AC Line Powered Relay Drive Circuit Eliminating DC Power Supply
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Solution Overview
Problem
In AC power supply systems, the need for an additional DC power supply to drive relays increases costs, as existing solutions like switching mode power supplies or linear transformers also incur additional expenses.
Innovation Solution
A relay drive circuit comprising diodes, transistors, and capacitors that directly transform AC voltage to DC voltage, eliminating the need for additional power supplies by using a rectifying and DC voltage converting circuit to control the relay's on/off state, thereby reducing costs and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional DC power supply is used to drive the relay in an AC power supply system, then the relay can operate reliably with proper DC voltage, but the system cost increases
Solution Approach 1:
The patent combines the AC-to-DC conversion function and relay driving function into a single integrated circuit. The circuit uses diodes, transistors, and capacitors to rectify AC voltage and generate the required DC voltage for the relay coil, eliminating the need for a separate DC power supply module while ensuring reliable relay operation.
Solution Approach 2:
The designed circuit serves multiple functions: it acts as both an AC-to-DC converter and a relay driver. By making the circuit multi-functional, the patent removes the need for dedicated DC power supply components, thereby reducing system complexity and cost while maintaining reliable relay control.
2Reliability
If a switching mode power supply or linear transformer is used to step down AC voltage to DC voltage for the relay, then the relay can be driven with proper voltage, but the system cost increases
Solution Approach 1:
The patent employs a simple, cost-effective circuit topology using basic electronic components (diodes, transistors, capacitors) instead of expensive switching mode power supplies or linear transformers. The circuit achieves adequate voltage conversion for relay driving without requiring complex or costly power conversion modules.
Solution Approach 2:
The patent extracts only the essential voltage conversion functionality needed for relay driving, removing unnecessary complexity of full-featured power supplies. The circuit implements a minimalistic approach by using simple rectification and voltage regulation components rather than complete power supply modules.
3Device complexity
If a simple AC to DC conversion circuit is used, then the system cost is reduced, but the reliability of relay operation may be compromised
Solution Approach 1:
The circuit incorporates feedback mechanisms through the transistor switching action and capacitor charging/discharging cycles to maintain stable voltage for the relay coil. The transistor acts as a switching element that regulates the voltage delivered to the relay, ensuring reliable operation even with simple component selection.
Solution Approach 2:
The circuit includes capacitors that store energy and provide voltage stabilization during AC cycles. These capacitors act as cushioning elements that maintain voltage levels during transitions, ensuring the relay receives sufficient voltage for reliable operation without requiring complex voltage regulation.
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 efficiently saves costs and resources by eliminating the need for additional power supplies and ensures reliable operation without accidental relay activation, with power consumption on the relay coil controlled through duty cycle and frequency adjustments.
Implementation Method 1
a first diode, a second diode, a third diode... The relay drive circuit is operable to transform an AC voltage to a DC voltage
Implementation Method 2
a first capacitor, and a second capacitor... transform an AC voltage to a DC voltage
Implementation Method 3
a first transistor, a second transistor... use the DC voltage to control on/off of the relay
Data Source
AI summary
Disclosed are exemplary embodiments of relay drive circuits. In an exemplary embodiment, a relay drive circuit generally includes a first diode, a second diode, a third diode, a first transistor, a second transistor, a first capacitor, and a second capacitor. The relay drive circuit is operable to transform an AC voltage to a DC voltage, and then use the DC voltage to control on/off of the relay.