max1848

Archive New Product Ideas
1

I have had problems with the carrier for the 6100 lcd knockoff.It consumes tops 140 mA due to backlit LEDS and the PIC refuses to boot up when operated from 3.6 volt.possibly due to noise

the Max1848 has adc input whereby a simple pot can be connected to provide variable backlight from 30mA to 100ma.Unfortunately the minimum order from MAXIM is a reel (2500 pieces)

I have had to open circuit the enable pin 4 of the TPS610 and connected it to one of the PIC port lines,to disable the LED’s when booting up the PIC.

Regards

RG

2

have you asked them nicely for samples? maxim is pretty easy…

3

Yes I have and received 2, but I sneezed and lost 1. (very very tiny sm)

Don’t want to be cheeky and ask for charity again!

The reason I consider that the MAX1848 is superior is because my prototype display is used in a portable application, so I need the ability to switch off the backlight (The VCC supply to the MAX is fed from four of the PIC’s port pins to deliver sufficient current) and also to vary the brightness of the LED’s to conserve battery power.I have yet to try the LT1054 (available from Farnells) which is a -ve voltage convertor with an enable pin such that the LED’s can be connected between -3.6 volts and + 3.6 volts, giving the required 6 or 7 volts.

Regards,

RG

4

Also TPS60403 -ve voltage convertor is available with a quiescent current of 65 uA.

Regards,

RG

5

Does the PIC your using have PWM ?

if so, why not just throw a fet on that pin and PWM control the led back light ?

6

Good idea ,not thought about that, but the prob still remains of generating the 6.5 volts for the LED’s.

Regards,

RG