Intelligent Power Switches for Demanding Safety Applications

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  • STMicroelectronics’ latest upgradation of its power switch family by addition of two new devices provides safe circuit operation in automation and process control machines
  • Both devices come with a wide electrical and thermal protection features

STMicroelectronics has added new fast-starting devices to its family of intelligent power switches for safety-instrumented systems. With power-on delay time of less than 60µs, the IPS160HF and IPS161HF meet standardised requirements for types C and D interfaces in Safety Integrity Level (SIL) Class 3 applications.

These devices safely drive complex resistive, capacitive and inductive loads such as valves, relays and lamps with one side ground connected. Besides SIL-rated applications such as safety sensors, they can be used in general factory-automation and process-control equipment such as Programmable Logic Controllers (PLCs), I/O peripherals and Computer Numerical Control (CNC) machines.

Efficiently driving circuits

The IPS160HF and IPS161HF intelligent power switches integrate a logic interface, driving circuitry, various protection features and an N-channel power-MOSFET output stage. The minimum output current for the IPS160HF and the IPS161HF is 2.5A and 0.7A respectively. Both devices can withstand an applied supply voltage of up to 65V and integrate active-clamp circuitry for handling inductive loads.

Electrical eatures

  • Input-voltage range = 8V-60V
  • Maximum switch resistance (RDS(on)) of 120mΩ 
  • Rise/fall time = 10µs
  • Propagation delay = 20µs 

Built-in protection to safeguard the IC and load against overstressing includes:

  • ground-disconnect and VCC-disconnect protection
  • thermal shutdown
  • undervoltage lockout
  • short-circuit cut-off 

The cut-off acts after a delay time, which has been programmed with an external capacitor and provides non-dissipative protection to minimise overheating.

These devices combine design flexibility, low power dissipation and fast response. Extended diagnostics allow the designing of safety-instrumented functions by indicating open load, over-current cut-off and over-temperature shutdown.

The IPS160HF and IPS161HF are in production now and available in the thermally enhanced PowerSSO12 package.


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