Intelligent switches have automotive aims

Family of high-side intelligent power switches incorporates accurate current-sensing and built-in protection circuits for 14V automotive applications.

International Rectifier has introduced the IR331x family of high-side intelligent power switches (IPS) devices with accurate current-sensing and built-in protection circuits for 14V automotive applications.

The new IPS devices enhance reliability in integrated lighting modules, intelligent glow-plug controls, auxiliary positive temperature coefficient (PTC) heaters for HVAC systems, engine cooling fan drivers and interior fan controllers.

The IR331x family provides accurate current feedback to +/-5% at maximum load current over the entire operating temperature range and demonstrates improved accuracy at low load current.

In PWM-controlled applications, the accurate current-sensing feature provides the required feedback that enables a microcontroller or ASIC to control the load current.

The current feedback bandwidth is 100kHz, also suitable for topologies where a low-side switch provides high frequency PWM, and enabling protection and load-current sensing for unidirectional DC motor drive applications.

The current-sensing feature also enables precise monitoring of load current in order to provide additional data to the microcontroller for diagnostic applications.

Typical examples include open-load detection for defective bulbs and lamps or early warning of overload conditions.

In addition, the IR3316S provides a slow-switching version of the IR3310S, which can help minimise noise in EMI-sensitive automotive applications.

In addition to the current-sense feedback, the IR331x family devices integrate overtemperature and overcurrent shutdown as well as reverse polarity protection, simplifying wiring harnesses and increasing reliability.

In many applications, additional protection devices such as fuses can be eliminated.

The overcurrent shutdown protection feature is programmable, which allows optimisation according to the requirements of the load or the application.

A soft-start mode is included for low-frequency switching.

In case of a reverse battery condition, an integrated protection circuit turns the main MOSFET switch on, helping to relieve the intrinsic body diode, reducing or eliminating thermal problems.

Additional features such as ESD protection and an active clamp circuit guarantee safe operation and protection under harsh automotive operating conditions.

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