How to run LM8560 clock in DC mode only?

Anyone know how make LM8560 in DC input only?

lm8560 schematic

If you want to run this clock IC in DC mode only, then you hv to supply the 50Hz signal to the 50/60 Hz pin.
Some people do this to get higher accuracy than the Mains derived 50Hz source.
There are many 50Hz timebase circuits available which suite this application.

lm8560 clock

Did anyone manage to find a suitable oscillator for this, as I want to convert my bedside clock (Phillips thing with a LM8560 in it) to run from 12VDC (from solar) so any info on this would be great thanks.

Is there an easy way to use a pic for this?

Bj

lm8560 pinout

You can use a PIC for this, one that has an external oscillator, like th 12x50x family. That way the oscillator is crystal controlled.
You simply write some code to produce a 50Hz output. If you need help, let me know.

lm8560 pins 15 and 26

Thanks for the prompt reply, I have got this clock "on the bench" (it's a Phillips 3150 clock radio) at the moment trying to decipher the power supply and where the clock is derived from. It seems to use two isolated rails (transformer has 2 x 6V windings) but doesn't seem to run for an external DC supply whilst still providing the clock pulse to the 50Hz pin 25.

Some of the segments light up in the wrong places if I use a common ground both of these supplies instead of them being from separate sources as the isolation is provided from the transformer.

So it may be a little harder to convert easily anyway. Has anyone manged to run a LM8560 from a DC supply at all? I could be chasing my tail here....

Thanks again

Bj

Added after 7 minutes:

More info... It uses the AC 50Hz to time the multiplexing to the display as I have now found an application schematic which explains this bit....

clock ic lm8560operation

For running this kind of clock from a DC power supply, you will need an oscillator of 50 or 60Hz.

This oscillator must have:
- 1 pin out for 50/60Hz signal. That will be connected to pin 25 of LM8560.
- You have to choose leave the pin 26 of LM8560 unconnected for 60Hz operation, or grounded (VSS, + terminal, pay attention, this is a PMOS IC) for 50Hz operation.
- The additional oscilator has to have 2 buffered outputs of 50/60Hz opposite-phase signals to drive the duplex display. If the display is wrong, just change over these pins to it.

Notes:
- LM8560 consumes high power, and now with the additional oscillator, so the battery will be "killed" very quickly. It is better to use an AC wall adapter instead of battery as the DC power supply.
- Some clocks have their colon LEDs light steady. You may want them flashing by connecting them to pin 14 of LM8560.

nguyennam

lm8560 digital clock 24 hr with alarm

BjBlaster said:

Did anyone manage to find a suitable oscillator for this, as I want to convert my bedside clock (Phillips thing with a LM8560 in it) to run from 12VDC (from solar) so any info on this would be great thanks.

Is there an easy way to use a pic for this?

Bj

Click to expand...

Here is a schematic of clock I have built and ran on 12V DC. It uses a crystal and some CMOS IC's for the clock to generate a 60 signal for the clock

lm8560 on 50hz mains

Very nice, It's not quite the same display setup but I'm going to change the guts of this clock to a PIC based clock that consumes way less power, as the 8560 looks like it's too heavy on the juice with all the external stuff added on.

Thanks for your input guys it's appreciated

Bj

lm8560+oscillator

PIC clock...
You can try this one.. www.josepino.com

clock lm8560

Hi

I look for a clock with lm8560 here **broken link removed**