Full Bridge Gate Drivers: Improving the Driver Experience with Electrification
As automotive systems become increasingly automated and electrified for safety and convenience, the safety, reliability, and longevity of the components that drive these systems must improve.
Smaller than competitive solutions, the 4 mm × 4 mm QFN package size allows for less space necessary on PCB and allows for the possibility of overall design size to be minimized depending on other components/applications. Integrated features help to minimize external components previously necessary with traditional relay designs. This allows designers to add features and reduce module size. Ultimately, the smaller design of the two solutions requires less material, which allows designers to lower their overall weight and costs throughout the larger systems often seen throughout vehicles and pass these values onto the consumer through better mileage.
The solid-state design (as opposed to a traditional mechanical relay design) offers a contactless, silent solution, bringing many tangible benefits and increased product longevity. These range from wear considerations to safety considerations, Solid state NMOS have a nearly infinite lifetime due to no mechanical components. Additional protections such as reverse battery protection afforded by SSD, further native safety features such as voltage and current protections including OVP, OCP and OCL, as well as decreased noise, making the solution more desirable and manageable for customers, and ultimately better for the end-user.
Figure 1. Schematic of the Solid-State-Design. Image used courtesy of Bodo’s Power Systems
Gate Driver Design Features
Allegro’s gate driver design offers flexibility for customers concerning advanced diagnostics and what they can see and control: Programmable timing allows PWM optimization for required load; on-the-fly current limit monitoring allows for enhanced safety for current management and heat management when in harsh conditions; short circuit protection is also built into the A89505 and A89506; lastly, from a designer perspective, current feedback output provides more in-depth information about what is causing fluctuations in load, a feature that is particularly helpful when confronted with issues such as stalls or pinches in load. These are all offered via integration into the solution rather than via interface with external components, reducing the need for excess external circuitry and components.
With many advanced features worked into a smaller footprint, the A89505 and A89506 are ideal for many ICE and EV applications of today, while their flexibility points towards being ideal for consumers’ ever-evolving desires for convenience-driven features as well as requirements for their designs, keeping Allegro’s partners ready for the future as technology advances.
As with other components, the A89505 and A89506 have distinct characteristics that make them an attractive option to varying parties at different points in their lifecycle, from engineers who chose them for adoption in a platform or solution to the overall benefit of the customers who use the final product. Many of the same aspects’ impact can be felt throughout the lifecycle, albeit in very different ways. While many of the already-mentioned aspects are advantages for system designers, it is important to note the advantages these components have for drivers and passengers of the vehicles the components are in. Many of these include convenience features such as a self-actuating tailgate lift (activated by motion detection under the rear bumper), buttons to control electronic parking brake locks, electronic seat movement, and folding side mirrors.
Figure 2. Button for electronic parking brake. Image used courtesy of Bodo’s Power Systems
Vehicle Electrification and EV Adoption
Once relegated to higher-end vehicles, these features have become increasingly adopted in vehicles across the entire pricing spectrum. As these become more commonplace—even standard features— and other newer technologies crop up, ready to leap across the price point gap, it is important to have technologies in place in systems that allow for reliable operation for years to come. Vehicle electrification and EV adoption will undoubtedly push customers to desire newer, cutting-edge convenience features as they are unveiled, and the stability of solid-state designs is an important part of their rollout. To further emphasize how important the reliability of components controlling many convenience features are, it should be noted that several of the previously mentioned features, and many others like them, are not simply convenience features but accessibility features for those with injuries and disabilities that significantly aid these consumers during their daily routines, remaining as stress-free as possible while on the road.
More stable and reliable components also reduce another major headache for the consumer in that vehicle electrification will lead to fewer visits to the mechanic for maintenance. As consumers overwhelmingly know, one of the largest headaches of vehicle ownership comes from the time and money, often compounding, that is spent at the mechanic when an issue occurs. Integrating solid-state components such as the A89505 and A89506 and stabilizing the reliability of systems throughout the vehicle, from HVAC to engine to suspension and brakes, will help to eliminate the headaches that no consumer likes to have but many surely expect to experience today.
Advantages for EV Drivers
A major convenience feature for EV drivers is a quiet drive. While road noise certainly plays a role in the experience in the cabin of a moving vehicle, the most obvious culprit is the engine. Electric vehicles run on batteries and as such are nearly silent in their propulsion. Solid state solutions operate entirely silently, as opposed to mechanical or relay-based designs, which contribute to the noise heard from the cabin; furthermore, as physical solutions age, they can begin to get progressively louder until they fail, wherein a visit to the mechanic is necessary. Reliable solid-state solutions help avoid this inconvenience and frustration.
As vehicles increasingly rely on electrical systems for controls and operation, and components are consistently weighed against one another for their reliability, solid-state designs are surely poised to have a higher adoption rate, and the A89505 and A89506 are primed and ready for integration into many solutions that are being developed. Allegro has meticulously created gate drivers that can withstand harsh conditions and current fluctuations, all while passing the benefits of silent operation, weight and space savings, and longevity onto the consumer. Designers looking for best-in-class solutions for their designs can trust that the Allegro A89505 and A89506 will fit seamlessly into their systems, giving their consumers the safest, quietest, most reliable experience possible.
This article is co-authored by Dan Jacques and Tyler Hendrigan, of Allegro MicroSystems, and originally appeared in Bodo’s Power Systems magazine.