ST AN1132 Application note

AN1132

®

APPLICATION NOTE

90W SMPS FOR MONITORS WITH STANDBY FUNCTION

by Claudio Adragna

Purpose of this note is to provide a brief summary of the specifications and the functionality of the ap­plication board implementing a 90W multioutput SMPS for monitors, based on t he L5991, current
mode PWM controller.

Evaluation results are also presented so as to underline the benefits offered by the L5991 in such a
new generation of SMPS that r equires a superior ef ficiency in standby conditions, aim ing at compli­ance with energy saving standards.

Design Specifications

Table 1 summarises the electrical specification of the applic ation. The complete electrical schematic is
shown in fig. 1 and the bill of material is listed in Table 2.

Table 1. Design Specification

Input Voltage Range (Vin) 88 to 264 Vac
Mains Frequency (fL) 50/60 Hz
Maximum Output Power (P

Outputs

Switching Frequency in Normal Mode (f
Switching Frequency in Suspend / OFF mode (fSB) 18kHz
Target Efficiency (@ Pout =90W, Vin =88 ÷264 Vac) (η) > 80%
Maximum Input Power (@ Pout = 0.5 W, Vin =88 ÷ 264 Vac)

) 90W

out

Horizontal Deflection

Video Amplifier

Vertical Deflection

Heater

) 40kHz

osc

V

I

out

Full load ripple = 1%

V

I

out

Full load ripple = 1%

V
I

out

Full load ripple = 1%

V

I

Full load ripple = 2%

= 200V

out

= 0.325A

= 80V

out

= 0.125A

= ±15V

out

= 0.33A

= 6.3V

out

= 0.8A

out

2W

≤

The selected topology is flyback. The operation mode (@ Pout = 90W ) is CCM (Continuous Conduction
Mode) at low mains voltage, DCM (Discontinuous Conduction Mode) at high mains voltage. This design
choice relieves the stress on the power components at low mains voltage, compared with a full DCM so­lution.

The application will benefit from the features of the L5991 PWM controller in order to minimise the power
drawn from the mains under light load conditions: low start-up and quiescent currents, and Standby
function.

September 2000

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AN1132 APPLICATION NOTE

Figure 1. Electrical Schematic.

200V

D07 BYT11-800
18

1

C01 4700pF 4KV C02

R31 4.7M R32 4.7M

65W

H1 1µH

D08 STTA106

17

C10

47nF

250V

3W

47K

R21

80V

10W

C14

C13

16

C15

22µF 100V

250V

100µF

100V

220µF

R23 C12

D06

STTA106

6.3V

GND

D9 BYW100-100

151314

4

7

D05 1N4148

5W

C16

1000µF

R22 22

16V

8T1

5W

+15V

C17

C18

470µF 25V

470µF 25V

D10 BYW100-100

111210

R12 22

C04 47µF

5W

-15V

47

R24

D11 BYW100-100

MF01

STP7NB60FI

R13 1K

C05

C19

R25R26

R15

R14

100pF

47µF 25V

2.7K

71

0.47

0.47
R16 100

VR1

C20

100K

C08

R27 470K

2

3.3nF

R30

R29

330K

1nF

C22

C21

330pF

4

6

R28

3

OP1

TPS5904

D99IN1070B

4.7K

2/12

RP1

F01

R01

KBU4G

C03 220µF

VAC

88 to 264

400V

D01

R03 56K

R02 56K

1N4148

R08 330KR07 47K

R09 22

C23 10nF

C09 56nF

8

10

13

12

91415

IC1

L5991

2

7

4

3

R34

4.7K
12K

R20

C06

C07 0.1µF

11

Q3

R19

6800pF

6

16

BC337

10K

5

R33

9.1K

Table 2. Compone nt List of the circ uit of fig. 1.

Symbol Value Note

R1 NOT USED (shorted)

R2, R3 56k

R7 47k

R8, R29 330k

R9, R12, R22 22

R13 1k

R14, R15 0.47

R16 100
R19 10k
R20 12k
R21 47k
R24 47
R26 2.7k
R27 470k
R28 4.7k

R31, R32 4.7M

R33 9.1k
VR1 100k

C1, C2 4.7nF 1kV

C3 220µF 400V, electrolytic, Panasonic TSUP or Roederstein EYS

C4, C19 47µF 25 V, electrolytic

C5 100pF plastic film
C6 6.8nF ceramic multilayer
C7 100nF plastic film
C8 3.3nF plastic film

C9 56nF plastic film
C10 47nF 250V, polypropylene o polystyrene film (Siemens-Matsushita)
C13 220µF 100 V electrolytic, Roederstein EKE or equivalent
C14 100µF 250 V, electrolytic, Roederstein EKS or equivalent
C15 22µF 100 V, electrolytic, Roederstein EKE or equivalent
C16 1000µF 16V, electrolytic, Panasonic FA or equivalent

C17, C18 470µF 25 V, electrolytic, Panasonic HFZ or equivalent

C21 330pF ceramic or plastic film
C22 1nF ceramic or plastic film
C23 10nF plastic film

D1, D5 1N4148
D6, D8 STTA106 ST, TurboSwitch

D7 BYT11-800 ST, Ultrafast

D9, D10, D11 BYW100-100 ST, Ultrafast

IC1 L5991 ST

T1 ETD4407 ITACOIL, see Table 3

OP1 TPS5904 TI
MF1 STP7NB60FI ST
RP1 KBU4G GI, or equivalent 4A rectifier bridge

Q3 BC337

F1 5A fuse

H1 1µH axial inductor

M1, M2, M3 connectors

Notes

: - if not otherwise specified, all resistors are 1/4 W, 1%

- the MOSFET is provided with a 9.5 °C/W heatsink

- components indicated in the PCB and not quoted in table 2 are not assembled

Ω
Ω

Ω
Ω
Ω

Ω

metallic film

Ω
Ω
Ω
Ω

3W

Ω

Ω

Ω

Ω

Ω

Ω

Ω

multiturns, Bourns 3296W or equivalent

AN1132 APPLICATION NOTE

3/12

AN1132 APPLICATION NOTE

Table 3. Transformer Specification (Part Number ETD4407, supplied by ITACOIL).

Core Philips ETD44, 3C85 Material
Bobbin Horizontal mounting, 18 pins
Air gap

Leakage inductance < 10µH

Winding Wire S-F Turns Notes

Pri1 4xAWG29 2-4 19

Sec1 AWG25 17-18 48

Windings

Spec & Build

Sec2 AWG25 15-16 32
Sec3 AWG25 13-14 3 Evenly spaced
Sec4 AWG25 11-12 6 Bifiliar with Sec5
Sec5 AWG26 10-11 6 Bifiliar with Sec4

Pri2 4xAWG29 1-2 19
Aux AWG29 8-7 8 Evenly spaced

Figure 2. PCB layout: Component side and bottom layer (top view); 1:1.33 scale

1 mm for an inductance 1-4 of 380 µH

≅

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