I would encourage people to use L6452 for HP45, if you mainly want to drive the HP45 not just for fun with circuits. Although the ST's support is the worst, I'm still thankful as they do provide this chip. Look at the waveform I captured, the edges were so clear, that was with 33ohm load.
I'm still working one the vboost/vsetup connection. As a partially switched on transistor can get very hot and even burn itself. Also, if the voltage is not right, the switch timing can change.
@Mahsa could you please be more specific with the vboost connection you suggested? even a pencil diagram would be very much appreciated.
Hacking the HP45
Re: Hacking the HP45
Last edited by david on Mon May 22, 2017 1:21 pm, edited 1 time in total.
Re: Hacking the HP45
David, how do you address 22 addr lines? You use both channels A and B and switch between channels to drive all nozzles? The switch is fast enough?
We'd all appreciate if you show how you connected the IC to the printhead.
We'd all appreciate if you show how you connected the IC to the printhead.
Re: Hacking the HP45
@david
I have a vague idea how the boost might work. Do you measure a diode between StepUpBoost and VstepUp? If so, in which direction does it point?
My guess is that an inductor is required between supply and StepUpBoost, and a capacitor on VstepUp to store and smooth the boosted voltage.
But this in only a guess, based on the fact that StepUpBoost looks like a high current switch point due to the dedicated ground connection right next to it. But it could also just be a gate driver for an external fet.
If you connect a 1K resistor between 12V and StepUpBoost, do you see any switching on it?
Thank you,
Errol
I have a vague idea how the boost might work. Do you measure a diode between StepUpBoost and VstepUp? If so, in which direction does it point?
My guess is that an inductor is required between supply and StepUpBoost, and a capacitor on VstepUp to store and smooth the boosted voltage.
But this in only a guess, based on the fact that StepUpBoost looks like a high current switch point due to the dedicated ground connection right next to it. But it could also just be a gate driver for an external fet.
If you connect a 1K resistor between 12V and StepUpBoost, do you see any switching on it?
Thank you,
Errol
Re: Hacking the HP45
@david
this is the schematic of vboost.
this is the schematic of vboost.
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- photo_2017-05-25_12-39-25.jpg (108.75 KiB) Viewed 12621 times
Re: Hacking the HP45
Hi all,
I've attached my driver design. I still have some work to do on the schematic but i'm close to my final design though.
Since I don't know how to use the internal stepup part of the L6452, I used LT1930 for VstepUP. It's enough for the low current input of the L6452.
I found it difficult to mess with its internal ADC/DAC so I'll read the HP45 resistor with ATMega. At least, I already have all the libraries for ADC.
TH1 thermistor will be used to read room temperature for calibrating head temperature in cartridge setup routine.
For now I really don't know if I have to lower primitive Vc inputs for adjusting firing energy. The datasheet states this voltage must be in 10.5...12.5V range. I suppose I'll lower the energy by trimming /LONGPULSE width.
I really don't know if this design really works but it's my opinion.
As a bonus, I packed in this file the component library for L6452 I designed.
The Vr,Va and Vc voltages of the driver will be tied together on the J3.
Please correct me if you find any error (beside the typo on the label - L6542 instead of L6452).
I've attached my driver design. I still have some work to do on the schematic but i'm close to my final design though.
Since I don't know how to use the internal stepup part of the L6452, I used LT1930 for VstepUP. It's enough for the low current input of the L6452.
I found it difficult to mess with its internal ADC/DAC so I'll read the HP45 resistor with ATMega. At least, I already have all the libraries for ADC.
TH1 thermistor will be used to read room temperature for calibrating head temperature in cartridge setup routine.
For now I really don't know if I have to lower primitive Vc inputs for adjusting firing energy. The datasheet states this voltage must be in 10.5...12.5V range. I suppose I'll lower the energy by trimming /LONGPULSE width.
I really don't know if this design really works but it's my opinion.
As a bonus, I packed in this file the component library for L6452 I designed.
The Vr,Va and Vc voltages of the driver will be tied together on the J3.
Please correct me if you find any error (beside the typo on the label - L6542 instead of L6452).
- Attachments
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- HP45_L6452.zip
- (221.5 KiB) Downloaded 1010 times
Re: Hacking the HP45
@dragonator
you can try CD4505bpwr. this ic is used for Printer.
you can try CD4505bpwr. this ic is used for Printer.
Re: Hacking the HP45
@davidk for those unused input pins on L6452, may I suggest connecting them to the ground.
Re: Hacking the HP45
Thanks. You're right, inputs should ALWAYS be tied to a certain level.
Did you use its internal ADC?
Did you use its internal ADC?
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Re: Hacking the HP45
@David, can you confirm that this wiring is correct for the L6452 (minus the inputs to ground). I have yet to try it but when I do it is nice to have a reference.
@Mahsa: I tried to find your component, but I got no matches on the internet.
I would love to post actual updates, but my PCB's are still in transit and it is currently 30C in the Netherlands and it is too hot for me to think. My first next step is the new 3D printed carrier for the HP45. The old one sucks, and I want a better one.
@Mahsa: I tried to find your component, but I got no matches on the internet.
I would love to post actual updates, but my PCB's are still in transit and it is currently 30C in the Netherlands and it is too hot for me to think. My first next step is the new 3D printed carrier for the HP45. The old one sucks, and I want a better one.
Re: Hacking the HP45
- Attachments
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- CD4504BPWR.jpg (37.03 KiB) Viewed 12583 times