Low-impact-current high-power-factor energy storage type countdown display circuit

Abstract

The invention provides a low-impact-current high-power-factor energy storage type countdown display circuit which comprises a signal lamp electricity-taking rectifying circuit, an isolation sampling circuit, an AC-DC switching power supply circuit, a DC-DC direct current voltage-reducing circuit, a MCU control circuit and an LED matrix display module. The input end of the signal lamp electricity-taking rectifying circuit is connected with a red signal lamp power supply, a green signal lamp power supply and a common port, and the positive output end of the signal lamp electricity-taking rectifying circuit is connected with the input end of the AC-DC switching power supply circuit. An energy storage capacitor is connected between the output end of the AC-DC switching power supply circuit and the ground in parallel. The output end of the AC-DC switching power supply circuit is connected with the DC-DC direct current voltage-reducing circuit. The DC-DC direct current voltage-reducing circuit reduces direct-current voltage output by the AC-DC switching power supply circuit and supplies power for the MCU control circuit and the LED matrix display module. The MCU control circuit is connected with the red signal lamp power supply, the green signal lamp power supply and the common port through the isolation sampling circuit.

Description

technical field [0001] The invention relates to a signal lamp countdown circuit, in particular to an energy storage type countdown display circuit with low impact current and high power factor. Background technique [0002] With the continuous expansion of city scale and the increase of roads and motor vehicles, the technological level of road traffic management is also constantly improving. Among them, the signal control of road intersections has become one of its important means. The amount and presentation method of , both for pedestrians and motor vehicle drivers, have a very important intuitive meaning. The countdown display plays an important role at traffic intersections. It can display the remaining time of traffic lights in a timely and accurate manner. Vehicle drivers can prepare for passing or stopping in advance by observing the countdown display, so as to pass the intersection quickly and safely. Thereby ensuring safe and smooth road traffic. The countdown dis...

AI Technical Summary

Problems solved by technology

However, placing a large energy storage capacitor in the primary will bring a series of adverse consequences, such as reducing the power factor of the switching power supply, and there will be a large inrush current when the countdown starts. The large inrush current will cause the air switch to protect the traffic signal when it is started.

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