Negative Charge Pump Circuit Voltage Adjustment
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Solution Overview
Problem
Existing negative charge pump circuits are limited in their ability to adjust the value of the negative voltage delivered to a capacitive load, which is a drawback in applications requiring adjustable negative voltages for controlling threshold voltages in semiconductor substrates.
Innovation Solution
A negative charge pump circuit design that includes a control circuit to alternately control selector switches linking capacitors to different nodes, allowing for periodic switching phases to establish a negative voltage between a reference potential and the opposite of the positive power supply potential, and additional capacitors and selector switches to enhance voltage adjustment capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing negative charge pump circuits are used, then the circuit structure is relatively simple, but the ability to adjust the negative voltage value is limited
Solution Approach 1:
The patent implements dynamic control of the charge pump circuit by introducing a control circuit that can switch between different operating modes (first mode and second mode). In the first mode, both selector switches operate alternately to pump charge; in the second mode, only the second selector switch operates while the first is forced to a fixed state. This dynamic switching enables continuous adjustment of the negative voltage output level without requiring additional hardware components, thereby improving adaptability while maintaining relatively simple circuit structure.
Solution Approach 2:
The patent changes the operational parameters of the existing circuit components by controlling the timing and state of the selector switches. By adjusting the duration and frequency of the first and second operating modes through the control circuit, the output negative voltage can be varied continuously. This parameter-based control approach allows voltage adjustment without adding physical components, resolving the contradiction between adjustability and circuit complexity.
2Adaptability or versatility
If additional switches are added to enable voltage adjustment, then the voltage adjustment capability is improved, but the device complexity increases
Solution Approach 1:
The patent makes the existing selector switches multi-functional by enabling them to operate in different configurations. The first selector switch can either pump charge (when operating alternately in first mode) or be held in a fixed state (when forced in second mode), while the second selector switch similarly alternates between pumping and fixed states. This multi-functionality of existing components enables voltage adjustment without adding new switches, improving adaptability while avoiding increased device complexity.
Solution Approach 2:
The control circuit achieves voltage adjustment by self-regulating the operation of existing switches rather than requiring external control of additional components. The control circuit generates appropriate control signals to switch between operating modes based on the desired output voltage, allowing the existing switch network to serve multiple functions through different timing configurations. This self-service approach enables voltage adjustment capability without the need for additional switches.
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
Enables the adjustment of the negative voltage applied to a capacitive load between 0 V and the opposite of the positive power supply potential without the need for additional switches, allowing for precise control of the voltage level.
Implementation Method 1
a first capacitor (11, 13), a first selector switch (15, 17) linking a first electrode (11) of the first capacitor (11, 13) either to a first node (Vbat) for applying a positive power supply potential or to a second node (Gnd) for applying a reference potential, and a second selector switch (19, 21) linking a second electrode (13) of the first capacitor (11, 13) either to the second node (Gnd) or to a third node (Vneg) for supplying a negative power supply potential
Data Source
AI summary
The disclosure relates to a negative charge pump circuit including a first capacitor; a first selector switch; a second selector switch; and a control circuit designed to, in a first phase of operation, alternately control the first and second selector switches in a first configuration in which the first and second electrodes of the first capacitor are respectively linked to the first and second nodes and in a second configuration in which the first and second electrodes of the first capacitor are respectively linked to the second and third nodes. In a second phase of operation, the control circuit forces the first selector switch to link the first electrode of the first capacitor to the second node and control the second selector switch so as to alternately link the second electrode of the first capacitor to the second and to the third node.