Charge Pump Current Regulation During Voltage Ramp-Up
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Solution Overview
Problem
The existing memory systems face challenges in regulating charge pump current during voltage ramp-up, leading to potential excessive current draw and inefficiencies due to varying load capacitance based on data patterns, which can exceed maximum allowed current limits.
Innovation Solution
Implementing a current regulation mode that uses a random duty cycle clock to maintain the charge pump input current at or near a target current, switching to a voltage regulation mode after reaching a threshold voltage, and employing a lookup table to map output voltage to target duty cycles for efficient current management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the charge pump ramps up the output voltage quickly, then the voltage ramp rate is improved, but the input current exceeds the maximum allowed current limit
Solution Approach 1:
The charge pump operates in two dynamic modes: current regulation mode during voltage ramp-up to limit input current, and voltage regulation mode after reaching threshold voltage to enable fast ramping. The system dynamically switches between modes based on operating conditions, optimizing both current consumption and voltage ramp rate.
Solution Approach 2:
The system changes the regulation parameter from current control to voltage control based on the output voltage threshold. During ramp-up, current regulation maintains input current below the maximum limit. After reaching the threshold voltage, the parameter switches to voltage regulation, allowing the voltage to ramp up quickly to the target level.
2Productivity
If the charge pump draws large current during voltage ramp-up, then the voltage ramp rate is improved, but the current exceeds the maximum allowed current limit from the host
Solution Approach 1:
The charge pump operates in two dynamic modes: current regulation mode during voltage ramp-up to limit input current, and voltage regulation mode after reaching threshold voltage to enable fast ramping. The system dynamically switches between modes based on operating conditions, optimizing both current consumption and voltage ramp rate.
Solution Approach 2:
The system continuously monitors the output voltage and adjusts the charge pump operation accordingly. During ramp-up, feedback ensures input current remains below the maximum limit. After reaching the threshold voltage, feedback enables aggressive voltage ramping to the target level, optimizing productivity while respecting current constraints.
3Device complexity
If the charge pump operates without current regulation during voltage ramp-up, then the device complexity is reduced, but the current draw becomes excessive and unpredictable
Solution Approach 1:
The control function is segmented into two distinct modes: current regulation mode for voltage ramp-up and voltage regulation mode for post-ramp operation. This segmentation allows each mode to be optimized independently, with current regulation preventing excessive current draw and voltage regulation enabling fast ramping, without requiring a single complex control circuit.
Solution Approach 2:
The system changes the regulation parameter from current control to voltage control based on the output voltage threshold. During ramp-up, current regulation maintains input current below the maximum limit. After reaching the threshold voltage, the parameter switches to voltage regulation, allowing the voltage to ramp up quickly to the target level.
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 approach ensures stable and efficient voltage ramp-up by maintaining charge pump current within allowed limits, allowing for faster ramp rates while preventing excessive current draw, thereby improving memory system performance and reliability.
Implementation Method 1
A charge pump typically uses capacitors as energy storage devices to provide an output voltage that is higher than the supply voltage
Implementation Method 2
providing a clock signal having a random duty cycle to a clock input of the charge pump
Data Source
AI summary
Technology is disclosed herein for a memory system that regulates charge pump current during a ramp up of the output voltage. The memory systems operates the charge pump in a current regulation mode while the charge pump output voltage ramps up. After the output voltage crosses a threshold voltage, the charge pump is operated in a voltage regulation mode in which the output voltage is regulated to a target output voltage. In one aspect, the memory system generates a random duty cycle clock in the current regulation mode. The memory system determines a target duty cycle for the random duty cycle clock that will regulate the input current of the charge pump to a target current, given the present output voltage. A clock based on the random duty cycle clock is provided to a clock input of the charge pump to regulate the charge pump current.