UVLO and enable hysteresis
UVLO and enable hysteresis with explicit circuit assumptions and worked equations.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Current-injection threshold: Vin = Vpin(1 + Rt/Rb) − Iinjected Rt
External-feedback threshold: Vin = Vpin(1 + Rt/Rb + Rt/Rh) − Vout Rt/Rh
Assumptions
- Rt connects supply to sense node; Rb connects node to ground. Positive pin current is injected into the node. External mode connects Rh from comparator output to node and assumes negligible loading of output high/low.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Hysteresis method
- current
- Desired rising input
- 12 V
- Desired falling input
- 10 V
- Rising pin threshold
- 1.2 V
- Falling pin threshold
- 1.2 V
- Current injected into pin before start
- 0.000001 A
- Current injected after start
- 0.000003 A
- Top resistor (external feedback)
- 100000 Ω
- Output high
- 5 V
- Output low
- 0 V
Results
- Top resistor
- 1000000 Ω
- Bottom resistor
- 101695 Ω
- Feedback resistor
- Internal current source Ω
- Rising threshold
- 12 V
- Falling threshold
- 10 V