Time-Based Digital DC-DC Control for Low-Voltage Multiphase Efficiency
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Solution Overview
Problem
Multi-phase DC-DC converters face challenges in improving efficiency, particularly when handling high load currents at low voltages, which complicates circuit design and reduces signal-to-noise ratio in analog-to-digital converters.
Innovation Solution
A DC-DC controller utilizing voltage-to-time converters, time-to-digital converters, and digital control circuits to generate pulse-width modulation signals, allowing for digital domain signal comparison and adjustment of duty cycles to achieve precise output voltage matching with a reference voltage, thereby enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multi-phase DC-DC converter is used to handle high load currents at low voltages, then converter bandwidth and transient response are improved, but circuit design complexity increases and signal-to-noise ratio deteriorates
Solution Approach 1:
The patent replaces traditional analog control circuits with a digital control system. The analog-to-digital converter (ADC) converts analog feedback signals to digital domain, where digital signal processing and digital pulse-width modulation (PWM) generation are performed. This substitution of analog mechanisms with digital ones simplifies circuit design while maintaining high converter bandwidth and transient response performance.
Solution Approach 2:
The patent introduces an intermediate digital domain as a mediator between the analog physical world and the control system. The ADC serves as an intermediary that translates analog signals to digital form, allowing complex control algorithms to be implemented in the digital domain without directly complicating the analog circuitry. This intermediary layer isolates the complexity from the analog front-end.
2Speed
If multi-phase DC-DC converter is used to handle high load currents at low voltages, then converter bandwidth and transient response are improved, but signal-to-noise ratio in analog-to-digital converters deteriorates
Solution Approach 1:
The patent substitutes analog signal processing with digital signal processing to improve signal-to-noise ratio. By performing control calculations in the digital domain after ADC conversion, the system avoids analog noise accumulation and interference. The digital processing can implement precise filtering and compensation algorithms that enhance signal quality while maintaining fast transient response.
Solution Approach 2:
The patent extracts the control functionality from the analog domain and relocates it to the digital domain. The ADC separates the signal acquisition function from the control processing function, allowing the control algorithm to operate on clean digital signals without being affected by analog noise. This extraction of control logic improves signal-to-noise ratio while preserving transient response performance.
3Measurement precision
If digital control circuit is used for signal comparison and duty cycle adjustment, then output voltage control precision is improved, but power consumption increases
Solution Approach 1:
The patent implements digital control with optimized precision levels. Rather than using maximum possible bit depth for all calculations, the system uses sufficient precision only where needed for accurate voltage control. The digital PWM generation and feedback comparison use appropriate precision levels to achieve the required output voltage control accuracy without unnecessary computational overhead that would increase power consumption.
Solution Approach 2:
The patent dynamically adjusts control parameters in the digital domain to optimize the trade-off between precision and power consumption. The digital control circuit can adaptively change sampling rates, calculation precision, and PWM update frequencies based on operating conditions, maintaining high output voltage control precision during critical transitions while reducing computational activity during steady-state operation to minimize power consumption.
Data Source
AI summary
The present application provides an all-digital multi-phase DC-DC controller. The digital DC-DC controller includes time-based analog-to-digital converters (ADCs) for converting analog voltage signals into digital-domain signals so as to benefit from gate length scaling without limited by the low voltage swing. Also, the DC-DC controller further includes a digital control circuit and a time-based modulator. The digital control circuit can control the time-based modulator in a digital domain, thereby reducing the affection caused by process, voltage and temperature (PVT) variation. Also, the time-based modulator can adjust the timing of the PWM signals and avoid the performance degradation caused by circuit mismatch. Since the digital control circuit can be fully synthesizable, it allows implementations in all kinds of digital CMOS processes with a small chip area.