Low Pass Filter Output Stabilization via Reverse Current Diode
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Solution Overview
Problem
Existing filter circuits for battery charger systems fail to stabilize output voltage across varying load resistances, leading to excessive voltage levels that exceed the tolerance of connected electronic equipment.
Innovation Solution
Incorporation of a reverse current diode that regenerates energy from the low-pass filter back to the input, stabilizing the output voltage and improving surge voltage resistance and HF filtering, with optional inclusion of a choke to reduce output ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a low-pass filter is used to smooth the voltage from the battery charger circuit, then the voltage fluctuation is reduced, but the output voltage increases excessively when load resistance increases, exceeding the tolerance of electronic equipment
Solution Approach 1:
The patent introduces a feedback mechanism where the output voltage is fed back to the input side through a feedback capacitor. When the output voltage rises excessively, the feedback capacitor conducts current to reduce the voltage, thereby stabilizing the output voltage within the tolerance range of electronic equipment while maintaining the smoothing effect.
Solution Approach 2:
The patent changes the operating parameters of the filter circuit by introducing a feedback capacitor that dynamically adjusts the effective capacitance and resistance values based on the output voltage level. This allows the filter to adapt its characteristics to prevent excessive voltage rise under varying load conditions.
2Reliability
If the filter circuit components are increased to handle higher load resistances, then the output voltage stability improves, but the circuit complexity and component requirements increase
Solution Approach 1:
The feedback capacitor serves multiple functions simultaneously: it provides voltage stabilization through feedback, acts as an additional filtering element, and enables the circuit to handle varying load conditions without requiring separate control circuits. This multi-functionality achieves reliable voltage stability while keeping the circuit structure simple.
3Stability of the object's composition
If the filter capacitance is increased to maintain voltage under heavy load, then the voltage stability improves, but the inrush current and surge voltage increase
Solution Approach 1:
The patent creates a dynamic response system where the feedback capacitor activates only when the output voltage rises excessively. This dynamic mechanism allows the filter to maintain voltage stability during normal operation without continuously drawing high inrush current, as the feedback path is engaged only when needed to correct voltage deviations.
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
The solution effectively limits output voltage fluctuations, ensuring it remains within the tolerance of electronic equipment even under increased load resistances without adding significant circuit complexity or active components, thereby stabilizing the output voltage.
Implementation Method 1
the output of the low-pass filter is regenerated over a reverse current diode with the input of the low-pass filter
Implementation Method 2
a first capacitor C1 with a capacitance of 4700 μF
Implementation Method 3
a first resistance R3 of 2.5Ω
Data Source
AI summary
In a filter circuit (6) with a low-pass filter (7), the output of the low-pass filter (7) is regenerated over a reverse current diode (11) with the input of the low-pass filter or of a further low-pass filter (8) pre-connected to the low-pass filter (7). A circuit arrangement includes such a filter circuit (6) and a battery charger circuit (1) with a battery (2) and a d.c. generator (A).