Hi,
We are dealing with a tracking device project for cars. For that we need someone to handle with the power circuitry.
The device will be connected to car battery. Therefore the input voltage is 9V to 30V.
The system is operating with 3.3V, and consumes 100 mAs at most. However there is one exeption. There is a GSM module, which is Sim900; it should be operated with approximately 4.3V. The working range for GSM module is 3.2V to 4.8V, however lower voltages effects functionality, therefore GSM module should be operated around 4.2V to 4.3V. The GSM module may consume up to 1.5A for a few picoseconds. Regular operation current is around 200 mAs. Please check hardware design manuel of Sim900 for details.
There will also be a Li-Ion (open for suggestions about the type) battery. When the device is disconnected from car battery (external power off), the Li-Ion battery will operate the system. And when there is external power, the battery will be charged. When Li-Ion battery powers the system, the GSM may be operated with lower voltages such as 3.3V etc.
The device will have closed box. Therefore input power regulator should be efficient, to prevent over heat etc. An efficient switching regulator will be convenient, but also having low cost is important. I used LM7805 before and it was definitely the wrong choice. LM2596 and same class regulators are better in terms of efficiency.
Over voltage and over current protection circuitries (fuse and varistor to input etc.) should be used if needed. The system will be connected to the car for 7/24 hours. It will be taken into sleep mode for most of the time, and this will lower the power consumption by %90. However it will be still connected to car.
Regulators, components will be selected by you. The system should be as small sized as possible. So we cannot include large heat sinks etc.
The system will work automatically, so we don't want hardware switches or buttons etc for operation.
In the attachments, you can find a very basic block diagram.
Regards
Budget: $250
Posted On: August 20, 2014 11:34 UTC
ID: 204425113
Category: Design & Multimedia > Engineering & Technical Design
Skills: Array, Array, Array, Array, Array
Country: Turkey
click to apply
from Online Job Search
We are dealing with a tracking device project for cars. For that we need someone to handle with the power circuitry.
The device will be connected to car battery. Therefore the input voltage is 9V to 30V.
The system is operating with 3.3V, and consumes 100 mAs at most. However there is one exeption. There is a GSM module, which is Sim900; it should be operated with approximately 4.3V. The working range for GSM module is 3.2V to 4.8V, however lower voltages effects functionality, therefore GSM module should be operated around 4.2V to 4.3V. The GSM module may consume up to 1.5A for a few picoseconds. Regular operation current is around 200 mAs. Please check hardware design manuel of Sim900 for details.
There will also be a Li-Ion (open for suggestions about the type) battery. When the device is disconnected from car battery (external power off), the Li-Ion battery will operate the system. And when there is external power, the battery will be charged. When Li-Ion battery powers the system, the GSM may be operated with lower voltages such as 3.3V etc.
The device will have closed box. Therefore input power regulator should be efficient, to prevent over heat etc. An efficient switching regulator will be convenient, but also having low cost is important. I used LM7805 before and it was definitely the wrong choice. LM2596 and same class regulators are better in terms of efficiency.
Over voltage and over current protection circuitries (fuse and varistor to input etc.) should be used if needed. The system will be connected to the car for 7/24 hours. It will be taken into sleep mode for most of the time, and this will lower the power consumption by %90. However it will be still connected to car.
Regulators, components will be selected by you. The system should be as small sized as possible. So we cannot include large heat sinks etc.
The system will work automatically, so we don't want hardware switches or buttons etc for operation.
In the attachments, you can find a very basic block diagram.
Regards
Budget: $250
Posted On: August 20, 2014 11:34 UTC
ID: 204425113
Category: Design & Multimedia > Engineering & Technical Design
Skills: Array, Array, Array, Array, Array
Country: Turkey
click to apply
from Online Job Search
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