Switched Capacitor Converter for Synchronized High-Voltage Measurement
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Solution Overview
Problem
Conventional DC-DC converters face challenges with high-accuracy current measurement due to space-intensive and power-consuming time-continuous comparators, requiring resistor dividers that cause voltage drops and suffer from flicker noise, especially when measuring high voltages.
Innovation Solution
Implementing a switched capacitor converter with a synchronized comparator that eliminates the need for an analog input switch and uses a power MOSFET to synchronize the measurement with the switching point of the power converter, allowing for a radiometric measurement without switching delays and reducing the circuit to a delta measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a time-continuous comparator is used for high-accuracy measurement, then measurement precision is improved, but the device area increases and power consumption increases
Solution Approach 1:
The patent implements a periodic sampling measurement approach where the analog-to-digital converter performs measurements at specific sampling points synchronized with the switching cycle of the power converter. This periodic action replaces the continuous comparison function, allowing accurate threshold detection at critical moments without requiring a continuously operating comparator, thereby reducing device area while maintaining measurement precision.
2Speed
If a time-continuous comparator is used for high-speed measurement, then measurement speed is improved, but power consumption increases
Solution Approach 1:
The system performs high-speed measurements periodically at synchronized sampling points rather than continuously. The analog-to-digital converter is activated only at these discrete moments to capture threshold exceedance events, achieving high measurement speed when needed while consuming minimal power between sampling events, unlike a continuously operating comparator.
3Measurement precision
If a resistor divider is used to direct high voltage into the supply area, then voltage measurement is enabled, but voltage drops occur and measurement accuracy decreases
Solution Approach 1:
The patent extracts the high-voltage sensing function from the main power path by using a separate capacitive voltage divider connected to the intermediate node. This extraction allows voltage measurement without forcing current through resistive elements in the power path, eliminating the harmful voltage drops associated with resistive dividers while maintaining accurate voltage sensing capability.
4Measurement precision
If continuous time measurements are used for highly accurate measurements, then measurement precision is improved, but flicker noise increases
Solution Approach 1:
The system transitions from continuous-time measurement to periodic sampling measurement synchronized with the switching cycle. By measuring only at these discrete, synchronized moments, the system avoids the low-frequency flicker noise inherent in continuous measurements while maintaining high accuracy for detecting threshold exceedances at the critical sampling points.
5Measurement precision
If an analog input switch is used for measurement, then high voltage measurement is enabled, but switching delays occur and circuit complexity increases
Solution Approach 1:
The patent replaces the mechanical analog switch with a capacitive coupling mechanism. The input capacitor directly couples the high-voltage intermediate node to the analog-to-digital converter without requiring a switching action. This substitution eliminates the switching delay inherent in analog switches while maintaining the ability to measure high voltages, as the capacitor naturally couples the voltage signal without introducing time delays.
Data Source
AI summary
A switched capacitor converter can comprise an input pad for applying an analog input voltage; an input capacitor, the first terminal of which is continuously electrically conductively connected to the input pad and the second terminal of which is electrically conductively connected to an input of an amplifier; the amplifier; and a switched capacitor circuit, which is electrically conductively connected to the amplifier input on the one hand, and can be switched between a reference potential and a predefined reference voltage on the other.