P-channel load switch and reverse protection
Gate clamp, constant-Miller slew estimate and capacitive-load inrush.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Assumptions
- Gate is pulled toward ground through RG; RGS and Zener connect gate to source. Source is the incoming supply.
- Constant Miller charge produces a linear-ramp approximation. Check turn-on SOA with TR-09; gate parasitics and load dynamics can change the ramp.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Input voltage
- 12 V
- Gate pull-down resistor
- 100000 Ω
- Gate-source pull-up resistor
- 1000000 Ω
- Gate-source Zener clamp
- 10 V
- Absolute gate voltage limit
- 20 V
- Miller plateau magnitude
- 4 V
- Miller charge
- 1e-8 C
- Added drain-gate capacitance
- 1e-9 F
- Load capacitance
- 0.001 F
- Steady load current
- 1 A
- RDS(on) at actual gate voltage
- 0.05 Ω
Results
- Capacitive inrush
- 41.4545 A
- Output rise time
- 0.000289474 s
- Steady gate-source magnitude
- 10 V
- Clamp current
- 0.00001 A
- Clamp power
- 0.0001 W
- Output slew estimate
- 41454.5 V/s
- Pass-device start energy
- 0.0737368 J
- Steady conduction loss
- 0.05 W