Renard64 Power Supply Calculations
Power Supply Calculations for Renard64
This will be divided into two parts. The first part is the power draw calculation, the second part is the power supply margin calculations for that load.
Power Draw
| Item | Calc | Value | Qty | Total |
|---|---|---|---|---|
| PIC16F688 | 3mA (assumed) | 3mA | 8 | 24ma |
| Power LED | 3V/300Ω | 10 mA | 1 | 10mA |
| RS485 RX chip | 0.5mA | 1mA | 1 | 1mA |
| RS485 TX chip | 0.9mA | 1mA | 1 | 1mA |
| RS485 Terminator | 3.6V/120Ω | 30 mA | 1 | 30mA |
| Channel LEDs | 3V/650 = 4.6mA | 4.6mA | 64 | 295mA |
| SSR Optos | 4V/650 = 6.2mA | 6.2mA | 64 | 394mA |
| SSR Power LEDs | 3V/650 = 4.6mA | 4.6mA | 8 | 37mA |
| Total | 792mA |
Notes:
1)680Ω Resistors are assumed to be at about -5% (650Ω)
2)PIC16F688 maximum current is not specified, but assumed to be 3mA.