There are all phase signals
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RE: DRV8305 Damage
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DRV8305 Damage
Hi everyone..
I'm using TMS320F28035 with DRV8305 motor driver. My custom board two layers. Top layer control unit. Bottom layer power unit and there are 6 mosfets (SUM110N06-3M9H-E3). I'm using BLDC_Sensorless project in constrolsuite(Trapezoidal control). When i don't connect motor all signal ok, but when i connect motor DRV is falling (PVDD_UVLO2). It doesn't appear short circuit. When i close all fault DRV on fire. How to fix this situation.
Thanks for your helps..
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RE: DRV8302 Fault pin always zero
Hi Rick,
I have run my circuit and Code Composer program. while EnableFlag=1, I have observed the following values.
1) PVDD=25V
2) GVDD=11V
3) AVDD=7V
4) DVDD=3V
5) EN_GATE=3V
6) M_PWM=3.2V
7)
INL_A=3.2V PWM
INL_B=3.2V PWM
INL_C=3.2V PWM
INH_A=3.2V PWM
INH_B=3.2V PWM
INH_C=3.2V PWM
8)
BST_A=11V
BST_B=11V
BST_C=11V
BST_BK=25V PWM
9)
GL_A=0V
GL_B=0V
GL_C=0V
GH_A=1V
GH_B=1V
GH_C=1V
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RE: DRV8303 Min PWM output frequency
Hi Shimizu,
Ideally the device can work at 100% duty cycle which means long time high side gate voltage sustain. So 7 Hz should be fine. Please make sure there is no external GS path even high resistance path.
But I think we don't have to go such low PWM frequency, we can alway has constant high PWM frequency but with low frequency modulation for the 3 or 6 PWM inputs. Such as 1% or 99% to replace the constant LOW and HIGH control.
Best regards,
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DRV8303 Min PWM output frequency
Hi,
Could you let me know minimum PWM output frequency, please?
I know that max frequency is 200kHz from datasheet.
Customer wants to use at 7Hz PWM input(very slow).
and sets motor speed by changing duty of 7Hz.
DRV8303 has bootstrap capacitor.
I am concerned about becoming output of high side weaker.
If it is difficult to answer for less information, could you advice me in case of EVM?
Best regards,
Shimizu
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RE: DRV8302 Fault pin always zero
I made my measurements using an oscilloscope so I can see pwm signal .
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RE: Issues with DRV8833
Hi Rick,
nSleep is logic high yes, I put the correct cap values and the motor turns now in one direction only. If I swap the input pins to VCC/GND nothing happens. I haven't found the reason for this yet. Also I didn't see any mention in datasheet that nFault needs to have an external pullup other than maybe in Figure 10. Thanks for the help!
Kenny
nSleep is logic high yes, I put the correct cap values and the motor turns now in one direction only. If I swap the input pins to VCC/GND nothing happens. I haven't found the reason for this yet. Also I didn't see any mention in datasheet that nFault needs to have an external pullup other than maybe in Figure 10. Thanks for the help!
Kenny
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Issues with DRV8833
Hi,
I've got a DRV8833 in HTSSOP16 package that I put on a TSSOP16 breakout (without heatsink). This leads to the heatsink not being connected to ground. I assumed this wouldn't matter since it's just used for heat sink, is this correct? I'm trying to build www.ti.com/.../drv8833.pdf (page 12, 8.2 typical application) but it doesn't work and I've checked the connections on my breakout board 3x now. I've got Ain1 and Ain2 in VCC (6V) and gnd respectively but no output. It seems that fault is low and I'm not quite sure why. Also, do I need the (correct) caps or should it work without them? Thanks!
EDIT: On page 3 in datasheet it says "both GND pin and device PowerPAD pust be connected to ground". I'm assuming this answers my question?
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RE: DRV8825 Reset Issue
Also please check if there is any nFAULT signal came out in the abnormal time.
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RE: DRV8825 Reset Issue
Hi Wilson,
1) All x595 are supplied by 3.3V/DGND supply lines. This 3.3v is generated off-board & supplied to this board
2) All DRV8825 connected to +24V/PGND lines.
3) There is single point of connection between DGND & PGND as following image shows... R9 is 0E resistor simply to specify single point connection between 2 grounds.
Is this okay?
Thanks,
Saumitra A Deshpande
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RE: DRV8825 Reset Issue
Hi,
Forgot to mention... nFAULT line doesn't get asserted. But since all x595 outputs are set 0, nRESET pin of DRV8825 gets asserted.
Saumitra A Deshpande
Forgot to mention... nFAULT line doesn't get asserted. But since all x595 outputs are set 0, nRESET pin of DRV8825 gets asserted.
Saumitra A Deshpande
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DRV8825 Reset Issue
Hi,
We have designed a board with 3 DRV8825 Drivers. The main controller is STM32 uC with configuration interface(Microstepping, Reset, Enable, Direction, Decay etc) through 74HC595 & 3 separate PWMs for each. Power supply for Motor & Controller is Dual Output SMPS with ratings of 24VDC/4A & 12VDC/1.5A.
Note that 595 shift registers & DRV8825 are on same PCB while STM32 is on separate PCB with single FRC cable used for inter-connect.
I am able to configure DRV8825 correctly through SPI of STM32 The issue we're facing is that sometimes while starting the motors or sometimes while motors are running it resets all shift registers making all of its output 0, leading to reset of all DRV8825. Note that there is no activity on any of shift-registers lines when this happens.
1) I assumed that it may be issue with shift registers of noise interfering & tried many things, but issue isn't solved.I am unable to catch any glitches on SPI lines with my scope.
