Max 1044 Battery consumption

markm · Post by **markm** » 02 Aug 2007, 11:48

Question here for the board;
Anyone know whether the MAX 1044 when used as a charge-pump, does it eat 9V batteries quickly or is it similar to "normal" battery consumption in any given circuit?

soulsonic · Post by **soulsonic** » 02 Aug 2007, 12:17

I've been wondering the same thing. I should be getting a couple here pretty soon to test my bipolar 18v circuit, so I'll get a chance to measure the consumption and see how much it eats batteries.
I wonder how they compare - battery eating-wise - to doing a similar circuit with a 555?

JHS · Post by **JHS** » 02 Aug 2007, 13:59

Every chip for a chargepump has some loss and you can't get more than 15-20 mA out of a MAX1044 powered by a normal battery.

I always calculate 50% for the CP-loss, that means if a circuit draw 6mA the battery has app. 10mA to deliver (Cp and circuit) and a std. 9V battery will be weak after 6-8 hours.

The better solution is to use 2 battries in series and not to use a charge pump.

JHS

vanessa · Post by **vanessa** » 02 Aug 2007, 18:58

JHS wrote: The better solution is to use 2 battries in series and not to use a charge pump.

JHS

+1

markm · Post by **markm** » 02 Aug 2007, 20:33

JHS wrote:Every chip for a chargepump has some loss and you can't get more than 15-20 mA out of a MAX1044 powered by a normal battery.

I always calculate 50% for the CP-loss, that means if a circuit draw 6mA the battery has app. 10mA to deliver (Cp and circuit) and a std. 9V battery will be weak after 6-8 hours.

The better solution is to use 2 battries in series and not to use a charge pump.

JHS

So, the consumption of two will obviously be less than one powering a charge pump.

soulsonic · Post by **soulsonic** » 02 Aug 2007, 23:39

I like using two batteries for a bipolar supply, but the biggest problem I have is finding space for the two to fit! That's why I'm interested in charge-pump circuits; to save space.

bajaman · Post by **bajaman** » 03 Aug 2007, 00:13

Lots of good info here, INCLUDING a high voltage inverter driven circuit for stepping up voltages etc.
bajaman

http://members.aol.com/sbench101/

markm · Post by **markm** » 03 Aug 2007, 00:58

soulsonic wrote:I like using two batteries for a bipolar supply, but the biggest problem I have is finding space for the two to fit! That's why I'm interested in charge-pump circuits; to save space.

I hear ya!
That's my main interest.
I'm really not a Wall-Wart kinda guy but, Maybe it's time to just build a P/S. And bajaman.....Thanks for that there link!

gaussmarkov · Post by **gaussmarkov** » 12 Aug 2007, 05:37

interesting. stobiepole and i used R.G.'s +/-9V supply circuit with a 1044 for a recent Gristleizer project. it worked well. stobiepole pointed out to me that there is an advantage to using the chip: you don't get any imbalance between +9V and -9V. they stay equal in magnitude. you may not get that with two batteries.

lmkv15 · Post by **lmkv15** » 12 Aug 2007, 07:36

Hi,
The LTC1044 has an own supply current demand of approx. 60 to 300 µ . I used the LTC 1044 by powering the FETboost with 18V with battery.

regards Uwe[/img]

markm · Post by **markm** » 12 Aug 2007, 13:24

Interesting.
Not to derail this thread but, welcome gm!!

gaussmarkov · Post by **gaussmarkov** » 12 Aug 2007, 13:53

markm wrote:Interesting.
Not to derail this thread but, welcome gm!!

thanks, mark!

@lmkv15: nice (eagle) layout.

gaussmarkov · Post by **gaussmarkov** » 12 Aug 2007, 14:23

perhaps someone would be willing to teach me how to read the supply current characteristics of these chips? i looked at both the MAX1044 and the LTC1044 and i do not see any particular limits. some of the graphs seem to show currents on the order of 40mA.

also, the LTC1044 seems to operate its oscillator in the neighborhood of 5kHz. i understand (from R.G. Keen's writing, GEOFEX) that this often causes a whine in effects pedals. but lmkv15, you did not have this problem. did you do anything special to prevent it?

cheers, gm

lmkv15 · Post by **lmkv15** » 12 Aug 2007, 15:39

Hi Gm,

I put the clock frequency highly. Pin 1 (Boost) wiring to power supply (connect Pin1 to Pin 8 ).
regards Uwe

kagaxdx · Post by **kagaxdx** » 12 Aug 2007, 18:11

connect pin 1 and 8 rsrs

gaussmarkov · Post by **gaussmarkov** » 12 Aug 2007, 18:14

how embarassing.

it's mentioned right at the top of the datasheet.

thanks, gm

markm · Post by **markm** » 13 Aug 2007, 14:54

You're not supposed to read the top part, just go right to the guts of the data sheet......I do that too sometimes!