I have a need for 12V 250ma and 5V 1.2A outputs from car battery. Input vol tage is clamped with TVS to
- posted
10 years ago
I have a need for 12V 250ma and 5V 1.2A outputs from car battery. Input vol tage is clamped with TVS to
Several people make boost-buck switchers that could keep your 12 volt output pretty much constant. Sepics and flying-inductor things.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
"Cold crank" (think upper peninsula of Michigan :-) specification is
4V which is where I designed my ignition systems to still function. ...Jim Thompson-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
voltage is clamped with TVS to
utdown during cranking.
for any regulator with a drop put voltage of 1-2V.
M2268X) and then another 12V to 5V buck regulator. What will be the output of adjustable buck switching regulator if the input voltage goes below the required output voltage? Will the o/p drop to zero or Vin - dropout?
converter like LMR64010.
tion.
The unit has a board/module inside which has operating range of 8V-12V and
5V is to the micro and peripherals. So operation down to 4V isn't really re quired.
If systems don't have to be functional during engine crank, a simple way is to simply hold those circuits in reset until the engine is running. For analog circuits simply think power management. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
There are several bucks that allow high duty-cycle operation. I have the same problem and have been using a TI TPS65320 for 5V. It's pretty cheap, works to 2MHz, and includes a free LDO (which switches from the input to the output when the buck turns on). As John points out, there are several boost/bucks around now. Some will operate the boost in pass-thru mode (boost shuts down) when the input voltage allows it. Look in the catalogs under the automotive parts. This is a very common need.
Have a look at system basis chips if you have a CAN/LIN requirement as well.
Most are linear, there are some buck/boost versions but I don't know any off the top of my head.
wrote in message news: snipped-for-privacy@googlegroups.com... I have a need for 12V 250ma and 5V 1.2A outputs from car battery. Input voltage is clamped with TVS to
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