Power Module Max Draw Capability Requirements
- James May (RIT Student)
2/27/23 Requirements
Changes: Removed future board(s) allotment
Absolute Maximum Draw
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 80 (LEDs) | 15 |
| Power | 277 | 0 | 1532 (from calculation below) |
| Autopilot | 0 | 760 | 0 |
| Radio | 605 | 0 | 0 |
| Sensor + PROMPT | 815 | 45 | 0 |
| Total | 1697 | 885 | 1547 |
Max Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (1697mA * 3.3V + 885mA * 5V) * 1.1 = 11,028mW
Current = 11,028mW / 7.2V = 1,532mA
Expected Draw
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 0 | 15 |
| Power | 107 | 0 | 394 (from calculation below) |
| Autopilot | 0 | 74 | 0 |
| Radio | 259 | 0 | 0 |
| Sensor + PROMPT | 265 | 25 | 0 |
| Total | 631 | 99 | 409 |
Expected Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (631mA * 3.3V + 99mA * 5V) * 1.1 = 2,835mW
Current = 2,835mW / 7.2V = 394mA
2/18/23 Requirements
Changes: Updated values from other modules & added expected draw
Absolute Maximum Draw
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 80 (LEDs) | 15 |
| Power | 277 | 0 | 2166 (from calculation below) |
| Autopilot | 0 | 760 | 0 |
| Radio | 605 | 0 | 0 |
| Sensor + PROMPT | 815 | 45 | 0 |
| Future Board(s) Allotment | 500 | 500 | 0 |
| Total | 2197 | 1385 | 2181 |
Max Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (2197mA * 3.3V + 1385mA * 5V) * 1.1 = 15,593mW
Current = 15,593mW / 7.2V = 2166mA
Expected Draw
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 0 | 15 |
| Power | 107 | 0 | 394 (from calculation below) |
| Autopilot | 0 | 74 | 0 |
| Radio | 259 | 0 | 0 |
| Sensor + PROMPT | 265 | 25 | 0 |
| Future Board(s) Allotment | 0 | 0 | 0 |
| Total | 631 | 99 | 409 |
Expected Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (631mA * 3.3V + 99mA * 5V) * 1.1 = 2,835mW
Current = 2,835mW / 7.2V = 394mA
11/4/22 Requirements
Changes: Updated power requirements from other modules
Absolute Maximum
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 0 | 55 |
| Power | 0 | 0 | 1584 (from calculation below) |
| Autopilot | 11 | 500 | 1000 |
| Radio | 565 | 0 | 0 |
| Sensor | 400 | 100 | 0 |
| Future Board(s) Allotment | 500 | 500 | 0 |
| Total | 1476 | 1100 | 2639 |
Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (1476mA * 3.3V + 1100mA * 5V) * 1.1 = 11,408mW
Current = 11,408mW / 7.2V = 1,584mA
Takeaways
- Battery shall be able to handle 2639mA transient power draw @ 7.2V
- 5V circuitry shall be able to supply 1100mA
- 3.3V circuitry shall be able to supply 1476mA
- All traces shall be rated for their appropriate current requirements
- 3.3V → 1100mA max
- 5V → 1476mA max
- 7.2V → 2639mA max
10/5/22 Requirements
2022 Backplane
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 0 | 60 |
| Power | 0 | 0 | 945 (from calculation below) |
| Autopilot | 0 | 500 | 1000 |
| Radio | 565 | 0 | 0 |
| Sensor | 400 | 100 | 0 |
| Total | 965 | 600 | 2005 |
Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (965mA * 3.3V + 600mA * 5V) * 1.1 = 6,803mW
Amperage = 6,803mW / 7.2V = 945mA
2022 Backplane & Future-proofing
| Module | 3.3V Rail Max Required Current (mA) | 5V Rail Max Required Current (mA) | 7.2V Battery Max Required Current (mA) |
|---|---|---|---|
| Backplane | 0 | 0 | 60 |
| Power | 0 | 0 | 2212 (from calculation below) |
| Autopilot | 0 | 500 | 1000 |
| Radio | 565 | 0 | 0 |
| Sensor | 400 | 100 | 0 |
| Future Board(s) Allotment | 1000 | 1000 | 1000 |
| Total | 1965 | 1600 | 4272 |
Power Board Battery Draw Calculation
Assume 90% step down efficiency
Power = (1965mA * 3.3V + 1600mA * 5V) * 1.1 = 15,933mW
Amp-hours = 15,933mW / 7.2V = 2,212mA
Takeaways
- Battery shall be able to handle 4,272mA transient power draw @ 7.2V
- Battery shall be able to handle 3,272mA continuous power draw @7.2V
- 5V circuitry shall be able to supply 1600mA
- 3.3V circuitry shall be able to supply 1965mA
- All traces shall be rated for their appropriate current requirements
- 3.3V → 1965mA max
- 5V → 1600mA max
- 7.2V → 4272mA max