low power/ high efficiency voltage regulation.

[lawrie]

Has anyone had experience of designing high efficiency low power supply circuitry?
I want a circuit that supplies 3.8v Dc. For 95% of the time it should supply 1 or 2 mA but the rest of the time it must supply nearer 200ma with occaisional peaks at 1A or so,(duration only mS or so). This circuit is itself powered from batteries that supply a fluctuating voltage between 10v and 16v.

My current power regulation circuit as supplied by the manufacturer draws 10ma even with no load or application attached, so to extend battery life dramatically I need to bring down the no load consumption of the power control circuitry while the application is drawing less than 1ma in sleep.
I have looked at some Analog Devices Chips, mainly the ADP range.
Can any one advise what the most efficient device or method may be for this.
Any help or suggestions would be gratefully received

 

[Lewish]

Well, I think you are asking for the impossible, but have a look at what Linear Technology offers. They seem to have about the highest rated efficieny regulators.

 

[47gandalf]

I have recently designed something very much like this. I suggest you look at suppliers like Texas Instruments, Micrel and others for a switched mode power supply circuit. In particular, some newer devices use PWM to control the output when you need to supply high currents, and switch to a PFM mechanism (internal and automatic) when the load is only a small percentage of the rated output current. This gives you a much higher overall efficiency of conversion from the battery inputs to the power supply circuit's outputs. In my case battery life extended from 1 week to over ten months. Our system is "asleep" for 99.75% of the time, drawing about 700 microamps. When "awake" (0.25% of the time) it draws 50 milliamps at 5 volts. We use a TPS61120 chip to create the 5 volts, and the LDO section of it to create 3.3 volts.

Efficiency is over 80% at all times with the new design. Self drain is in the low microamps, compared with the 10 mA you're seeing now.