STEVAL-ISA011V1 STMicroelectronics, STEVAL-ISA011V1 Datasheet - Page 5

• Manufacturer Part Number: STEVAL-ISA011V1
• Description: BOARD EVAL VIPER12A LP AC/DC
• Manufacturer: STMicroelectronics
• Series: VIPER™r
• Type: AC/DC Switching Convertersr

Specifications of STEVAL-ISA011V1

• Design Resources: STEVAL-ISA011V1 Gerber Files STEVAL-ISA011V1 Schematic STEVAL-ISA011V1 Bill of Materials
• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 1, Isolated
• Power - Output: 4.1W
• Voltage - Output: 4.5V
• Current - Output: 900mA
• Voltage - Input: 88 ~ 265VAC
• Regulator Topology: Flyback
• Frequency - Switching: 60kHz
• Board Type: Fully Populated
• Utilized Ic / Part: VIPer12A
• Input Voltage: 88 V to 265 V
• Output Voltage: 4.5 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: VIPER12ADIP-E
• Kit Application Type: Power Management - Voltage Regulator
• Application Sub Type: AC / DC Adapter
• Kit Contents: Board
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: VIPer12A
• Other names: 497-6413; STEVAL-ISA011V1

AN2272 - Application Note
1.1
1.1.1
1
In order to improve regulation, the feedback loop is designed to have enough bandwidth so
the converter can react on time to load changes. As is shown in the
Load Regulation Tests on page 20
very low variations in the output voltage.
The flyback converter is designed to work in Discontinuous Conduction Mode (DCM) in all
operating conditions (i.e. Minimum Input Voltage, Maximum Load), because it provides
better dynamic performance.
Primary Side
Step 1, Input Capacitor Selection
The first design step is to calculate the input capacitor value (C2a + C2b see
ISA011V Demo Board Schematic on page 30
Equation 1
Where,
C
P
V
V
In this case, the P
power and
AC(min)pk
T = the time between the two conduction cycles of the input bridge diodes,
IN
IN
DC(min)
= input capacitor value,
= input power,
= selected minimum input voltage required for the flyback (converter) stage.
STEVAL-ISA011V1 Board Design
= sinusoidal input waveform peaks (when AC voltage is at its minimum), and
is the overall expected efficiency (70% in this example).
IN
value used is calculated as P
C
IN
, the board is able to handle high load step changes with
=
-----------------------------------------------------------------
V
Rev. 1
2
AC min pk
2 P
).
Equation 1
IN
–
O
/ , where P
V
2
DC m in
T
STEVAL-ISA011V1 Board Design
is useful for this purpose:
O
is the maximum output
Section 2.3: Dynamic
STEVAL-
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