28V overvoltage surge suppression circuit

Abstract

The invention belongs to the technical field of power supplies, and relates to a 28V overvoltage surge suppression circuit. Comprising a field effect transistor, a voltage stabilizing tube, a linear optocoupler, a precise voltage stabilizing source, a filter capacitor, a divider resistor, an integrating capacitor and a current limiting resistor. The 28V overvoltage surge suppression circuit can adjust voltages at two ends of a grid electrode and a drain electrode of a field effect transistor by utilizing different conduction impedances when the field effect transistor is not completely conducted when an overvoltage surge occurs at a 28V input end, so that the purpose of adjusting the voltages at two ends of a source electrode and a drain electrode of the field effect transistor is achieved, and the stability of an output voltage is further ensured; the circuit is reasonable in design, small in size and few in used components, the used components are conventional components such as conventional field effect transistors, resistors, capacitors, linear optocouplers, voltage-regulator tubes and precise voltage-regulator sources, complex IC integrated chips are not needed, and the circuit is high in reliability, high in practicability and convenient to popularize and use.

Description

technical field [0001] The invention belongs to the technical field of power supplies and relates to a 28V overvoltage surge suppression circuit. Background technique [0002] Aircraft power supply systems are divided into AC and DC power supply systems. Due to normal disturbances caused by changes in electrical load or engine speed, changes in voltage are voltage surges, and electrical equipment must have the ability to withstand voltage surges. [0003] According to the requirements of GJB181-86 "Aircraft Power Supply Characteristics and Requirements for Electrical Equipment" on DC 28V electrical equipment "electrical equipment should withstand five overvoltage surges, and the time interval between two overvoltage surges is 1 minutes. The method of each overvoltage surge is as follows: firstly, the electrical equipment supplies power under the normal steady-state voltage, and then the input voltage of the electrical equipment is increased to 80V, and the duration is 50 mil...

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Problems solved by technology

[0006] The above method 1 has a large number of transient suppression diodes used, large volume, large surge instantaneous power, and heat dissipation design is required, which is difficult to meet the requirements of miniaturization of airborne equipment; the circuit of the above method 2 needs to be closed-loop design, the circuit is complex, and the inductor volume , heavy weight, suitable for medium and high power occasions, and is also not conducive to the requirements of equipment miniaturization; the response speed of the circuit system in the above method 3 is slow, and there is a problem of large output voltage ripple; the circuit composition of the above method 4 is relatively complicated, higher cost

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