PMIC Thermal Shutdown Using Time-Division Temperature Sensing
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Solution Overview
Problem
Existing system-on-chip (SoC) technologies face challenges in reducing the size of power management integrated circuits (PMIC) while effectively managing thermal shutdown and power consumption.
Innovation Solution
The implementation of a power management circuit (PMIC) with DC-DC converters, voltage devices, and a time division sensing circuit that generates temperature voltages inversely proportional to ambient temperature, allowing for thermal shutdown by comparing these voltages with a reference voltage using a time division scheme, thereby reducing PMIC size and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the PMIC size is reduced, then the device integration is improved, but the thermal management capability deteriorates
Solution Approach 1:
The sensing circuit is divided into multiple sensing units, each responsible for sensing temperature at different locations within the PMIC. This segmentation allows comprehensive thermal monitoring across the reduced-size device without requiring a single large sensing area.
Solution Approach 2:
The patent transitions from spatial distribution of sensing elements to temporal distribution by using time-division multiplexing. Multiple sensing units share a single sensing circuit through time-division, allowing the PMIC to monitor temperature at multiple locations without proportionally increasing circuit area.
2Measurement precision
If multiple sensing circuits are used to monitor different locations, then the thermal monitoring precision is improved, but the power consumption increases
Solution Approach 1:
Multiple sensing units share a single sensing circuit through time-division multiplexing. The sensing circuit is sequentially allocated to different sensing units during different time periods, combining the functionality of multiple dedicated circuits into one shared resource, thereby reducing overall power consumption.
Solution Approach 2:
The sensing circuit operates periodically, alternating between different sensing units in a time-division scheme. Each sensing unit is activated at specific time intervals to sense temperature at its location, rather than all circuits operating continuously, which significantly reduces power consumption while maintaining monitoring precision.
3Reliability
If dedicated sensing circuits are allocated to each DC-DC converter, then the thermal shutdown reliability is improved, but the device complexity increases
Solution Approach 1:
A single sensing circuit is designed to serve multiple DC-DC converters through time-division multiplexing. The sensing circuit can be sequentially allocated to monitor temperature at different locations associated with different converters, making the sensing circuit universal rather than dedicated to a single converter, thereby reducing overall circuit complexity.
Solution Approach 2:
The sensing circuit allocation is dynamic rather than static. The circuit can be reconfigured and reassigned to different sensing units based on operational requirements, allowing flexible thermal monitoring across multiple converters without requiring fixed dedicated connections for each converter.
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 solution enables thermal shutdown with reduced PMIC size and lower power consumption by efficiently monitoring ambient temperatures and activating thermal shutdown when necessary, without increasing the occupied area or power usage.
Implementation Method 1
a plurality of voltage devices generate a plurality of temperature voltages that are inversely proportional to ambient temperatures
Data Source
AI summary
An example electronic device includes a power management circuit (PMIC), a plurality of voltage devices, and a time division sensing circuit. The PMIC includes a plurality of direct current (DC)-DC converters that generate a plurality of power supply voltages, respectively, based on a battery voltage. The voltage devices are distributed in the PMIC, and generate a plurality of temperature voltages that are inversely proportional to an ambient temperature. The time division sensing circuit converts the temperature voltages to sensed voltages, generates a decision signal indicating that at least one of the plurality of sensed voltages is equal to or smaller than a reference voltage based on a result of comparing each of the sensed voltages with the reference voltage by a time division scheme during a sensing period, and provides the decision signal to the PMIC. The PMIC performs a thermal shutdown on at least one of the DC-DC converters.