Switched-Capacitor DC-DC Converter Voltage Precision
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Solution Overview
Problem
Conventional switched-capacitor DC-DC power converters face challenges in maintaining a stable output voltage within a precise range, making them inadequate for certain circuit architectures, especially in small-sized ICs where external inductors are not feasible.
Innovation Solution
A DC-DC power converter circuit incorporating a switched-capacitor circuit, an error amplifier, and a latched comparator, which generates an error amplification signal to compare the output voltage with a reference voltage, using a frequency reference signal to control the switching operation between phases, thereby adjusting the output voltage precisely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional switched-capacitor power converter is used to reduce size and integrate into small ICs, then the device volume is reduced and integration is enabled, but the output voltage cannot be stably maintained within a precise range
Solution Approach 1:
The patent implements a feedback control mechanism where the output voltage is continuously monitored and compared against a reference voltage. The difference (error signal) is amplified and used to adjust the switching duty cycle of the switched-capacitor circuit, ensuring the output voltage remains stable and precise even in integrated small-sized ICs without external inductors.
Solution Approach 2:
The patent introduces an intermediary control circuit that includes an error amplifier and a pulse width modulation (PWM) controller. This intermediary system mediates between the switched-capacitor power conversion process and the load, precisely regulating the output voltage by adjusting the switching duty cycle based on the error signal, thereby achieving precise voltage control in a compact integrated design.
2Reliability
If the switching duty cycle is adjusted to maintain output voltage, then the average output voltage is stabilized, but ripple in the output voltage increases
Solution Approach 1:
The patent employs periodic switching action with optimized duty cycle control to maintain stable average output voltage. By using synchronized periodic switching of the capacitor banks and implementing duty cycle adjustment through PWM control based on error feedback, the system stabilizes the average output voltage while minimizing ripple through controlled periodic energy transfer.
Solution Approach 2:
The patent utilizes parameter changes in the switching duty cycle and frequency to optimize the balance between output voltage stability and ripple reduction. By dynamically adjusting the duty cycle parameter based on load conditions and input voltage variations, the system maintains stable average output voltage while minimizing harmful voltage ripple through optimal parameter selection.
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 solution effectively maintains the average output voltage around a preset level, reducing ripple and ensuring stability even with changes in input voltage or load resistance, without affecting the original pulse frequency modulation (PFM) architecture, and allows for integration of the power converter within small ICs.
Implementation Method 1
The error amplifier is configured to amplify a difference between the output voltage and the reference voltage to output an error amplification signal
Implementation Method 2
The latched comparator is configured to compare the output voltage and the error amplification signal according to the frequency reference signal, and output a comparison signal
Implementation Method 3
The switched-capacitor circuit is coupled between an input terminal and an output terminal, and configured to receive an input voltage from the input terminal, perform a switching operation between a first phase and a second phase to generate an output voltage at the output terminal
Data Source
AI summary
A DC-DC power converter circuit includes a switched-capacitor circuit, an error amplifier, a latched comparator and a switching controller. The error amplifier adjusts an error amplification signal of the error amplifier in response to an output voltage of the switched-capacitor circuit and a reference voltage. The error amplification signal is then fed to the latched comparator as a comparison reference, resulting in the DC-DC power converter circuit being able to more precisely maintain the output voltage within a predetermined range.