STEVAL-ISA052V1 STMicroelectronics, STEVAL-ISA052V1 Datasheet - Page 21

• Manufacturer Part Number: STEVAL-ISA052V1
• Description: KIT EVAL PM6675S HE CTLR 2A REG
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISA052V1

• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 2, Non-Isolated
• Voltage - Output: 1.5V, 0.6 ~ 3.3V
• Current - Output: 10A, 2A
• Voltage - Input: 4.5 ~ 28 V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6675
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-8426

PM6675S
The duty-cycle of the buck converter is, in steady-state conditions, given by
Equation 2
The switching frequency is thus calculated as
Equation 3
where
Equation 4a
Equation 4b
Referring to the typical application schematic (figures on cover page and
final expression is then:
Equation 5
Even if the switching frequency is theoretically independent from battery and output
voltages, parasitic parameters involved in the power path (like MOSFET on-resistance and
inductor DCR) introduce voltage drops responsible for a slight dependence on load current.
In addition, the internal delay is due to a small dependence on input voltage.
The PM6675S switching frequency can be set by an external divider connected to the
VOSC pin.
f
SW
=
f
SW
T
D
ON
=
K
α
=
α
α
OSC
OSC
K
OSC
OUT
D
OSC
=
V
=
V
OUT
=
=
V
--------------
IN
R
V
V
V
OUT
1
V
-------------- -
V
--------------
V
OSC
SNS
IN
R
V
+
OSC
SNS
OUT
2
IN
R
2
=
⋅
α
α
K
OSC
OUT
OSC
1
⋅
K
OSC
1
Device description
Figure 33
), the
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