Dynamic Linear Charger Circuit for Accurate Termination Sensing
Here’s PatSnap Eureka !
Summary
Problems
Linear charger circuits face accuracy issues in sensing and controlling charge current, particularly at lower charge current ranges, leading to unreliable termination of charging operations in portable IoT devices, due to large sense ratios between pass and sense devices, which also result in high current consumption at high charge currents.
Innovation solutions
A linear charger circuit design that includes first and second replica devices in parallel with a pass device, forming a current mirror, and a control circuit to dynamically adjust the sense ratio based on current thresholds, allowing for accurate termination current determination without increasing power consumption. This design uses a multi-slice replica device and comparator circuits to enable the first circuit path only when necessary, reducing the sense ratio at low charge currents and maintaining efficiency at high charge currents.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the sense ratio between pass device and sense device is increased to improve termination current accuracy at low charge currents, then the accuracy of termination current determination is improved, but current consumption increases at high charge currents
Why choose this principle:
The patent applies dynamics by making the sense ratio adjustable rather than fixed. The circuit dynamically switches between a first sense ratio for low charge currents (improving termination current accuracy) and a second sense ratio for high charge currents (reducing current consumption). This is achieved through switchable current mirror configurations that adapt the sense device scaling factor based on operating conditions.
Principle concept:
If the sense ratio between pass device and sense device is increased to improve termination current accuracy at low charge currents, then the accuracy of termination current determination is improved, but current consumption increases at high charge currents
Why choose this principle:
The patent changes the sense ratio parameter based on operating conditions. By varying the effective sense ratio between two discrete values (first and second sense ratios), the circuit optimizes performance across different charge current ranges. The parameter change is controlled by monitoring circuit conditions and switching accordingly between configuration modes.
Application Domain
Data Source
AI summary:
A linear charger circuit design that includes first and second replica devices in parallel with a pass device, forming a current mirror, and a control circuit to dynamically adjust the sense ratio based on current thresholds, allowing for accurate termination current determination without increasing power consumption. This design uses a multi-slice replica device and comparator circuits to enable the first circuit path only when necessary, reducing the sense ratio at low charge currents and maintaining efficiency at high charge currents.
Abstract
A linear charger circuit and method for providing an output current at an output node is presented. The circuit contains a pass device connected between an input node and the output node, first and second replica devices connected in parallel to the pass device, with their control terminals coupled to a control terminal of the pass device. The first replica device is coupled to a first circuit path for determining whether current output by the linear charger circuit shall be terminated. The second replica device is coupled to a second circuit path for providing feedback for controlling the pass device, a control circuit coupled to the second circuit path for controlling the pass device based on a quantity indicative of a current flowing through the second circuit path, and a switching circuit coupled to the second circuit path.