Description
📝 Overview
The PN Labs FlexTrip module is a unidirectional, adjustable electronic fuse plus ideal diode designed for 3-22 V with up to 5 A of continuous current. Featuring overcurrent levels ranging from 0.5-5.5 A via solder jumpers, it fits nicely onto a standard breadboard and even has castellated edges making it suitable for soldering to a larger PCB.
This module is an excellent replacement for fast-blow resistive fuses that have to be reset often. Upgrading older fuses with newer technology removes the need of having to swap one out every time it trips- just reset the module electronically or mechanically.
✅ Key Features
- Solderable jumpers for setting overcurrent levels of 0.5, 1, 2, 3, 5, 5.5 A.
- Power Switch Capability:
Toggle loads via pulling the reset (RST) pin high. - Power Good (PG) Signal
Open-drain PG signal is normally pulled high to Vcc and otherwise goes LOW during a fault event—tells your microcontroller that power is safely flowing through the IC. - Status LED: A green SAFE LED visually indicates that power is safely flowing through the IC.
- Thermal Shutdown feature and on-board SMD fuse: In the event that the steady state current draw is exceeded and the board overheats, the IC has a thermal shutdown feature that will kick in around 140-150 C. There is also an 8 A series fuse on the module as a last resort in case a rapid power surge destroys the IC before the shutdown can respond.
- Soft-start feature: The output gets ramped at around 1 V/ms into your circuit, which helps reduce inrush current on start up and provides a smooth turn-on.
Breadboard and SMT Compatible, with space for terminal blocks (included):
A small 20×26 mm footprint that fits on a standard breadboard makes this ideal for prototyping circuits. It also can be soldered to a larger PCB via castellated pads (SMT footprint available).
Response to Over-Current
FlexTrip is meant to replace fast blow DC fuses that operate at voltages between 3-22 V.
When the current limit is exceeded, it operates in either fast trip or active current limiting mode.
If the exceeded current is lower than double the set threshold current , the device will act like a linear regulator and drop some of the voltage across itself to maintain the threshold current. If the temperature limit of the device is exceeded in this mode, the unit shuts down and is not enabled unless the reset (RST) button is pressed or a 3-15 V signal is applied to the reset pin.
If the current exceeds more than double the set limit, the device turns off without any active current limiting (fast-trip mode)
🟢Normal Operation
When operating within safe voltage limits:
The SAFE (green) LED is illuminated
The Power Good (PG) signal pin is pulled high to Vcc.
- The series resistance of the module is approximately 37 mOhm.
🔌 Resetting the Module after overcurrent events
When the module experiences an overcurrent event and shuts off, it can be reset by pushing the reset (RST) button or by sending an electrical pulse to the reset pin ranging from 3 to 15 V.
Note that this board is only rated for 5 A of continuous current. The 5.5 A setting is meant as a transient condition only. The thermal shutdown feature of the IC will trigger if you attempt to draw this much current continuously without a heat sink.
📘 Additional Resources
Learn more information to effectively use the FlexTrip in a variety of applications. All content belongs to the original owners, which we have linked.
[Continuous Over-Voltage Protection Circuits]:
- Understand the pros/cons of solid-state OVP circuits on our blog post here.
[Power ORing and Multiplexing]:
- Intro to Power Multiplexing: Texas Instruments Application Report (Basics of Power Mux)
- Concerns of Power Mux: Texas Instruments Application Report (Power Multiplexing Using Load Switches and eFuses)
[Intro to e-Fuses]:
- GreatScott! Explains how eFuses work and why they are awesome (YouTube)
Compare FlexTrip with the Protect Nano, which has built in over and under voltage cutoffs.
Nice product. I use it to protect my battery from being shorted from my ESP32 project that i have put outdoors.