Hello Mike,
Allow me to look into this and reply back soon.
Thank you.
Allow me to look into this and reply back soon.
Thank you.
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RE: DRV8332: Facilitate testing of DRV8332
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RE: DRV10983: Lock 2 on startup
Hi, sorry for the delay due to some equipment repairs.
The phase current waveform is around 2 Hz at about 3 amp PP. Top speed is around 1.5 KHz. In slow speed lockup it will not respond to the speed demand signal (analogue). Setting the demand to zero will clear the problem.
The phase current waveform is around 2 Hz at about 3 amp PP. Top speed is around 1.5 KHz. In slow speed lockup it will not respond to the speed demand signal (analogue). Setting the demand to zero will clear the problem.
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RE: DRV10983: Lock 2 on startup
I can't see a way to post the jpg of the current waveform.
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RE: DRV10983: Lock 2 on startup
Got it ! Here is the phase current waveform.
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DRV10983: Lock 2 on startup
Part Number: DRV10983
Hi,
We are driving a small BDCM with an impeller. Normal operation is fine, but occasionally we get false starts where the motor rotates at low speed and lock2 comes on. This situation can be provoked by providing speed demand when the motor has been spinning and is still slowing down (nearly stopped) when the speed voltage is increased again. I have tried unchecking some of the lock detects but the problem persists. Taking the speed voltage to zero clears the condition.
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RE: DRV8332: Facilitate testing of DRV8332
Mike,
There is not a DRV8332 EVM. Could you leverage the DRV8312 EVM which is similar in functionality? The difference, the DRV8312 does not have the current handling capability of the DRV8332. If this works for you, there are two options you can evaluate, DRV8312-69M-KIT and DRV8312-C2-KIT. Thank you.
-Luis Riveros
There is not a DRV8332 EVM. Could you leverage the DRV8312 EVM which is similar in functionality? The difference, the DRV8312 does not have the current handling capability of the DRV8332. If this works for you, there are two options you can evaluate, DRV8312-69M-KIT and DRV8312-C2-KIT. Thank you.
-Luis Riveros
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RE: DRV8332: Facilitate testing of DRV8332
Hi Luis,
We selected the DVR8332 precisely for its current handling capability. The DRV8312 does not meet our application requirement. TI should seriously consider facilitating testing and eventual selection of its product. Thank you for your consideration.
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DRV8332: Facilitate testing of DRV8332
Part Number: DRV8332
There appears to be no evaluation module available for mounting and testing of the DRV8332. We are interested in interfacing it to a brushless DC motor and performing some rudimentary tests. Your suggestions on alternative ways to accomplish this desired task would be greatly appreciated. Thank you.
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RE: DRV8301 : Trickle Charge Circuitry and Internal Handshake
Hi everyone,
I have exactly the same problem trying to drive two dc motors having one of the poles connected to the positive supply.
The problem seems to be solved connecting a 1M resistor from gate to source of the high side mosfets, but I don't know why.
Have anyone analyzed the matter further?
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DRV8301 : Trickle Charge Circuitry and Internal Handshake
I'm using the DRV8301 to drive a two-phase buck-converter to charge a 24V battery. In this situation, the half-bridge outputs have a non-zero voltage (about 24V) present on them before the DRV8301 starts driving the FET gates.
The presence of 24V almost guarantees that the output bootstrap capacitors will start with no charge. If the half-bridge output is 24V, the BST_x pins will have higher voltage on them than the GVDD voltage of ~10V. I believe this causes a small reverse leakage current through the internal bootstrap diode which discharges the bootstrap capacitor to have zero or slightly negative voltage.
At first I hoped the DRV8301 trickle charge circuitry would counteract any leakage on the bootstrap capacitor. However, the trickle charge circuitry only seems to operate when the INH_x input is high. This makes sense, since the datasheet only specifies the trickle charge circuitry allows 100% duty operation, not that it pre-charges the bootstrap cap:
"Bootstraps are used in highside FETs of three-phase pre-gate driver. Trickle charge circuitry is used to replenish current leakage from bootstrap cap and support 100% duty cycle operation."
It would be nice if the trickle charging was operating all the time and the bootstrap cap would automatically be charged a few milliseconds DRV8301 gate enable signal was asserted.
With most bootstrap-based gate drivers without trickle charging, you need to pulse the lowside FET on for a few short bursts before enabling the normal PWM operation. These short on pulses on the lowside FET will drive output voltage to zero and charge the bootstrap capacitor through the bootstrap diode. The short pulses also slowly pump up the bootstrap capacitor instead bringing it to full voltage all at once.
In my case the short pumping pulses work... but only sometimes. Much of the time, the DRV8301 totally ignores the low-side gate pulse (the input get the signal, but the LS gate output does not do anything). When the lowside gate pulse is ignored, it is always ignored, no mater how long it is run. This is not caused by a FAULT or OCTW. I tie both signals together and never not see it assert low when DRV8301 is ignoring low-side pulses. However, I do get a OC fault on the high-side FET the first time the highside input is asserted. I believe this is because there is no voltage on the bootstrap capacitor and no voltage voltage to HS FET Vgs. The FET is not turned on and the OC detects this as a high-side MOSFET is over current.