2) Also using 2 separate power supplies sometimes masks the issue, but in the long run shift-registers get reset.
3) Interestingly, we've another configuration using exact same motors, same power supply. Only Shift registers are on STM32 PCB while we've 3 separate DRV8825 boards inter-connected through 3 FRC cables. It's been running without any issues for last 12 months 24x7.
So is it possible to have multiple DRV8825s on same PCB, sharing common Power Supply tracks(+VM & GND)? Or issue is still with shift-registers?
I am attaching images of TOP & BOTTOM layers of my DRV8825 PCB.
Any help will be greatly appreciated.
Thanks in advance.
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RE: DRV8711 high temperature
Hi Thorsten,
Thank you for the additional information, and for studying the documents prior to contacting us.
A few questions about the scope captures and the overall system:
1) What resistance value did you place in series with the low side gate driver?
2) When measuring the low side gate voltage, where is the signal and GND reference? It should be at the gate of the transistor and the ground reference should be at the top of the sense resistor. This will confirm that the voltage spike shown on the low side could be turning the low side FET on.
3) How hot are the FETs? Are they contributing to the bulk of the board heat?
4) How is the thermal pad connected to the board? Is it one large ground plane where the DRV8711 dissipate the heat generated inside the device?
5) How much current is the 5V regulator providing?
Please try the following and let us know if you see a difference:
1) Reduce the IDRIVEP to the minimum. This should minimize coupling from the high side FET turning on to the low side gate.
2) If using a series resistor closer to 120Ohms, please lower the sense resistor to 47Ohms
Thank you for the additional information, and for studying the documents prior to contacting us.
A few questions about the scope captures and the overall system:
1) What resistance value did you place in series with the low side gate driver?
2) When measuring the low side gate voltage, where is the signal and GND reference? It should be at the gate of the transistor and the ground reference should be at the top of the sense resistor. This will confirm that the voltage spike shown on the low side could be turning the low side FET on.
3) How hot are the FETs? Are they contributing to the bulk of the board heat?
4) How is the thermal pad connected to the board? Is it one large ground plane where the DRV8711 dissipate the heat generated inside the device?
5) How much current is the 5V regulator providing?
Please try the following and let us know if you see a difference:
1) Reduce the IDRIVEP to the minimum. This should minimize coupling from the high side FET turning on to the low side gate.
2) If using a series resistor closer to 120Ohms, please lower the sense resistor to 47Ohms
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RE: DRV8711 high temperature
Hi Rick,
1) R(sense) is 40mR as I wrote above.
2) Signal reference is directly at the gate of the FET, GND was connected to the GND supply input of the board. I can do additional measurements tomorrow if required.
3) The temperature of the FETs is the same than for the PCB, around 70°C
4) The ground plane on the top side is only .55x0.55", interrupted by traces and vias. But there are ground layers on the other three layers connected with by 12 0.4mm vias in total. I will do optimisation at this point, the fan-out isn't very good here.
5) We do not draw current from the 5V regulator. /Sleep is pulled up high by a high impedance voltage divider plus a 5.1V zener to ensure auto-power up. The rest of the board (mainly a small micro) is powered by a seperate linear regulator.
I will try your tipps tomorrow. Series resistors on low side FETs are 47R. At first we tried without, but had problems with predriver faults.
With kind regards,
Thorsten Ostermann
1) R(sense) is 40mR as I wrote above.
2) Signal reference is directly at the gate of the FET, GND was connected to the GND supply input of the board. I can do additional measurements tomorrow if required.
3) The temperature of the FETs is the same than for the PCB, around 70°C
4) The ground plane on the top side is only .55x0.55", interrupted by traces and vias. But there are ground layers on the other three layers connected with by 12 0.4mm vias in total. I will do optimisation at this point, the fan-out isn't very good here.
5) We do not draw current from the 5V regulator. /Sleep is pulled up high by a high impedance voltage divider plus a 5.1V zener to ensure auto-power up. The rest of the board (mainly a small micro) is powered by a seperate linear regulator.
I will try your tipps tomorrow. Series resistors on low side FETs are 47R. At first we tried without, but had problems with predriver faults.
With kind regards,
Thorsten Ostermann
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RE: [ DRV8303 ] Bootstrap Diode Characteristics
Hi Phil, Nick,
Can you please help me to have the information of trickle charge?
I would like to make sure min, typ and max value of trickle charge current.
Sorry for rushing you.
Regards,
Ken
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RE: DRV8825 / about software.
Hi Nagai,
Better to use DRV8824/25EVM.
You don't need to use the two together.
COM port must be set correctly.
Best regards,
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RE: DRV8825 / about software.
Hello wilson,
Thank you very much for rapid reply!
Many thanks!
Nagai
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DRV8825 / about software.
Hi all,
Please let us know about software of DRV8825EVM.
I found the two software, "DRV8824/25 EVM" and "CPG004 DRV88xx EVM".
We have questions as follow;
- Are these can be used together ?
- Can we set to any COM-port of software?
Best regards,
Nagai
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RE: DRV8711 high temperature
Hi again,
I did some additional measurements: Ch1=High side FET gate, Ch2=Low side FET gate, Ch3=Rsense, all GNDs connected to Rsense GND pad.
First shot: Same conditions than yesterday (IDRIVEN=01, IDRIVEP=10). 2nd one: IDRIVEN=00, IDRIVEP=00 (default setting). 3rd one: IDRIVEP=01, series R @lowside FET reduced from 47R to 22R to reduce ringing.
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RE: How to control current in DRV10983
Hi Datta,
Our experts have been notified and should reply soon.
Our experts have been notified and should reply soon.
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