On-Demand Charge Pump LDO for Low Power Refresh
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Solution Overview
Problem
Microcontrollers face challenges in minimizing power consumption during low power modes due to the significant power cost of charge pumps and monitoring control loops, which increase the die size and power management complexity.
Innovation Solution
An on-demand charge pump monitoring control loop is implemented, activating only when the voltage regulator output needs correction, minimizing continuous monitoring and regulation in low power modes by using a control enable signal based on comparator outputs to manage the charge pump and monitoring control loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge pump and monitoring control loop are implemented to regulate voltage regulator output, then voltage regulation capability is improved, but power consumption and device complexity increase
Solution Approach 1:
The patent implements periodic action by using a refresh signal to activate the charge pump and monitoring control loop at specific intervals rather than continuously. The refresh circuit generates periodic refresh signals that trigger the charge pump to recharge the pump output capacitor, ensuring voltage regulation capability is maintained only when needed while minimizing continuous power consumption during low power modes.
Solution Approach 2:
The patent applies dynamics by making the charge pump and monitoring control loop operational status dynamic rather than static. The system transitions between active and inactive states based on power mode requirements, with the pump monitor and charge pump being enabled only when a refresh signal is asserted, allowing the system to adapt its power consumption characteristics to operational demands.
2Reliability
If a charge pump and monitoring control loop are implemented to regulate voltage regulator output, then voltage regulation capability is improved, but die size increases
Solution Approach 1:
The refresh signal mechanism enables periodic operation of the charge pump and monitoring control loop, allowing these components to be smaller since they do not need to support continuous high-power operation. The pump output capacitor can be smaller because it only needs to maintain voltage during intervals between refresh cycles, reducing the overall die area required for voltage regulation functionality.
3Measurement precision
If continuous monitoring and regulation is implemented, then voltage regulation precision is maintained, but power consumption increases
Solution Approach 1:
The patent resolves this contradiction by implementing periodic monitoring and regulation instead of continuous operation. The refresh signal triggers the pump monitor and charge pump at specific intervals, maintaining voltage regulation precision when needed while allowing the system to enter low power modes between refresh cycles, significantly reducing average power consumption.
Solution Approach 2:
The system implements self-service through the refresh circuit that automatically generates periodic refresh signals based on temperature or elapsed time conditions, enabling the voltage regulation system to self-manage its operation without continuous external control, maintaining precision when required while minimizing power consumption during normal operation.
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
This approach reduces the overall power penalty of the charge pump and monitoring control loop, allowing for more efficient power management and smaller die size while maintaining voltage regulation, thereby minimizing power consumption in low power modes.
Implementation Method 1
One method to raise the voltage applied to the pass gate above VDD is to implement a charge pump
Implementation Method 2
a voltage regulator that includes a first comparator configured to compare an output voltage of the voltage regulator to a reference voltage and provide a signal indicating the voltage based on output of the voltage regulator is lower than a specified value
Implementation Method 3
a pump monitor configured to detect when the charge pump output voltage requires up-regulation
Implementation Method 4
a pass gate having some minimal gate length... A control voltage is applied to the pass gate
Data Source
AI summary
A voltage regulation system includes a voltage regulator configured to output a control signal indicating whether a voltage based on output of the voltage regulator is lower than a specified value. A charge pump is configured to output a voltage and a charging current. A pump monitor is configured to receive the control signal and the output voltage of the charge pump, and activate the charge pump when the control signal indicates the voltage based on output of the voltage regulator is lower than a specified value and the output voltage of the charge pump is lower than a threshold value.