Hi,
My schematics here.
Charge pump not working. I changed 10nf capasitor and I tried 4 differend IC. Problem not solved.
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RE: DRV8814: IC not working.
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RE: DRV8844EVM: Motor Drivers Forum
Thank you very much James! Since I'm using a single power supply J2 is in place connecting VM- and LGRD.
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DRV8844EVM: Motor Drivers Forum
Part Number: DRV8844EVM
Hi. I'm trying to use DRV8844EVM to drive four 24V DC 1A (Festo MH3) solenoid valves. I'm generating four square waves (this wave has frequency, duty cycle, phase info in it already) in LabView and use its analog outputs to provide the control signal to DRV8844EVM. Here are couple questions that I'm trying to solve:
1- I will take the jumpers off from J3 for four inputs (IN1 to IN4) and put my square wave analog signals positive voltage (only at driver's side not microcontroller side) but what am I supposed to use as the ground for these analog signals? Just LGND may be?
2- Similar problem with the output from DRV8844EVM. How am I going to ground the output voltages that are going to solenoid valves from DRV8844EVM?
3- There are test stakes on DRV8844EVM. These are provided for measurements with probes for sure. What is the easiest way to connect a cable on these? Just hold o cable touching it and then solder?
Thank you very much for the help!
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RE: DRV8812: May we have Bipolar Stepper Motor Driver with 4-Level Current Regulation that Vin can down to 6V(Vmax is 45V)?
Hi Chen,
The devices that operate at 45V do not operate at 6V. Likewise, the devices that operate at 6V do no operate at 45V.
If you need VM min 6V to VM max 45V, you will need to increase the voltage above the VM min when operating at 6V. This can be done by adding a boost regulator to increase the voltage.
How long will the voltage be 6V? Another option is to add a diode in series with VM and place a large bulk cap to keep the voltage above minimum VM.
The devices that operate at 45V do not operate at 6V. Likewise, the devices that operate at 6V do no operate at 45V.
If you need VM min 6V to VM max 45V, you will need to increase the voltage above the VM min when operating at 6V. This can be done by adding a boost regulator to increase the voltage.
How long will the voltage be 6V? Another option is to add a diode in series with VM and place a large bulk cap to keep the voltage above minimum VM.
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RE: DRV8814: IC not working.
Hi Motor,
There could be a problem with the layout, or a connection problem like a solder bridge. If this is a layout problem, the devices could be damaged on power up.
If VM = 20V, VCP should either be ~19V when nSLEEP is low or ~32V when nSLEEP is high.
Please check your layout and then your connections after placing the device on the board. Also, if possible please power the board up slowly looking for potential problems. This should be done with a low (50mA or less) current limit on the power supply.
There could be a problem with the layout, or a connection problem like a solder bridge. If this is a layout problem, the devices could be damaged on power up.
If VM = 20V, VCP should either be ~19V when nSLEEP is low or ~32V when nSLEEP is high.
Please check your layout and then your connections after placing the device on the board. Also, if possible please power the board up slowly looking for potential problems. This should be done with a low (50mA or less) current limit on the power supply.
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RE: DRV8885: Internal clock
Hi Aoyama-san,
Has the customer confirmed that the DRV8885 creates the noise, or are there other microcontrollers and switching regulators on the board that may create the noise?
If it is the DRV8885, then it might be from the digital clock. Make sure the decoupling capacitor on DVDD is placed as close to the part as possible.
Has the customer confirmed that the DRV8885 creates the noise, or are there other microcontrollers and switching regulators on the board that may create the noise?
If it is the DRV8885, then it might be from the digital clock. Make sure the decoupling capacitor on DVDD is placed as close to the part as possible.
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RE: DRV8308: Pre-Driver PWM Pulse Width with Closed-Loop Speed Control
Hi Rick,
Thank you for the clarifications. With respect to the PWM resolution and output frequency details, is any of this information in the datasheet? I know that it is in the text that the master oscillator runs at 100 MHz, but there is nothing in any of the electrical specification tables about this clock or the limitations it imposes on the rest of the system. I certainly don't recall seeing anything about which bits of the PWM output are actually used depending on the PWM output frequency selection.
