STEVAL-ISA053V2 STMicroelectronics, STEVAL-ISA053V2 Datasheet - Page 20
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STEVAL-ISA053V2
Manufacturer Part Number
STEVAL-ISA053V2
Description
BOARD EVALUATION FOR PM6680A
Manufacturer
STMicroelectronics
Type
DC/DC Switching Converters, Regulators & Controllersr
Specifications of STEVAL-ISA053V2
Design Resources
STEVAL-ISA053V2 Gerber Files PM6680A Eval Kit Schematic STEVAL-ISA053V2 Bill of Material
Main Purpose
DC/DC, Step Down with LDO
Outputs And Type
3, Non-Isolated
Voltage - Output
1.8V, 3.3V, 5V
Current - Output
2.5A, 2.5A, 100mA
Voltage - Input
6 ~ 28V
Regulator Topology
Buck
Frequency - Switching
200kHz, 300kHz
Board Type
Fully Populated
Utilized Ic / Part
PM6680A
Input Voltage
6 V to 36 V
Output Voltage
5 V
Product
Power Management Modules
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
For Use With/related Products
PM6680A
Other names
497-6379
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-ISA053V2
Manufacturer:
STMicroelectronics
Quantity:
1
Device description
7.2
20/48
Constant on time architecture
Figure 29
off-time constrain (350 ns typ.) is introduced to allow inductor valley current sensing on
synchronous switch. A minimum on-time (130 ns) is also introduced to assure the start-up
switching sequence.
PM6680A has a one-shot generator for each power section that turns on the high side
MOSFET when the following conditions are satisfied simultaneously: the PWM comparator
is high, the synchronous rectifier current is below the current limit threshold, and the
minimum off-time has timed out.
Once the on-time has timed out, the high side switch is turned off, while the synchronous
switch is turned on according to the anti-cross conduction circuitry management.
When the negative input voltage at the PWM comparator
down replica of the output voltage (see the external R1/R2 divider in
valley limit (determined by internal reference Vr = 0.9 V), the low-side MOSFET is turned off
according to the anti-cross conduction logic once again, and a new cycle begins.
Figure 29. Constant on-time block diagram
In steady state the FB pin voltage is about Vr and the regulated output voltage depends on
the external divider:
Equation 4
shows the simplified block diagram of a constant on time controller. A minimum
OUT
=
Vr
×
⎛
⎝
1
+
R
------ -
R
2
1
⎞
⎠
(Figure
29), which is a scaled-
Figure
29), reaches the
PM6680A