Electronic – Does an over voltage, over current and reverse polarity protection IC exist


I'm designing a circuit that has the following protection requirements:

  • Reverse polarity
  • Over voltage (60v max)
  • Over current (approx 1A)

There's quite a large input voltage range, 10v to 60v.

48v is nominal, drawing about 150mA. At 10vin, it draws rougly 750mA.

I made and tested the following circuit to satisfy the conditions: (Values are working but not proved optimal)
Protection circuit 00

M1 was my starting point for reverse polarity, then the zener, divider & M2 were added for over voltage.

I found that D1 was needed when I breadboarded it, much to my annoyance as I wanted to avoid much voltage drop. (I smell redundancy…)

The fuse is the most frustrating element. I don't want to have to replace any components if there is a fault (even a fuse in a housing), so I was working with a PTC resettable fuse. Not only does this have an horrific tripping time (~4 seconds!), it also has a large footprint on the PCB; much too large for me I'm afraid 🙁

I decided it is more beneficial to me to monitor the current and turn off a FET for example, than to crowbar the circuit if such a fault should occur.

My question is…

A) Is there an IC that can take care of these three elements? I've been looking at battery charger protection ICs but I haven't found anything yet.

B) Does anyone have a suggestion about incorporating the over current requirement in my circuit without a fuse? My initial thoughts were to use a sense resistor, comparator and another FET, but I can't help but think the whole circuit could then be simplified a great deal.

Thanks for looking.

Best Answer

Try this IC: http://www.linear.com/product/LT4356-1

LT4356-1 and -2 - Surge Stopper Features

Stops High Voltage Surges
Adjustable Output Clamp Voltage
Overcurrent Protection
Wide Operation Range: 4V to 80V
Reverse Input Protection to –60V
Low 7μA Shutdown Current, LT4356-1
Adjustable Fault Timer
Controls N-channel MOSFET
Shutdown Pin Withstands –60V to 100V
Fault Output Indication
Guaranteed Operation to 125°C
Auxiliary Amplifier for Level Detection Comparator or Linear Regulator Controller
Available in (4mm × 3mm) 12-Pin DFN, 10-Pin MSOP or 16-Pin SO Packages

You should note that the previously commended LT4361 IC is similar but does not support your input voltage range requirements; many ICs out there are intended to support protection of low voltage supply buses, less support the higher voltage ranges you seek. LTC4361-1/LTC4361-2 - Overvoltage/Overcurrent Protection Controller Features

2.5V to 5.5V Operation
Overvoltage Protection Up to 80V
No Input Capacitor or TVS Required for Most Applications
2% Accurate 5.8V Overvoltage Threshold
10% Accurate 50mV Overcurrent Circuit Breaker
<1μs Overvoltage Turn-Off, Gentle Shutdown
Controls N-Channel MOSFET
Adjustable Power-Up dV/dt Limits Inrush Current
Reverse Voltage Protection
Power Good Output
Low Current Shutdown
Latchoff (LTC4361-1) or Auto-Retry (LTC4361-2) After Overcurrent
Available in 8-Lead ThinSOT™ and 8-Lead (2mm × 2mm) DFN Packages