269 results about "Ring circuit" patented technology

The invention provides a method and a device for processing the internet group management protocol (IGMP) messages, and enables a port in a blocked state to treat IGMP messages in advance, wherein, the method comprises the following steps: when receiving or sending an IGMP message through the port in a blocked state, a switch determinates whether a list item including the IGMP message information exists in an IGMP message list arranged corresponding to the port or not; if no, the list item including the IGMP message information is established in the IGMP message list arranged corresponding to the port, the IGMP message is forwarded; and when the IGMP message is an IGMP adding message, the IGMP message is utilized to establish and forward the list item; if yes, the IGMP message is discarded. The invention can shorten the time of interrupting multicast stream after switching a link circuit, and avoid the broadcast caused by the ring circuit of the IGMP messages.

The invention discloses an insulated gate bipolar translator (IGBT) series connection type high-voltage pulse generator. The voltage is provided for the high-voltage pulse generator by a high-voltage power supply, and after the energy storage of an energy storage capacitor, high-voltage pulses are generated through a multistage IGBT series connection circuit. A programmable logic controller (PLC) generates pulse-width modulation (PWM) control pulses, the PWM control pulses are input into an optical fiber isolation circuit after passing through a PWM amplification circuit, further, the IGBT series connection circuit is driven, and the power supply required by the work of the IGBT series connection circuit is provided by a secondary circuit of the isolation power supply connected with the IGBT series connection circuit. Commercial electricity is changed into direct current through a rectifying circuit and a filter circuit, the direct current is changed into high-frequency square waves through a high-frequency power metal-oxide-semiconductor field-effect transistor (MOSFET) full-bridge inverter circuit driven by a power MOSFET driving circuit, and the high-frequency square waves are input into the secondary circuit of the isolation power supply after being isolated by a series connection magnetic ring circuit. When the IGBT series connection circuit generates faults, fault signals are input into the PLC through a fault output circuit and an optical fiber feedback circuit, the PLC interrupts control signals so that the IGBT series connection circuit is in a switch-off state, and the whole system is further protected.

The invention relates to a whole-course adjustable digital pulse width modulator based on an oscillation ring circuit, which comprises an oscillation ring-counting comparator circuit and an output logic circuit, wherein the oscillation ring circuit is formed by connecting K stages of D triggers end to end and used for generating a reset signal required by the D trigger and output by the output logic circuit together with a multi-channel gating device and the counting comparator circuit according to an digital duty cycle control signal externally input, thereby resetting an output signal of the output D trigger to a low level; and the clock end of the output D trigger is used for controlling a high level at the input end to be transferred to the output end, and the reset signal and a clock signal act jointly for finally generating a duty cycle signal at the output end. The whole-course adjustable digital pulse width modulator can not only keep the advantages of a conventional oscillation ring structure digital pulse width modulator, but also enlarge the adjustable range of output duty cycle, thereby being very applicable to being integrated in high-frequency DC(direct current)-DC switching mode power supplies (SMPS) in power supply management systems of miniature handheld devices.