25 Parallel LEDs Instead of 3 Series LEDs

Before I start, let me state that 25 parallel diodes in place of the 3 series diode branches is not doable. The 9 volts will turn on all the diodes and the IC will have no effect. That means the rest of what I am about to say is meaningless. With that said lets continue. I am a little rusty but I will give it a shot anyhow. I see two things that you need to look at. One is the sink currents of the IC and the other is the forward bias voltages of the diodes. Each input that is sinking current has a limit, and if exceeded, you will get into a state of thermal runaway. The 4060s max is around 10mA, typical CMOS Ics. If the input is on, and sinking more than the Imax, it might not shut off when internally switched or not fast enough to be viewed during the RC timing. The other issue is in the diodes. Do you have the forward bias specs, and did you measure the forward bias voltage. A lot of the cheap China LEDs have a much lower forward bias voltage and a higher forward current. The 9 volts might be enough to forward bias the 6 in series diodes. These issues will make your circuit fail and even self destruct. (i hope you didn't just hook up 25 diodes in parallel across 9 volts) There are better ways to do this. If you want to continue on this path you have two options. Parallel the 4060s to accommodate the diodes, if that is the problem, or have the 4060 drive solid state relays that will operate the diodes. Current limiting is a must with so many parallel diodes. Have at it there tiger and best of luck.

Well, the thing is, i thought that i may be able to hook up 25 diodes in parallel just using bunch of resistors. Now i understand this is much series than i thought. However i must say that im not a genius.. anyway, using solid state relays is the best way i think. thanks a lot for the information.

When it comes to LEDs the amount of forward current is directly related to its brightness, illumination. Adding resistance just to lower the branch currents to satisfy the IC may affect the LED. Using current limiting resistors for safe current levels through diodes and to protect against surge currents is fine. The power supply should be the last thing you consider. You have to know the demands of the circuit first, and then add in some other considerations before your selection. You do not have to be a genius! Leds are very simple to understand and in using ICs the work is already done for you. You just have to understand it's limitations. The best place for this is TI, Texes Instruments. Get the data sheet and take a look. It is online, I know it is, I just checked: http://focus.ti.com/lit/ds/symlink/cd4060b.pdf Once again, have a great day and go get'em tiger.

Great !

after you send the data sheet i did looked for the data sheet of the ic i used.

file:///C:/Documents%20and%20Settings/Ryan%20Silva/My%20Documents/My%20Pictures/4060.htm

this is it. now i have some idea about how is the ic switching the LEDs. i think the signal from the pins 4,5 and 6 is enough to switch the Relays, and the relay can do the rest, right? now im working on it.

thanks again.

Eep! This circuit is so wrong on so many levels that it can't possibly work. 1. The oscillator has to be connected to DC ground, so the common point of the 470K and 10K resistors, and of the 0.1uF capacitor (all on the left of the diagram) has to be connected to the negative of the 9V battery (pins 88 and 12 of the IC). 2. Only ONE of the IC's pins 4,5,and 6 should be connected to a given set of 6 LEDs. Connecting all pins will make the logic' the top LEDs in the circuit light when either pin 4,5, or 6 are sinking. And if one pin is sinking and another is sourcing, the circuit won't work. 3. The sinking and sourcing currents for pins 4, 5, and 6 individually are fractions of a milliamp, meaning that a given pin can neither source nor sink the current needed for a series of three LEDs, let alone several series in parallel. 4. Since the 4060B IC can't sink or source enough current (and because of comment 1 above, maybe the timing oscillator doesn't work), each branch of the circuit amounts to six LEDs in series being connected to a 9V battery. 5. In a given branch, each LED's current will be the same as that of all others, but the VOLTAGE across each one will vary from one LED to another, even for LEDs with identical part numbers. Depending on the V-vs-I curve of the individual LEDs, some LEDs will light brighter than others. 6. Last time I looked, putting 1-2 volts across an LED with no current-limiting resistor (the 4060B doesn't work so doesn't provide any) means rapid burnout. And the pièce de résistance ... 7. Texas Instruments doesn't manufacture the 4060B IC any more. You may be facing an electronics seller who's trying to unload his stock of out-of-manufacture ICs. Cheers! DZ

I agree that this circuit leaves much to be desired, however, DZ, you are wrong about the oscillator circuit, the chip is designed to work with precisely this RC configuration, none of the components are connected to ground, this is a typical CMOS oscillator circuit.

A 9-volt battery is a poor selection as they are expensive and provide little total power. With LEDs as a load, at least C-cells or D-cells should be used unless you decide to use a wall-wart power pack (see below).

Basically, the 4060 chip is designed to source and sink a nominal 2.25mA with a 10 volt power supply (of course, it may be able to put out a bit more but the voltage drop in the driver output will increase of course, further limiting the available power). The designer of the circuit in question obviously is depending on circuit parameters to limit the current load through the LEDs and the chip. He is not going to get much light out, particularly with the higher voltage drops of the other colors (red demands the least voltage on the whole for a given level of drive). Since this circuit will not draw much current, a 9-volt battery will probably last awhile but provide rather dim lighting for a fairly short time before the voltage drops below a usable level.

For the OP's purpose, he should be using a stouter power supply, say at least 12-15 volts, individual resistor values for each color (since the voltage drop will be different), use a series-parallel connection scheme for the LEDs and a good buffer for the 4060's outputs, say a 4050. Then you would get reasonable brightness at a reasonable current drain. You definitely don't want to try and run 150 LEDs off of small batteries, they won't last long (lead batteries are good of course if you have to have battery power).

Although TI does not make the 4060, it is still available from other brands, check Mouser, Digi-Key, Jameco, Allied or Newark. There are still a lot of surplus chips available so I rather doubt a short supply of these will happen any time soon.

before i start modifying the circuit, i build the circuit on a small PCB and it blinked 6 LED channels perfectly as the flash animation indicated on the link i have posted (each pair flashing three different flashing rates.) Yes i dont understand much about how is the circuit works. but somehow it worked. soon after i saw its working i got the idea about adding 6 LED strings to each channel can give it a cracking look.usin relays it might be done, im now working on it.

file:///C:/Documents%20and%20Settings/Ryan%20Silva/My%20Documents/My%20Pictures/4060.htm

and i had a look at this one. In sri lanka ( im a sri lankan) all shops are filled with chinese products. this is the ic i got.

play the animation,

check the output of pin 4, 5, 6. when a pin gives a pulse three of six LEDs ore on. on the falling edge other three LEDs are on thats how i understood.