When a four-diode bridge rectifier is in operation, two of the four diodes are conducting at all times, resulting in continuous conduction losses through the bridge diodes that manifests itself in the form of waste heat. The generation of waste heat, in turn, typically necessitates the use of fans and large heat sinks to provide forced convection cooling of the converter.
Diode conduction losses and the power used to operate the convection fans waste energy that could conserve or power other systems.
Many electronic devices, such as laser printers and laser copy machines, operate at or near their maximum power limit allowed by a single power cord and standard 15-ampere receptacle, requiring two power cords if this limit is exceeded. Environmental Protection Agency “low power limit” requirements are also becoming increasingly difficult to satisfy.
Electronic devices, including Laser Copy Machine printers and copiers, would benefit from a more efficient primary AC-to-DC conversion process that conserves energy, requires less space, and eliminates the need for heat sinks and forced convection cooling to remove waste heat.
The present invention introduces a synchronous full-wave AC rectifier designed for connection to an AC voltage source. In one embodiment, this synchronous rectifier features a full-wave diode bridge composed of four bridge diodes. Each bridge diode has a power switch connected in parallel, and every power switch includes a control gate.
Laser Copy Machine has A dedicated power switch control circuit also connects in parallel with each bridge diode.
This control circuit generates a first control voltage to activate its power switch when the bridge diode becomes forward biased.
Conversely, it generates a second control voltage that deactivates the power switch when the bridge diode reverses bias.
Synchronized control circuits ensure power switches turn on and off with the AC source, efficiently producing a full-wave rectified output.
In a second embodiment, the synchronous rectifier features a full-wave diode bridge consisting of four bridge diodes. Each power switch pairs with a bridge diode connected in parallel and equips a control gate. A comparator circuit links to each bridge diode and its corresponding power switch control gate. These comparator circuits compare the voltage across the bridge diode to a reference voltage. When the voltage exceeds the reference level, the comparator sends a first control voltage to activate the power switch. If the voltage drops below the reference, the comparator sends a control voltage to turn off the power switch. Additionally, three charge pump circuits supply the necessary biasing voltage to the comparator circuits. This setup synchronizes power switches with the AC source, ensuring a reliable full-wave rectified output.
The invention offers a method to produce a full-wave rectified AC output from an AC voltage source.
The method involves receiving the AC voltage and applying it to a four-diode full-wave rectifier.