AN2097

APPLICATION NOTE
VIPower: 10W POWER SMPS USING VIPer22A
FOR AIR-CONDITIONER APPLICATION

1. ABSTRCT Figure 1. Board Layout

New air-conditioner systems use two main low-
voltage outputs to supply the internal electronic
equipment, respectively these values are +12V
and +5V. These low output voltages are generated
by a switch mode power supply. Many important
features are requested by the power supply: high
efficiency, light weight with compact size and low
power consumption in stand-by condition just to
mention some of them.
VIPerX2 family allows to develop power supply
having all these features together hence these
devices are a suitable solution to develop air-
conditioner applications. Specifically, the board
shown here following has been developed in order
to improve the features explained in figure 1.
The application, mentioned in this note, complains
the technical specifics summarized in table 1.

Table 1. Electrical Specification

Input AC range 85-265 Vac
Output 1 12V
Output 2 5V/400mA (linear regulator from output 1)
Ripple <50mV
Output current (12V & 5V) 800mA - continuous
900mA - peak, less than 5 minutes
Stand-by consumption <1W

1. VIPERX2A DESCRIPTION 1.1. General Features

The VIPerX2A family combines a dedicated The VIPerx2A devices are built in the proprietary
current mode PWM controller with a high voltage VIPower M0-3 H.V.
Power MOSFET, on the same monolithic chip, The M0-3 H.V. technology allows to put the low
within one package only. That allows to obtain a voltage systems (PWM) and the power stage with
components reduction achieving a cost reduction vertical current flow in the same chip by means of
and a design and PCB simplification. For these a P-type buried layer, as illustrated in figure 2.
reasons this family is widely used in many off-line
The VIPerX2A devices have the below general
switching mode power supplies. Furthermore, a
features:
tiny size package for SMD technology is available ■ Automatic thermal shutdown.
(SO-8). VIPer family is able to meet the Blue
■ High voltage start-up current source.
Angels and Energy Star standards in matter of
■ HICCUP mode in order to avoid the break-down
stand-by power consumption (less than 1W).
condition for output short circuits.
■ Burst mode to assure low-power consumption in
low-load condition.

Rev. 1
December 2004 1/8
AN2097 - APPLICATION NOTE

Moreover, VIPower M0-3 Technology allows to shows the device power capability, in different
develop Power MOSFETs able to guarantee a packages and different work conditions.
minimum breakdown voltage of 730V. Table 2

Figure 2. M0-3 Technology

Table 2. Power Capability for Different Input Range and Different Package
Wide Range (85-265V) Single Range (180-265V)
SO-8 DIP SO-8 DIP
VIPer12A 5W 8W 8W 13W
VIPer22A 7W 12W 12W 20W

Figure 3. Block Diagram

DRAIN

ON/OFF
60kHz
REGULATOR OSCILLATOR

INTERNAL PWM
S LATCH
SUPPLY OVERTEMP.
R1 FF
Q
DETECTOR
R2 R3 R4

VDD _ +
BLANKING
8/14.5V _ 0.23 V
+
OVERVOLTAGE
LATCH 230 Ω
R
+
S FF Q
42V _

1 kΩ
FB

SOURCE

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 AN2097 - APPLICATION NOTE

1.2. Block Diagram condition is reached, the Power MOSFET starts to

Examining the block diagram in figure 3, it is switch. Burst mode condition works skipping same
possible to observe that the power section is switching cycles decreasing the power
driven by a current mode structure with a fast consumptions when the load becomes light.
comparator using the current delivered by the N-
MOS sense and by the feed-back pin (FB). The 2. AIR-CONDITIONER APPLICATION
comparator output is connected to the Blanking
2.1 Schematic
Time Block in order to assure the minimum turn on
time. An internal oscillator fixes the switching Figure 4 gives the schematic of the power supply
frequency at 60kHz, so further external with VIPer22 used in the air-conditioner
component will not be necessary. Other internal application described in this note. It is designed to
blocks are the Regulator, used by internal supply have two voltage outputs, respectively 12V and
and able to even support 45V on VDD pin and the 5V. The maximum power capability is 10W and it
Over-temperature Detector to provide the thermal is delivered on the 12V output. Peak current value
shutdown at 170°C typical. of this output is 900mA. Instead, the second output
(5V) is obtained connecting in the first output in
The device system control is a current mode
structure in which the N-MOS sense current and cascade of a linear voltage regulator (7805) and a
the FB current are summed in the resistor R2. The zener diode D9 that is used in order to share the
voltage drop. This solution allows to have a very
voltage across R2 depends on this current value
high accuracy in 5V output voltage value,
and this voltage value is compared with an internal
fixed voltage reference (0.23V). The comparator therefore this solution is suitable for supplying
microcontroller or/and logical circuit, LCD and
output drives the MOSFET, therefore the
buzzer. The current capability of this second
switching frequency depends on the feedback
output is 400mA. The solution proposed, shown in
current value and the Id value. In this application
the feedback loop is implemented by driving this figure 4, is an isolated fly-back topology in
secondary feedback. The control loop is obtained
FB pin with the output voltage using an
through an optocoupler, with a high stability
optocoupler in order to assure the electrical
isolation between the input and the output. V DD voltage reference (TL431), in order to check the
voltage is monitored by a hysteresis comparator 12V output assuring the complete insulation
between the input and the output. A transil
able to manage the start-up current generator. In
snubber circuit (D6-D7), allows to have a reliable
fact, it is switched on in order to charge the V DD
capacitor in as long as the V DD voltage value protection for spikes voltage due to the reflected
voltage and the leakage inductance.
becomes greater than the VDDON value. Once this

