Overcurrent Protection Integrated Circuit

Thread Starter

Peter523

Joined Aug 15, 2021
91
Hello,

i have designed some DC-DC converters (buck and boost) and i would like to add some overcurrent protection in series with the load connected on the output of the converters. Is there any IC offering this protection (maybe something like creating an open circuit on the output when current reaches a threshold)?

Thanks.
 

Papabravo

Joined Feb 24, 2006
16,936
Hello,

i have designed some DC-DC converters (buck and boost) and i would like to add some overcurrent protection in series with the load connected on the output of the converters. Is there any IC offering this protection (maybe something like creating an open circuit on the output when current reaches a threshold)?

Thanks.
There are a variety of techniques for doing this, but I am not aware of a dedicated IC that performs this function ONLY. It is however a feature of many SMPS controller IC's which seem to have ever higher levels of functional integration. This high level of integration comes at a higher price and perhaps other compromises. Using current mode control in your control scheme is usually the first level of protection.
 

schmitt trigger

Joined Jul 12, 2010
467
There was a device by Maxim Semiconductor that would do exactly what you want.
But for the life of me I can’t remember the part number.

The device was designed for backplane hot-swap controller, which includes current limiting, re-start options, soft starting and other goodies.

You may want to perform a Google check.
 

Thread Starter

Peter523

Joined Aug 15, 2021
91
You didn't specify anything about your Load.
Here are 2 examples that may give You some ideas ...........
.
.
.
Well i have in mind something like your first attachement. For now, let's assume that my load is ohmic (voltage on it 12V,5V and 3.3V) and the max current that may pass through is about 3.5 or 4 Amps.
 

LowQCab

Joined Nov 6, 2012
1,183
The LTC1153 Controller, (plus MOSFET), might be quite a bit more
complexity than You really need.

The NTE15005E Family of pre-set, 2-Wire devices,
is probably better suited to protecting Micro-Controllers and individual Chips.
.
.
.
 

Thread Starter

Peter523

Joined Aug 15, 2021
91
The LTC1153 Controller, (plus MOSFET), might be quite a bit more
complexity than You really need.

The NTE15005E Family of pre-set, 2-Wire devices,
is probably better suited to protecting Micro-Controllers and individual Chips.
.
.
.
As i observe ,the NTE15005E provides protection up to 1 Amps but i would like to have protection from currents higher than ~3.5-4Amps.
 

LowQCab

Joined Nov 6, 2012
1,183
Individual means of protection is far safer for the protected individual devices
because the Current-Trip-Level can be much closer to
the amount of Current that the device normally draws.

Poly-Switch Fuse selection can be tricky to get right, because they are Thermal-based.

The LTC1153 Controller can be tailored to anything that You need,
and can be instant, or utilize a delay, and will trip at a precisely set level of Current.
The Current-Range is virtually unlimited.
.
.
.
 

Papabravo

Joined Feb 24, 2006
16,936
So when current reaches Itrip the circuit will be immediately cut off.
I don't think so. The mechanism is more like a variable resistor than a switch. The overcurrent condition generates heat and the heat changes the device from low resistance to a higher resistance which reduces the current and thus the heat. It does not shut the current off completely, it just reduces the magnitude.
 

Thread Starter

Peter523

Joined Aug 15, 2021
91
I don't think so. The mechanism is more like a variable resistor than a switch. The overcurrent condition generates heat and the heat changes the device from low resistance to a higher resistance which reduces the current and thus the heat. It does not shut the current off completely, it just reduces the magnitude.
That's excactly why i ask. I would like something that immediatly cuts the circuit off. As @LowQCab mentioned LTC1153 seems appropriate solution but its min supply voltage is 4.5V and i can only supply 3.3 Volts.
 

Deleted member 115935

Joined Dec 31, 1969
0
look at the analog devices web site,
a complete bunch of power control chips,
including hot swap and "fuses"

Ti have a fair range as well,
 

LowQCab

Joined Nov 6, 2012
1,183
"" As @@LowQCab mentioned LTC1153 seems appropriate solution but its min supply voltage is 4.5V and i can only supply 3.3 Volts. ""

You stated earlier that You have 3 Voltages,
now it's only 3.3-Volts ?
I'm pretty sure that the Chip can be powered separately from the Load.
I'd have to look again to make sure.
.
.
.
 

Thread Starter

Peter523

Joined Aug 15, 2021
91
"" As @@LowQCab mentioned LTC1153 seems appropriate solution but its min supply voltage is 4.5V and i can only supply 3.3 Volts. ""

You stated earlier that You have 3 Voltages,
now it's only 3.3-Volts ?
I'm pretty sure that the Chip can be powered separately from the Load.
I'd have to look again to make sure.
.
.
.
The 3 voltages are the outputs of the DC-DC converters and on them will be connected the loads. My supply voltage comes from a microcontroller and it is 3.3V . (sorry if not clear).
 

LowQCab

Joined Nov 6, 2012
1,183
A Fuse and a 5-Watt Zener-Diode will do the job of protection from Over-Voltage.
Appropriate Load-Resistors will prevent any Over-Current problems.
.
.
.
 

Thread Starter

Peter523

Joined Aug 15, 2021
91
A Fuse and a 5-Watt Zener-Diode will do the job of protection from Over-Voltage.
Appropriate Load-Resistors will prevent any Over-Current problems.
.
.
.
What do you mean with Load-Resistors?To add resistors in series with load to reduce the current?
 
Top