Configurable Multistage Charge Pump with Supply Detect
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Solution Overview
Problem
Conventional charge pumps with a fixed number of stages and capacity are inadequate for systems with a wide input supply voltage range, leading to insufficient load drive or high ripple, particularly in battery-powered systems with varying load conditions.
Innovation Solution
A configurable multistage charge pump with a supply detect mechanism that adjusts the number of pumpcell stages and capacity based on the input supply voltage, using control logic and bypass switches to enable or disable pumpcells, ensuring stable output voltage and current levels across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed number of pumpcell stages is used in the charge pump, then the device complexity is reduced, but the load drive capability becomes insufficient when input supply voltage varies widely
Solution Approach 1:
The charge pump employs dynamic configuration where the number of active pumpcell stages is adjusted based on the detected input supply voltage level. Control logic dynamically enables or disables specific pumpcells to match the input voltage conditions, allowing the system to adapt between wide voltage ranges (e.g., 1.7V to 3.6V) while maintaining stable output voltage (e.g., 5.5V) and adequate load drive capability.
2Power
If the number of pumpcell stages is increased to handle low input supply voltage, then the load drive capability is improved, but the ripple increases when operating at high input supply voltage
Solution Approach 1:
The system changes the operational parameters of the charge pump by adjusting the number of active pumpcell stages according to the input supply voltage level. When input voltage is low, more stages are activated to increase voltage multiplication and load drive capability. When input voltage is high, fewer stages are activated to prevent excessive voltage multiplication that would cause high output ripple, thus optimizing performance across the entire input voltage range.
3Reliability
If a fixed capacity charge pump is used, then the manufacturing precision is simplified, but the output voltage stability deteriorates under varying load conditions
Solution Approach 1:
The charge pump implements dynamic stage configuration where control logic detects the input supply voltage level and selectively enables or disables pumpcells to maintain optimal output voltage stability. This dynamic adjustment ensures that the charge pump can handle varying load conditions and wide input voltage ranges (1.7V to 3.6V) while maintaining stable output voltage (5.5V), thereby improving reliability without requiring complex variable capacitance structures.
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
The solution provides low ripple and adequate load drive, ensuring reliable voltage and current delivery to non-volatile memory bitcells, even under varying input supply conditions, thereby enhancing data retention and programming efficiency.
Implementation Method 1
A supply detect mechanism is provided which detects an input supply level and determines a number of pumpcell stages to activate
Implementation Method 2
Multiple pumpcells are provided, each having a clock input, an inverted bypass input, a clock enable input and a controlled output
Data Source
AI summary
A configurable multistage charge pump including multiple pumpcells, at least one bypass switch and control logic. The pumpcells are coupled together in series including a first pumpcell receiving an input voltage and at least one remaining pumpcell including a last pumpcell which generates an output voltage. Each bypass switch is coupled to selectively provide the input voltage to a pumpcell input of a corresponding one of the remaining pumpcells. The control logic is configured to determine one of multiple voltage ranges of the input voltage, to enable each pumpcell for a first voltage range and to disable and bypass at least one pumpcell for at least one other voltage range. A method of operating a multistage charge pump including detecting an input voltage, selecting a voltage range based on an input voltage, and enabling a number of cascaded pumpcells corresponding to the selected voltage range.