TNY289KG データシートの表示（PDF） - Power Integrations, Inc

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TNY289KG

Energy-Effcient, Off-Line Switcher With Line Compensated Overload Power

Power Integrations, Inc 

TNY284-290

BR1

2KBP10M

1000 V

L1

10 mH

RT1

6Ω

C1

100 nF

F1 275 VAC

5A

90 - 295

VAC

C2

68 µF

450 V

C3

2.2 nF

1 kV

VR1

P6KE150A

R12

2 MΩ

R13

2 MΩ

R1

22 Ω

1/2 W

D1

UF4006-E3

D

TinySwitch-4

U1

TNY290PG

S

EN/UV

BP/M

C16

100 nF

100 V

C13

2.2 nF

250 VAC

1 9,10

R3 C5

4.7 Ω 1.5 nF

1/2 W 100 V

C6, C7

1500 µF

10 V

D4

STPS30L60CT

7,8

4

3

5

T1

EE22

R15

1.5 MΩ

1/8 W

D3

1N4937

R2

8.2 Ω

C4

100 µF

50 V

VR2

1N5254

27 V

R4

30 kΩ

1/8 W

C9

10 µF

16 V

U3

PC817

C11

2.2 µF

50 V

C8

1000 µF

10 V

L2

2.2 µH

R9

47 Ω

R6

10 kΩ

1%

5 V, 4 A

RTN

R8

1 kΩ

1/8 W

R14 C10

3.3 kΩ 47 nF

1/8 W 100 V

U2

TL431

R7

10 kΩ

1%

PI-6559-062012

In a PC standby application input stage

will be part of main power supply input

Figure 16. TNY290PG, 5 V, 4 A Universal Input Power Supply.

Applications Example

The circuit shown in Figure 16 is a low cost, high efficiency,

flyback power supply designed for 5 V, 4 A output from

universal input using the TNY290PG.

The supply features undervoltage lockout, primary sensed

output overvoltage latching shutdown protection, high

efficiency (>80%), and very low no-load consumption (<50 mW

at 265 VAC). Output regulation is accomplished using a simple

Zener reference and optocoupler feedback.

The rectified and filtered input voltage is applied to the primary

winding of T1. The other side of the transformer primary is

driven by the integrated MOSFET in U1. Diode D1, C3, R1, and

VR1 comprise the clamp circuit, limiting the leakage inductance

turn-off voltage spike on the DRAIN pin to a safe value.

The output voltage is regulated by TL431 U2. When the output

voltage ripple exceeds the sum of the U2 (CATHODE D6) and

optocoupler LED forward drop, current will flow in the

optocoupler LED. This will cause the transistor of the

optocoupler to sink current. When this current exceeds the

ENABLE pin threshold current the next switching cycle is

inhibited. When the output voltage falls below the feedback

threshold, a conduction cycle is allowed to occur and, by

adjusting the number of enabled cycles, output regulation is

maintained. As the load reduces, the number of enabled

cycles decreases, lowering the effective switching frequency

and scaling switching losses with load. This provides almost

constant efficiency down to very light loads, ideal for meeting

energy efficiency requirements.

As the TinySwitch-4 devices are completely self-powered, there

is no requirement for an auxiliary or bias winding on the

transformer. However by adding a bias winding, the output

overvoltage protection feature can be configured, protecting the

load against open feedback loop faults.

When an overvoltage condition occurs, such that bias voltage

exceeds the sum of VR2 and the BYPASS/MULTIFUNCTION

(BYPASS/MULTI-FUNCTIONAL) pin voltage, current begins to

flow into the BYPASS/MULTI-FUNCTIONAL pin. When this

current exceeds ISD the internal latching shutdown circuit in

TinySwitch-4 is activated. This condition is reset when the

ENABLE/UNDERVOLTAGE pin current flowing through R12 and

R13 drop below 18.75 mA each AC line half-cycle. The

configuration of Figure 16 is therefore non-latching for an

overvoltage fault. Latching overvoltage protection can be

achieved by connecting R12 and R13 to the positive terminal of

C2, at the expense of higher standby consumption. In the

example shown, on opening the loop, the OVP trips at an

output of 17 V.

For lower no-load input power consumption, the bias winding

may also be used to supply the TinySwitch-4 device. Resistor

8

Rev. A 09/12

www.powerint.com

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