- more stringent load characteristic;
- the ability to control discrete digital signals;
- improved maintainability.
The launch of these power sources is a master oscillator (MO), usually in integrated circuit, performance. For the ZG it is necessary to provide initial power from some external source. Sometimes for this purpose, use the mains supply with a sequentially dividing capacitor, hereinafter - the rectifier, a smoothing capacitor and a Zener diode (Fig.1).
Fig.1
However, significant power consumed by the master oscillator, this is not an option, since the scheme as it freezes, increasing the voltage drop across the capacitor C1 and before reaching the supply voltage ZG determined by the Zener diode VD5. Increase in the capacity of C1 is not effective. The same power from ZG additional network transformer lowers the dignity circuit solutions pulse source.
Proposed for initial start-up, use a transformerless circuit with a storage capacitor and a diode-thyristor optocoupler (Fig.2).
In this embodiment, as compared with the circuit of Fig. 1, there is no "hang-up" schemes with a significant compatibiltiy ZG. Cumulative capacitor is the capacitance C2. It charges through C1 and the rectifier VD1...VD4 to a value determined by the Zener diode VD5. The efficiency of the storage capacitor even when a small value of capacitor C1 is ensured by the absence of current supply ZG, because dinistor the optocoupler is closed.
The selection of resistor R1 optoelectronic couple VU1 is configured as a voltage slightly lower East VD5. At the time of opening VU1 is formed powerful enough for the initial launch of the scheme ZG current pulse, depending on the energy storage capacitor. Further, the power supply is provided from the output voltage of the scorer Converter.
Diode VD6 is isolation, preventing shunting of the scheme is run by the output resistance of the power circuit of the Converter.
Authors: P. red'ko, I. Rusetsky, Novopolotsk; Publication: N. Bolshakov, rf.atnn.ru