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# [SOLVED]"incremental" output IC name search

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#### zakkos

##### Newbie level 6
Hello all, i found myself in need of something that can turn on a series of output in an incremental fashion but i don't know the name of such ic and even if it exists.
What I need is something that behaves like a hibrid of a counter/shift register and a vumeter ic.
The only difference is that it doesn't have to take an analog voltage input but either a direction/clock pair or something like an address, BCD or whatever.

Thank you all!

Hi,

How many outputs?
What supply voltage?
What signal(levels)?
And a better descripion. It seems you have two options (up/down and address). Describe both functions.
Is only one output ON, or may there be many outputs ON at the same time?

Klaus

Hi Klaus! I try to explain a bit further.

Actually i'm more interested in the name of the IC function (even more than an actual number part) so i can adapt designs to it and/or choose the right one. So i'm not very concerned about number of outputs, levels and supply voltage, but roughly i'd go for something like 8 outputs (possibly chainable to other ICs) in the 0-5v range, powered at 5v. Positive or negative logic doesn't matter.

The function i need is akin to that of an analog vumeter ic (think lm3915) only digital in nature. As for the counter/address it's because either way it's ok for me but if an IC exists with a counter behaviour that's better.

I'm more of a firmware guy so I'll try to explain with a binary number (4 bits for simplicity) what i mean. I assume here a counter behaviour with positive logic, dir: 1 = increment, transition on the clock's rising edge:

Let's start with a blank state, startup or reset, whatever.

Code:
output: 0000
dir: x
clk: x

next "state" I put a 1 on the DIR input and strobe the CLK

Code:
O: 0001
dir: 1
clk: 0->1->0

O: 0011
dir: 1
clk: 0->1->0

O: 0111
dir: 1
clk: 0->1->0

O: 1111
dir: 1
clk: 0->1->0

Now the other way around:

Code:
O: 0111
dir: 0
clk: 0->1->0

O: 0011
dir: 0
clk: 0->1->0

O: 0001
dir: 0
clk: 0->1->0

O: 0000
dir: 0
clk: 0->1->0

So it's like a decade counter but with non mutually exclusive outputs

?? start with Analog MUX ( multiplexer)

Hi,

this seems to be similar to a power sequencer. but those are running up and down timing controlled automatically.

Or like a bargraph controller with digital input. Never seen as an IC.

It´s an easy task of a PLD or a ucontroller.

Klaus

zakkos

### zakkos

Points: 2
Re: &quot;incremental&quot; output IC name search

Hi SunnySkygui, I don't think a mux/demux is what I need.
For what I understand multiplexers switch between multiple inputs into a single output and the other way around for demux.
As I explained I need something that does not switch off one output when another one is selected. I need something that turns on outputs in sequence but adding one to another (or subtracting if it's going in reverse). If I understood right it's more or less a johnson counter with up/down directions.

- - - Updated - - -

Hi,

this seems to be similar to a power sequencer. but those are running up and down timing controlled automatically.

Or like a bargraph controller with digital input. Never seen as an IC.

It´s an easy task of a PLD or a ucontroller.

Klaus

Thank you Klaus, in the end I might just use a microcontroller like you suggested. I just wanted to know that. Thank you again!

One at a time, maybe you want a Johnson counter.
Like CD4017. Or a binary followed by a demux /
decode, which could net you up/down rather than
up / wrap or up / reset operation, depending.

Analog style, the LED bar graph ICs from National
(LM3915? I forget), the linear input rather than the
log (audio) input version. Not sure these are still
production-current, and you're not interested in
analog.

Each in turn, staying lit, probably want a shift reg
with "1" data, and gang turnoff by reset (or if you
have a bidirectional SR, you could go back the way
you came).

Hi,

just found the HC194.

4 bit bidir shift register.

Clear on power up.
Set fix DSR = 1 and DL = 0
select direction with S0/S1 (one inverter needed because S1 = !S0)
clock with CP

it should be cascadable.

Klaus

zakkos

### zakkos

Points: 2
Re: &quot;incremental&quot; output IC name search

Hi SunnySkygui, I don't think a mux/demux is what I need.
For what I understand multiplexers switch between multiple inputs into a single output and the other way around for demux.
As I explained I need something that does not switch off one output when another one is selected. I need something that turns on outputs in sequence but adding one to another (or subtracting if it's going in reverse). If I understood right it's more or less a johnson counter with up/down directions.
In logic , that would be an up/dn binary counter and binary demux for individual output control. I made this once in late 70'S for a chaser light show, with variable frequency up/dn control to ZVS pulse cct to drive 30A Triacs and also base drum sound activated increment pulse.

For my thesis project I made a sound activated 1 of 16 toggle switch for quadriplegics. It used a sequencer for rows then columns and a mic for puff control to stop or if they could whistle pitch control like DTMF except one note at a time using BPF. THis could be used for phone, lights TV remote etc. THis just used binary logic demux. That was in 1975. Now you can do all the logic in PIC or CPLD.

Tony Stewart

Could it be 1-of-8 data selector, 74LS151?

4-line to 16-output decoder? 74154.

Just a hint:
What if describe this behaviour at some HDL language to see what circuit show up ?
This could give us some insight.

;-)

Re: &quot;incremental&quot; output IC name search

Hi,

just found the HC194.

4 bit bidir shift register.

Clear on power up.
Set fix DSR = 1 and DL = 0
select direction with S0/S1 (one inverter needed because S1 = !S0)
clock with CP

it should be cascadable.

Klaus

Hi Klaus! That's exactly the behaviour I was after!
So, just to recap, there isn't a single IC that does exactly that on purpose, and by further research I think "that" can be called an up down johnson counter.
The same behaviour can be obtained with a bidirectional shift register with a proper setup.
thank you very much, good finding. Also thank you all for pointing me to the name of this thing. It's incredibly hard to find something you know how it works but don't know the name!

- - - Updated - - -

In logic , that would be an up/dn binary counter and binary demux for individual output control.
[...]
Now you can do all the logic in PIC or CPLD.

Tony Stewart

Just for the sake of learning i'll take a look at that, thank you. As for the PIC part i was actually looking for something to relieve a uC from some trivial work while allowing it to do some more heavy computational stuff. In the end probably an all internal solution might just be the best thing. But hey, it's nice to know!

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