Lightning strikes, battery failures, power surges, and disasters result in costly, unnecessary downtimes. Faults are inevitable, but system power protection ICs avert field failures and unanticipated downtime by diminishing the damaging consequences of reverse voltage, overcurrent, over-temperature, hot-swap, and overvoltage fault conditions often encountered in industrial, medical, e-mobility, and other environments. Integrated power protection ICs also reduce BOM cost and design time. These ICs secure all voltage, temperature, and current faults within a single chip. This blog will discuss common failures and how Maxim Integrated's protection ICs can safeguard the power system.
The power supply and its components must be shielded from load faults for any electrical or electronic system to work properly. The load must be defended against excessive current, voltage, or other supply faults. These faults range from a short circuit and associated high currents, to electrostatic discharge induced transients and voltage spikes. A few faults happen as a result of component failure, while others can be traced back to a wiring mistake, such as a reverse voltage connection. A system fault can be the consequence of deficient supply voltage.
Power protection ICs ensure that the input voltage to a load to ensure it remains within designated bounds. Detection of an out-of-bounds level compels the protection and control ICs to either regulate the voltage, current or switch off the power source to protect the load from damage. Reverse-voltage protection prevents system damage if the input voltage is accidentally reversed or when the output voltage is shorted to a higher voltage rail. They also offer an assortment of functions, from load switching (for example, with USB power switches) to fully configurable undervoltage, overcurrent, and overvoltage monitoring. Dedicated protection and control circuits administer in-rush current and redundant power systems for hot board insertion applications.
Maxim Integrated offers a wide variety of system protection ICs integrated with back-to-back MOSFETs for tough protection with nanosecond response times. Product attributes include inrush current limit, thermally controlled current fold back, e-Fuse/overload limit, reverse voltage, current monitoring, and power limit. We will discuss a few power protection IC with use-case applications.
MAX17613 - Current-Limiter with OV, UV, and Reverse Protection IC
Maxim's MAX17613 series IC is an integrated system protection solution from the Olympus series. This solution is a compact, adjustable overcurrent and overvoltage protection device, suited for shielding systems against positive and negative input voltage faults within the +60V and -65V range. It features low RDS (ON) FETs with an input overvoltage protection range from 5.5V to 60V, and undervoltage protection range from 4.5V to 59V. The maximum programmable current-limit protection is 3A. It is thus important to control the inrush current during startup while charging high capacitance at the output. When the device current reaches the scheduled threshold, the device modulates the FET resistance to stop further rise in current. A dual purpose SETI pin characterizes this device to set the current limit through the device, programmed by a resistor connected from SETI to GND. The current limit can be programmed between 0.15A to 3A. This pin also presents a voltage concerning GND, proportional to the device current under normal operation, and reflects the current flowing through the on-board FETs, enabling current monitoring capability.
There exist three distinct ways to program it under the current-limit condition: auto-retry, continuous, or latchoff modes. The MAX17613 series IC features thermal shutdown protection against excessive power dissipation. It is available in a small, 20-pin (4mm x 4mm) TQFN-EP package and operates over the -40°C to +125°C extended temperature range. Figure 1 illustrates an application circuit using this IC. The MAX17613 finds wide use in sensor systems, process instrumentation, condition monitoring, and factory sensors.
Figure 1: MAX17613 Typical Application Circuit
MAX17612 - 4.5V to 60V, 250mA Current-Limiter with OV, UV, and Reverse Protection IC
The current limiter MAX17612 series comes with adjustable overvoltage, reverse protection, and undervoltage IC. It is a good fit to safeguard systems against negative or positive input voltage faults within the +60V to -65V range, and features low 1.42Ω RDS(ON) FETs. The overvoltage protection range is 5.5V to 60V, and the undervoltage protection range is 4.5V to 59V.
The attributes of the MAX17612 include programmable current-limit protection up to 250mA. It consequently controls the inrush current during startup while charging high capacitances at the output. When the device current stretches to the programmed threshold, the component inhibits further increases through FET resistance modulation. It is available in a compact 10-pin (3mm x 3mm) TDFN-EP package, which conserves board space. These devices work over the -40°C to +125°C extended temperature range. Figure 2 illustrates a typical MAX17612 series IC application circuit. This series IC is widely used in weighting and batching systems, industrial applications such as PLCs, Battery-Operated Modules, Control networks, and Modules.
Figure 2: MAX17612 Typical Application Circuit. (MAX17612A blocks current flowing in the reverse direction whereas MAX17612B allows current flow in the reverse direction.)
MAX17526 - 5.5V to 60V, 6A Current-Limiter with OV, UV, Reverse protection and Power Limit IC
The MAX17526 series is a 6A Current-Limiter with OV, UV, Reverse Protection, and Power Limit IC. This adjustable power limiter, among multiple protection features, offers some unique features to restrict power extracted from supplies or delivered to loads. Such protection attributes include adjustable input overvoltage and under-voltage protection, overcurrent protection, positive and negative input voltage protection, reverse-current protection, and over-temperature protection. The device comes with an integrated low RDS(ON) (30mΩ type) NFET, along with an integrated gate driver for an optional external NFET. It underlines a power restriction feature that permits planned current limit reductions as an inverse function of an external voltage. Input or output power limit is accomplished by restricting the current through the device as a function of input or output voltages, respectively.
The input undervoltage protection level can be adjusted between 5.5V and 24V, and the overvoltage protection level is adjustable from 6V to 40V. It features programmable current limit protection up to 6A. The continuous current limit feature offers inrush current control during startup while charging high capacitances at the output side. MAX17526 is available in three different versions A, B, and C, with different inrush current capacity as a function of the current limit level. The MAX17526A version has inrush as 1x the current limit, while the B and C version has 1.5x and 2.0x. Thus, MAX17626C allows the inrush current to reach twice as much the set current limit, permitting the system to charge large output capacitors twice as fast.
The MAX17526A also caters to input reverse voltage polarity protection and reverse-current protection when installed with an external NFET and integrated overtemperature protection. It is available in a 20-pin 5mm x 5mm TQFNEP package. The MAX17526A finds use in applications like Industrial Power Distribution Systems, Human Machine Interfaces, and Control and Automation systems.
Figure 3: MAX17526 Typical Application circuit
Power management plays a major role in virtually every piece of electronic equipment. If you'd like to know more about how to approach power management in your designs or products, click here for more information.
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