Rectifier Device Stand-by Detection Circuit
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Solution Overview
Problem
Conventional rectifier circuits using silicon diodes experience significant power dissipation due to the forward voltage drop, which is a concern especially for low voltage applications, and active rectification with power transistors has challenges with quiescent current consumption during standby modes.
Innovation Solution
A rectifier device employing a power MOS transistor with a parallel diode and a control circuit that switches on the MOS transistor when the diode is forward biased, utilizing a cycle detection circuit and timer to manage power usage, thereby reducing power dissipation and quiescent current during standby.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silicon diodes are used for rectification, then the rectifier structure is simple and reliable, but power dissipation is high due to forward voltage drop
Solution Approach 1:
The patent changes the operating parameters of the rectifier by using power transistors with controllable on-resistance instead of fixed forward voltage diodes. The transistor's resistance can be optimized to minimize power dissipation while maintaining rectification function, directly addressing the energy loss issue without requiring complete structural redesign
Solution Approach 2:
The invention introduces dynamic control of the transistor switching states based on the AC input voltage phase. The control circuit dynamically adjusts which transistors are conducting during each half-cycle, enabling optimal power dissipation characteristics while maintaining the rectifier's structural integrity and reliability
2Loss of energy
If power transistors are used for active rectification, then power dissipation is reduced, but quiescent current consumption increases during standby mode
Solution Approach 1:
The patent implements periodic switching of the transistor pairs based on the AC voltage cycles. During standby mode when no AC voltage is present, the control circuit periodically monitors for voltage presence and only activates the power transistors when needed, allowing the system to enter low-power states during idle periods while maintaining readiness for active rectification
Solution Approach 2:
The control circuit automatically detects the presence or absence of AC input voltage and self-adjusts the transistor switching states accordingly. When no AC voltage is detected, the system automatically transitions to a low-quiescent-current state without external intervention, effectively managing power consumption based on actual operational needs
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 reduces power dissipation and quiescent current consumption, improving efficiency and reducing energy loss in rectification processes, especially in low voltage applications and standby modes.
Implementation Method 1
a diode connected parallel to the load current path, wherein an alternating input voltage is operably applied across the load current path and the diode
Implementation Method 2
A control circuit is configured to switch on the first MOS transistor for an on-time period, during which the diode is forward biased
Implementation Method 3
A stand-by detection circuit includes a cycle detection circuit configured to detect cycles of the alternating input voltage
Implementation Method 4
The timer is configured to be reset by the cycle detection circuit upon detection of a cycle of the alternating input voltage, and to disconnect a supply line of the control circuit unless reset before a maximum time span has elapsed
Data Source
AI summary
A rectifier device is described herein. In accordance with one example, the rectifier includes a first MOS transistor, which has a load current path and a diode connected parallel to the load current path, wherein an alternating input voltage is operably applied across the load current path and the diode. The rectifier device further includes a control circuit that is configured to switch on the first MOS transistor for an on-time period, during which the diode is forward biased. A stand-by detection circuit includes a cycle detection circuit configured to detect cycles of the alternating input voltage and a timer that is coupled to the cycle detection circuit. The timer is configured to be reset by the cycle detection circuit upon detection of a cycle of the alternating input voltage, and to disconnect a supply line of the control circuit unless reset before a maximum time span has elapsed.