional voltage regulators, thereby reducing device size and enhancing charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a step-down switching DC-DC converter is used to adjust power supplied to the charging circuit, then charging efficiency is improved, but device size increases due to the capacitor and inductor components
Solution Approach 1:
The patent extracts and removes the step-down switching DC-DC converter from the charging system. By eliminating this voltage regulation component, the device size is reduced while maintaining charging efficiency through direct voltage tracking between the power supply and battery charging circuits.
Solution Approach 2:
The charge control circuit is designed to perform multiple functions: it directly tracks and adjusts voltage levels, controls power transistor operation, and manages charging current without requiring separate voltage regulation stages. This multi-functionality eliminates the need for additional components like capacitors and inductors.
2Loss of energy
If a step-down switching DC-DC converter is used to reduce voltage difference between input and output, then charging efficiency is improved, but the charging device size increases
Solution Approach 1:
The patent removes the step-down switching DC-DC converter from the charging device architecture. The voltage difference between input and output is managed through direct voltage tracking control, eliminating the need for bulky voltage regulation components and reducing overall device footprint.
3Stability of the object's composition
If additional voltage regulators are included in the charge control circuit, then voltage stability is improved, but device size and complexity increase
Solution Approach 1:
The charge control circuit implements self-service voltage stabilization through voltage tracking. The circuit automatically adjusts its own operating voltage to match the battery charging requirements, eliminating the need for external voltage regulators while maintaining voltage stability through feedback control.
Solution Approach 2:
The patent employs feedback control mechanisms where the charge control circuit continuously monitors voltage levels and adjusts power transistor operation accordingly. This feedback loop ensures voltage stability without requiring additional voltage regulation components.
Data Source
AI summary
A charge control circuit includes: a charge current control circuit configured to receive an input voltage at a first node, output a sensing current to a second node, and turn on a power transistor; a comparator configured to compare a voltage level of the second node with a voltage level of a third node, wherein the third node receives a charging current from the power transistor; a current mirror configured to generate a mirror current corresponding to the sensing current; and an amplifier configured to receive a first feedback voltage based on the mirror current, and amplify a difference between the first feedback voltage and a reference voltage to generate a switch control signal, wherein in response to the switch control signal and a plurality of control signals, the charge current control circuit is configured to decrease the sensing current and turn on the power transistor.