When the DRV8301 does let the low side pulses through, it does so immediately. I've never see it drop the first few drop the first few pulses and then start working later. However, when the pulses do go through, they usually work again if I reset the DRV8301 and restart soon after.
I have the software write and verify the DRV8301 control registers before sending the first PWM signal, so I'm sure the DRV8301 is powered-up and operating. I also poll the GVDD_UV status bit through the SPI, so I know the GVDD is happy before starting up. I've also tried a different board so it is unlikely that the problem is caused by a damaged DRV8301.
If I don't have an external 24V on the half-bridge before starting, the low-side pulses always go through without issue. However, there will always be an external 24V on the half-bridge outputs in the real system, so this is not a fix.
I'm guessing there is something wrong with the handshaking between the lowside and highside signals when there is no voltage on the bootstrap cap. Is it possible to get a description on how the handshaking operates, or a confirmation that this might be an issue?
I would also appreciate any suggestions on how to trick the trickle charge circuitry into the pre-charging the bootstrap capacitor. I am considering putting the DRV8301 in OC protect mode, pulsing the high-side PWM, and then waiting for OCTW/FAULT to stop occurring before switching to a full PWM. This is an ugly hack, but might work.
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RE: DRV10983: ISD fail due to Noise
Hi Rocky,
Add resistor on all phases, because BEMF comparator is connected across 2 phases internally. Capacitor will cause inrush current since phase pin are switching between VCC and GND. I don't recommend connecting capacitor across phases.
Regards,
Krushal
Add resistor on all phases, because BEMF comparator is connected across 2 phases internally. Capacitor will cause inrush current since phase pin are switching between VCC and GND. I don't recommend connecting capacitor across phases.
Regards,
Krushal
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DRV10983: ISD fail due to Noise
Part Number: DRV10983
When motor is stationary it need some amount of external torque /push to start rotate from stationary state and execute IPD.
As per DRV working principle algorithm given in datasheet that before IPD , actually ISD condition is checked and if that is failed then only it moves to IPD (assume IPD and ISD are enabled).
AS per my observation ,in the stationary case, it read random speed value and driver always try to drive motor as in close loop state directly using ISD function and fails to drive.
DRV getting signal which is strong enough for it to executes direcly close loop drive case even if it is in stationary state.
This signal we can call it noise across Motor Wire.
By giving some external push to motor, IPD condition gets executed (i heard IPD noise in motor) and motor starts rotating.
I have seen some other people also facing same issue which i am facing.
Can any expert give solution for for this because by disabling ISD problem gets solved but i want ISD function because it is my application requirement.
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RE: DRV8801: VPROPI Output current
Update: Increasing the output resistance to ground to 150K still does not solve the problem. Is there a resistance in series or a voltage divider circuit inside the part?
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RE: DRV8711: Can DRV8711 operate without SPI?
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RE: DRV8830: VIH for I2C line
Hi Rick-san,
I understand. Thank you very much for your support.
Best Regards,
Kawai
I understand. Thank you very much for your support.
Best Regards,
Kawai
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RE: DRV8835: 12-Pin WSON Adapter Board
Hi Hayden,
Please try a web search for "dip to qfn adapter". Hopefully you will find what you are looking for.
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DRV8835: 12-Pin WSON Adapter Board
Part Number: DRV8835
Hi Team,
I'm looking to do some development with the DRV8835 on some existing PCBs and was wondering if you have a 12-pin WSON adapter board similar to the DIP-ADAPTER-EVM and Universal Op Amp EVM.
If not, are you aware of any P-WSON adapter boards that exist or have any suggestion on how I could prototype with it?
Regards,
Hayden
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RE: Using BLDC motor with scalar control algorithm
Hello Sasha,
Induction Motors are very similar to BLDC motors, the difference is in the rotor. IM has a squirrel cage rotor while BLDCs rotors are construct with permanent magnets. This may or may not be relevant to what you are studying. This white paper explains some of the differences www.ti.com/.../slyy083.pdf
I hope this helps.
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Using BLDC motor with scalar control algorithm
Hello!
I need to study Scalar (V/f) Control of 3-Phase Induction Motors. I would like to test my firmware on a hardware. But I haven't 3 phase induction motor. Can I use for test this algoriths BLDC motor? Or this is different types of motors, need to different algorithms?
Regards
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RE: DRV8701: DRV8791 Evaluation GUI Software won't run
Hello Kevin,
Are you following the DRV8701 User's Guide? www.ti.com/.../slvuag3.pdf
Section 2.1 explains where to locate the files once downloaded.
This should solve your problem. Please let me know if after following this you run into other problems. Thank you.
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