ST AN3290 Application note

AN3290

Application Note

Reference design for double output SMPS for power line modem applications using ALTAIR04-900 primary controller

Introduction

This application note introduces a new “all-primary sensing” switching regulator ALTAIR04900, used to build an innovative solution to supply a power line communication.

A demonstration board, implementing a wide-range double-output power supply, has been developed and the results of its bench evaluation are reported in this document.

The board uses the new ALTAIR04-900, a quasi-resonant (QR) current-mode controller IC specifically designed for QR ZVS (zero voltage switching at switch turn-on) flyback converters, which combines a high-performance low-voltage PWM controller chip and a typical 16 RDSon, 900 V, avalanche-rugged power MOSFET in the same package.

The device is capable of providing constant output voltage regulation using primary-sensing constant voltage loop (CV loop). This eliminates the need for the optocoupler and the secondary voltage reference while still maintaining quite accurate regulation.

Also, using the primary constant current loop (CC loop), it is possible to set the maximum deliverable output current without any secondary components or current sensor.

April 2011

Doc ID 18038 Rev 1

1/34

www.st.com

Contents	AN3290

Contents

1	Test board design and evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 5
2	Output voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		11
3	Efficiency and no load measurements . . . . . . . . . . . . . . . . . . . . . . . . .		12
4	Typical board waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		13
5	Protection features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		20
	5.1	Overload and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . .	20
	5.2	Auxiliary winding disconnection (brownout) . . . . . . . . . . . . . . . . . . . . . . .	22

5.3Secondary winding short-circuit and transformer saturation protection . . 23

6	Conducted noise measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
7	Modifications for ultra wide-range operations . . . . . . . . . . . . . . . . . . .	29
8	Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	31
9	Demonstration tools and documentation . . . . . . . . . . . . . . . . . . . . . . .	32
10	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	33

2/34	Doc ID 18038 Rev 1

AN3290	List of Tables

List of Tables

Table 1. ALTAIR04-900 power supply: electrical specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Table 2. ALTAIR04-900 power supply - bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 3. ALTAIR04-900 power supply: transformer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 10 Table 4. ALTAIR04-900 power supply: bill of material for 440 VAC input voltage option. . . . . . . . . 30 Table 5. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Doc ID 18038 Rev 1

3/34

List of figures	AN3290

List of figures

Figure 1. Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 2. PCB: component side (not to scale) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 3. Demonstration board image: power supply board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 4. Demonstration board image: complete (power supply and PLM boards). . . . . . . . . . . . . . . 8 Figure 5. ALTAIR04-900 power supply: transformer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 6. Output voltage characteristics with 3V3 @ 40 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 7. Output voltage characteristics with 3V3 @ 80 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 8. Efficiency vs. output power with 3V3 @ 40 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 9. Efficiency vs. output power with 3V3 @ 80 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 10. Normal operations in TX mode at 85 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 11. Normal operations in TX mode at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 12. Normal operations in TX mode at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 13. Normal operations in TX mode at 264 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 14. Normal operation in TX mode at 85 VAC and IOUT2=40 mA . . . . . . . . . . . . . . . . . . . . . . 15 Figure 15. Normal operation in TX mode at 85 VAC and IOUT2=80 mA . . . . . . . . . . . . . . . . . . . . . . 16 Figure 16. Normal operation in TX mode at 115 VAC and IOUT2=40 mA . . . . . . . . . . . . . . . . . . . . . 16 Figure 17. Normal operation in TX mode at 115 VAC and IOUT2=80 mA . . . . . . . . . . . . . . . . . . . . . 17 Figure 18. Normal operation in TX mode at 230 VAC and IOUT2=40 mA . . . . . . . . . . . . . . . . . . . . . 17 Figure 19. Normal operation in TX mode at 230 VAC and IOUT2=80 mA . . . . . . . . . . . . . . . . . . . . . 18 Figure 20. Normal operation in TX mode at 264 VAC and IOUT2=40 mA . . . . . . . . . . . . . . . . . . . . . 18 Figure 21. Normal operation in TX mode at 264 VAC and IOUT2=80 mA . . . . . . . . . . . . . . . . . . . . . 19 Figure 22. Short-circuit mode: 13 V shorted at 115 VAC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 23. Short-circuit mode: 13 V shorted at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Figure 24. Brownout protection activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Figure 25. Hiccup mode OCP: protection tripping at VIN=115 VAC and full load . . . . . . . . . . . . . . . . 23 Figure 26. Hiccup mode OCP: protection tripping at VIN=230 VAC and full load . . . . . . . . . . . . . . . . 24 Figure 27. Hiccup mode OCP: operating condition at VIN=115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . 24 Figure 28. Hiccup mode OCP: operating condition at VIN=230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . 25 Figure 29. CE average measurement at 115 VAC and full load: line . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 30. CE average measurement at 115 VAC and full load: neutral . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 31. CE average measurement at 230 VAC and full load: line . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 32. CE average measurement at 230 VAC and full load: neutral . . . . . . . . . . . . . . . . . . . . . . . 28 Figure 33. Electrical schematic for 440 VAC input voltage option . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4/34	Doc ID 18038 Rev 1

