Power Amplifier Supply Circuit With Standby Voltage to Cut Rush Current
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Solution Overview
Problem
Conventional power management circuits in wireless communication devices face challenges in reducing rush current during large variations in time-variant voltages, which can lead to reduced battery life and operational failures, especially under low battery conditions.
Innovation Solution
A power management circuit that maintains time-variant voltages at a non-zero standby level when power amplifiers are inactive, reducing the variation in voltage and thus minimizing rush current, and uses a voltage circuit with a multi-level charge pump and LC circuit to generate reference voltages for quick and efficient voltage changes when the power amplifiers become active.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power management circuit makes large variations of time-variant voltage (e.g., from 0 V to 5 V) within a defined temporal limit to enable dynamic power control, then the adaptability of power amplification is improved, but rush current increases proportionally which reduces battery life
Solution Approach 1:
The power management circuit maintains the time-variant voltage at a non-zero standby voltage level (e.g., 2.5 V) before the power amplifier becomes active. This preliminary action reduces the voltage variation range when the amplifier activates, thereby reducing rush current while still enabling fast voltage changes within the temporal limit when needed.
2Loss of energy
If the power management circuit maintains time-variant voltage at a non-zero standby level to reduce rush current, then battery life is prolonged, but the voltage variation range available for dynamic power control is reduced
Solution Approach 1:
The system dynamically adjusts the voltage based on the operational state. When the power amplifier is inactive, the voltage is maintained at a non-zero standby level to reduce rush current. When the amplifier becomes active, the voltage can quickly vary to the required level, thus maintaining adaptability while reducing energy loss during idle periods.
3Productivity
If the power management circuit enables fast voltage changes within 0.5 μs to meet Wi-Fi IFS requirements, then the productivity of power adaptation is improved, but the rush current caused by large voltage variations increases
Solution Approach 1:
By maintaining the voltage at a non-zero standby level before the power amplifier activates, the circuit performs a preliminary action that reduces the required voltage swing. This allows fast voltage changes within the 0.5 μs temporal limit while minimizing rush current, as the voltage only needs to change from 2.5 V to the target level rather than from 0 V.
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 prolongs battery life by reducing rush current and ensuring the device remains operational, even under low battery conditions, by minimizing the impact of voltage changes on the battery and maintaining efficient power delivery.
Implementation Method 1
a voltage circuit with a multi-level charge pump and LC circuit to generate reference voltages for quick and efficient voltage changes
Implementation Method 2
a voltage circuit with a multi-level charge pump and LC circuit to generate reference voltages
Implementation Method 3
a voltage circuit with a multi-level charge pump and LC circuit to generate reference voltages
Data Source
AI summary
A power management circuit operable to reduce rush current is provided. The power management circuit is configured to provide a time-variant voltage(s) to a power amplifier(s) for amplifying a radio frequency (RF) signal(s). Notably, a variation in the time-variant voltage(s) can cause a rush current that is proportionally related to the variation of the time-variant voltage(s). To reduce the rush current, the power management circuit is configured to maintain the time-variant voltage(s) at a non-zero standby voltage level when the power amplifier(s) is inactive. When the power amplifier(s) becomes active and the time-variant voltage(s) needs to be raised or reduced from the non-zero standby voltage level, the rush current will be smaller as a result of reduced variation in the time-variant voltage(s). As such, it is possible to prolong the battery life in a device employing the power management circuit.