Arrow DECA User Manual page 61

On the DECA board, Rshunt value is 0.003 (R27 resistance). Bus Voltage (V
(V ) are actual measured values saved in registers. With these two values INA230 can work out
S
current (Is = V / Rs ) and power (P = V
S
calculating manually according equation; the other is using INA230 CAL setting.
Take this project as an example. For the first way, two registers values are Bus_Voltage =960,
Shunt_Voltage=11, and INA230 Bus Voltage 1LSB is 1.25mV, then, Bus Voltage =960 * 1.25mV =
1.2V. In the same way, Shunt Voltage 1LSB is 2.5uV, then, Shunt Voltage = 11 * 2.5uV= 27.5uV.
The final results are Is = V
way, suppose Current register 1LSB = 0.1mA, then, CAL Register value=0.00512 / ( Current_LSB
* R ) = 0.00512/(0.1mA *0.003) =17066. When setting CAL Register value to 17066, current
SHUNT
register value is read about 92 (Is=92*0.1mA). P (Power) value can also be read in Power register.
Power register 1LSB = 2.5mW, and power actual value is P =10.92mW, then, the Power register
will show value 4~5 (P=4*2.5mW=10mW). In the system CD there is a demo which can use Altera
SignalTap II to observe the Current /Power real-time value.
 Design Tools
 Quartus II v15.0
 Demonstration Source Code
 Project directory: DECA_Power_Monitor
 Bitstream used: DECA_Power_Monitor.sof
 SignalTap II :PowerM.stp
 Demonstration Batch File
 Demo batch file folder: \DECA_Power_Monitor\demo_batch
DECA User Manual
* Is). There are two ways to work out Is and P: One is
B
/ R = 9.1mA; P = V
S S
60
* Is = 1.2V *9.1mA = 10.92mW. For the second
B
) and Short Voltage
B
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May 22, 2015