STEVAL-ISA019V2 STMicroelectronics, STEVAL-ISA019V2 Datasheet - Page 6

• Manufacturer Part Number: STEVAL-ISA019V2
• Description: BOARD EVAL SMPS L6565 3PHASE APP
• Manufacturer: STMicroelectronics
• Type: Motor / Motion Controllers & Driversr

Specifications of STEVAL-ISA019V2

• Mfg Application Notes: L6565/STC04IE170HV AppNote
• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 1, Isolated
• Power - Output: 80W
• Voltage - Output: 24V
• Current - Output: 3.33A
• Voltage - Input: 250 ~ 850V
• Regulator Topology: Flyback
• Board Type: Fully Populated
• Utilized Ic / Part: L6565, STC04IE170HV
• Input Voltage: 250 V to 850 V
• Output Voltage: 24 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6565, STC04IE170HV
• Other names: 497-6339

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Flyback stage design
As commonly known, the voltage stress on the device (power switch) is given by:
Equation 1
where V
allowed by the clamping network. It has been set at 200 V. N
primary side, while N
Taking into account a 200 V margin, the maximum flyback voltage that can be chosen is:
Equation 2
After calculating the flyback voltage, proceed with the next step in the converter design.
The turn ratio between primary and secondary side is calculated with the following formula:
Equation 3
As a first approximation, since the turn-on of the device occurs immediately after the energy
stored on the primary side inductance has been totally transferred to the secondary side:
Equation 4
and
Equation 5
where T
transformer inductance and T
Combining the two previous equations, T
Equation 6
The next step is to calculate the peak current. According to the converter specification in
Table
does not take into account the losses on the power switch, on the input bridge, and on the
rectified network, we have:
Equation 7
1, output power of 80 W and desired efficiency (at least 80%), by using a formula that
onmax
fl
= flyback voltage = (V
V
is the maximum on time, T
fl
=
BV V
s
–
is the number of turns on the main output secondary winding.
inmax
P
IN
N
------ -
N
=
S
–
p
s
Doc ID 13127 Rev 4
out
is the switching time.
1.25P
V
T
V
=
spike
onmax
off
V
+ V
--------------------------------------- -
V
dcmin
out
T
=
OUT
F
onmax
–
, diode)*N
V
+
V
=
T
inmax
V
reset
=
onmax
m
V
onmax
fl
------------------------------ -
V
F diode
arg
1
-- - L
2
----------------------- -
,
dcmin
+
V
•
in
is the time needed to demagnetize the
T
fl
–
T
=
reset
•
is:
V
S
P
=
p
T
I
fl
1700 1000 200
=
+
/N
P
S
–
V
V
2
=
--------------- -
24
=
s
fl
V
fl
250
T
and V
T
spike
≅
–
+
1
-- - V
2
---------------------------------------------- -
reset
S
10μs
1
dcmin
=
spike
10
L
–
P
p
2
T
T
is the number of turns on the
S
is the maximum overvoltage
onmax
–
250
2
=
250V
AN2495