Buck 2 click
PID:
MIKROE-2911
Weight:
25 g
Buck 2 click
is a powerful step down DC-DC switching regulator. It gives a high precision
regulated voltage at its output and it can handle an ample amount of current. Buck 2 click is
highly configurable - the output voltage, maximum current limiting, and the switching
frequency parameters can be controlled via the IC pins routed to the mikroBUS™ socket,
providing a simple and secure connection to the host MCU.
The input voltage can range from 4.5V to 19V and the output can be set to work in several
discrete steps, ranging from 0.7V to 3.3V. Features, such as the wide range of input
voltages, pin configurable working parameters, internal soft start, thermal shutdown,
hiccup mode short-circuit protection and high switching efficiency, make this device a
perfect choice for any step-down application which demands reasonably high current and
accurate voltage regulation with clean and ripple-free low voltage power supply - such as
the embedded electronic devices, servers, routers, data storage devices, low power ICs and
similar.
How does it work?
The step down DC-DC regulator used on this click
board™
is the MIC45404, a 19V 5A ultra-
low profile DC-to-DC power module by Microchip. This IC is a valley current mode
controlled power module, meaning that it has a faster response than the traditional peak
current mode control, thus better response to transients. This IC requires a minimal
number of external components, which makes the whole device pretty robust and easy to
work with. Unlike other traditional switching regulators, this one does not require external
feedback components - it is enough to directly connect the OUTSNS pin to the output
voltage. This allows for more accurate control over the voltage regulation.
Buck 2 click offers a possibility to configure certain working parameters such as the output
voltage, current limit threshold, and PWM switching frequency, by changing the states of
the dedicated pins. Those pins are either routed to the
mikroBUS™
socket or equipped with
the SMD jumpers so that they could be set by the end user. These pins can be set to the GND
level, VCC level or can be left afloat - high impedance mode (HIGH-Z). They are sampled as
soon as the internal voltage is stabilized, and their state is latched - further changes will not
affect the selected configuration. Tables for the configurable pins settings and their values
can be found below.
Output voltage level is selected by the VOSET0 and VOSET1 pins of the MIC45404 IC,
routed to the mikroBUS™ AN and RST pins, respectively. This gives a total of nine possible
voltage level combinations.
PWM switching frequency can be changed by the FREQ pin, routed to the PWM pin of the
mikroBUS™ socket. The switching frequency is related to the selected output voltage and
for this reason, it is routed to the mikroBUS™ socket, so that the voltage output and the
corresponding frequency for the selected voltage can be set. There are three possible
frequency values: 400kHz, 565kHz, and 790kHz.
The current limiting is selected by the onboard SMD jumper, labeled as ILIM SEL. It is
possible to limit the current to 3A, 4A, and 5A. The current limiting is instantaneous and
the MIC45404 IC offers current limit and current sensing on both high-side and low-side
internal MOSFET switches. It also features a special Hiccup mode, which reduces power
dissipation in prolonged overload or short circuit situations. When a low-end MOSFET
current limiting event occurs, the internal counter is incremented. A PWM cycle with no
low-end MOSFET limiting events will decrease the internal counter. If the internal counter
reaches 0Fh, both MOSFETs will be tri-stated and the power to the output will be cut off.
After a predetermined wait time has expired, the MIC45404 IC will be restarted and will
attempt a new soft-startup sequence. This mechanism ensures that no false overload
events are generated.
The EN/DLY pin is used to enable the device. A HIGH logic level on this pin will start up the
internal sections of the MIC45404 IC. This pin is routed to the mikroBUS™ CS pin, and since
it is in an open drain configuration, it is pulled by the resistor to the GND.
The PG pin is used to indicate the power good condition of the output. When the voltage on
the output (OUTSNS) drops under 90% of the regulated voltage, this pin is set to a LOW
logic level, indicating irregular output voltage. This pin is pulled to a HIGH logic level by an
on-board pull-up resistor since it is configured as the open drain output. It is routed to the
mikroBUS™ INT pin.
Buck 2 click is equipped with two screw terminals, used to connect the input voltage source
as well as the output load. The input voltage source is selectable between the +5V rail from
the
mikroBUS™ and the voltage at the input terminal. It also has an onboard LOGIC SEL
SMD jumper, used to set up the logic voltage level, so that both 3.3V and 5V capable MCUs
can be used.
Output voltage selection
VOSET1
0
0
1
1
VOSET0
0
1
0
1
Output Voltage [V]
3.3
790
2.5
1.8
565
1.5
Required Sw. Freq. [kHz]
0
High-Z
1
High-Z
High-Z
High-Z
0
High-Z
1
High-Z
1.2
1.0
0.9
0.8
0.7
400
Switching frequency
FQ pin
High-Z (open)
0 (GND)
1 (VDDA)
Frequency [KHz]
400
565
790
Specifications
Type
Buck
A perfect choice for step-down applications for
embedded electronic devices, servers, routers, data
storage devices, low power ICs, etc
MIC45404, a 19V 5A ultra-low profile DC-to-DC power
module by Microchip
Applications
On-board
modules
Key Features
Buck 2 click features a wide range of input voltages, pin
configurable working parameters, internal soft start,
thermal shutdown, hiccup mode short-circuit protection
and high switching efficiency
GPIO
3.3V or 5V
Interface
Input Voltage
Click board
size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on
Buck 2 click
corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
VOSET0 input
VOSET1 input
Enable
VSO
VS1
EN
NC
NC
NC
1
2
3
4
5
6
7
AN
RST
CS
SCK
MISO
MOSI
3.3V
PWM
INT
RX
TX
SCL
SDA
5V
16
15
14
13
12
11
10
FQ
PG
NC
NC
NC
NC
+5V
FREQ input
Power good output
Power supply
+3.3V
Power supply
微控制器 MCU
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