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Low-Cost Automotive Power Management Solutions

Designing power management control systems in automotive applications has become quite complex due to the continuous changes in technology. While 5-volt devices are preferred by automotive engineers for the robustness of the I/Os, every new generation of devices require a new, smaller operating voltage. On-board management of all the multiple voltage supplies becomes quite a challenge.

Devices that require their supply voltages to be applied in a very specific sequence to insure correct operation further complicate this challenge. All too often a “traditional” power management solution is applied to these “turbo-charged” power management requirements, resulting in circuit board designs that are inefficient, costly and usually compromised by tradeoffs.

Looking for powerful, cost effective solutions, several automotive customers requested Lattice provide the popular power manager devices in an automotive temperature range. Lattice responded, and in February 2008 announced the release of the automotive temperature LA-ispPAC-POWER1014/A power manager devices. The Lattice POWR-1014/A are the only fully-programmable power managers offered in automotive temperature.

The POWER1014/A incorporates both in-system programmable logic and in-system programmable analog circuits to perform the special functions that are optimized for power supply control, sequencing and monitoring. The POWR-1014A has 10 analog inputs for voltage monitoring, and can control up to 14 outputs. A built-in reset generator is available for control of external microprocessors.

By using a programmable, mixed signal power management device. Automotive designers can standardize on this “power management PLD,” using the device across all the automobile's ECUs, resulting in reduced cost as well as increased reliability.

Disposable Cars?

Recently another FPGA supplier announced their first family of AEC-Q100 automotive qualified devices.  They received quite a bit of press due to their testing to automotive Grade-1 that equates to a temperature range of -40C to +135C Junction.  According to the datasheet these devices have a Maximum Tj of +150C.  This sounds very attractive to automotive customers looking to use FPGA devices in under the hood applications.

I thought, “Wow, this is impressive”.  My initial excitement was soon dashed when I looked through the datasheet and found their HTR (High Temperature Data Retention) results.  This is the amount of time the internal Flash memory is not expected to have a failure due to flash cell leakage.   Operating these devices at +70C provides an HTR value of +100 years, however at +125C the HTR value drops to 6.2 years and at under the hood temperature of +135C the value is 4.4 years (+150C = 2.2 years).

For some consumers an engine or brake system failure after 4.4 years of service may not be an issue, but for others it can be a life-threatening situation.

The Lattice FPGA temperature ratings are (Grade 2, -40C to +125C Tj) and the HTR results for Lattice Flash based devices is greater than 100 years at full temperature.  This means almost no chance of an automotive system malfunction due to Flash memory retention issues.  I know that I want any vehicle my family travels in to continue to operate even in high temperature conditions.  Lattice FPGA devices provide me that peace of mind.

Lattice Automotive (LA-) Devices Complete Media Interface

Recently I was sent a design that shows the value of Lattice AEC-Q100 automotive qualified CPLDs.  This design was provided to Lattice by the system designer and is shown here with their permission.

The design is for an Automotive Network Gateway.  The system is a protocol converter that handles communication between the various automobile buses: MOST, FlexRay, Ethernet, CAN and LIN.  The bulk of the processing is performed in the Freescale PowerPC processor that has on-board network Media Access Controllers that directly interface with many of the external physical transceivers.  The one device that does not directly connect is the SMSC MOST to MediaLB transceiver.  The MediaLB interface is 3 or 5-wire interface that is a multi-drop bus which is similar in operation to I2C and I2S.

For this application, the designer found that some signal translation and manipulation was required between the SMSC device and the microprocessors.  After reviewing the available options, these functions were implemented in the Lattice Mach4064V.

This functionality could have been performed in discrete logic, but in addition to the MediaLB interface, the designer was able to incorporate other system functionality and glue logic required in the design into this one CPLD device.  The Mach4064V provides a fast, small footprint solution that is very inexpensive.  As Lattice is the only TS16949 certified CPLD supplier that offers a –40C to +125C ambient device that is fully AEC-Q100 qualified, this customer was able to easily meet their customer’s temperature requirements.

While Lattice offers automotive qualified crossover CPLDs in the LA-MachXO family and has high performance FPGA’s on the roadmap, we can’t forget the small CPLDs that can easily solve many of the logic problems that automotive designers encounter every day.

Automotive Multimedia Meets Consumer Products

Travel just about anywhere today and you see someone wearing headphones plugged into a ubiquitous portable consumer multimedia device. These small units have the ability to store large amounts of audio and video content; more recent devices include streaming multimedia combined into a cell phone. The one place you ‘hopefully’ won’t see these units in use is by the operator of a vehicle on public roads and highways or in conjunction with any form of transportation.

The inability to play multimedia files from portable media in automobiles is a frustration for drivers. There are some workarounds that allow them to be used: FM Transmitters, Cassette tape adapters, but these generally produce less than desirable results. Some factory radios now have auxiliary audio inputs for interfacing with a media player or the option for direct iPod connection. While the iPod connection usually allows control of the iPod from the auto multimedia system, it does exclude the other 50% of the non-Apple portable player market.

Automotive manufacturers are working on new systems to allow additional connections to portable consumer devices. Implementation of these connections is through one of more of the following: Bluetooth, SD/SDIO, WiMAX, USB and proprietary connections. Recently the MOST consortium announced that their automotive media bus is now available for incorporation into consumer devices. This may open the way for additional connection methodologies.

Automotive manufacturers are also building multimedia platforms with hard disk and DVD drives. These have been incorporated to allow additional functionality in the areas of Navigation mapping, audio and video content. Combined with a wireless interface, it is also possible to use a wireless network system to download multimedia content to the local hard drive for playback. As most new HDD and DVD drives are using Serial ATA, the automotive manufacturers must now incorporate S-ATA interfaces into their systems.

Lattice is working with automotive manufacturers to provide complete hardware and software solutions for vehicle electronics. From the automotive versions of the LA-MACH4000 CPLD families to the LatticeECP2M FPGA that has on-chip SERDES and can support S-ATA and PCI Express. Lattice is helping automotive customers meet their overall functionality goals - at a lower system cost coupled with a faster time to market.