Rev. C 09/12

9

TNY375-380

www.powerint.com

Key Application considerations

TinySwitch-PK Design Considerations

Output Power Table

Data sheet maximum output power table (Table 1) represents

the maximum practical continuous output power level that can

be obtained under the following assumed conditions:

1. The minimum DC input voltage is 100 V or higher for 85 VAC

input, or 220 V or higher for 230 VAC input or 115 VAC with

a voltage doubler. The value of the input capacitance should

be sized to meet these criteria for AC input designs.

2. Efficiency of 75%.

4. Transformer primary inductance tolerance of ±10%.

5. Reflected output voltage (V

6. Voltage only output of 12 V with an ultrafast PN rectifier diode.

7. Continuous conduction mode operation with transient K

value of 0.25.

8. Increased current limit is selected for peak and open frame

power columns and standard current limit for adapter

columns.

9. The part is board mounted with SOURCE pins soldered to

sufficient area of copper and/or a heat sink is used to keep

the SOURCE pin temperature at or below 110 °C for P and

G package and 100 °C for D packaged devices.

10. Ambient temperature of 50 °C for open frame designs and

40 °C for sealed adapters.

*K

Below a value of 1, K

current. A transient K

premature termination of switching cycles due to initial current

limit (I

power capability.

The values shown in Table 1 for peak power assume operation

in I

powers for each family member at all three selectable current

limit modes.

For both Table 1 and Table 2, the peak output power values are

differently, with sufficient heat sinking, these values could be

delivered indefinitely, but in most cases this would be

impractical. Adapter and open frame power values are

thermally limited and represent the practical continuous (or

average) output power in two common thermal environments.

Over Voltage Protection

The output overvoltage protection provided by TinySwitch-PK

uses an internal latch that is triggered by a threshold current of

approximately 7 mA into the BYPASS pin. In addition to an

internal filter, the BYPASS pin capacitor forms an external filter,

providing noise immunity from inadvertent triggering. For the

bypass capacitor to be effective as a high frequency filter, it

Peak Output Power Table

Product

230 VAC ± 15%

85-265 VAC

I

LIMIT-

PEAKred

I

LIMITPEAK

I

LIMIT-

PEAKinc

I

LIMIT-

PEAKred

I

LIMITPEAK

I

LIMIT-

PEAKinc

TNY375P/G/D

8.5 W

14.5 W 16.5 W

5.5 W

11.5 W 12.5 W

TNY376P/G/D

10 W

19 W

22 W

6 W

15 W

17 W

TNY377P/G

13 W

23 W

28 W

8 W

18 W

23 W

TNY378P/G

16 W

27.5 W

34 W

10 W

21.5 W

27 W

TNY379P/G

18 W

31.5 W

39 W

12 W

25 W

31 W

TNY380P/G

20 W

36 W

45 W

14 W

28 W

35 W

Table 2.

Peak Output Power Capability vs Current Limit Mode Selection.

U1

TNY380P

C1

10

µF

400 V

C2

22

µF

400 V

L1

1 mH

R1

1 k

Ω

R9

3.9 M

Ω

R5

47

Ω

1/8 W

R3

2 k

Ω

1/8 W

R4

20

Ω

R2

390

Ω

1/8 W

R6

21 k

Ω

1%

R10

3.9 M

Ω

C8

10 nF

1 kV

C7

1

µF

50 V

C3

1000

µF

16 V

C4

1000

µF

16 V

C5

220

µF

16 V

C6

10

µF

50 V

U2

PC817A

VR2

1N5251B, 22 V

VR1

BZX55B11

11 V, 2%

C9

2.2 nF

250 VAC

R7

22

Ω

1/2 W

F1

3.15 A

185 - 265

VAC

+12 V

RTN

L

N

D1

1N4007

D2

1N4007

D7

UF4007

D5

SB560

VR3

P6KE170A

D6

UF4004

D3

1N4007

D4

1N4007

PI-4674-012009

T1

EFD25

9,10

1

3

6,7,8

5

2

D

S

EN/UV

BP

TinySwitch-PK

L2

3.3

µH

Figure 15. Single 230 VAC Input 20 W Continuous and 45 W Peak Power Supply Using TNY380PN.