The beneficial ripple effect of new automotive power devices

One of the many things we learn from the history of technology advances in materials, techniques, production, components, and more is that advances in one area are often adopted and adapted and so lead to breakthroughs in others. In some cases, the related advance is in a related field, while in others the benefits are leveraged in fairly distant areas, apparently unrelated applications.

The best exposition of this ongoing back-and-forth scenario was in Connections, a 1970s British television series created, written, and presented by science historian James Burke. He showed how seemingly unrelated developments led directly and indirectly to advances developed by others. Although some of the relationships and paths he highlighted were perhaps somewhat tenuous, the message is still very valid, timely, and relevant. (Fortunately, the episodes are still fascinating despite their age and are available on YouTube.)

As just one example: the heat-resistant Pyrex borosilicate glass used in consumer bakeware was first developed in 1893 by German chemist and glass technologist Otto Schott, founder of Schott AG. However, it was not developed for kitchen needs. Instead, Eugene Sullivan, director of research at Corning Glass Works, enhanced it and developed Nonex (then modified and named Pyrex) with the goal of reducing the serious problem of glass self-shattering due to the thermal shock.

This occurred when hot lantern globes, railway signals, and even battery jars (the glass containers of widely used rechargeable lead-acid batteries of that period would heat up during charge/discharge cycles) were exposed to cooling rain. Sullivan then had his wife test this glass in bakeware and the rest in consumer-product history, as they say.

I suspect that the outpouring of new power components we are seeing as automobiles are increasingly electrified in their power train, infotainment systems, accessories, and more will have similar unanticipated ripple effect for non-automotive situations others where higher voltages/currents, ruggedness, and temperature-range performance is needed.

It’s not practical or useful to provide a comprehensive list, but here are four of the automotive power-handling and power-related new products I have seen recently, all meeting the relevant AEC-Qxxx standards:

1. The TLX9160T solid-state photorelay from Toshiba Electronic Devices and Storage Corporation (TAEC) targets vehicle requirements related to the battery management system (BMS), ground fault detection, and identifying faults with mechanical relays. This photorelay is the solid-state functional equivalent of the basic, normally open (NO), 1-Form-A classic single-pole single-throw (SPST) electromechanical relay, Figure 1.

Figure 1 The TLX9160T solid-state photorelay from Toshiba Electronic Devices and Storage Corporation (TAEC) comes very close to being the solid-state functional equivalent of the basic, normally open (NO), 1-Form-A classic single-pole single-throw (SPST) electromechanical relay, while also bringing some other benefits.

2. The Texas Instruments LM74720-Q1 and similar LM74721-Q1 ideal diodes provide high-performance control over a pair of external n-channel MOSFETs via a dual gate-drive topology, for active rectification and reverse-battery protection on automotive DC rails, Figure 2. One of these MOSFETs is controlled to emulate an ideal diode while the other MOSFET is for power-path on/off control, inrush-current limiting, and overvoltage protection. 

Figure 2 The Texas Instruments LM74720-Q1 and similar LM74721-Q1 ideal diodes enable high-performance active rectification and reverse-battery protection. 

3. The INN3947CQ-TL and INN3949CQ-TL AEC-Q100-qualified switching power-supply ICs developed by Power Integrations integrate a 1,700-V-rated SiC MOSFET to power low-voltage electrical systems in 600- and 800-V battery and fuel-cell electric vehicles, Figure 3. These additions to their InnoSwitch 3-AQ family are the core of a simple, compact solution useful for providing up to 70 W for air conditioners, body control electronics, and other vehicle subsystems.

Figure 3 The INN3947CQ-TL and INN3949CQ-TL switching power-supply ICs from Power Integrations integrate a 1,700-V-rated SiC MOSFET for 600- and 800-V battery packs and fuel cells.

4. The VN9D30Q100F from STMicroelectronics is multichannel high-side driver, Figure 4. The six-channel device has two 33-mW and four 90-mW channels while the similar VN9D5D20FN is a four-channel device with two 7.6-mW and two 20-mW channels. They target both inductive motor loads such as power-assisted motor-driven windows and resistive loads such as heated seats, and include SPI connectivity and digital current sensing as well as many on-chip diagnostic features.

Figure 4 The VN9D30Q100F from STMicroelectronics is 6-channel high-side driver with digital “smarts” as well as extensive diagnostic and fault-detection/reporting features.

Can you see a place for these components in non-automotive designs? Have you ever found the solution to your design difficulty by reaching out to devices which were ostensibly targeted at other applications, rather than yours?

Bill Schweber is an EE who has written three textbooks, hundreds of technical articles, opinion columns, and product features.

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