Digital DC-DC Converter Control Without ADC Voltage Feedback
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Solution Overview
Problem
Existing DC-DC converters face challenges in reducing energy loss during voltage conversion, requiring expensive and large analog circuitry for precise voltage regulation, and often rely on analog-to-digital converters that are costly and area-intensive.
Innovation Solution
A digitally controlled DC-DC converter using a digital regulation loop with a digital-to-analog converter (DAC), error amplifier, and comparator to generate a control signal based on a comparison between the output voltage and a reference voltage, eliminating the need for an analog-to-digital converter (ADC) and utilizing a pulse width modulation signal to adjust the duty cycle of switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precision analog voltage regulation circuitry is used to control output voltage, then voltage regulation accuracy is improved, but device cost and area increase
Solution Approach 1:
The patent replaces the analog voltage regulation system with a digital control system. The digital regulation loop uses a DAC to generate a control voltage from digital words, eliminating the need for precision analog circuitry while maintaining voltage regulation accuracy through digital processing and feedback control.
Solution Approach 2:
The patent changes the regulation approach from analog parameter adjustment to digital parameter control. By using digital words to control the DAC and implementing regulation through digital processing of feedback signals, the system achieves accurate voltage control without requiring expensive precision analog components.
2Measurement precision
If a high quality ADC is used in digital regulation loop to compare analog output voltage to digital reference, then voltage accuracy is improved, but device cost and area increase
Solution Approach 1:
The patent extracts and eliminates the ADC from the regulation loop. Instead of converting the analog output voltage to digital for comparison, the system uses the DAC to generate a control voltage from digital words and compares this directly with the feedback voltage, removing the need for an ADC while maintaining regulation accuracy.
Solution Approach 2:
The patent inverts the traditional digital regulation approach. Rather than converting analog voltage to digital (ADC) for comparison, the system converts digital words to analog control voltage (DAC) and compares this with the feedback signal, reversing the conventional signal flow and eliminating the ADC requirement.
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 solution provides accurate and inexpensive voltage regulation, reducing energy loss and extending battery life in battery-powered devices, while maintaining consistent output voltage over time without the need for expensive ADCs.
Implementation Method 1
A digital-to analog converter is coupled to the adjustment block, the power stage input voltage and the logic circuit to receive the control word from the logic circuit and to generate a converter voltage representing the control word using another voltage
Data Source
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AI summary
A digitally controlled DC-DC converter has a power stage coupled to an input voltage and to a control signal to generate an output voltage in response to the control signal. A controller generates the control signal and has an adjustment block to compare the output voltage to a reference voltage to generate a comparison signal, a logic circuit coupled to the adjustment block to receive the comparison signal and to generate the control signal in response to the comparison signal using a control word, and a digital-to analog converter coupled to the adjustment block, the power stage input voltage and the logic circuit to receive the control word from the logic circuit and to generate a converter voltage representing the control word using another voltage, the converter voltage being applied to the adjustment block to adjust the comparison signal.