Brown-Out Detector With Falling-Flank Boost for Low-Power Reset
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Solution Overview
Problem
Existing brown out detection systems in electronic devices consume significant power, particularly in portable devices, leading to reduced battery runtime and slower response times, while compromising reliability and accuracy.
Innovation Solution
A brown out detector (BOD) with falling flank detection, utilizing a track module, sample module, and comparator to minimize power consumption by duty-cycling sampled reference voltages and providing a boost current to improve response times, allowing for optimized detection without continuous current draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical BOD uses continuous current draw to ensure reliable detection, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The BOD circuit operates in periodic cycles, alternating between a sampling phase where the reference voltage is compared against the supply voltage and a power-down phase where current consumption is minimized. This periodic operation allows the system to achieve reliable detection while dramatically reducing average power consumption compared to continuous monitoring approaches.
Solution Approach 2:
The reference voltage is pre-established through voltage division before the comparison phase begins. This preliminary setup allows the actual detection phase to proceed quickly and efficiently without requiring continuous power consumption, as the reference conditions are already in place when needed.
2Speed
If a typical BOD uses continuous monitoring to improve response time, then response time is improved, but power consumption increases
Solution Approach 1:
The BOD employs periodic monitoring cycles with sufficiently short duration to detect brown-out conditions quickly while maintaining low average power consumption. The sampling phase is designed to complete voltage comparisons rapidly, ensuring that response time requirements are met even though monitoring is not continuous.
Solution Approach 2:
The BOD circuit dynamically switches between active sampling modes and low-power standby modes. During normal operation, the circuit transitions to a high-current sampling mode only when a brown-out condition is suspected, allowing fast response when needed while minimizing power consumption during stable operating conditions.
3Use of energy by moving object
If a BOD uses duty-cycled sampled reference voltages to reduce power consumption, then power consumption is reduced, but detection accuracy may be compromised
Solution Approach 1:
The reference voltage is pre-calculated and established through a voltage divider network before the duty-cycled sampling begins. This preliminary establishment of accurate reference conditions ensures that even though sampling is intermittent, the accuracy of voltage comparison is maintained when sampling does occur.
Solution Approach 2:
The patent replaces continuous analog monitoring with a duty-cycled sampling approach that uses capacitive storage to hold reference voltage values between sampling intervals. This substitution allows accurate detection to be achieved through periodic measurements rather than continuous monitoring, reducing power consumption while maintaining detection precision.
Data Source
AI summary
A brown out detector (BOD), configured to provide a BOD reset in the event of a brown out event, is provided. The BOD includes means for tracking a reference voltage that is updated through duty cycling schemes so as to reduce power consumption, as well as means for detecting a falling flank of a supply voltage so as to optimize response times. More specifically, the BOD includes at least one track module, at least one sample module, at least one detector module and at least one comparator. The comparator is configured to compare a duty cycled tracked reference voltage with a duty cycled sampled reference voltage and to output a BOD reset if the tracked reference voltage is less than the sampled reference voltage. The comparator is further capable of exhibiting improved response times when a boost current is received. The boost current is provided by the detector module when the supply voltage falls beyond a predetermined threshold.