Thanks,
Jim
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RE: DRV8834: Decay mode
Aoyama-san,
After reset, both phases will be in slow decay at the home postion. Once you issue the first step command, one phase will increase the current level and remain in slow decay. The other phase will decrease current level and begin regulating in mixed decay.
I think the reason you saw 8 steps in slow decay is because you are microstepping at 1/8, and you were looking at the increasing phase. If you looked at the phase with decreasing current, you would have seen the mixed decay.
After reset, both phases will be in slow decay at the home postion. Once you issue the first step command, one phase will increase the current level and remain in slow decay. The other phase will decrease current level and begin regulating in mixed decay.
I think the reason you saw 8 steps in slow decay is because you are microstepping at 1/8, and you were looking at the increasing phase. If you looked at the phase with decreasing current, you would have seen the mixed decay.
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RE: DRV8308: Pre-Driver PWM Pulse Width with Closed-Loop Speed Control
Hi Jim,
Unfortunately, there is not any information in the datasheet regarding this. This is something that was discovered based on your question. It did not make sense how the device could operate with 1.22ns resolution using a 100MHz clock.
This clarification will be added in the next update.
Unfortunately, there is not any information in the datasheet regarding this. This is something that was discovered based on your question. It did not make sense how the device could operate with 1.22ns resolution using a 100MHz clock.
This clarification will be added in the next update.
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RE: DRV8308EVM: How to Reset Fault on DRV8308EVM Board
Hello Michael,
To check the kind of fault you are experiencing, please do a read to register 0x2A. Please note that the CPFAIL ad UVLO are set at power up but should clear as the voltage rises past the thresholds. thank you.
To check the kind of fault you are experiencing, please do a read to register 0x2A. Please note that the CPFAIL ad UVLO are set at power up but should clear as the voltage rises past the thresholds. thank you.
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RE: DRV8308: Pre-Driver PWM Pulse Width with Closed-Loop Speed Control
Hi Rick,
Could you please make sure that the 10 ns minimum and the SPEED register clarification that you detailed are both in the next datasheet update?
Thanks,
Jim
Could you please make sure that the 10 ns minimum and the SPEED register clarification that you detailed are both in the next datasheet update?
Thanks,
Jim
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RE: DRV8308EVM: How to Reset Fault on DRV8308EVM Board
Thanks for the response Luis.
We've tried to read from the 0x2A register, but get nothing. Sorry for the novice questions, but we're assuming the read request is accessed from the 3rd page, lower right corner of the GUI (see attached screen shot).
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DRV8308EVM: How to Reset Fault on DRV8308EVM Board
Part Number: DRV8308EVM
Recently bought 2 DRV8308EVM developer kits. Had the kits working with the Telcon motor (that came along with the kit) and with an Anaheim motor (another BLDC 3 phase motor). One of the boards has recently thrown a "fault" for no apparent reason (fault LED is on with line pulled low). Resets through the code composer SW does not reset, and there is no indication of why fault is thrown. Is there a way to reset fault or test as to what occurred to throw the fault?
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RE: DRV8308: Pre-Driver PWM Pulse Width with Closed-Loop Speed Control
Hi Jim,
Yes we have both in our list to be added. Thank you for the post.
Yes we have both in our list to be added. Thank you for the post.
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DRV8308: Pre-Driver PWM Pulse Width with Closed-Loop Speed Control
Part Number: DRV8308
What is the balance between PWM frequency, duty cycle and the control loop for closed-loop control with Clock Frequency Mode?
I have an application that normally needs a motor RMS current of 5 to 20 mA and has a maximum current limit of 340 mA (calculated from the maximum torque limit). The motor has low winding inductance (85 uH) and resistance (5.5-ohm). I plan to operate the DRV8308 with a supply voltage of 8.5 V. Due to the low winding inductance, the di/dt is very fast, so I would like to understand the relationship between using a high PWM frequency and the ability to manage speed and current.
Also, if the PWM Ton time (PWM pulse width) is shorter than the Current Limit blank time (TBLANK), does the Current Limit circuitry even have an impact? (I presume the blank time is reset at the beginning of every PWM cycle.)
