STMicroelectronics Introduces Next-Generation Technology for Smaller, Smarter Automotive Electronics

Pioneered by ST, intelligent high-side switches provide a more reliable and efficient replacement for conventional relays. For several generations, ST’s VIPower family has offered advantages such as a common package style for many devices in the range. This allows tier-one suppliers to build several module variants using the same basic hardware and software so car makers can address differing requirements in international markets and offer various model specifications and options cost-effectively. The common-package approach has become widely adopted among high-side switch vendors.

In the seventh generation of ST’s VIPower family, the M0-7 series announced today, 75% of family members are available in a 5 x 4mm package, which is 40% smaller than the smallest competing devices. This allows car electronics designers to save pc-board space and aim for smaller module sizes. Moreover, various internal design changes increase precision, enhance diagnostic feedback, and improve reliability.

Specifically, performance improvements include greater protection against short circuits, more accurate voltage and temperature feedback, increased current-sense precision, and best-in-class electromagnetic emission (EMI) performance.

Samples of all family members are available now. The first device to enter production will be the dual-channel VND7020AJ-E, in Q2 2013, priced from $1.10 for orders over 1,000 pieces. The full range of package types available across the new family will include PowerSSO-16, PowerSSO-36, Octapak, and SO-8.

Major features of M0-7 series:
• Precise load-current, voltage and temperature-monitor feedback
• Integrated sense multiplexer
• Power-limitation and over-temperature latch-off
• Bulb / LED mode (quad channel)
• Flexible fault-reset management
• Reverse-polarity protection
• Full on- and off-state diagnostics capability
• Ultra-low quiescent current

Background to Automotive High-Side Switches
The intelligent high-side switch has an important role in the development of advanced automotive electronics. It combines a power MOSFET as the main electronically controlled switch, with logic, control and sensing circuitry in a single package. It is connected between a microprocessor and loads such as lights, motors, heaters or valves, allowing the microprocessor to control the loads in response to inputs such as dashboard switches or sensors, as well as information from the intelligent circuitry in the high-side switch. The sensors may be ambient-light sensors, rain sensors, cabin-temperature sensors, wheel-speed sensors or others depending on the type of subsystem.

By integrating sensing, control and logic circuitry, the intelligent high-side switch is able to operate reliably with different types of loads, such as highly inductive loads like motors, or resistive loads like heaters.

Moreover, these intelligent features allow the switch to perform many functions without intervention from the microprocessor, which helps engineers simplify software and utilize processor resources efficiently.

Built-in protection against conditions such as over-voltage, over-temperature and open or short circuits helps prevent damage to subsystems, modules or wiring, and allows the switch to restart when safe.

Since it is specially designed to operate on the high side of the load, connected directly to the battery voltage, the high-side switch allows the negative terminal of the load to be connected directly to the vehicle chassis. This cuts significant cost and weight from the vehicle by reducing wiring and connectors.