Guess we all have used those staples. Those kinds are about the only cheap PWM chips when it comes to voltages above logic levels. However, unfortunately they were designed before the energy crisis and need lots of quiescent current. Is there anything available or maybe in design with the following specs:
a. buck, or multi-mode b. internal switch c.
Output current rating of the internal switch?
RL
That can be well under 100mA. It's for low power apps. Most of the modern versions have surprising current capabilities. It's just that they are priced way outside my usual wiggle room.
-- Regards, Joerg http://www.analogconsultants.com
For a low power application jelly-bean, the last thing you'd intentionally impose on a device is a high input voltage. In that case you'd be looking for methods to cut the thing off completely, when not needed and to bootstrap the control supply when it's running.
For < 1mA quiescent high voltage operating current, I don't see an integrated buck regulator below 1.25. (lm5009)
LM2574, with a built-in shutdown capability, is 0.75. There are many others like it.
At 100ma you could probably bodge something in any particular application. Isn't that what the high-priced help is for?
If you could get by with buck-boost, using the positive input as the ground connection, there are a host of commodity low power HV integrated switchmode controllers that might be re-applied between 15 and 40V. The control inversion generally puts people off.
RL
Yep, it usually is. But most of the time that help leads to a discrete solution. Looks like it does again this time. It's hard to beat 1.5c transistors and 0.3c resistors, even when there are a lot of them.
Oh, that wouldn't put me off at all. I love unorthodox solution, at least in electronics ;-)
-- Regards, Joerg http://www.analogconsultants.com
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