DC-DC Converter with Switched Capacitor Filter for Rapid Voltage Transients
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Solution Overview
Problem
Existing voltage regulators struggle to provide high bandwidth/high power and low bandwidth/low power regulated voltages efficiently, especially in applications requiring rapid voltage adjustments, such as envelope tracking in wireless communications, where they often result in energy loss and distorted signals due to inefficiencies in switching transistors at low power levels.
Innovation Solution
A voltage regulator system that includes a series switch element, a shunt switch element, and a switched output filter with multiple capacitors, controlled by a mode controller to disconnect and reconnect capacitors for rapid voltage adjustments, minimizing energy loss and maintaining output stability across varying power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a switched-mode converter is used to provide rapid voltage adjustments for envelope tracking, then the response speed is improved, but efficiency deteriorates at low power levels due to fixed switching overhead
Solution Approach 1:
The patent implements dynamic operation mode switching between pulse-width modulation (PWM) and pulse-frequency modulation (PFM) based on load conditions. At high power levels, PWM mode provides rapid voltage adjustment for envelope tracking. At low power levels, PFM mode disables switching when not needed, eliminating fixed overhead losses and improving efficiency.
Solution Approach 2:
The converter dynamically changes operating parameters including switching frequency and duty cycle based on load demands. The switching frequency is adjusted between high-frequency PWM operation for fast response and low-frequency or zero-switching PFM operation for efficiency, allowing the system to optimize between speed and energy loss.
2Speed
If the output voltage is changed rapidly from one value to another, then the response time is improved, but output stability deteriorates due to voltage transients and inrush current
Solution Approach 1:
The patent employs output capacitance that is pre-charged to the target voltage value before being switched into the output circuit. This preliminary charging action ensures that when the capacitor is connected, no voltage transient or inrush current occurs, maintaining output stability during rapid voltage changes.
Solution Approach 2:
The patent uses an intermediary switched capacitor that acts as a buffer between the voltage source and the output load. This intermediary capacitor can be charged to the desired voltage level and then switched into position, mediating the voltage transition and preventing direct transients from affecting the output.
3Stability of the object's composition
If linear regulators are used for envelope tracking, then output stability is maintained, but energy loss increases due to dissipation in the regulator
Solution Approach 1:
The patent replaces the linear regulator's dissipative mechanism with a switched-mode power conversion mechanism. Instead of dissipating excess voltage as heat through resistive elements, the system uses switching transistors and capacitors to transfer energy efficiently, substituting mechanical/electrical switching for thermal dissipation.
4Speed
If switched-mode converters operate at high frequency, then response speed is improved, but device complexity increases due to switching losses and control requirements
Solution Approach 1:
The patent implements dynamic switching between different operating modes (PWM and PFM) and adjustable switching frequencies based on load conditions. This dynamic adaptation allows the system to use high-frequency PWM when fast response is needed while switching to lower-frequency or zero-switching PFM when efficiency is prioritized, reducing overall complexity.
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
The system achieves efficient voltage regulation with minimal energy dissipation, supporting both high-bandwidth envelope tracking and low-bandwidth pulse skipping modes, reducing spurious signals and improving overall system efficiency by dynamically adjusting capacitance and switching frequencies.
Implementation Method 1
a switching voltage is generated through controlled closing and opening of the series switch element and the shunt switch element
Implementation Method 2
a switched output filter for filtering the switching voltage and generating an output voltage
Implementation Method 3
the switched output filter comprises a plurality of capacitors that are selectively connected and included within the switched output filter
Data Source
AI summary
Embodiments for methods, apparatus and systems for operating a voltage regulator are disclosed. One embodiment of the voltage regulator generates a switching voltage through controlled closing and opening of a series switch element and a shunt switch element. The voltage regulator further includes a switched output filter that includes a plurality of capacitors for filtering the switching voltage and generating an output voltage. A mode controller is operative to disconnect at least one of the plurality of capacitors upon receiving a first indicator, where disconnecting causes the at least one of the plurality of capacitors to electrically float, wherein while the at least one capacitor is disconnected the output voltage is changed from a first value to a second value, return the output voltage to a first value or a third value upon receiving a second indicator, and reconnect the at least one of the plurality of capacitors.