Protect
The Protect module is your essential safeguard for preventing accidental incorrect applications of DC power from destroying your electronics.
We provide tested and proven solutions so that you can be assured your project has safeguards in place for unpredicted events.
Overview
The Protect module is an in-line circuit protection device for low-voltage DC applications between 5 V and 30 V. Use it to protect valuable downstream loads from an incorrect application of DC power from an upstream power source.
- Reverse Polarity Protection
- Adjustable 5-30V Overvoltage Protection with auto recovery behavior.
- Load Switch: Control high power loads with a mechanical switch
- Logic Level Fault Signal
- Fault Indicator LED
- Safe Indicator LED
Operation
The Protect module adjusts the overvoltage cut off (OVC) limit as a function of the OVC resistance, according to the equation:
OVC Res = (OVC – 1.95) / 2.89
Turning the potentiometer with a screwdriver adjusts this resistance with high resolution. Measure the resistance with a multimeter while rotating the potentiometer to accurately set the over voltage cutoff to the calculated cutoff.
Note: Ensure that the Protect module is unpowered while adjusting the OVC Res.
When the voltage at the input exceeds the OVC limit, the module shuts off the output within microseconds while turning the OV Fault light on and pulling the fault signal to ground. It will turn back on automatically when the voltage dips a volt or two below the OVC limit.
During normal operation, the Safe light is on and the fault signal is pulled up to Vcc.
The Protect module can also act like a high power switch by adding a single-pole-single-throw (SPST) switch to the Enable terminal block. By connecting points 1 and 2, the module is put into low power mode and disconnects the output.
Overvoltage Resistance (OVC Res) Calculator
Dimensions
The board has overall dimensions of 59.75 x 41.5 mm.
Four M2 mounting holes are included and are dimensioned as shown:
Product Specifications
Operating Voltage: 5 – 30 V
Maximum Continuous Wattage: 750 W
Maximum Continuous Operating Current: 25 A @ 25 °C ambient temperature. See picture below for 28.5 A stress test and efficiency data.
Ambient Temperature Range: 0 °C – 45 °C
WARNING: Ensure that the board temperature does not exceed 110 °C.
Overload Thermal Testing (5V 28.5A @ 25C Ambient - Least Efficient)
1. How does this product work?
The Protect module uses comparators to enable or disable back to back MOSFETs to provide over-voltage and reverse polarity protection.
Adjusting the OVC Resistor biases the overvoltage comparator that turns the blocking FET off in the event that the input voltage goes too high. The appropriate value of the OVC Resistor can be calculated from the equation in the description.
2. Why does this product work?
By adding this module in series between a power source and load, dangerous overvoltage events can be detected and blocked before they damage your circuit. The exact response time needed for an application depends upon factors such as load capacitance and the overall voltage sensitivity of the device you’re trying to protect.
3. What happens if I buy this product and I find that it doesn't work?
At PN Labs we take quality control seriously. Our automated testing procedures allow us to test each of our modules in-house to ensure functionality before being packaged and shipped.
If you find that your newly purchased product does not work, send us a message via Amazon Buyer-Seller Messaging.