HEF4046 Phase lock loop IC

[engineer1000]

I have an oscillator running at 130khz driving an ultrasonic transdcuer. The oscillator drifts slightly say 2% over a day. I've been asked to stablize it. I'm thinking of using a HEF4046 PLL. I've looked at the data sheet and am a bit confused.
Do I need use my present oscillator to drive in to pin14 of the HEF4046 and were should I take my feed back into one of the Comparators from?
how acurate does a PLL make the oscillator ie at 130khz how stable would it be?

 

[:Dark_Force]

Hi

Whether you can use your existing VCO or not depends on its ability to be pulled by the PLL and its loop filter. If your oscillator is not meant to be tuned by a dc-voltage, then you should rather use the internal VCO of the HEF4046. On the pin SIG_IN you should connect your reference oscillator which should be very stable! The HEF4046 then generates a frequency at VCO_OUT that is N times the frequency your oscillator at SIG_IN does, unless it would become higher than fmax (2MHz)!

 

[Audioguru]

The oscillator in a phase-locked-loop is synchronized with another oscillator that can be very stable. But you do not have another oscillator that is stable so you do not need a phase-locked-loop.

Use as CD4060 that is an oscillator that has a digital divider. Make its oscillator a crystal oscillator that has an extremely accurate frequency. Select an oscillator crystal frequency that produces 130kHz when it is divided down.

 

[engineer1000]

The oscillator in a phase-locked-loop is synchronized with another oscillator that can be very stable. But you do not have another oscillator that is stable so you do not need a phase-locked-loop.

Use as CD4060 that is an oscillator that has a digital divider. Make its oscillator a crystal oscillator that has an extremely accurate frequency. Select an oscillator crystal frequency that produces 130kHz when it is divided down.

Right what I'm after is this. I have a 130khz oscillator to drive a half bridge which inturn drives a single 130khz ceramic transducer. Now when the transdcuer is run it draws approx 0.5A as it warms up the current goes down so I need to retune the oscillator slightly to get the current back up.
I am after something that tracks the current and adjusts the frequency to suit. Would a pll do this?

- - - Updated - - -

Right what I'm after is this. I have a 130khz oscillator to drive a half bridge which inturn drives a single 130khz ceramic transducer. Now when the transdcuer is run it draws approx 0.5A as it warms up the current goes down so I need to retune the oscillator slightly to get the current back up.
I am after something that tracks the current and adjusts the frequency to suit. Would a pll do this?

 

[Audioguru]

First you said that the oscillator (frequency?) drifts. Now you are saying that the transducer current decreases as it heats up requiring you to retune the oscillator for the original higher current.

I do not know how retuning the oscillator frequency increases the transducer current. Usually increasing the oscillator output level increases the transducer current.

If you actually want to retune the frequency of an oscillator then the voltage controlled oscillator (VCO) in the CD4046 can have its frequency changed with a voltage change. The current of the transducer can be measured and converted to a voltage to retune the VCO frequency.

 

[FvM]

So you want to tune the frequency automatically instead of stabilizing it. It can work with a PLL if you are able to derive a signal with monotone frequency to phase characteristic, e.g. transducer current or voltage, and feed it to the phase detector. The PLL frequency range has to be constrained respectively.

 

[Audioguru]

A piezo beeper has its oscillator working at the resonant frequency of its transducer for maximum output.

 

[FvM]

A piezo beeper has its oscillator working at the resonant frequency of its transducer for maximum output.

Yes, by using a simple self-oscillating output stage. That's the other option besides tuning.

 

[norezmi]

Hi,,,im also have a problem similar to use. Is the HEF4060 can drive mosfet? and at the same time stabilize the PWM?

 

[Audioguru]

Hi,,,im also have a problem similar to use. Is the HEF4060 can drive mosfet? and at the same time stabilize the PWM?

What do you want to stabilize? Output level? Frequency? Pulse width? All of them?

 

[norezmi]

pulse width and frequency...i want to differentiate the result between with PLL and open loop sytem

 

[schmitt trigger]

pulse width and frequency...i want to differentiate the result between with PLL and open loop sytem

The 4046's output is always 50% duty.

I don't understand what you mean by "differentiate the result between PLL and open loop".

 

[norezmi]

Actually, im trying to track the operating frequency 1MHZ using PLL (feedback circuit). The output of PLL will drive the MOSFET to ensure the ZVS of inverter. Before that, ive drive mosfet without any feedback. Ive got the output and there is overlap of ZVS. So, for my intention to use PLL. Any suggestion?Is it possible? Thank you very much if you can assist me to understand about it...im still in study...