Charge Pump Controller Stabilizing Output Voltage
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Solution Overview
Problem
Current charge pump systems based on capacitive multipliers in audio amplifiers are sensitive to variations in battery voltage, leading to significant variations in output voltage, which degrade the quality of the audio signal.
Innovation Solution
A method and controller for a charge pump that operates in multiple modes by adjusting the conversion ratio based on a target output voltage, using a selector to calculate and compare the product of the conversion ratio and input voltage with the target value, and maintaining the selected mode for a predetermined time before adjusting, thereby stabilizing the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a capacitive converter is used to increase battery voltage, then the size of the circuit is reduced, but the output voltage becomes highly sensitive to battery voltage variations
Solution Approach 1:
The charge pump operates in multiple dynamic modes with different conversion ratios (e.g., 1x, 1.5x, 2x, 3x) that can be switched based on battery voltage conditions. This dynamic adaptation allows the system to maintain stable output voltage across varying battery conditions while using a compact capacitive converter architecture.
Solution Approach 2:
The system changes the conversion ratio parameter of the charge pump based on detected battery voltage levels. When battery voltage drops, the controller switches to a higher conversion ratio mode to compensate and maintain the required output voltage, thereby stabilizing the audio signal quality despite battery depletion.
2Power
If the audio signal increases requiring more power, then the audio quality improves, but the battery voltage decreases causing output voltage variations
Solution Approach 1:
The controller continuously monitors battery voltage and audio signal levels, using this feedback to dynamically adjust the charge pump's conversion ratio. When the audio signal increases and battery voltage drops, the feedback mechanism triggers a mode switch to a higher conversion ratio, compensating for the voltage drop and maintaining stable output voltage for consistent audio quality.
3Reliability
If the conversion ratio is frequently adjusted to maintain output voltage, then the output voltage stability improves, but the system oscillations increase
Solution Approach 1:
The controller predicts future battery voltage conditions based on current audio signal levels and power consumption trends. By proactively switching to a higher conversion ratio mode before the battery voltage drops too low, the system prevents voltage instability without needing frequent mode switching, thereby reducing oscillations while maintaining output stability.
Data Source
AI summary
A charge pump controller for controlling a charge pump adapted to convert an input voltage into an output voltage with a conversion ratio is presented. The charge pump is operable in a plurality of modes corresponding to different conversion ratios. The controller includes a first selector for selecting a mode of operation of the charge pump. The first selector comprises a first input for coupling to a voltage supply; and a second input for coupling to a source signal. The first selector identifies a target value of the output voltage. The selector calculates a product of the conversion ratio and the input voltage. The selector compares the product with the target value and selects a mode of operation of the charge pump by increasing or decreasing the conversion ratio based on the comparison. The selector maintains the conversion ratio for a length of time before decreasing the conversion ratio.