As for the PWM output for the MOSFET pre-drivers (assuming 120° commutation, not sine-wave-drive), my understanding is that the duty cycle is based on the output of the speed control loop (differentiator, integrator, digital filter, etc.) which results in a 12-bit duty cycle to be applied as Ton for the next PWM cycle. That said, if the PWM frequency is set to 200 kHz, the PWM cycle time is 1/200 kHz = 5 us. Then with the 12-bit duty cycle, the PWM Ton time can be as small as 5 us / 4095 = 1.22 ns (e.g. a 50% duty cycle would have a 2.5 us Ton time or a count of 2048 where 2048*1.22 = 2.5 us). Is this the correct understanding of how the PWM output works?
However, a minimum PWM Ton time (PWM pulse width) of 1.22 ns doesn't even seem realistic since it would require a transistor gate charge of about 0.15 nC just to turn on with the DRV8308 maximum output drive current of 130 mA (rise time = gate charge [C] / pre-driver current [A]). That doesn't even allow the FET to fully conduct and a power MOSFET with that low of a gate charge is not readily available to the masses.
Overall, I'd like to make sure I am correctly understanding the closed-loop speed control operation and the associated PWM output duty cycle operation and timing resolution. Once I correctly understand those and the relationship between PWM Ton time and Current Limit blank time, I believe I can determine how to properly use the DRV8308 in my application.
Thank you,
Jim
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RE: UC2625: UC2625
Hey Youssef,
After doing some consulting, the Operating Temperature refers to the Junction Temperature (TJ) from -40 to 105C. There is a mistake on TI.com that I'll will signify that the range needs to be fixed. Thank you for your patience. Just note that newer devices refer to ambient temperature instead of junction temperature when they say "operating temperature". When in doubt, check what the datasheet has defined operating temperature.
Anyways, you are right the SSTART, in normal operation, is pulled up to approximately VREF (5V or 4.5V in your case). In addition, both components are required for operation.
When a fault occurs (VCC drop out or overcurrent condition), the base/gate of the transistor will be set (note the S in the block diagram) to "1" and which pulls down SSTART to GND. The resistor is needed because the act of pulling down the pin to GND would be shorting VREF to GND in the fault condition (which is not safe). As a result, the resistor limits the current from VREF during the fault condition but lightly pulls the pin to VREF during normal operation.
For the capacitor, we need to look at when the transistion occurs from the fault condition to normal operation. When the base/gate of the transistor is set back to 0, which makes the SSTART pin no longer tied to GND, there is a 10uA current source that is fed back into the pin. This current will charge the capacitor and help raise the voltage back to VREF. Without the capcitor, the 10uA has no where to go and the voltage will not rise as expected.
Hope this helps,
-Cole
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UC2625: UC2625
Part Number: UC2625
Hello,
I am using the UC2625 and i have come across "E/A OUT range" in the datasheet. There seems to be minimal description in the datasheet about what that range refers to or affects. It would be great if someone could clear up my confusion.
Thank You
Youssef
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RE: DRV8834: Decay mode
Hello James-san,
Yes, yes, your answer is right. It is same as the experiment results of the customer.
I will feedback the customer this information.
Thanks,
Naoki Aoyama
Yes, yes, your answer is right. It is same as the experiment results of the customer.
I will feedback the customer this information.
Thanks,
Naoki Aoyama
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RE: DRV8332: Brushless Hub Motor - Low Phase Voltage Output
Also, the current readings coming in from the source match the reading on the power supply, reaching roughly 6.5 amps before shutting down.
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DRV8332: Brushless Hub Motor - Low Phase Voltage Output
Part Number: DRV8332
Hello All,
Another question regarding the DRV8332: we have the driver hooked up to run a 750 W brushless hub motor. We tried supplying 24 V as well as 36 V to PVDD, but both times the phase voltages were reduced to 10.6 V on the output. The motor won't draw any current.
Our third test supplied 4 V to the motor, and it drew roughly 2 A from the power supply in order to spin. Raising the voltage to 5 V or higher caused the motor to stop immediately. Does anyone know why the voltage is so much lower than PVDD, or why the motor will run only at low voltages?
Any help is much appreciated.
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