Relay Delay Circuit for Sleep-Mode Switching Noise Control
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Solution Overview
Problem
Conventional relay switching methods in power supply devices cause noise and reduce the service life of relay switches when operated in sleep mode due to frequent switching between on and off states.
Innovation Solution
A delay circuit comprising a first diode, a second diode, a BJT element, and a delay unit is coupled to the relay switch, applying a time-delaying process to the power signal, extending the rising time of switch-on pulses to match or exceed the pulse width of power-on pulses, thereby controlling switching actions and reducing noise and extending relay switch lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the relay switch is controlled by the power signal VCCO to switch between on and off states in sleep mode, then the power supply device can be awakened periodically for power management, but the relay switch produces noise and its service life is reduced due to frequent switching
Solution Approach 1:
The delay circuit is pre-configured with a delay unit that automatically delays the power signal VCCO before it reaches the relay switch. This preliminary action prevents the relay switch from responding to frequent wake-up signals during sleep mode, thereby reducing switching frequency while maintaining power management functionality.
Solution Approach 2:
The delay circuit acts as an intermediary between the power signal VCCO and the relay switch. The delay unit within this intermediary circuit modifies the timing characteristics of the power signal, filtering out frequent wake-up pulses and allowing only sustained power-on signals to trigger relay switching, thus protecting the relay from excessive switching.
2Use of energy by moving object
If the relay switch switches frequently in sleep mode, then power management can be implemented, but noise is produced
Solution Approach 1:
The delay circuit pre-processes the power signal VCCO by introducing a time delay that filters out short-duration wake-up pulses. This preliminary filtering action prevents these pulses from reaching the relay switch, thereby eliminating the noise generated by frequent relay switching while preserving the intended power management wake-up functionality.
3Adaptability or versatility
If the relay switch is controlled to switch on and off alternately during sleep mode, then power states can be managed, but the product service life is reduced
Solution Approach 1:
The delay unit in the delay circuit performs a preliminary filtering action on the power signal VCCO, extending the rising time of switch-on pulses. This preliminary processing ensures that only sustained power-on commands (not transient wake-up signals) can trigger relay switching, thereby reducing the total number of switching cycles and extending the service life of the relay switch while maintaining power state management adaptability.
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 delay circuit effectively reduces noise and extends the service life of relay switches by ensuring the relay switch remains in a consistent off state during sleep mode, minimizing wear and tear.
Implementation Method 1
the delay unit applies a time delaying process to a power signal (VCCO) that is transmitted to the relay switch, such that a rising time of each of switch-on pulses contained by the power signal is delayed for a specific time
Implementation Method 2
a first diode, a second diode, a BJT element, and a delay unit
Data Source
AI summary
A delay circuit is disclosed. The delay circuit is coupled to a relay switch that is contained in a power conversion device. When an electronic device having the power conversion device is operated in a sleep mode, the delay circuit applies a time delaying process to a power signal that is transmitted to the relay switch, such that a rising time of each of switch-on pulses contained by the power signal is delayed for a specific time. The specific time is set to be longer than a pulse width of each of power-on pulses contained by a power switching signal of the power conversion device. As such, when the electronic device is operated in the sleep mode, switching actions of the relay switch is properly controlled, thereby making the power conversion device not produce noise. Moreover, the service life of the relay unit is also extended.