AN2528 datasheet(11/21 Pages) STMICROELECTRONICS

Part #	AN2528

Description	Very wide input voltage range 6 W SMPS for metering

PDF	21 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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11 / 21 page

AN2528

Experimental results: waveforms

11/21

Ten is big enough to remove any ringing and the additional power dissipation on it is

practically negligible due to the very low current flowing through it. Finally, knowing that Vcc

is about 15 V:

Equation 14

After bench verification a final RCC of 2.2 kΩ has been fixed. A smaller base current than the

forecasted one flows into the base (higher IC/IB ratio) compensated by a higher base current

during the peak (much lower IC/IB ratio for a very short time).

Experimental results: waveforms

The following figures show the main waveforms in steady state condition at full load. Notice

the behavior of the base current with an initial high peak pulse needed to minimize the effect

of the dynamic saturation voltage.

Figure 7.

110 Vac input voltage overall1

Figure 8.

110 Vac input voltage overall2

15V

12.5mA

---------------------

1.2K

Ω

AN2528 Datasheet(PDF) 11 Page - STMicroelectronics