Negative Charge Pump Feedback Circuit Using Switch-Capacitor Voltage Division
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Solution Overview
Problem
Existing negative charge pump feedback circuits occupy a large area, have slow feedback speed, and produce significant output voltage ripple due to the use of resistor voltage-division circuits and the need for additional positive-negative voltage conversion.
Innovation Solution
A switch-capacitor circuit is integrated into the feedback loop, allowing for simultaneous voltage division and positive-negative voltage conversion, eliminating the need for additional conversion circuits and reducing circuit area, with capacitors like MOM or MIM capacitors used to regulate the feedback signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a resistor voltage-division circuit is used in the feedback circuit, then the voltage division function is achieved, but the circuit area occupied is large
Solution Approach 1:
The patent replaces the resistor voltage-division circuit with a switch-capacitor circuit. Instead of using resistors to divide voltage, the invention uses capacitors (specifically MOM or MIM capacitors) controlled by switches to achieve the same voltage division function. This substitution eliminates the need for multiple resistors interconnected in series, thereby significantly reducing the circuit area and simplifying the circuit structure while maintaining the voltage division capability.
Solution Approach 2:
The switch-capacitor circuit performs multiple functions: it acts as both a voltage-division circuit and a positive-negative voltage conversion circuit. By integrating these functions into a single circuit block, the patent eliminates the need for separate conversion circuits, further reducing the overall circuit area and complexity.
2Speed
If a positive-negative voltage conversion circuit is added to convert the component voltage, then the voltage polarity is corrected, but the feedback speed becomes slow
Solution Approach 1:
The patent merges the voltage-division function and the positive-negative voltage conversion function into a single switch-capacitor circuit. The switch-capacitor circuit simultaneously divides the negative voltage and converts it to a positive voltage, eliminating the need for a separate positive-negative voltage conversion circuit. This integration accelerates the feedback speed by removing additional conversion stages while maintaining the necessary voltage polarity correction.
Solution Approach 2:
The switch-capacitor circuit is designed to perform dual functions: voltage division and positive-negative voltage conversion. By making this single circuit block universal, the patent achieves both voltage scaling and polarity inversion without requiring multiple separate circuits, thereby improving feedback speed and reducing circuit complexity.
3Object-generated harmful factors
If a resistor voltage-division circuit and positive-negative voltage conversion circuit are used, then the feedback function is complete, but the output voltage ripple is significant
Solution Approach 1:
The patent substitutes the resistor-based voltage-division circuit with a switch-capacitor circuit. Capacitors inherently have lower noise and ripple characteristics compared to resistors. The switch-capacitor circuit provides cleaner voltage division with minimal ripple generation, directly addressing the output voltage ripple issue while also reducing the circuit area.
Solution Approach 2:
The integrated switch-capacitor circuit simultaneously achieves voltage division, positive-negative voltage conversion, and ripple reduction. By combining these functions, the patent eliminates the ripple-introducing interfaces between separate circuits while maintaining complete feedback functionality, thereby reducing output voltage ripple without increasing circuit area.
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 configuration significantly reduces circuit area, increases feedback speed, and minimizes output voltage ripple by using a switch-capacitor circuit to achieve voltage division and conversion, thereby improving the performance of the negative charge pump feedback circuit.
Implementation Method 1
a first capacitor, a first terminal of which is connected to the output terminal of the charge pump through a first switch and grounded through a second switch; a second capacitor, a first terminal of which is connected to a second terminal of the first capacitor
Data Source
AI summary
The present invention discloses a negative charge pump feedback circuit, wherein the feedback circuit is connected between an AND gate and the output terminal of the negative charge pump, and a clock signal is connected to the negative charge pump through the AND gate and under the control of the feedback signal, with the feedback circuit including a switch-capacitor circuit and a comparator; a first terminal of a first capacitor of the switch-capacitor circuit is connected to the output terminal of the negative charge pump through a first switch, and grounded through a second switch; a first terminal of a second capacitor is connected to a second terminal of the first capacitor, grounded though a third switch, and connected to the comparator though a fourth switch; an adjustable capacitor is connected in parallel to both terminals of the second capacitor; a positive-phase input terminal of the comparator is connected to a reference voltage. The switch-capacitor circuit is made to switch constantly between two states by the control of four control signals over the four switches, achieving voltage division and positive/negative voltage conversion simultaneously. The present invention can reduce the circuit area, increase the feedback speed, and reduce the output voltage ripple of the charge pump.