[SOLVED] Op-amp low-power bipolar power supply options

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I have finished a prototype design using an mBed 1768 with some fet input opamps for analogue I/O conditioning.

To power the OP-amps I used a (Murata) single inline DC to DC power module to derive my +/-12V supplies.

But I'm now looking for what other options there are for powering a few opamps?
Has anyone found anything for 5V (4V to 6V) input to +/- 12V (well at least +/-9V) at say 10mA, preferably with an enable pin, i.e. low quirescent current when at standby?
 

What is the application? Is this PSU to be re-used, for experiments? Or is it to install on a circuit board? Or what?
 

It is a compact battery powered instrument (currently manually switched on an off for occasional measurements).
The dual supply is required on board, hence as compact as possible.
The analogue circuitry and sensors are only required to be powered for 20 seconds, hence an enable pin would be great. The mBed is powered longer for calculations, data storage and results display.

The analogue circuitry and sensor only require around 10mA for about a second and then the current is less than 1mA for the remaining time, hence DC-DC to converter is operating at a low efficiency point.

I was wondering if there was any charge pump modules (similar to used in RS232 drivers) for this type of application?
 

Well, I might have solved my own problem. Searching the RS Components website I came across two dual charge pump integrated circuits by Maxim.

The more versatile one MAX864EEE+ RS part 622-9033 is a Vin to +/-2Vin, i.e. output reflects input and even has shutdown pin which will be ideal.

Has anyone used a charge pump IC before and if so any advice/warnings?

They look straight forward so I might design a little PCB that could replace the SIP DC-DC converter module that I currently use....
 

So has anyone any comments on the charge pump idea for this application?

How do you power your bipolar opamps in portable applications when you need greater than the available battery voltage?
 

Here is a negative charge pump.

Six stages are needed to produce -11.5 V from a 5V positive pulse train.



The diodes need to have a low forward threshold (such as Schottky type).

The 555 timer IC can be replaced by any pulse generator, as long as it can source and sink current.

- - - Updated - - -

If you reverse the diodes, you will get +11.7 VDC output.
 
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I have not used these ICs, but I've made charge pump split
-/- 10V floating supplies using a LM555 timer, diodes & caps
for powering instrumentation amps in an automotive environment.
Looks like the Maxim part would just be a bit neater and probably
more efficient (switched rectification rather than diode with the
forward losses) and probably have more current-throw.

You can also find DC-DC converter boards with almost any
from:to you can imagine, on eBay for dirt cheap. If you just
want to hook it up and go.
 
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Or better still, use only 4 multiplier stages, by connecting the first diode to the positive supply:



The transistor half-bridge is not absolutely necessary, but it is included to illustrate how to obtain more power, in case the 555 IC alone is unable to provide sufficient current.
 
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