[Dragonfly]

Here it is. I can make it a lot larger but the file size will grow.

[H500]

What power voltage are you using?

Hopefully you did not connect or disconnect the motor while the power is on. That would likely kill the chip.

Try disconnecting the motor. Does it still get hot?

How are you producing 5v? Did you check to make sure it's steady?

What is U3?

[Dragonfly]

I am using a computer PS for the test.
Of course I know and have read a lot about precautions and especially connecting and disconnecting under power.
I've tried 2 chips. With the first one I used a simple arrangement of four LED's in pairs with reversed polarity and 1K resistor for each pair. With it I've tested other drivers I've made and it visually displays the phase sequence under low step pulse rate.
Here though one LED started gleaming even without 12V motor power applied and when it is applied the chip started warming up significantly, with 1K resistors instead of coils. I thought the lack of significant current may confuse the internal logic and the bridges are driven in a wrong way.
Put higher sense resistors and connected a motor. With it, there is no characteristic hissing and the chip gets extremely hot for a few seconds. Feeding step pulses has no effect. The chopper does not start IMO.
I made 2 boards so I populated the other one with only the minimal required components and another driver chip. Didn't feed 12V and at first didn't solder the sense resistors. Powered just the 5V to check the control signals. RESET goes high, ENABLE is held low by design if the board is not connected to the BOB. I bring the ENABLE high manually and expected to see the chopper oscillator working at pin 7 wit an oscilloscope. But there's no pulse generation.
Because it is my first encounter with TB6560 I have nothing to compare with. But I do not exclude the option of faulty chips. A friend was ordering for him and ordered some for me at low price. He hasn't used his yet so no way to check the possibility.
But if the chip is actually so sensitive, so fragile, I'll not use it on a machine where conditions are far from those in a printer or large copier.

P.S. U3 is the symbol of the power pins of the 74HC14.

[H500]

You are using a pnp for q2. That won't work. U3.5 will be subjected to the full high voltage when its output is high. Although the current is limited by the 100k resistor, the 12v might damage U3 or even the tb6560. At best, the delay circuit won't work as intended. To be sure, use a npn and adjust the reset logic accordingly.

[Dragonfly]

OK, I agree the solution is not good. But currently it has no importance to the global problem of the Toshiba chip not even coming to life at all.
For the testing I have eliminated the automatic power switch.
What I need ATM is a definite answer are there pulses from the chopper oscillator on pin 7 and when the chopper starts working. As far as my comprehension of the data sheet goes, it should start with only 5V (Vdd) applied and RESET and ENABLE inputs in high logical state.

[lucas]

What voltage do you measure on the Reset pin when it is high? The MCP120 has an open drain output and I see no pull up resistor. Isn't the reset floating at a too low voltage?

There are some differences between schematic and layout: check C6, C7 and C13.

Do you have a link to the original schematic wich you borrowed? Can't remember seeing something like this.

I do have some spare proto drives here so I can do the test for you, maybe this evening.

Regards,
Luc.

[Dragonfly]

On the second attempt I didn't use the MCP, wired a resistor from Vdd to /RESET and a capacitor from there to ground. Just for a delay.
The difference on the schematic is there because I did some corrections afterwards on it. The filtering capacitors were initially placed after the MOSFET switch.
Voltage at RESET pin is 3.6V, which I consider normal because of the internal diodes at the input.
Anyway, as have said already, those are in my opinion not decisive factors, because I eliminated every extra on the second test.
Before anything else I must see the low voltage part of the chip coming to life. But no one seems to be able to give an advice about how to check it's functional.
This is the original schematic I've downloaded from somewhere here.

[Dragonfly]

I think it's time to give up although I don't do it easily. Have no base for comparison to determine whether the chips are functional.
Today I milled a test board with edge pads where I made a socket by soldering on either side a half of a cut DIL28 IC socket. Soldered everything almost lead to lead. To no avail. Even with pull-up resistors of 10K two of the control inputs have voltage below 1V - sourcing current. /RESET and ENABLE go to a stable high state only after switching on motor supply voltage, otherwise are below 1.5V. No pulse generation at OSC pin, voltage there goes to 7 V after applying 12V to motor power.
No sign of chopper working, current limited to 500mA with 1 Ohm sense resistors but the chip is ready to melt in seconds.

