Zener Diode Isolation for Switch Power Supply Backup Battery
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Solution Overview
Problem
Existing switch power supply circuits with backup batteries suffer from reduced output power and conversion efficiency due to the use of isolation diodes, which consume battery energy and hinder the backup function.
Innovation Solution
A switch power circuit design that replaces the isolation diode with a zener diode, utilizing its reverse conduction and cut-off characteristics to isolate the backup battery from the switch power supply, and employs a negative feedback module to stabilize output voltage and prevent discharge during normal operation, thereby enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolation diode is series connected to the output end of the switch power supply to prevent backward flowing, then the backup battery can be isolated from the switch power supply, but the output power of the switch power supply is greatly reduced and conversion efficiency decreases
Solution Approach 1:
The patent changes the electrical parameter (voltage threshold) of the isolation component by using a Zener diode with a specific breakdown voltage instead of a regular diode. The Zener diode is selected with a breakdown voltage higher than the battery voltage but lower than the normal output voltage, allowing it to block battery discharge during normal operation while conducting during power failures, thus isolating the battery without significantly reducing conversion efficiency.
Solution Approach 2:
The isolation component dynamically changes its electrical state based on voltage conditions. The Zener diode transitions from a high-impedance blocking state during normal operation to a low-impedance conducting state during power failures, providing adaptive isolation that maintains efficiency during normal operation while enabling backup function activation when needed.
2Reliability
If multiple diodes are used for isolation of two power supply units, then backward flowing is prevented, but output power is reduced and conversion efficiency decreases
Solution Approach 1:
The patent uses a Zener diode with a specific breakdown voltage parameter selected to be higher than the battery voltage but lower than the normal output voltage. This parameter selection allows the diode to remain non-conductive during normal operation (preserving full output power) while becoming conductive during power failures (enabling isolation function).
Solution Approach 2:
The patent extracts the isolation function from the output path by using a parallel Zener diode configuration instead of series diodes. The Zener diode is placed in parallel with the battery connection, allowing the main power path to remain unobstructed during normal operation while providing isolation capability when needed.
3Loss of energy
If an isolation diode is series connected to prevent charge of switch power supply to battery, then battery energy consumption is reduced, but output power and conversion efficiency are reduced
Solution Approach 1:
The patent changes the voltage threshold parameter of the isolation component by using a Zener diode with a breakdown voltage higher than the battery voltage. This ensures that during normal operation, the Zener diode remains non-conductive and prevents battery charging, while during power failures, it becomes conductive and allows battery discharge to support the load.
Solution Approach 2:
The Zener diode acts as an intermediary component that mediates between the battery and the power supply circuit. It provides conditional connectivity based on voltage conditions, allowing the battery to discharge during power failures while preventing it from charging during normal operation, thus protecting battery energy without obstructing normal power output.
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 design improves conversion efficiency and reduces output consumption by effectively isolating the backup battery, ensuring its preservation and maintaining stable output voltage during normal operation while preventing discharge during power supply issues.
Implementation Method 1
The present invention utilizes the reverse conduction and the reverse cut-off characteristics of the zener diode
Implementation Method 2
an PWM switch control module, a transformer module
Implementation Method 3
The input rectifier module, the PWM switch control module and the transformer module are connected in sequence
Data Source
AI summary
The present invention provides a switch power circuit with a backup battery for power supply, comprising an input rectifier module, an PWM switch control module, a transformer module, an output rectifier diode, a negative feedback module, a backup battery, an isolation diode unit and a zener diode; the anode of the output rectifier diode is connected with the positive output end of the transformer unit, the cathode of the output rectifier diode is connected with the cathode of the isolation diode unit, the anode of the isolation diode unit is connected with the anode of the backup battery, the cathode of the backup battery is connected with the negative output end of the transformer module; the cathode of the zener diode is connected between the cathode of the isolation diode unit and the cathode of the output rectifier diode; one end of the negative feedback module is connected with the anode of the zener diode, and the other end of the negative feedback module is connected with the control port of the PWM switch control module. The present invention has beneficial effects of reducing output consumption of switch power supply and increasing conversion efficiency of switch power supply.