Charge Pump Suspend Mode for Audio Power Management
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Solution Overview
Problem
Charge pumps in audio devices consume excessive power due to continuous quiescent current, even when not outputting power, leading to over-design for worst-case loads and inefficient power management.
Innovation Solution
A charge pump assembly with a controller that selectively decouples from the power source during low loads, using an output capacitor to store voltage and recouple when high loads are detected, reducing power consumption by minimizing quiescent current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge pump is designed to cope with worst-case loads, then it can meet high current and high negative voltage demands, but the quiescent current is excessively high even during normal operation
Solution Approach 1:
The charge pump transitions from a static design (fixed switching frequency and capacitance optimized for worst-case loads) to a dynamic design where the switching frequency is adjusted in real-time based on actual load conditions. The controller monitors load demands and adapts the charge pump's operating parameters, using high switching frequencies only when high current is demanded and lower frequencies during normal operation, thereby reducing quiescent current while maintaining reliability.
Solution Approach 2:
The invention changes the operating parameters of the charge pump dynamically. The switching frequency is varied according to load conditions: high frequencies are used temporarily when high current demands occur, and lower frequencies are used during normal operation. This parameter adaptation allows the system to maintain the capability to handle worst-case loads while significantly reducing average power consumption.
2Speed
If the charge pump operates continuously at high switching frequency to meet worst-case demands, then it can provide high current quickly, but power consumption increases unnecessarily during normal operation
Solution Approach 1:
The charge pump's switching frequency is made dynamic rather than fixed. The controller adjusts the switching frequency based on real-time load monitoring: high frequencies are activated only when high current demands are detected, and lower frequencies are used during normal operation. This dynamic adjustment maintains fast response capability when needed while minimizing energy loss during normal operation.
Solution Approach 2:
The charge pump operates in periodic cycles with variable frequency. Instead of running continuously at maximum frequency, it alternates between high-frequency periods (when high current is demanded) and low-frequency periods (during normal operation). This periodic action with adaptive frequency allows the system to maintain responsiveness while reducing average power consumption.
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 significantly reduces power consumption by decoupling the charge pump from the power source during low loads, ensuring high voltage availability and rapid response to high loads, thus optimizing power usage in audio devices.
Implementation Method 1
a low-pass filter comprising an output capacitor, the output capacitor being arranged to average the PWM voltage and output a given voltage (the filtered voltage)
Data Source
AI summary
A device may be associated with a power source. The device may include a charge pump configured to output a pulse-width modulated voltage based upon an input voltage from the power source, with the pulse-width modulated voltage varying between a first voltage and a second voltage. The device may also include a low-pass filter comprising an output capacitor, with the output capacitor being configured to average the pulsed-width modulated voltage and to output a filtered voltage having a value different than that of the input voltage. The device may further include a controller configured to selectively decouple the charge pump from the power source when a load imposed on the low-pass filter is below a threshold load.