Hardware Reference
In-Depth Information
The regulated output voltage is easily adjusted by a multiturn trim pot on the PCB.
Adjust the pot while you read your DMM.
The specifications for the unit I purchased are provided in Table
2-1
for your general
amusement. Notice the wide range of input voltages and the fact that it operates at
a temperature as low as -40°C. The wide range of input voltages and current up to 3
A clearly makes this a great device to attach to solar panels that might vary widely in
voltage.
Table 2-1.
DC-DC buck converter specifications
Parameter
Min
Max Units
Parameter
Min
Max
Units
Input voltage
4.00
35.0
Volts
Output ripple
30.9
mA
Input current
3.0
Amps
Load regulation
±0.5
%
Output voltage
1.23
30.0
Volts
Voltage
regulation
±2.5
%
Conversion
efficiency
92
%
Working
temperature
-40
+85
°C
Switching
frequency
150
kHz
PCB size
45×20×12
mm
Net weight
10
g
The specification claims up to a 92% conversion efficiency. Using 15 V on the input,
I performed my own little experiment with measurements. With the unit adjusted to
produce 5.1 V at the output, the readings shown in Table
2-2
were taken.
Table 2-2.
Readings taken from experiment
Parameter
Input
Output
Units
Voltage
15.13
5.10
Volts
Current
0.190
0.410
Amps
Power
2.87
2.09
Watts
From the table we expected to see more power used on the input side (2.87 W).
The power used on the output side was 2.09 W. The efficiency then becomes a matter of
division:
209
287
.
.
=
0 728
.
From this we can conclude that the measured conversion efficiency was about 72.8%.
