STEVAL-ISV006V1 STMicroelectronics, STEVAL-ISV006V1 Datasheet - Page 15

• 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

AN3319
Irms is the self rising temperature of the inductor, affecting the nominal inductance value. In
particular, the inductance decreases with Irms and the temperature increases. As a
consequence the inductor current peak can reach or surpass 1.7 A.
Inductor size also affects the maximum current deliverable to the load. In any case, the
saturation current of the choke should be higher than the peak current limit of the input
source. Hence, the suggested saturation current must be > 1.7 A.
At the same size, small inductance values guarantee both faster response to load transients
and higher efficiency.
Inductors with low series resistance are suggested in order to guarantee high efficiency.
Output voltage capacitor
A minimum output capacitance must be added at the output in order to reduce the voltage
ripple.
Critical parameters for capacitors are: capacitance, maximum voltage, and ESR.
According to the maximum current (Isc) provided by the PV panel connected at the input,
the following formula can be used to select the proper capacitance value (C
specified maximum output voltage ripple (Vout_rp_max):
Maximum voltage of this capacitor is strictly dependent on the output voltage range.
SPV1040 can support up to 5.5 V, so the suggested maximum voltage for these capacitors
is 10 V.
Low-ESR capacitors are a good choice to increase the whole system efficiency.
Output voltage partitioning
R1 and R2 are the two resistors used for partitioning the output voltage.
The said V
according to the following rule:
Also, in order to optimize the efficiency of the whole system, when selecting R1 and R2,
their power dissipation must be taken into account.
Assuming a negligible current flowing into the V
series R1+R2 is:
Cout ≥
P
R
R
vout
1
2
=
1
_
V
sns
out
Fsw
. 1
=
OUT_MAX
25
_
V (
max
*
R
out
Vout
1
−
+
_
Iout
1
max
R
_
the maximum output voltage of the battery, R1 and R2 must be selected
2
)
rp
2
_
max
Doc ID 18265 Rev 1
ctrl
pin, maximum power dissipation on the
External component selection
out1
) for a
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