Modulated Reference Voltage Circuit for Charge Pump Ripple Reduction
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Solution Overview
Problem
Power supplies, particularly charge pump regulators, experience significant output voltage ripple due to intrinsic delays in feedback paths, which can only be mitigated by increasing the capacitance of output capacitors, occupying valuable chip area.
Innovation Solution
A modulated reference voltage circuit dynamically switches between two reference voltage values to compensate for intrinsic delays, allowing earlier switching of the enabling signal and reducing output voltage ripple without increasing capacitor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the capacitance of output capacitors is increased to mitigate output voltage ripple, then the output voltage ripple is reduced, but the chip area occupied increases
Solution Approach 1:
The reference voltage is adjusted in advance based on the detected ripple condition before the ripple becomes problematic. The ripple detection circuit continuously monitors the output voltage and proactively modifies the reference voltage to counteract upcoming ripple issues, rather than reactively increasing capacitor size after the problem manifests.
Solution Approach 2:
The patent dynamically changes the reference voltage parameter based on detected ripple conditions. By detecting the ripple voltage and adjusting the reference voltage accordingly (increasing it when ripple is detected), the system modifies an electrical parameter to compensate for ripple effects without requiring physical changes to capacitor size, thereby resolving the contradiction between ripple reduction and chip area consumption.
2Stability of the object's composition
If the capacitance of output capacitors is increased to mitigate output voltage ripple, then the output voltage stability is improved, but the device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the ripple detection circuit continuously monitors the output voltage and feeds this information back to the reference voltage adjustment logic. This closed-loop feedback system dynamically adjusts the reference voltage based on real-time ripple conditions, providing stable output voltage through active control rather than passive component scaling, thus improving stability without proportionally increasing device complexity.
Solution Approach 2:
The system performs self-adjustment by automatically detecting its own output ripple conditions and correcting them through reference voltage modification. The charge pump controller autonomously monitors its performance and makes necessary adjustments without external intervention, enabling the system to maintain stability while avoiding the complexity of additional external stabilization components.
3Loss of time
If the reference voltage is dynamically adjusted to compensate for delays, then the switching timing is improved, but the control circuit complexity increases
Solution Approach 1:
The patent introduces a reference voltage adjustment mechanism that acts as an intermediary between the ripple detection circuit and the charge pump controller. Instead of directly modifying the controller's timing logic (which would increase complexity), the system uses the reference voltage as a mediator parameter that indirectly influences switching timing. This intermediary approach compensates for delays while keeping the control circuit relatively simple.
Data Source
AI summary
Reducing output voltage ripple of power supplies. In some embodiments, an electronic circuit may include a first node configured to receive an input signal proportional to an output voltage produced by a power supply, a second node configured to receive a reference voltage configured to alternate between two voltage values during operation of the power supply, and a third node configured to output an enabling signal configured to control the operation of the power supply in response to a comparison between the input signal and the reference voltage. In other embodiments, a method may include turning on a power supply in response to a falling ripple being smaller than a first reference voltage value, and turning off the power supply in response to a rising ripple being greater than a second reference voltage value, where the second reference voltage value is smaller than the first reference voltage value.