STEVAL-ISA019V2 STMicroelectronics, STEVAL-ISA019V2 Datasheet - Page 17

• 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

AN2495
5
Startup network design
To allow the circuit to start as soon as the line voltage is applied, it is necessary to pre-
charge both C
A resistor connected to the DC bus directly makes the pre-charge of C
capacitance. The circuit must start at a minimum DC input voltage of 250 V. The current
required by the L6565 driver during the startup time determines the (R
Considering that the L6565 driver needs a 0.07 mA maximum startup current, we obtain:
Equation 33
Startup resistance must be lower than 3.6 MΩ to reach the best trade-off between power
dissipation and time-to-start. As a consequence, before choosing the startup resistor, we
must determine the C
must be able to supply the L6565 driver until the steady state behavior of the converter is
established. The time from bench verification is 20 ms maximum. Given a L6565 minimum
hysteresis-voltage (difference between startup threshold and undervoltage threshold) of 3.7
V, the voltage across C5 must decrease less than 3.7 V during the startup period. From the
L6565 datasheet we know that maximum quiescent current after turn-on is 3.5 mA, so C5
must be chosen such that:
Equation 34
C
Finally, we can set the startup resistance value to reduce time-to-start and simultaneously
optimize standby power dissipation. The L6565 has a maximum startup threshold of 14.5 V,
therefore the maximum time-to-start is approximately:
Equation 35
A good choice is to put in series four 200 kΩ resistors (R
dissipate less than 1 W of standby power.
The pre-charge of C
L6565 through a diode in series with a 2.2 kΩ resistor.
5
=33 µF is a good choice to guarantee a good margin.
Time - to - start
5
and C
=
8
5
-------------------------------------------------------------------------
⎛
⎝
8
base capacitance is carries out by connecting it to the OUT pin of the
--------------------------------------------------- -
(
capacitance value, which is set according to another requirement. C
ΔV
R
capacitances.
(
1
R
+
1
=
+
R
V
I
----------------
C
2
R
Q
inmin
Doc ID 13127 Rev 4
C
5
+
2
•
5
•
+
R
Δt
14.5V
3
R
<
+
3
3.7V
+
R
4
R
)
4
⎞
⎠
)
⇒
–
<
I
V
----------------
C
SU
inmin
I
5
SU
>
≤
3.5mA 20ms
-------------------------------------- -
2
=
sec
-------------------- -
0.07mA
3.7V
250V
⇒
•
1
= R
(
R
1
≅
2
+
3.6MΩ
= R
≅
R
19μF
2
3
+
Startup network design
= R
R
1
3
+ R
5
4
+
= 200 kΩ), which
electrolytic
R
2
4
+ R
)
≤
808kΩ
3
+ R
4
) value.
17/34
5