AN3290	Test board design and evaluation

1 Test board design and evaluation

As a reference design, a 7.48 W nameplate output power SMPS has been specifically designed and developed according to the specifications for a complete power line communication based on ST7580 (by STMicroelectronics).

The power supply provides a 13 V output voltage to supply the power line modem (PLM) and the analog circuitry, and a post-regulated 3.3 V to supply digital circuitry and an optional external microcontroller.

Table 1 summarizes the electrical specifications of the power supply, Table 2 provides the bill of material and Table 3 lists the transformer specifications. The electrical schematic is shown in Figure 2 and the PCB layout in Figure 3 and 4.

Table 1.	ALTAIR04-900 power supply: electrical specification
Parameter		Note	Min.	Typ.	Max.	Unit
AC main input voltage			85		265	VAC
Mains frequency (fL)			50		60	Hz
Output voltage 1		Analog supply voltage	11.7	13	14.3	V
Output current 1		Rx mode	12			mA
		Tx mode	35		550	mA
Output voltage 2		Digital supply voltage		3.3		V
Output current 2		No external microcontroller connection		40	50	mA
		External microcontroller connection			100	mA
Total rated output power					7.48	W
Maximum output power		In TX mode	4.2			W

The input stage, consists of an NTC (NTC1) which limits the inrush current produced by the capacitor charging at plug-in and a varistor (RV1) that protects the power supply against temporary line overvoltage transients. The input EMI filter is a classic Pi-filter, 1-cell for common and differential mode noise. The clamping network (D2-D3) limits the peak of the leakage inductance voltage spike at turn-off, assuring reliable operation of the ALTAIR04900.

The sense resistor R2 and the transformer primary-to-secondary turn ratio fix the maximum output current limitation, whereas the voltage divider made up of R6, R7, and R8 is used to set the output voltage setpoint, in order to ensure the desired output voltage regulation. The network connected on the COMP pin is used to compensate the loop, ensuring the right gain and phase margin to the system, whereas the voltage across the capacitor C10 is used to fix the voltage level for the CC loop; the value of this capacitor is not critical and e few nF are enough to ensure correct operation. The secondary side is provided by two output voltages; a nameplate 13 V output voltage is directly used to supply the analog circuitry of the PLM, whereas the lower voltage is achieved by a 3V3 LDO and is intended to supply the digital parts.

Doc ID 18038 Rev 1

5/34

Test board design and evaluation	AN3290
Figure 1. Electrical schematic

75

'

/

9$

17&

3'

6736

X+

RKP:

$& , 1

)

') 6

&

'

$

&0

3 .($

&

&

&

5

X)

Q)

X)

X)

N

59

&

9

$& , 1

9

Q);

'

677+ /$

/

P+

4

/)$%

'

5

'

9$

,1

287

&

&

%$7

6736 /$

*1'

&

&

5

Q)

X)

5

X)

X)

1 &

8

.

$/7$,5

9''

'5$,1

*1'

9

&855 (17

&

&21752/

)% =& '

&203

,5()

*1'

6285& (

Q) <&$3

5

5

&

.

.

