STEVAL-ISV006V1 STMicroelectronics, STEVAL-ISV006V1 Datasheet - Page 14

• Manufacturer Part Number: STEVAL-ISV006V1
• Description: IC LINEAR
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISV006V1

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-11418

External component selection
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Input voltage sensing capacitor
C4 is placed in parallel to R4 and as close as possible to the V
V
However, V
input voltage variations.
It means that the time constant [(R3//R4)*C4] must be chosen according to system
properties, which is the MPPT tracking time (Tmpp~=1 ms). The rule below must be
followed in order to select C4 capacitance:
For example, if R3//R4 = 100 kΩ then:
Inductor selection
Inductor selection is a crucial point for this application. The following application constraints
must be taken into account:
●
●
●
●
The input current from the PV panel flows into the inductor, so:
According to
depends on the applied voltage (Vin) on the inductance (L
Considering the maximum duty cycle (90 %):
Taking into account the overcurrent threshold:
Finally, inductance should be chosen according to the following formula:
A safer choice is to replace Vmp with Voc.
Usually, inductances ranging between 10 µH to 100 µH satisfy most application
requirements.
Other critical parameters for the inductor choice are Irms, saturation current, and size.
I
I
I
C
L
L
1 L
L
MPP-SET
1
1
1
4
(
(
(
pk
rms
pk
>
≥
Maximum input current (i.e. Imp and Isc of PV panel)
Maximum input voltage (i.e. Vmp and Voc of PV panel)
Overcurrent threshold of SPV1040 (1.7A)
Maximum duty cycle of SPV1040 (90 %).
)
1
2
)
T
≅
<
mpp
)
*
≅
I
1
2
L
V
voltage.
I
1
7 .
−
*
mp
(
mp
MPP-SET
rms
A
I
R
L
Figure 3
1
3
*
<
(
rms
9
//
1
)
I
μ
sc
+
R
s
4
1
2
)
must be able to follow the V
=
=
*
, during the charge phase (switch ON), peak current on the inductor
2
1
V
1
m
L
mp
*
1
*
V
R
*
mp
2
9
3
−
μ
//
*
Doc ID 18265 Rev 1
1
I
s
mp
9
R
μ
4
s
C ≥
4
10
nF
IN
waveform to allow SPV1040 to monitor
1
), and on the duty cycle (T
MPP-SET
pin to reject noise on
AN3319
on
).