STEVAL-ISA056V1 STMicroelectronics, STEVAL-ISA056V1 Datasheet - Page 52

• Manufacturer Part Number: STEVAL-ISA056V1
• Description: BOARD EVAL BASED ON PM6600
• Manufacturer: STMicroelectronics
• Type: PWM Controllersr

Specifications of STEVAL-ISA056V1

• Design Resources: STEVAL-ISA056V1 Gerber Files STEVAL-ISA056V1 Schematic STEVAL-ISA056V1 Bill of Material
• Current - Output / Channel: 30mA
• Outputs And Type: 6, Non-Isolated
• Voltage - Output: 36 V
• Features: Dimmable
• Voltage - Input: 4.5 ~ 28V
• Utilized Ic / Part: PM6600
• Input Voltage: 4.5 V to 28 V
• Output Voltage: 36 V
• Product: Power Management Modules
• Core Chip: PM6600
• Topology: Boost
• No. Of Outputs: 1
• Dimming Control Type: PWM
• Mcu Supported Families: PM6600
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PM6600
• Other names: 497-8414

Application note
B.4.5
B.4.6
52/60
defining D
The worst case for the output voltage ripple is when input voltage is lower (V
A simple way to select the C
In order to affect as less as possible the current generators, it would be better to fix the
maximum ripple lower than the typical voltage across the generators.
For example considering ΔV
leading generator), the required capacitance is:
Equation 35
A margin from the calculated value should be taken into account because of the
capacitance drop due to the applied voltage when MLCCs are used.
A 4.7 µF MLCC can be a good choice for this application (two 2.2 μF MLCC in parallel can
be also a good solution).
In case a dimming duty cycle different from 100% is used, a further contribution to the
capacitor discharge (during the off time of the dimming cycle) should be considered.
Input capacitor choice
The input capacitor of a boost converter is less critical than the output capacitor, due to the
fact that the inductor is in series with the input, and hence, the input current waveform is
continuous.
A low ESR capacitor is always recommended.
A capacitor of 10 µF is tentatively a good choice for most of the applications.
Overvoltage protection divider setting
The overvoltage protection (OVP) divider provides a partition of the output voltage to the
OVSEL pin. The OVP divider setting not only fixes the OVP threshold, but also the open-
channel detection threshold (93% of the OVP threshold).
The proper OVP divider setting can be calculated by the equation:
Equation 36
2
as:
D
2
=
C
2
OUT
OUT
R
OUT
⋅
F
0
Doc ID 14248 Rev 7
SW
⋅
lower than 80 mV (i.e. the 20% of the voltage across the
value is fixing a maximum voltage ripple.
(
M
>
⋅
L
(
−
I
R
, L
⋅
1
peak
M
1
)
2
=
Δ ⋅
=
R
−
⎧
⎨
⎩
V
2
I
. 0
OUT
⎛
⎜
⎝
OUT
. 0
. 1
263
V
OVP
23
235
,
max
)
⋅
T
OFF
@
−
@
1
⎞
⎟
⎠
=
V
V
. 2
IN
IN
,
,
02
max
min
μ
F
=
=
9
14
6 .
4 .
V
V
IN,min
= 9.6 V).
PM6600