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Small, Efficient PoL Converters for Automotive Applications

By Tu Bui, Senior Marketing and Application Manager


As today’s cars are putting more and more demands on their electrical power systems, they must achieve high efficiency to reduce heat dissipation and cut electricity consumption. At the same time, they need to be small enough to fit wherever needed, with suitable performance and flexibility.

To give one example, the automotive industry is increasingly looking for small form factor solutions for panel displays. This then requires compact designs and high efficiency from power components, such as point of load (PoL) converters in distributed power architectures.

Another demand on these converters is the requirement to cope with a range of input voltages, so that they can be used in 12V-, 24V-, and 48V-based automotive systems. Designers also want to minimize external component count, where possible, and so components must be suitable for the harsh environments and extended temperature ranges that they are likely to experience in a vehicle.

To help meet these requirements, Diodes Incorporated has introduced two new synchronous buck converters. Targeted at automotive PoL applications, the AP66200Q and AP66300Q offer excellent power efficiency, a wide operating voltage range, and a small footprint.

The two PoL converters are automotive-compliant and deliver highly efficient step-down conversion in vehicle powertrain, telematics, infotainment, and lighting systems. They cover a wide input voltage range—from 3.8V to 60V. The AP66200Q provides a continuous load current of up to 2A, and the AP66300Q similarly provides up to 3A.

To increase flexibility for designers, the converters can be easily configured to operate in either pulse frequency modulation (PFM) or pulse width modulation (PWM) modes. When in PFM mode, efficiency is improved at light loads; operating in PWM mode will result in low ripple across all loads. As a result, designers can choose between a high-efficiency operation or a smaller system design.

The two PoL converters have a low quiescent current (IQ) of only 40μA in PFM mode, which improves the light-load efficiency, and enables the converters to meet the <100µA standby requirements of many automotive applications. They also have an ultra-low 2.2μA shutdown current. Their low on-state resistance (RDS(ON)) and enhanced efficiency modes allow for low internal power dissipation to maximize efficiency and avoid heat dissipation problems.

Both devices have adjustable switching frequency capabilities (up to 2.5MHz) and can be synchronized to an external clock. Additionally, the soft-start pin is programmable to reduce inrush current and for various power sequencing schemes.

As they are highly integrated, board layout is simplified and PCB space requirements are reduced, with minimal need for external components. This also helps reduce the overall bill of materials (BOM) cost.

The converters are AEC-Q100 Grade 1 qualified, manufactured in IATF 16949 certified facilities, and support PPAP documentation. They are supplied in compact 16-pin U-QFN4040-16/SWP (Type UXB) packages that support automatic optical inspection (AOI).

Where efficiency, flexibility, and simplicity are all on the must-have list, PoL converters such as the AP66200Q and AP66300Q enable automotive designers to meet all their power system requirements.


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