Charge Pump Control Circuit Using Pulse Modulation for Voltage Regulation
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Solution Overview
Problem
Conventional charge pump circuits require additional power transistors to adjust output voltage, increasing circuit complexity and area, and efficiency is compromised due to power loss from these transistors.
Innovation Solution
A control circuit for a charge pump that includes a first and second switch group, a pulse modulator, and a driver, which adjusts the duty ratio of a pulse signal to stabilize the output voltage without the need for additional regulators, by controlling the charging and discharging periods of flying and output capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power transistor is inserted to adjust output voltage, then the output voltage can be adjusted to a desired value, but the circuit area and complexity increase
Solution Approach 1:
The invention extracts and eliminates the power transistor from the circuit by implementing voltage adjustment through pulse width modulation of the charge pump's internal switches. The control circuit generates a pulse signal with adjustable duty ratio to control the charging/discharging timing of the flying capacitor, thereby adjusting the output voltage without requiring external power transistors.
Solution Approach 2:
The invention introduces dynamic control through pulse width modulation, where the duty ratio of the pulse signal is dynamically adjusted based on feedback voltage comparison with a reference voltage. This dynamic adjustment mechanism replaces the static voltage adjustment that would require power transistors, enabling flexible output voltage control while maintaining a compact circuit structure.
2Adaptability or versatility
If a power transistor is inserted to adjust output voltage, then the output voltage can be adjusted to a desired value, but power loss increases due to on-resistance
Solution Approach 1:
The invention removes the power transistor that causes power loss due to its on-resistance. Instead, it uses the existing switches within the charge pump circuit, which are controlled through pulse width modulation to achieve voltage adjustment without the additional power loss associated with external power transistors.
Solution Approach 2:
The invention implements a feedback control mechanism where the feedback voltage (derived from the output voltage) is compared with a reference voltage to dynamically adjust the pulse signal duty ratio. This closed-loop control ensures accurate output voltage regulation while minimizing power loss by optimizing the switching timing of the charge pump's internal components.
3Reliability
If additional regulators are added to adjust output voltage, then the output voltage can be stabilized, but the circuit scale increases
Solution Approach 1:
The invention makes the charge pump circuit's control mechanism multi-functional by using the same pulse width modulation approach to both generate the output voltage and stabilize it. The control circuit that generates the pulse signal also provides the stabilization function through feedback, eliminating the need for separate regulator circuits and reducing overall circuit scale while maintaining voltage stability.
Solution Approach 2:
The invention uses dynamic pulse width modulation controlled by feedback to stabilize the output voltage. The duty ratio of the pulse signal is continuously adjusted based on the comparison between feedback voltage and reference voltage, providing real-time voltage stabilization without requiring additional static regulator components that would increase circuit scale.
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 allows for stable output voltage adjustment without increasing circuit size and eliminates the need for power transistors, enhancing efficiency and reducing current consumption.
Implementation Method 1
a pulse modulator which generates a pulse signal having a duty ratio adjusted so that a feedback voltage corresponding to an output voltage of the charge pump circuit matches a given reference voltage
Implementation Method 2
a charge pump circuit having at least one flying capacitor and at least one output capacitor
Data Source
AI summary
A first switch group includes switches provided on a path for charging a flying capacitor using an input voltage. A second switch group includes switches provided on a path for charging an output capacitor using charge stored in the flying capacitor. A pulse modulator generates a pulse signal having a duty ratio adjusted so that a feedback voltage corresponding to an output voltage of a charge pump circuit matches a given reference voltage. A driver receives the pulse signal from the pulse modulator, and turns on either one of the first switch group and the second switch group during a period corresponding to a high-time of the pulse signal and turns on the other switch group during a period corresponding to a low-time thereof.