PLL Charge Pump With Digital Current DACs for Precision Control
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Solution Overview
Problem
Existing regulated power supplies and switching power converters face challenges in providing precise voltage and current characteristics efficiently, especially for microelectronic devices like microprocessors and memory devices.
Innovation Solution
A charge pump system is introduced, comprising a first current digital to analog converter connected to a supply voltage terminal and a second current digital to analog converter connected to a reference voltage terminal, both with adjustable resistances controlled by digital codes. Switches connect these converters to an output terminal, allowing current sourcing and sinking based on the frequency of the output signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If switching power converters are used to provide high efficiency and high current capability, then power supply efficiency is improved, but voltage and current precision deteriorates
Solution Approach 1:
The charge pump is divided into separate current source and current sink modules, each with independent digital-to-analog converters. This segmentation allows precise control of current characteristics while maintaining the high efficiency of switching power conversion, resolving the contradiction between efficiency and precision.
Solution Approach 2:
The patent uses digital control codes to dynamically adjust resistance values in the current digital-to-analog converters, enabling precise control of current magnitude and characteristics. This parameter adjustment capability allows the system to maintain precision while operating in high-efficiency switching mode.
2Measurement precision
If regulated power supplies are used to provide precise voltage and current, then voltage and current precision is improved, but power supply efficiency deteriorates
Solution Approach 1:
The charge pump employs dynamic control through phase-frequency detector signals that continuously adjust the switching timing and duration of current sources and sinks. This dynamic operation enables the system to achieve precise voltage and current control while maintaining high efficiency through optimized switching operation, avoiding the continuous power dissipation of traditional linear regulators.
Solution Approach 2:
By using digital control codes to adjust resistance parameters in the current converters and varying the switching duty cycle based on phase and frequency detection, the system dynamically optimizes both precision and efficiency, resolving the contradiction between precise regulation and power efficiency.
3Device complexity
If fixed resistance current converters are used, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
The charge pump implements variable resistance current converters controlled by digital codes, allowing the resistance values to be dynamically adjusted. This enables the same hardware structure to adapt to different current requirements without increasing physical complexity, as the adjustment is achieved through digital control of existing switchable resistor elements.
Data Source
AI summary
A charge pump has a first current digital to analog converter connected to a supply voltage terminal and having a first resistance configurable based on a first digital control code, a first switch connected between the first current digital to analog converter and an output terminal, a second current digital to analog converter connected to a reference voltage terminal and having a second resistance configurable based on a second digital control code, and a second switch connected between the output terminal and the second current digital to analog converter, wherein the first current digital to analog converter sources a first current based on the first resistance responsive to the first switch being closed, and the second current digital to analog converter sinks a second current based on the second resistance responsive to the second switch being closed.