Fluorescent lamp electronic ballast circuit 2

(2) Fluorescent lamp electronic ballast circuit 2
    DZJ series electronic ballasts include 13W, 15W, 20W, 30W, 40W, etc. The circuit is shown in Figure 2-12.
The values ​​marked in the figure are the component parameters of the 30W electronic ballast .
    The circuit consists of a rectifier filter circuit (VC, Cl), a high-frequency oscillation switching circuit (Ri, C4, VDz, VTi, VT2
and T) and an output load resonant circuit (L, C6). C5 is an anti-interference capacitor.
    In Figure 2-12, capacitor C2 plays the role of DC blocking; diodes VDa and VD4 play the role of voltage peak damping to prevent
the early ends of the lamp from blackening; the frequency of the resonant circuit is mainly determined by the inductor L and capacitor C6, and the oscillation frequency is 30~ 60kHz.
C5 and W3 also have a certain impact on frequency.
    The high back pressure switches VTi and VTz need to be paired and require BVCe. >400V, BVcb. >500v, and the breakdown characteristic curve
should be hard breakdown; p>7 (test conditions: base current is 0.2A); saturation voltage drop BV of the tube. . . ≤1.5V.