Power Integrations reserves the right to make changes to its products at any time to improve reliability or

manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit

described herein. POWER INTEGRATIONS MAKES NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL

WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS

FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. The products and applications

illustrated herein (transformer construction and circuits external to the products) may be covered by one or more U.S.

and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A

complete list of Power Integrations' patents may be found at

www.powerint.com. Power Integrations grants its

customers a license under certain patent rights as set forth at http://www.powerint.com/ip.htm.

The PI logo,

TOPSwitch, TinySwitch, LinkSwitch, DPA-Switch, PeakSwitch, EcoSmart,

Clampless, E-Shield, Filterfuse, StackFET, PI Expert and PI FACTS are trademarks of Power

Integrations, Inc. Other trademarks are property of their respective companies. ©Copyright 2006, Power Integrations, Inc.

For the latest updates, visit

www.powerint.com

Rev. A 11/06

Power Integrations

5245 Hellyer Avenue

San Jose, CA 95138

Phone: 1-408-414-9200

Apps: 1-408-414-9660

Apps Fax: 1-408-414-9760

For a complete listing of worldwide

sales offices, please visit

www.powerint.com

function within U1, a shield winding in T1, and two small

Y-capacitors (C10 and C19) across T1 reduce the generation of

conducted EMI so that a single common mode choke (L1), a

small X-capacitor (C3) and two smallY-capacitors (C1 and C2)

attheinputallowthesupplytomeetEN55022Blimitswithmore

than 12 dBµV of margin. A combination RCD-Zener clamp

(R3, C5, D6 and VR1) limits the peak drain-node voltage to

below the 700 V rating of the integrated MOSFET.

If JP3 is removed, an external variable resistor (R20) adjusts

the voltage across R12 and therefore, the output voltage.

The externally supplied motor speed regulating voltage

(3.6to10VDC)changesthevoltageatthenodeofR12andVR2,

which effectively adjusts the output voltage. Diode D12 blocks

reverse current flow through R19 if the external adjustment

voltage is less than about 3.6 VDC.

Key Design Points

• The externally supplied voltage adjusts the motor speed as

follows: ≤3.6 V sets the output voltage to about 12 V (the

highest motor speed) and ≥7 V sets the output voltage to

about 2 V (the lowest motor speed).

• If the resistive speed control circuit is to be used, jumper

J3 must be removed from the PCB.

Figure 3. Conducted EMI: 230 VAC in, I

Figure 2. Efficiency Across Extended Motor Load Range.

• If the motor is stopped externally for more than

30 ms, U1ʼs latching shutdown function activates, and

MOSFET switching latches off until AC input power

is removed and reapplied. If latching shutdown is not

needed,thefunctioncanbedisabledandthepartscount

reduced by not installing D5, C7, R5 and R6.

1

5

3

8

10 15

30 35

25

20

50

40

Output Power (W)

100

80

60

40

20

0

1.0

0.15

10.0

100.0

-20

-10

0

10

20

30

40

50

60

80

70

MHz

QP

AV

QP

AV

Table 1. Transformer Design Parameters.

TIW = Triple Insulated Wire, NC = No Connect, FL = Flying Lead

TRANSFORMER PARAMETERS

Core Material

PC40EE25-Z

Bobbin

EE25 Vertical

Winding Details

1/2 Primary: 19T, 2

× 31 AWG

Bias: 5T, 2

×29 AWG

Secondary: 4T, 4

×23 AWG

Shield: 7T, 4

×23 AWG

1/2 Primary: 19T, 2

× 31 AWG

Winding Order

(pin numbers)

1/2 Primary (1-3), Bias (4-5),

Secondary (7,8-9, 10), Shield

(1-NC), 1/2 Primary (3-2)

Inductance

145

µH

Leakage

Inductance

5.4

µH

Primary Resonant

Frequency

3.4 MHz (minimum)