Charge Pump Voltage Overshoot Control via Switching Unit
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Solution Overview
Problem
Conventional semiconductor memory devices experience abnormal operation due to overshooting of the third voltage, which occurs when the load capacitance at the output terminal of the second voltage generation unit is greater than that of the third voltage generation unit, leading to unstable voltage levels.
Innovation Solution
The implementation of a semiconductor device with a switching unit that connects a first charge pump to a second charge pump, using pump clock generators and charge pumps to generate and regulate voltages, ensuring that the second pump output voltage reaches a target level before the first pump output voltage, thereby preventing overshooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the second charge pump operates independently without coordination with the first charge pump, then the third voltage can be generated quickly, but the third voltage may overshoot and become higher than the second voltage causing abnormal operation
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the third voltage level and adjusts the switching between first and second charge pumps accordingly. When the third voltage approaches the target level, the controller switches from the second charge pump to the first charge pump to prevent overshooting, ensuring stable voltage generation.
Solution Approach 2:
The patent uses a preliminary action by pre-charging the output capacitor through the second charge pump before switching to the first charge pump for fine-tuned voltage regulation. This preliminary high-speed charging phase is followed by a precision regulation phase, preventing overshoot while maintaining fast response.
2Reliability
If a switching unit is added to control the connection between first and second charge pumps, then voltage overshooting is prevented, but the device complexity increases
Solution Approach 1:
The patent merges the control functions of two charge pumps into a unified system managed by a single controller. The switching unit integrates both charge pump operations and voltage regulation logic into one coordinated system, reducing overall control complexity despite adding switching components.
Solution Approach 2:
The controller performs multiple functions: it manages the second charge pump for rapid voltage buildup, controls the switching unit for seamless transition, and regulates the first charge pump for precision voltage control. This multi-functionality reduces the need for separate control circuits.
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 solution stabilizes the voltage levels by ensuring the second pump output voltage is maintained at a target level, preventing overshooting and ensuring normal operation of the semiconductor device.
Implementation Method 1
a first charge pump configured to generate a first pump output voltage in response to the first pump clock signal
Implementation Method 2
a second charge pump configured to generate a second pump output voltage in response to the second pump clock signal
Data Source
AI summary
A semiconductor memory device includes a first pump clock generator configured to generate a first pump clock signal based on a power supply voltage. The device also includes a first charge pump configured to generate a first pump output voltage in response to the first pump clock signal. The device also includes a second pump clock generator configured to generate a second pump clock signal based on the first pump output voltage. The device also includes a second charge pump configured to generate a second pump output voltage in response to the second pump clock signal. The device also includes a switching unit configured to selectively connect the first charge pump to the second charge pump.