Charge Pump Circuit Power Management Jitter Trade-off
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Solution Overview
Problem
Existing charge pumps in phase-locked loops (PLLs) face a trade-off between power consumption and jitter reduction, with current methods either increasing power consumption to reduce jitter or tolerating higher jitter to conserve power.
Innovation Solution
A charge pump with power management capabilities, incorporating a charging/discharging circuit, voltage generator, reference voltage circuit, and control logic gates to dynamically control power consumption and jitter through multiple operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge sharing removal circuit (OTA) is added to reduce PLL output jitter, then jitter is reduced, but power consumption increases
Solution Approach 1:
The patent implements a dynamic power management mechanism that allows the charge pump to switch between different operational modes (normal mode and low-power mode) based on system requirements. The control logic gate dynamically adjusts the switching behavior and voltage generator operation, enabling the system to adapt its power consumption characteristics while maintaining jitter performance when needed.
Solution Approach 2:
The patent changes the operational parameters of the charge pump by introducing a voltage generator that can provide different voltage levels (first voltage to reduce charge sharing, second voltage for normal operation). By adjusting these voltage parameters dynamically through control logic, the system can reduce jitter when required while consuming less power during normal operation, effectively resolving the contradiction between jitter reduction and power consumption.
2Use of energy by moving object
If switches are turned off to reduce power consumption, then power consumption decreases, but charge sharing effect increases causing higher jitter
Solution Approach 1:
The patent applies preliminary action by using the voltage generator to pre-charge or pre-discharge the parasitic capacitor at the output node before the main switching operation. This preliminary voltage adjustment prevents excessive voltage changes when switches are turned off, thereby reducing charge sharing effects and jitter while allowing the system to operate in low-power mode with switches off for extended periods.
Solution Approach 2:
The voltage generator acts as an intermediary element between the current sources and the output node. It mediates the charge transfer process by providing controlled voltage levels that prevent uncontrolled charge sharing when switches are off, thus enabling low-power operation without significant jitter penalty.
3Reliability
If voltage is applied to maintain Vbp at reference voltage to reduce charge sharing, then charge sharing is reduced, but power consumption increases
Solution Approach 1:
The patent implements periodic action by alternating between normal mode (with voltage generator active, reducing charge sharing) and low-power mode (with voltage generator inactive, accepting higher charge sharing). The control logic gate periodically switches between these modes based on system requirements, allowing the system to reduce power consumption by disabling the voltage generator when jitter reduction is not critical, while still providing jitter reduction capability when needed.
Data Source
AI summary
This invention provides a charge pump circuit used in phase-locked loop (PLL) having the function of power management for portable application. According to different applications, power management adjusts the power consumption modes of this PLL that will also correspond to different jitter degree. There are three kinds of modes contained in the PLL: the first mode is normal mode having the larger power consumption and smaller jitter, second mode is low power mode having moderate power consumption and moderate jitter, and third mode is the traditional mode having the smaller power consumption and the larger jitter.