TNY254GN-TL Datasheet, PDF (7/18 Pages) Power Integrations, Inc. – Energy Efficient, Low Power Off-line Switchers

TNY253/254/255
D1
1N4005
D2
1N4005
85 - 265
VAC
RF1
10 Ω
Fusible
C1
6.8 μF
400 V
D3
D4
1N4005 _1N4005
D5
T1
FR201
1
10
C4
R2
2200 pF
100 kΩ
1W
2
5
D6
C5
220 μF
25 V
1N4937
D
TinySwitch
EN
C2
4.7 μF
400 V
U1
BP
TNY254P
S
U2
LTV817
R7
100 Ω
R9
47 Ω
R3
Q1
22 Ω
R1
1.2 kΩ
C3
0.1 μF
2N3904
R5
18 Ω
1/8 W
L2
3.3 μH
C6
220 μF
16 V
R8
820 Ω
+ 5.2 V
RTN
VR1
1N5230B
4.7 V
L1
560 μH
C8
2.2 nF
Y1 Safety
R4
R6
1 Ω 0.82 Ω
1 W 1/2 W
Figure 11. 3.6 W Constant Voltage-Constant Current Cellular Phone Charger Circuit.
PI-2244-082898
D1
1N4004
D3
T1 ^1N3934
1
10
C6
100 μF
16V
5
6
+9V
VR1
1N5239B
RTN
115 VAC
± 15%
C1
2.2 μF
200 V
RF1
1.8 Ω
D2
1N4004
Fusible
C2
2.2 μF
200 V
R2
100 Ω
C4
68 pF
1 KV
D
TinySwitch
U1
TNY253P
S
EN
BP
C3
0.1 μF
C5
2.2 nF
Y1 Safety
Figure 12. 0.5 W Open Loop AC Adapter Circuit.
PI-2190-031501
Figure 11 shows a 5.2 V, 3.6 W cellular phone charger circuit
that uses the TNY254 and provides constant voltage and constant
current output over an universal input (85 to 265 VAC) range.
The AC input is rectified and filtered by D1 - D4, C1 and C2
to create a high-voltage DC bus connected to T1 in series with
the high-voltage MOSFET inside the TNY254.The inductor
L1 forms a π-filter in conjunction with C1 and C2.The resistor
R1 damps resonances in the inductor L1.The low frequency of
operation of TNY254 (44 kHz) allows use of the simple π-filter
described above in combination with a singleY1-capacitor C8
to meet worldwide conducted EMI standards.The diode D6,
capacitor C4 and resistor R2 comprise the clamp circuit that
limits the turn-off voltage spike on the TinySwitch DRAIN pin
to a safe value.The secondary winding is rectified and filtered
by D5 and C5 to provide the 5.2 V output.Additional filtering
is provided by L2 and C6.The output voltage is determined
by the sum of the optocoupler U2LED forward drop (~ 1 V)
and Zener diode VR1 voltage.The resistor R8, maintains a
bias current through the Zener to improve its voltage tolerance.
A simple constant current circuit is implemented using the V_BE
of transistor Q1 to sense the voltage across the current sense
resistor R4, which can be made up of one or more resistors to
Rev E
02/12
7