Hi,
I am trying to understand a circuit which is a part of current loop and it is protected for current > 100mA.
I tried simulating it using spice model (from mfgs) on LTSPICE (attached is .asc file and .lib files)
R_Load (or sense resistor), voltage across R_Load is fed to signal conditioning circuitry for decision making (which is not included).
My question/doubts are:
1. Is MOSFET working in linear region here rather than being in cutoff once overcurrent limit reaches?
Reason: Observed in simulation results
2. I have included two circuits in .asc file, one with current source (PWL - 0 to 100mA) and another with Voltage source to understand the functionality
2a. Current source to understand the functionality as this circuit is used in current loop.
2b. voltage source to check for short to battery requirement (28V)
3. As per my understanding, once the voltage across R1 (or R3) i.e. 5.6 ohm reaches above 550mV (at ~100mA). Q1 (or Q2) should TURN ON and U1 (or U2) the MOSFET should TURN OFF, is this correct?
4. Is base resistor required for Q1 (or Q2)?
4a. If base resistor is not used, is there a chance of BJT being damaged, since no base resistor is there?
5. The way I am doing the simulation is wrong?
Thanks in Advance
I am trying to understand a circuit which is a part of current loop and it is protected for current > 100mA.
I tried simulating it using spice model (from mfgs) on LTSPICE (attached is .asc file and .lib files)
R_Load (or sense resistor), voltage across R_Load is fed to signal conditioning circuitry for decision making (which is not included).
My question/doubts are:
1. Is MOSFET working in linear region here rather than being in cutoff once overcurrent limit reaches?
Reason: Observed in simulation results
2. I have included two circuits in .asc file, one with current source (PWL - 0 to 100mA) and another with Voltage source to understand the functionality
2a. Current source to understand the functionality as this circuit is used in current loop.
2b. voltage source to check for short to battery requirement (28V)
3. As per my understanding, once the voltage across R1 (or R3) i.e. 5.6 ohm reaches above 550mV (at ~100mA). Q1 (or Q2) should TURN ON and U1 (or U2) the MOSFET should TURN OFF, is this correct?
4. Is base resistor required for Q1 (or Q2)?
4a. If base resistor is not used, is there a chance of BJT being damaged, since no base resistor is there?
5. The way I am doing the simulation is wrong?
Thanks in Advance
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