stoui333
Junior Member level 2
Hi All,
I did the below calculations but i`m not sure if i figure them correctly especially when i need to add the DCDC converters efficiency and the external ACDC PSU.
So my example:
Board 1: 12v x 2A = 24w
Board 2: 28v x 1A = 28w
Board 3: 5v x 2A = 10w
Each board is power by a different DCDC converter (12v, 28v, 5v) and each converter has 90% efficiency.
The whole system is powered by an external ACDC PSU with output 30v.
My calculations:
Total system power consumption: 24w + 28w + 10w = 62w
DCDC converter efficiency 90%, 62/0.9= 6.8w
3x DCDC converters 6.8wx3=20.6w (due to efficiency)
New total system power consumption=62w+20.6=82.6w
For the external ACDC PSU which runs on 30v:
I=82.6w/30v =2.75A is required
Questions 1: Is the efficiency calculation correct?
Question 2: I found somewhere that for the efficiency calculation i need to use this approach "multiply the input current by 1 + (100/efficiency)" but the values i get are not logical (*4.34A vs 2.75A)
*1+(100/90)=2.1
Input current = 62w / 30v = 2.06A
2.06A * 2.1 = 4.43A
Thanks,
Christos D
I did the below calculations but i`m not sure if i figure them correctly especially when i need to add the DCDC converters efficiency and the external ACDC PSU.
So my example:
Board 1: 12v x 2A = 24w
Board 2: 28v x 1A = 28w
Board 3: 5v x 2A = 10w
Each board is power by a different DCDC converter (12v, 28v, 5v) and each converter has 90% efficiency.
The whole system is powered by an external ACDC PSU with output 30v.
My calculations:
Total system power consumption: 24w + 28w + 10w = 62w
DCDC converter efficiency 90%, 62/0.9= 6.8w
3x DCDC converters 6.8wx3=20.6w (due to efficiency)
New total system power consumption=62w+20.6=82.6w
For the external ACDC PSU which runs on 30v:
I=82.6w/30v =2.75A is required
Questions 1: Is the efficiency calculation correct?
Question 2: I found somewhere that for the efficiency calculation i need to use this approach "multiply the input current by 1 + (100/efficiency)" but the values i get are not logical (*4.34A vs 2.75A)
*1+(100/90)=2.1
Input current = 62w / 30v = 2.06A
2.06A * 2.1 = 4.43A
Thanks,
Christos D