Electronic energy-saving lamp circuit (3)

Figure 289 is an electronic front-end desk lamp made using VK05CIl. ASIC produced by STMicroelectronics (ST)
, which can light up 5-15W low-power compact fluorescent lamps (FL).
    VK05cFI. It is
an integrated external device composed of a bipolar high-voltage composite transistor and a low-voltage IOSFF.T specially designed to drive o~23W low-power compact fluorescent lamps. Its maximum operating frequency is 200kHz.
The power device has a current collector and a source. The high voltage between them is 520V, and the rated collector current is 250mA. It adopts an 8
-pin s() package. The ⑤, ⑥, ⑦, and ⑧ pins are the collectors of NPN high-voltage composite transistors, and the ① pin is
the low-voltage power M(JSFFT source, that is, the emitter of the high-voltage composite transistor. In the device It also integrates bidirectional
trigger = tube DJA (1 and other components.
    In addition, VD1 ~ VD4 are bridge rectifier circuits. C, and L. form a filter, R., (j and A2 pin
②, ③ internal The connected general diode DJAC forms a starting circuit, two VK05CFI. and transformer T
and other components form a half-bridge inverter circuit, L. and cl(, form a series resonant circuit (before the lamp starts,
the resistance value of is small , it can be considered that the current does not pass through (1.,). The high-frequency current passes through RT to preheat the lamp. After about 07-12s
, the RT temperature rises to the Curie point and immediately exhibits high resistance exhaustion. Streaming G The current passes through (1,,,, causing /
and G, etc. to resonate in the series circuit composed of C, 1, and G. 7 generates high-voltage pulses to make the lamp F light up quickly.
The normal operation of the lamp is called I. It can stabilize the flow.
    The transformer T is made of F5 type ferrite core and ≠Zmm high-strength polyester enameled wire, ,
. Pad 0 3mn1 kraft paper, the specific company
is selected through experiments. RT uses RTC, thermistor, such as M21113, M2fi4, etc. The circuit is suitable for _ Dingj-ljw
low-power compact fluorescent desk lamp, if using o-23W low-power Compact fluorescent lamp. L needs to
change R, R from the original 2 2kn to ikC!; change C., C. to I (JOOpF, and the L. turns of the appropriate small
transformer