Power Adapter Safety Protections: OVP, OCP, SCP, OTP Explained

Power supplies usually come with multiple protection circuit designs including over voltage protection (OVP), under voltage protection(UVP), over current protection (OCP), over power protection (OPP), over temperature protection (OTP), and short circuit protection (SCP). Most suppliers of this product skip some of these, e.g., OCP and OTP, in their product due to lower probability of occurrence. We noticed some posts on the Internet concerning computer burnout and scorched power supplies. Fortunately no fire accidents were reported. Most FSP products are designed with OTP to power off the power supplies when internal temperature is too high. Otherwise, components in the power supply may get burnt and lead to a fire due to over temperature.

Most power supplies are safety certified. Usually they are tested and certified under conditions of output at full load, but not always at high ambient temperature. A test standard of 35°C is normal as internal temperature of most computers is at this level. Some suppliers may get a safety certification at ambient temperature of 25°C for cost saving while those more concerned about quality may test at temperature of 40°C. Still other manufacturers test their power supplies at temperature of 50°C to set them the top server grade specification compliant.

Most FSP power supplies are designed with safety certification at ambient temperature of 40°C. Products featuring OTP are subject to vigorous internal design verification process. Under conditions of rated lower or upper limit of input voltage at full load and ambient temperature beginning at the safety specification value, the test goes by raising temperature in steps of 5°C upward until the OTP mechanism is enabled. The product then goes through a full range of inspections including identifying any of its key components suffers temperature over its rated upper limit and none of them were burnt out before triggering the protection mechanism. See the table below for the test results of our flagship product—650W power supplies with OTP:

AC input: 90Vac/264Vac

Frequency: 47Hz/63Hz

Ambient temperature: Start from 45°C till OTP occur, 5°C/step

Load:

( UNIT:℃)

The increasing popularity of virtual reality (VR) products is leading to fast growing demands for advanced computers of compact size, which suffers worse ventilation compared to their tower counterparts with larger volume and radiation space. High-end graphics card built in these computers raise their internal ambient temperature above 35°C. It is beyond our worst imagination for systems built with power supplies without OTP feature. Gamers, please pay special attention to this electric specification most often neglected.

Modern battery chargers are packed with smart protection features to prevent damage, ensure user safety, and extend battery life. But what do all those acronyms—OVP, SCP, OTP, etc.—actually mean?

In this guide, we’ll break down the most common battery protection features used in intelligent chargers and Battery Management Systems (BMS), and explain why each one matters.

1.OVP – Overvoltage Protection

What it does:

Prevents the battery from receiving a voltage higher than its safe limit.

Why it matters:

Too much voltage can overcharge lithium batteries, risking thermal runaway, swelling, or even fire. OVP shuts down or limits the charger to stay within safe voltage parameters.

2.OTP – Overtemperature Protection

What it does:

Monitors the charger and battery temperature. If it gets too hot, charging is paused or slowed down.

Why it matters:

Heat is a battery’s enemy. OTP protects against overheating, preventing damage to internal cells, chargers, and surrounding electronics.

3.SCP – Short Circuit Protection

What it does:

Instantly stops current flow if a short circuit is detected in the output.

Why it matters:

Short circuits can cause sudden current surges, damaging chargers and batteries. SCP is a critical safety feature in both home and industrial use.

4.OCP – Overcurrent Protection

What it does:

Limits the current output to prevent excess flow beyond safe levels.

Why it matters:

Overcurrent can lead to overheating, cell imbalance, or damage to sensitive battery chemistries (especially in Li-ion or LiFePO₄). OCP ensures smooth, safe charging.

5.RVP – Reverse Polarity Protection

What it does:

Prevents charging if the battery is connected with the wrong polarity.

Why it matters:

Accidental reverse wiring is a common issue. RVP protects the charger and battery by blocking current or triggering an alert if cables are reversed.

6.UVP – Undervoltage Protection

What it does:

Stops the charger from operating if the battery voltage drops too low.

Why it matters:

Discharging a battery too far (especially lithium types) can cause permanent damage. UVP ensures that charging only begins when the battery is within a recoverable range.

Why These Features Matter

Smart protection is not optional—it’s essential for:

• User safety
• Battery longevity
• Reliable performance in tough environments
• Compliance with international standards

Looking for a charger with full protection? Explore our Smart Charger Series that includes OVP, OCP, SCP, OTP, RVP, UVP and more.

Bonus: Want More?

Learn how smart chargers and BMS work together to optimize battery health in real time: