Tag Archives: HVAC

Designing next-gen LIN systems with Atmel (Part 1)

The LIN (Local Interconnect Network) bus is a vehicle standard used within the latest automotive network architectures. The low-cost, single-wire serial communication system for distributed electronics in vehicles is highly suited to body control applications, including power windows, mirrors, smart wipers, door locks, seat/roof/lighting control, lamps and indicators, dashboard instruments, steering wheels, climate and air-conditioning (HVAC) systems, motors, switch panels and sensors.

“It is primarily used as a cost-effective sub-network of a CAN bus to integrate intelligent sensor devices or actuators where the LIN master node also acts as a gateway to connect the LIN bus with the corresponding CAN bus,” an Atmel engineering rep told Bits & Pieces. “Going hand in hand with rapid LIN market growth, the requirements for greater system efficiency and lower costs exerted on LIN products have continued to increase as well.”

To be sure, in-vehicle electronic systems are rapidly evolving and increasing in number, as are the number of switches for controlling various applications. In addition, applications with switches located far away from the control electronics and wires integrated within the wiring harness require high-voltage switches.

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“And that is precisely why Atmel offers a next-generation ATA6641/42 System Basis Chip (SBC) with an eight-channel high-voltage switch interface, a LIN2.1 and SAEJ2602-2-compliant LIN transceiver and lowdrop voltage regulator,” the Atmel engineering rep continued. “The ATA6641/42 also boasts an adjustable window watchdog, facilitating the development of inexpensive, low-end, but also powerful slave and master nodes for LIN bus systems meeting the latest OEM requirements.”

Due to its optimized architecture, the ATA6641/42 provides a high degree of flexibility for deployment in various applications such as switch connection through the wiring harness, port/contact monitoring, contact cleaning, switches (towards GND or VBAT) and LED/relay/power transistor control.

Two versions of the System Basis Chip are currently available: the ATA6641 with a 3.3V voltage regulator and the ATA6642 with a 5V voltage regulator. The voltage regulator delivers up to 80mA load current. Sleep mode and active low-power mode guarantee very low current consumption even in the case of a floating bus line or a short circuit on the LIN bus to GND. To maintain very low current consumption in sleep mode, a special technique ensures that the circuit switches back to sleep mode after approximately 10ms if the bus line is floating or in case of a short circuit.

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Improved slope control at the LIN driver ensures secure data communication of up to 20kBaud, while data rates of up to 250kBaud also enable high-speed data communication. Most features can be configured via the 16-bit SPI interface which streamlines and accelerates configuration of the slave/master LIN node for any given application.

Want to learn more about Atmel’s ATA6641/42? Be sure to check out part two and three of this series.

Atmel motor control systems for the automotive masses

Atmel has more than 15 years of experience with driver ICs for DC motors, supplying products at a high-volume for a variety of common body electronic applications, including mirror control and flap control in HVACs.

Although Atmel driver ICs are equipped with a variety of types of driver stages, they all share the same protection features – short-circuit protection, temperature warning and switch off, low voltage protection and open load detection – all of which are a must for automotive electronics.

“The continuously growing Atmel driver family includes a wide variety of combinations of integrated high-side and low-side output stages, enabling designers to easily tailor solutions to their needs,” an Atmel engineering rep told Bits & Pieces.

“Our driver portfolio includes ICs for small DC motors controlled directly from the output stages. At the heart of the Atmel portfolio are motor driver system basis chips, with integrated gate drivers or pre-drivers to control separate NMOSFETs. These drivers can be used to control almost any size of NMOSFETs, for use in a broad range of applications.”

With few external components, the Atmel driver ICs with LIN communication and the Atmel AVR microcontrollers combine to create cost-efficient motor driver modules, complete with LIN functionality for harsh automotive conditions.

“In short, the Atmel motor driver family targets applications with brushed and brushless DC motors for standard temperature applications, as well as demanding high-temperature ‘under-the-hood’ applications,” the engineering rep added.

Interested in learning more about Atmel’s motor control systems? Be sure to check out our full device breakdown here.