Dual Charge Pump Circuit for Phase-Change Memory Voltage Generation
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Solution Overview
Problem
Existing semiconductor devices face inefficiencies in generating internal supply voltages for phase-change memory, leading to wasteful power consumption and increased ripple noise due to the same power supply being used for both set and reset pulses, and the need for large circuit areas to handle varying current demands.
Innovation Solution
A dual charge pump circuit system where a first charge pump generates a first internal supply voltage and a second charge pump generates a higher voltage, with the secondary output of the first charge pump connected to the charging terminal of the second, allowing for stable and efficient voltage boosting without excessive ripple noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single charge pump circuit is used to generate both set and reset pulses, then the circuit area is reduced, but power consumption increases and ripple noise is excessive
Solution Approach 1:
The single charge pump circuit is divided into two separate charge pump circuits: a first charge pump circuit for generating set pulses and a second charge pump circuit for generating reset pulses. This segmentation allows each circuit to be optimized for its specific function, reducing overall power consumption while maintaining compact area through specialized design of each unit.
2Device complexity
If a single charge pump circuit is used to generate both set and reset pulses, then device complexity is reduced, but ripple noise increases
Solution Approach 1:
By segmenting the charge pump functionality into separate first and second charge pump circuits, each operating independently for set and reset operations respectively, the ripple noise from each circuit is isolated and reduced compared to a single circuit handling both operations simultaneously.
3Reliability
If charge pump boosts voltage to maximum level, then sufficient voltage is provided for reset pulse, but power consumption increases unnecessarily for set pulse
Solution Approach 1:
The first charge pump circuit is designed with local quality optimized for set pulse generation, providing just the necessary voltage level for set operations. The second charge pump circuit is designed with local quality optimized for reset pulse generation, providing the higher voltage level needed for reset operations. This localized optimization ensures each circuit provides only the voltage necessary for its specific function, avoiding unnecessary power consumption.
4Adaptability or versatility
If external supply voltage varies within specification limits, then adaptability is improved, but voltage stability for charge pumping deteriorates
Solution Approach 1:
Voltage detection circuits monitor the external supply voltage and provide feedback to control circuits, which adjust the operation of the first and second charge pump circuits accordingly. This feedback mechanism maintains stable internal voltages for charge pumping even when external supply voltage varies within specification limits, ensuring reliable operation across the full voltage range.
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 prevents wasteful power consumption and reduces ripple noise by ensuring the second supply voltage is generated using the first supply voltage, maintaining stability and efficiency across varying external supply voltage limits, thereby reducing circuit area and improving writing accuracy in phase-change memory cells.
Implementation Method 1
a first charge pump circuit that generates a first internal supply voltage
Implementation Method 2
a second charge pump circuit that generates a second internal supply voltage having a voltage value larger than that of the first internal supply voltage in terms of absolute value
Data Source
AI summary
A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.