&

Q)

&

Q)

5

Q)

5

5

1 &

N

!-V

Figure 2. PCB: component side (not to scale)

!-V

6/34	Doc ID 18038 Rev 1

AN3290	Test board design and evaluation

Figure 3. Demonstration board image: power supply board

Doc ID 18038 Rev 1

7/34

Test board design and evaluation	AN3290

Figure 4. Demonstration board image: complete (power supply and PLM boards)

Table 2.	ALTAIR04-900 power supply - bill of material
Reference	Part	Description	Note
R1		1.8 kΩ
R2		1.3 Ω	1% tolerance
R3, R5		N.C.
R4		8.2 kΩ
R6		8.2 kΩ	1% tolerance
R7		27 kΩ	1% tolerance
R8		5.1 kΩ	1% tolerance
R9		0Ω
C1	B41044A4108M	1000 μF - 16 V electrolytic	EPCOS
C2	B41858C4477M	470 μF - 16 V electrolytic	EPCOS
C3	B43851F9226M	22 μF - 400 V electrolytic	EPCOS
C4, C9		100 nF ceramic – 35 V
C5	B41851A3477M	470 μF - 10 V electrolytic	EPCOS

8/34	Doc ID 18038 Rev 1

AN3290			Test board design and evaluation
	Table 2.	ALTAIR04-900 power supply - bill of material (continued)
	Reference	Part	Description	Note
	C6	B32922C3224M	220 nF - X2	EPCOS
	C7		2.2 nF - Y-CAP
	C8		470 nF ceramic - 25 V
	C10		4.7 nF ceramic - 25 V
	C11		1 nF ceramic - 25 V
	C12		3.3 μF - 35 V electrolytic
	C13	ZLH series	100 μF - 16 V electrolytic	Rubycon
	D1	STPS2150A	Power Schottky diode	STMicroelectronics
	D2	P6KE200A	Transil™	STMicroelectronics
	D3	STTH1L06A	Ultra-fast high voltage diode	STMicroelectronics
	D4	STPS1L30A	Power Schottky diode	STMicroelectronics
	D5	BAT41	Small signal Schottky	STMicroelectronics
	PD1	DF06S	Input bridge rectifier
	L1	B82462G4472M	4.7 μH power inductor	EPCOS
	L2	B82422H1105K	1 mH SMT inductor	EPCOS
	IC1	ALTAIR04-900	Primary switching regulator	STMicroelectronics
	Q1	LF33AB	3.3 V LDO voltage regulator	STMicroelectronics
	CM	B82721K2701	CM Choke	EPCOS
		744612101		Wurth
	TF1	ECO2017SEO-X05V015	Flyback transformer	TDK
		760-871-431		Wurth
	NTC1	B57236S0160M	NTC inrush current limiter	EPCOS
	RV1	B72214S0321K	320 V Varistor	EPCOS
	F1		2 A fuse
Note:	If not otherwise specified, all resistors are 5%, ¼ W.

Doc ID 18038 Rev 1

9/34

Test board design and evaluation			AN3290
Table 3.	ALTAIR04-900 power supply: transformer characteristics
	Core		E16
Primary inductance			2 mH
Leakage inductance			1.42% nom.
Primary winding			7.68 ± 5%
	Np1		111 turns
	Np2		55 turns
	Ns1		13 turns
	Ns2		6 turns
	Naux		17 turns
Primary to auxiliary turn ratio			5.59 ± 5%
Primary saturation current			550 mA (@ 100 °C)
Insulation primary-secondary			AC 3 kV (1 s – 2 mA)
Figure 5.	ALTAIR04-900 power supply: transformer characteristics
	1		10
	Npri	Nsec1
	3		9
	5		8
	Naux	Nsec2
	4		7

10/34	Doc ID 18038 Rev 1

AN3290	Output voltage characteristics

2 Output voltage characteristics

Figure 6 and 7 show the load and the line regulation of the output 1 when the other output is charged with 40 mA and 80 mA respectively.

All output voltages have been measured on the output connector of the board.

When the output 2 is heavy loaded and the output 1 is light loaded, VOUT1 increases due to the cross regulation. In any case, the voltages are within the tolerance given in the

specifications.

Figure 6. Output voltage characteristics with 3V3 @ 40 mA

/UTPUT VOLTAGE;6=

	6AC
	6AC
	6AC
	6AC

		/UTPUT CURRENTT;M!=

!-V

Figure 7. Output voltage characteristics with 3V3 @ 80 mA

							9DF
							9DF
	2XWSXW YROWDJH >9@						9DF
							9DF
				2XWSXW FXUUHQW >P$@

!-V

Doc ID 18038 Rev 1

11/34