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Automotive LED Lighting Solutions: Challenges and Solutions
- Q: Dear Dilip£¬ With contineous operation LED life / light output drops drastically due to temperature effect. How it should be taken care in the design without adding any flicker or heat sink. Best Regards£¬ Ganesh Mohol
- A: for power LEDs. :-best way is provide better Heatsink Metal core PCB + Thermal paste + heatsink to maintain junction temp within specified limits. Heat sink calculation tools are available Flow therm by Mentor graphics or Our channel partner Future electronics ( website www.futurelightingsolutions.com) has heat sink design tool called as QLED software .or can use National Semiconductor Webench tool. The another method is to use Temp sensor ( mount on Heat sink) to sense LEd temp . this feedback you can give to u controller . ucontroller will adjust DIM signal to reduce the LED current if LED temp is more than specified temp.
- Q: I want to measure the intensity of a LED used in automotive application. I have a LuxX meter which will give interms of LUX. But I need interms of Candela. please provide me the conversion equatio
- A: Susanto, You can use Spectrophotometer to measure Intensity in candela. you can download lux to candela conversion tools from www.google.com or you can use Photometric distance law or Inverse square law Ev = Iv / d*d where , Ev = Illuminance (lux) Iv = Luminous intensity ( Candela) d = Distance of lamp source from surface
- Q: i want to boost 12vdc to 20-30vdc with current limit not more than .90amps
- A: You can use LM5022 boost LED driver to boost 12V to 20/30V @ 1Amp or less for more details pls contact National Semiconductor Bangalore ofice email :- Dilip.Mohol@nsc.com
Making Point-of-Load Power Supply Design Easier
- Q: Welcome to National Semiconductor online seminar
- A: Attendees who complete and return survey after the webinar will get a PowerWise polo shirt made of easy dry material to keep you cool.
- Q: is it possible to implement on Mobile phonep product?
- A: The products we presented today are for input voltages in the medium and high voltage range. These products finds applications in industrial, automotive and telecom segments. This is because almost all of these devices handle voltages in the range of 6V to 42V and some upto 75V. Where as in Mobile applications we use one Li-Ion battery as source and voltages lesser than 5V. But National has a big range of devices to cater to mobile handsets. You may refer to them at: http://www.national.com/analog/portable
- Q: do you have anything which serves both buck and boost
- A: Yes. National has devices for applications which require both buck and boost. LM5118 is one such device. You can access the datasheet, design tools and other application notes on this device at: http://www.national.com/pf/LM/LM5118.html
Design Made Easy with National's Online Design Tool
- Q: I need to design a signal conditioning unit for piezo electric accelerometer£¬ i.e. charge amplier£¬ ADC
- A: May we know specification of your piezo electric accelerometer and operating condition of your system? thanks.
- Q: my board fan dont¡°t work ?
- A: can you explain more details? What is content of your board?
- Q: Sensitivity and Stability is very important factor for designing sensor front-end circuit. How to evaluate the sensor design is optimized for sensitivity and stability.
- A: good question ! 1.Sensitivity depend on your sensor and AMP. After senosr chose ,you should chos precision amp. to get high sensitivity . In your application you can change differnt amplifiers to meet you sensitivity in our sensor Webench. 2.Stability : B
Advanced Measurement Techniques for OFDM and MIMO Based Systems
- Q: Please explain what is the algorithm of MIMO?
- A: MIMO allows simultaneous transmission and reception of 2 or more signals. This means that there are 2 or more antennas at the base station and 2 or more antennas at the mobile device.
- Q: What aspects will MIMO and OFDM be applied?
- A: MIMO is being used in WLAN and WiMAX.
- Q: What is Multi-carrier OFDM schemes? How does it work?
- A: OFDMA (Orthogonal Frequency Division Multiple Access). OFDMA is a multiple access transmission technique that uses OFDM modulation techniques. However, individual sets of subcarriers can be assigned to different users so that many users can simultaneously use the channel at the same time. WiMAX dynamically adjusts the allocation of subcarriers, time slots, and bandwidth for optimal throughput for multiple uses. OFDM is the modulation technique used in WiMAX.
Optimize System Performance with FPGA/PCB Co-Design
- Q: How does I/O Designer stay current with the latest FPGA vendor devices?
- A: Mentor Graphics has very strong relationships with the FPGA vendors. There are regular meetings where new device and software plans are exchanged. Based on this information exchange, the I/O Designer team can quickly support new families and devices through software releases or library updates.
- Q: When a device is supported by I/O Designer, does that include pin assignment and swap rules?
- A: Yes. This is called intelligent I/O assignment. I/O Designer allows only legal pin assignments to be made. This is a very powerful capability of I/O Designer that enables I/O optimization. Without this capability, I/O optimization would be very difficult if not impossible.
- Q: What is the difference between pin swapping and I/O optimization?
- A: Good question. Pin swapping requires that swap groups are added to the PCB component and is done in the PCB layout tool. The pin changes are then backannontated to the schematic and then to I/O Designer. I/O optimization is done in I/O Designer and is based on actual PCB layout connectivity. I/O Designer will change pin assignments to remove crossovers and shorten nets. I/O Designer will then update the schematic with the changes.
Maximize Gain & Speed Decompensated Amplifiers
- Q: I want to learn interface of ADc with Philips ARM controller may be 2148 £¬ 669 series £º Texas £º Sigma delta ADC £º
- A: The interface between an ADC and the controller should be in digital form, buffer/amp would normally be use between the sensor/signal-source and the ADC. National has wide ranges of op. amp. meeting various needs.
- Q: What is the meaning of decompensation in amplifiers
- A: Decompensation is the functional deterioration of a previously working structure or system. In Amplifiers, it is a modification of the existing structure to acheive higher bandwidth and safes power. However, this modification makes the amplifier NOT unity gain stable. Therefore, a decompensated amplifier has a minimum gain requirement. If you wished to used the decompensated amplifier below the minimum gain, then you can you the technique introduced in this presentation.
- Q: I couldn't understand how you are calcualating the phase margin from the Gain Vs Frequency graph?
- A: Phase margin was calculated at the point where the 1/F curve and A curve intersects.
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