[lucas]

Some of your results are really weird, I've build a lot of these and never had problems.

No pulse generation at OSC pin, voltage there goes to 7 V after applying 12V to motor power.

This is definatly wrong, every control signal should be at or below the +5 level.

To duplicate your tests I took one of my drives without motor, only +5 and +VM are connected:

- It doesn't heat up.
- Reset is at +4V.
- OSC has a waveform between 0.5V and 2V approx.

This looks more and more to be true:
" But I do not exclude the option of faulty chips. A friend was ordering for him and ordered some for me at low price."

Fake ones? Where did he buy them?

If you want to continue with these chips: I can send you one or even a semi proto board.

But I would seriously consider using the THB6064H for a new design, it has higher ratings and a real current adjust method iso of fiddling with current sense resistors.

[Dragonfly]

Thanks, Lucas.
I don't know where my friend ordered them from. But no matter how sensitive and capricious the chip, it should come to life even for a short time. AFAIK on some Chinese boards the powering requirements are not met but they still work for a while.
If indeed it is so sensitive, my view is that such device is not suitable for the somewhat harsh environment of a CNC machine.
I'll try to find a working driver board and do some measurements on it. Problem is that the chips are not available for buying locally, otherwise I'd swallow the blown up price of the electronic stores and buy one from them just to be sure. For my projects I've made successfully Linisteppers, L297-298 and SLA7062M driver boards which work fine and as expected.

P.S. It seems that while the Internet is full of offers of those chips at low price, the big electronic suppliers do not list them on offer. 6560AHQ is not present in Farnell lists and even there the AFG type is listed as 3.5A driver.

[lucas]

Normally these are not that sensitive, I"ve blown only one for reasons still unknown.

Digikey has 18,527 pcs in stock at 5,2 Euro.

But as said before: I would seriously consider to use the THB6064H = TB6564AHQ for a new design.

[Dragonfly]

It's OT here, but are TB6564AHQ available?

[lucas]

Didn't search hard for a local 6564 source, Digikey doen't have them (yet?) but I have 10 pcs on order from China at 7 USD each, real cheap if they perform well.
Delivery will be 3-4 weeks maybe, but I'm not in a hurry.

What do you mean with "OT" ?

[Dragonfly]

Off Topic - widely used forum abbreviation

Digikey are not an option for me - they'll be at the price of gold with the shipping cost. Although Bulgaria is in EU, its been treated as an alien country on the other side of the world. Even shipping rates from Germany are hair rising.

[lucas]

Shipping costs can be strange.
From Belgium to Bulgaria for a 1Kg pakket : 10 or 14 Euro.
6 Euro for up to 350gr, not that bad?

[Annirak]

Off Topic - widely used forum abbreviation

Digikey are not an option for me - they'll be at the price of gold with the shipping cost. Although Bulgaria is in EU, its been treated as an alien country on the other side of the world. Even shipping rates from Germany are hair rising.

Have you checked dealextreme?

IC TB6560AHQ for Stepper Motor Driver Controller - Free Shipping - DealExtreme

[Dragonfly]

Funny, the one on the picture there has the same production date code (I think it is production date) as the ones I have - 028GB11
I don't know where my friend ordered them from, but am a bit afraid to order from such places. Until there is a definite conclusion that they are not faulty and it's me who is at fault.

[Annirak]

Funny, the one on the picture there has the same production date code (I think it is production date) as the ones I have - 028GB11
I don't know where my friend ordered them from, but am a bit afraid to order from such places. Until there is a definite conclusion that they are not faulty and it's me who is at fault.

Well, I'm working on a 6-axis design, so I'll have to order some. I'll let you know how it goes.

[H500]

I ordered many parts from Ebay/China. Most arrived without problem. One batch of mosfets turned out to be factory rejects, but he sent twice as many as advertized.

[Dragonfly]

Just a quick update. My friend replaced two burnt chips on his Chinese 3 axis board with chips from the same lot he gave to me and the result is they never came to life, only getting hot.