TOP221 Ver la hoja de datos (PDF) - Power Integrations, Inc
Número de pieza
componentes Descripción
Fabricante
TOP221 Datasheet PDF : 20 Pages
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TOP221-227
VR1
P6KE200
L2
22 mH
BR1
400 V
C1
D1
BYV26C
47 µF
C6
0.1 µF
250 VAC
400 V
TOPSwitch-II
D
U1
TOP224P
T1
CONTROL
C
F1
J1 3.15 A
L
R3
S
6.8 Ω
C5
47 µF
N
Figure 8. Schematic Diagram of a 20 W Universal Input TOPSwitch-II Power Supply using an 8 lead PDIP.
D2
MUR420
C2
330 µF
35 V
L1
3.3 µH
C3
220 µF
35 V
D3
1N4148
C4
0.1 µF
R1
100 Ω
U2
PC817A
R2
220 Ω
C7
1 nF
250 VAC
Y1
VR2
1N5241B
11 V
+12 V
RTN
PI-2019-033197
20 W Universal Supply using 8 Lead PDIP
Figure 8 shows a 12 V, 20 W secondary regulated flyback
power supply using the TOP224P in an eight lead PDIP
package and operating from universal 85 to 265 VAC input
voltage. This example demonstrates the advantage of the
higher power 8 pin leadframe used with the TOPSwitch-II
family. This low cost package transfers heat directly to the
board through six source pins, eliminating the heatsink and
the associated cost. Efficiency is typically 80% at low line
input. Output voltage is directly sensed by optocoupler U2
and Zener diode VR2. The output voltage is determined by
the Zener diode (VR2) voltage and the voltage drops across
the optocoupler (U2) LED and resistor R1. Other output
voltages are possible by adjusting the transformer turns ratio
and value of Zener diode VR2.
AC power is rectified and filtered by BR1 and C1 to create
the high voltage DC bus applied to the primary winding of
T1. The other side of the transformer primary is driven by
the integrated TOPSwitch-II high-voltage MOSFET. D1 and
VR1 clamp leading-edge voltage spikes caused by trans-
former leakage inductance. The power secondary winding
is rectified and filtered by D2, C2, L1, and C3 to create the
12 V output voltage. R2 and VR2 provide a slight pre-load
on the 12 V output to improve load regulation at light loads.
The bias winding is rectified and filtered by D3 and C4 to
create a TOPSwitch bias voltage. L2 and Y1-safety capaci-
tor C7 attenuate common mode emission currents caused
by high-voltage switching waveforms on the DRAIN side of
the primary winding and the primary to secondary capaci-
tance. Leakage inductance of L2 with C1 and C6 attenu-
ates differential-mode emission currents caused by the
fundamental and harmonics of the trapezoidal or triangular
primary current waveform. C5 filters internal MOSFET gate
drive charge current spikes on the CONTROL pin, deter-
mines the auto-restart frequency, and together with R1 and
R3, compensates the control loop.
www.power.com
7
Rev. G 08/16
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