Switched Capacitor Voltage Regulator Diode Protection
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Solution Overview
Problem
Conventional DC-DC converters face challenges in maintaining a stable output voltage across varying battery voltages in small electronic devices, particularly due to the use of inductors being avoided in switched capacitor circuitry.
Innovation Solution
A switched-capacitor type voltage regulator with a flying capacitor and transistors operating as switches, utilizing pulse-frequency-modulated control signals to regulate output voltage by coupling the flying capacitor to input voltage during one phase and providing output voltage during another phase, with an additional switch acting as a diode to prevent p-n junction activation when input voltage exceeds output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If inductors are used in DC-DC converters to maintain stable output voltage, then voltage stability is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the inductor component from the DC-DC converter circuit, replacing it with a switched capacitor topology. This removes the harmful factor (inductor complexity) while maintaining the essential function of voltage conversion and stabilization through capacitor-based charge pumping mechanisms.
Solution Approach 2:
The patent substitutes the magnetic field-based inductor mechanism with an electric field-based capacitor switching mechanism. The switched capacitor circuit uses transistor switches to transfer charge between capacitors, replacing the inductor's energy storage and voltage transformation function with an equivalent capacitor-based approach.
2Device complexity
If transistor switches are used in switched capacitor circuitry to avoid inductors, then device complexity is reduced, but p-n junction activation occurs when input voltage exceeds output voltage
Solution Approach 1:
The patent introduces a diode as an intermediary component between the transistor switch and the rest of the circuit. This diode acts as a protective element that prevents reverse voltage from activating the p-n junction in the transistor, thereby eliminating the harmful effect while allowing the transistor to function as intended in the switched capacitor topology.
Solution Approach 2:
The patent applies preliminary protective action by placing the diode in reverse bias configuration before any harmful voltage conditions can occur. The diode is positioned to preemptively block any reverse voltage that might activate the transistor's p-n junction, preventing the harmful effect before it can manifest.
3Stability of the object's composition
If pulse frequency modulation is used to regulate output voltage in switched capacitor converters, then voltage regulation is achieved, but loss of time occurs due to switching operations
Solution Approach 1:
The patent employs periodic switching action where transistors alternately connect capacitors to different circuit nodes in regular cycles. This periodic switching enables voltage regulation through pulse frequency modulation, where the duty cycle and frequency of switching are adjusted to maintain stable output voltage despite variations in input voltage or load conditions.
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 effectively regulates output voltage to a desired value, such as 5.0V, while allowing input voltage to vary from 3.0V to 5.5V, ensuring efficient voltage conversion without inductor use and maintaining p-n junction integrity.
Implementation Method 1
the other switch is closed so that the transistor that the other switch is connected to operates as a diode
Implementation Method 2
A switched-capacitor type voltage regulator that includes a flying capacitor and switches
Data Source
AI summary
A switched-capacitor type voltage regulator is provided. The regulator includes a flying capacitor and switches, including first and second transistors which operate as switches. The switches are arranged to operate such that the flying capacitor is coupled to an input voltage during a first phase, and switched to provide an output voltage during a second phase. During the first phase, the first transistor is employed to couple the capacitor to the input voltage, and a second transistor is employed to couple (the other side of) the capacitor to another node (e.g. Ground). Additionally, another switch is coupled between the gate and the drain of either the first transistor or the second transistor. Also, during the first phase, if the input voltage is greater than the output voltage, the other switch is closed so that the transistor that the other switch is connected to operates as a diode.