Programmable Power Supply Under-Voltage Protection Circuit
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Solution Overview
Problem
Programmable power supplies fail to protect batteries from over-discharging, as the output voltage drops below a safe level, potentially damaging lithium batteries due to the lack of an effective under-voltage protection mechanism.
Innovation Solution
A control circuit comprising a current-sense, voltage-sense, output voltage regulation, and time-delay circuit that generates and adjusts current and voltage reference signals to regulate output current and voltage, implementing a programmable under-voltage protection mechanism by decreasing the current reference signal when the output voltage falls below a protection threshold, thereby preventing damage to batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power supply provides constant output voltage to meet programming requirements, then the power supply is versatile and programmable, but the battery suffers from over-discharging when voltage drops too low
Solution Approach 1:
The patent implements preliminary protection by setting a predetermined voltage threshold before the battery can reach dangerous discharge levels. The control circuit is configured with this threshold in advance, and when the output voltage approaches or drops below this threshold, the system proactively reduces the output current to prevent further voltage decline. This preliminary action prevents the harmful condition of over-discharging before it occurs, while still allowing the power supply to operate at various programmable voltage levels during normal operation.
2Productivity
If the power supply allows output voltage to drop to maintain constant current output, then the current limit function works effectively, but the battery is permanently damaged due to excessive voltage drop
Solution Approach 1:
The patent introduces dynamic adjustment of the current reference signal based on the monitored output voltage. Instead of maintaining a fixed constant current, the system dynamically modifies the current level in response to voltage conditions. When voltage is above the threshold, normal constant current charging occurs; when voltage drops below the threshold, the current is automatically reduced. This dynamic behavior allows the system to adapt to changing conditions and protect the battery effectively.
Solution Approach 2:
The patent implements a feedback mechanism where the control circuit continuously monitors the output voltage of the power supply. When the output voltage drops below a predetermined threshold, the control circuit automatically adjusts the current reference signal to reduce the output current. This closed-loop feedback system ensures that the battery is protected from both over-current and under-voltage conditions, resolving the contradiction between maintaining constant current for safety and preventing damage from voltage drops.
Data Source
AI summary
A control circuit of a power supply is provided. The power supply includes a current-sense circuit, a voltage-sense circuit, an output voltage regulation circuit, and a current regulation circuit. The current-sense circuit generates a current-sense signal in response to an output current of the power supply. The voltage-sense circuit generates a voltage-sense signal in response to an output voltage of the power supply. The output voltage regulation circuit is coupled to regulate the output voltage of the power supply according to a voltage reference signal and the voltage-sense signal. The output current regulation circuit is coupled to regulate the output current of the power supply according to a current reference signal and the current-sense signal. The output voltage of said power supply is programmable.