Figure 4. Air-Conditioner SMPS Schematic

F1 D1 D2

J1 1A/275VAC 1N4007 1N4007

C1 C4
2 100nF/275VAC 47uF/400V
1
D3 D4
Input RT1
NTC-5
1N4007 1N4007

D8
L2
D6 T1 +12V
+12V
P6KE200 47uH
STPS2H100

D7 R3 D9
1N4007 220R 4.2V/2W
U4
R1 C8 C9 +5V
470uF/25V 100uF/25V Vin Vout +5V
10R GND
C11
L7805 100uF/10V
D5
1N4148

U2A
R2 C5 R4
4.7K 22uF/50V 1K
U2B R6
U1 PC817 C10 17.8K
Vdd
Drain U3 100nF
C7
FB FB TL431
PC817 Control R7
2.2nF/250VAC 4.7K
C6 Source
47nF VIPer22A

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AN2097 - APPLICATION NOTE

2.2 Result wide range (85-265 VAC). The stand-by power

The main purpose of this application is to have consumption is always lower than 1W, as shown in
both the output voltages very accurate. The first figure 5, satisfying the Energy Star rules regarding
one (12V) has a high accurateness because it is in stand-by power consumption.
secondary regulation feedback, while the second Instead, figure 6 shows the efficiency
one (5V) has a high precision because this line is measurement achieved keeping the 5V output in
obtained using a standard linear regulator. This no-load condition.
air-conditioner application is developed to work in

Figure 5. Power consumption in stand-by condition

Standby Power
0.8
0.7
) 0.6
W
r 0.5
(

o0.4
w

P
u0.3
t
p
I 0.2
n

0.1
0
50 100 150 200 250 300
Input Voltage (V)

Figure 6. Efficiency measurement

Efficiency
75.0%
70.0%
65.0%

60.0%
Vin=85v
55.0% Vin=265v
50.0%
45.0%
40.0%
0 200 400 600 800 1000 1200
Iout (mA)

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 AN2097 - APPLICATION NOTE

3. DEMOBOARD DESCRIPTION represented in figure 7. This PCB Layout

3.1 Board Layout dimension is 50mm x 40mm.
It is a single layer type with copper on bottom side,
and serigraphy on top side. Both of them are

Figure 7. PCB Layout (dimension is 50mmX40mm)

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AN2097 - APPLICATION NOTE

3.2 Bill of material

Table 3 gives the list of the components used to
develop this application.

Table 3. Bill of Material

Reference Value Description
C1 100nF/275VAC X-Capacitor Evox Rifa
C4 47µF/400V Polarized Capacitor (Radial)
C5 22µF/50V Polarized Capacitor (Radial)
C6 47nF Capacitor
C7 2.2nF/250VAC Y-Capacitor Evox Rifa
C8 470µF/25V Polarized Capacitor (Radial)
C9 100µF/25V Polarized Capacitor (Radial)
C10 100nF Capacitor
C11 100µF/10V Polarized Capacitor (Radial)
D1 1N4007 1.0A General Purpose Rectifier
D2 1N4007 1.0A General Purpose Rectifier
D3 1N4007 1.0A General Purpose Rectifier
D4 1N4007 1.0A General Purpose Rectifier
D5 1N4148 80V-0.5A Schottky Diode
D6 P6KE200 STMicroelectronics Zener Diode
D7 1N4007 Default Diode
D8 STPS2H100 STMicroelectronics 100V-2A Power Schottky Diode
D9 4.2V/2W Zener Diode
F1 1A/275VAC Fuse
J1 Input Header, 2-Pin
L2 47µH Inductor
R1 10R Resistor
R2 4.7KΩ Resistor
R3 220R Resistor
R4 1K Resistor
R6 17.8KΩ Resistor
R7 4.7KΩ Resistor
RT1 NTC-5 NTC Resistor
T1 Three-winding Transformer (Non-Ideal)
U1 VIPer22A STMicroelectronics Off Line SMPS
U2 PC817 Photocoupler Sharp
U3 TL431 STMicroelectronics Programmable Voltage Reference
U4 L7805 STMicroelectronics 1A Voltage Regulator

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 AN2097 - APPLICATION NOTE

3.3 Transformer Parameters electrical, mechanical and winding specifications

The transformer used in this SMPS for air- are given in table 4 and figure 8.
conditioner application is wound in E19 core. The

Table 4. Transformer parameters

Core size: E19/8/5

Primary Winding Primary Inductance 3.0mH

Turns 133
Coil 0.25mm

Auxiliary Winding Turns 21

Coil 0.25mm

Secondary Winding Turns 17

Coil 0.6mm

Figure 8. Transformer Structure Description

Pin1 Pin5

Primary Secondary

Pin2 Pin7
Pin3

Auxiliary

Pin4

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AN2097 - APPLICATION NOTE

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of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

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