LDO Regulator Power Management via Dynamic Enable Time Control
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Solution Overview
Problem
Low dropout (LDO) regulators in microcontrollers and microprocessors face challenges in quickly switching on and off to conserve power, leading to unpredictable output voltages due to long settling times and increased power consumption, especially in portable devices where devices are active for short periods.
Innovation Solution
Implementing a method to determine the actual active time of power requests and enabling the LDO regulator for a duration sufficient to settle the output voltage, then disabling it, and optionally prolonging the enable time for every nth power request to maintain voltage stability within tolerance ranges, reducing power consumption without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the LDO regulator is switched on and off quickly to save power, then power consumption is reduced, but the output voltage cannot settle properly leading to unpredictable voltages
Solution Approach 1:
The system determines the actual active time of power requests in advance and proactively extends the regulator enable time beyond the minimum active time to ensure proper settling. This preliminary timing calculation prevents voltage instability before it occurs by guaranteeing sufficient settling time is allocated.
Solution Approach 2:
The enable time of the LDO regulator is made dynamic rather than fixed. It adapts based on the actual active time of power requests, extending only when needed to ensure proper settling. This dynamic adjustment allows the system to minimize power consumption while maintaining voltage stability.
2Reliability
If the LDO regulator enable time is extended to allow proper settling, then output voltage stability is improved, but power consumption increases
Solution Approach 1:
The system applies partial extension of the enable time beyond the minimum active time, but not excessively. It calculates the precise extension needed to ensure settling occurs, avoiding unnecessary prolonged operation. This partial action approach achieves voltage stability while minimizing power consumption.
Solution Approach 2:
The enable time parameter is dynamically changed based on the actual active time of power requests. Rather than using a fixed conservative value, the system adjusts this parameter to match actual needs, ensuring sufficient settling time while reducing power consumption during low-activity periods.
3Measurement precision
If a window comparator is used to monitor and correct output voltage, then voltage accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts and removes the window comparator circuitry from the system. Instead of using active monitoring and correction, it relies on proactive timing control to prevent voltage errors before they occur. This extraction simplifies the circuit while maintaining voltage accuracy through proper enable time management.
Solution Approach 2:
The LDO regulator system serves itself through proper timing control rather than requiring external monitoring and correction circuits. By ensuring the regulator is enabled long enough to settle properly, the system achieves voltage accuracy through self-timing mechanisms rather than needing additional comparator circuitry.
Data Source
AI summary
A method of switching a low dropout regulator includes determining an actual active time of a power request from an electronic device; enabling the low dropout regulator in response to said power request at a time corresponding to a start of the actual active time of the power request for an active enabled time having a duration at least the same as the actual active time and long enough to sufficiently settle the output voltage of the low dropout regulator; and disabling the low dropout regulator. In embodiments, the active enabled time is prolonged beyond the actual active time of the power request for all or at least some power requests. An electronic device includes circuits for controlling the switching of a low dropout in the described manner.