Bootstrap supply of high side driver (Fig. 2 +3) doesn't work for static operation (permanently on). Discrete circuit (Fig. 1) has no suitable high side driver supply and no measures against cross-conduction or supply brown-out.
--- Updated ---
See continuous gate-drive paragraph in this application note (pg. 17f)
I have more than 12 different gate drivers and a dozen N-MOS and trying to find the general schematic for making a low-switching 12-36 DC motor that can control via Arduino MCU which is isolated via optocouplers,Hi,
a motor control is designed for a motor .. and is desigend with your own ideas / specifications / requirements.
This is the target. But we don´t know any of your targets.
So what´s your motor specifications? V, I, run time
What´s your power supply specification?
What´s your input signals specification? signal levels, PWM frequency?
also what about additiional features like: Overcurrent handling (on stalled motor, or so..)
******
If one knows the design goals one can focus on the solution:
My first idea is to use ready to buy modules ...
If this is not possible/available, then I´d design one with the help of application notes, design examples, proven circuits (just to preven to re invent the wheel and make mistakes others already have solved)
Designin a motor control the discrete way .. never came into my mind . in the last decades of professionally designing circuits.
Not that it´s not possible, or that I don´t have the skills for it. It´s because a "switching power" PCB needs to be carefully designed. And this takes a lot of time and experience. Discrete design means more parts, bigger PCB, more lengthy signals, bigger GND planes ... all this calles for possible problems ... caused by the swiching currents.
I don´t know how experienced in designing critical PCBs you are ... For me - as a rather experienced PCB designer: I´d avoid a discrete design.
*****
Referring to your last scematic:
Rather focussing on reducing the signal count (to 2 only: DIR and EN) .. I´d fosuc on stable and reliable function.
* 4.7 uF at VCC seems way too small ... in detail it depends on your power supply, switching frequency, wiring stray inductance....
* what´s the use of R20, C14, C15?
* It seems you want to use mature CMOS logic ICs. Are you sure they are: rugged enough, are compatible to your (unkonwn) arduino signal levels, fast enough...
* are you sure you want "fast decay" motor driving method. It makes the control more "PWM to torque" (with unstable RPM) than "PWM to RPM" (independent of torque) ... in detail it depends on yoour need...
* no filter on the motor side?
* no HF filter on the VCC side?
* are you sure you can handle the expectable GND bounce not to violate the arduino control signals
* how is your Arduino powered? You will need a wiring scheme
Klaus
so your motor has no current and the PWM no frequency....So what´s your motor specifications? V, I, run time
What´s your power supply specification?
What´s your input signals specification? signal levels, PWM frequency?
....If one knows the design goals one can focus on the solution:
I don´t know what to do with this information. Is regarding discrete vs IC?I have more than 12 different gate drivers and a dozen N-MOS and trying to find the general schematic for making a low-switching 12-36 DC motor that can control via Arduino MCU which is isolated via optocouplers,
Yes. Also manufacturer application notes say, probably not always clear enough.you said the half-bridge driver is only good for high-switching applications and not for static operation ?!!!!
DC motor operation would be simple, with no high switching, the only consideration is using the direction instead of enabling/disabling the PWM signal on each half-bridgeso your motor has no current and the PWM no frequency....
....
I don´t know what to do with this information. Is regarding discrete vs IC?
And if you have them laying around, why not use them? What´s wrong with them?
And if the gate drivers are different, then what´s the idea to find a "general schematic". Each device comes with it´s datasheet that shows how to use it.
To me this sounds like to have a sports team and try to find the "general size" for their shoes. They all are different and all need shoes that fit their feet.
Optocouplers - when used correctly - may prevent from grund boucne problems. But we don´t see optocouplers, nor how you wired them.
Klaus
I use NAND so it won't work when both signals are highLogic not right. You want to drive the non-switching half-bridge low, therefore AND instead of NAND logic needed. There's an erroneous junction point right of IC12.1
As stated before, PWM duty cycle must not exceed 95 - 98%, also with LN8322.
LN8322.4 should connect to 12V rather than Vcc.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?