SLVUD11 March 2025
When multiple devices are in parallel, the best mode of operation is for all devices to deliver the same amount of current to the load. Since the main factor in current sharing equality is the proportional relationship between the power stage transconductance (gmps in the device data sheet) of each device, the current sharing performance of any implementation is dependent on the gmps values of the devices in the parallel system.
The EVM was modified by placing a wire between the inductor and VOUT plane of the EVM to allow current probes to measure the RMS current of each phase during operation. Table Table 3-2 shows the collected data. The second column shows the target RMS current per device, that is the current through each converter if the sharing was equal. The last four columns show the deviation for each device from the target current sharing value as a percentage of the target device current.
Because the current sharing performance of any set of devices is dependent on the gmps values, each EVM has different current sharing characteristics. Therefore, the data provided in Table 3-2 is not the same as other TPS7H4011QEVM-CVAL boards.
|
RMS Current Per Device (A) |
Deviation From Target Current (%) |
||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Total Current (A) |
Target Current Per Device (A) |
Device 1 |
Device 2 |
Device 3 |
Device 4 |
Device 1 |
Device 2 |
Device 3 |
Device 4 |
|
2.03 |
0.51 |
0.51 |
0.51 |
0.48 |
0.53 |
1.46% | 0.13% | -5.95% | 4.36% |
|
3.03 |
0.76 |
0.77 |
0.76 |
0.72 |
0.78 |
2.06% | -0.33% | -4.35% | 2.62% |
|
3.93 |
0.98 |
1.01 |
0.98 |
0.95 |
1.00 |
2.50% | -0.41% | -3.50% | 1.41% |
|
5.11 |
1.28 |
1.31 |
1.27 |
1.24 |
1.29 |
2.72% | -0.91% | -2.61% | 0.80% |
|
6.29 |
1.57 |
1.62 |
1.56 |
1.54 |
1.58 |
2.97% | -1.09% | -2.02% | 0.14% |
|
7.25 |
1.81 |
1.87 |
1.79 |
1.78 |
1.81 |
2.97% | -1.23% | -1.63% | -0.11% |
|
8.25 |
2.06 |
2.12 |
2.04 |
2.03 |
2.06 |
2.93% | -1.18% | -1.55% | -0.20% |
|
9.22 |
2.31 |
2.37 |
2.27 |
2.28 |
2.30 |
2.96% | -1.50% | -1.25% | -0.21% |
|
10.19 |
2.55 |
2.63 |
2.51 |
2.52 |
2.54 |
3.05% | -1.51% | -1.19% | -0.35% |
|
14.70 |
3.67 |
3.79 |
3.61 |
3.64 |
3.65 |
3.17% | -1.73% | -0.83% | -0.61% |
|
19.44 |
4.86 |
5.01 |
4.78 |
4.83 |
4.82 |
3.19% | -1.73% | -0.70% | -0.77% |
|
24.28 |
6.07 |
6.26 |
5.97 |
6.03 |
6.03 |
3.05% | -1.72% | -0.60% | -0.74% |
|
29.27 |
7.32 |
7.53 |
7.19 |
7.28 |
7.27 |
2.91% | -1.74% | -0.53% | -0.64% |
|
34.12 |
8.53 |
8.78 |
8.38 |
8.49 |
8.47 |
2.97% | -1.79% | -0.50% | -0.68% |
|
38.35 |
9.59 |
9.88 |
9.41 |
9.54 |
9.53 |
3.04% | -1.88% | -0.53% | -0.64% |
|
42.75 |
10.69 |
11.02 |
10.48 |
10.62 |
10.63 |
3.09% | -1.91% | -0.63% | -0.55% |
|
46.94 |
11.74 |
12.11 |
11.49 |
11.65 |
11.69 |
3.17% | -2.06% | -0.72% | -0.38% |