Part Number: DRV8305
I was trying to configure the driver to single pwm mode.
2 of the 3 phase which are supposed have signals are working fine but the phase in which high z state is to be present is not occurring.
No matter what the GPIO input sequence is given, the co responding high z state phase high side mosfet is always turned on.
Please help,
Regards
shashank
Part Number: DRV8838
Hello,
In the datasheet for the DRV8838 on Page 10 there is the functional block diagram and customer pointed out that there are two separate symbols for ground. Is there a particular reason for this?
Cheers,
Akash
Hi Alex,
Thank you so much for your very detailed answer. I really appreciate it. You have answered most of my questions. Also by using super large RC delay to generate >10ms time, we are able to start up the driver without issue.
For more details, my application is just a DC fan drive. I wanted to use DRV595 as a buck converter to generate a DC output voltage. The output voltage can be controlled linearly with the change of input reference voltage. The input is differential input with no ground shared with the DRV595. Now we still have two questions to ask:
1. Since we are looking for a DC output to drive a DC fan, I would prefer to use 1SPW mode, which means I would only need one half bridge switching. Also, we are only having positive output. This means the driver can pretty much work like a buck converter. In this case, for the OUTN half-bridge, can I remove the inductor associated with it? This way would make it more like a buck converter.
2. This question follows the last question: If we are using it as a buck converter, can I remove the two common mode caps after the output filter inductors?
3. Our max load is about 2A, 12VDC. the current can have some 5-10kHz ripple with 0.5A amplitude. In this case, I am wondering what kind of input decoupling cap we will need.
Thanks a lot!
Lixing
Hi Lixing,
About your question about the output filter, as Alex explained above, you have to reserve two inductor+capacitor filters for the OUT+ and OUT-. OUT- ouptut is still switching in 1spw mode for small input/output signal. But the common capacitor can't be remove. As the following picture showing, L1, L2, C11 and C13 can NOT be removed. But C12 can be removed.
For the power supply decoupling capacitor, you can use 220uF+0.1uF+1nF paralleled for PVCC. It works well on our EVM. For the hardware SCH&PCB design, please refer to our DRV595 EVM design http://www.ti.com/lit/ug/slau479/slau479.pdf It's a pretty good example.
Best regards,
Shawn Zheng
Hi Yamamoto-san,
We will investigate and reply soon. We are approaching a holiday so this may take until late next week.
Part Number: DRV8305
Dear all,
I tested DRV8305 and had question.
*I attached test file
CH1:yellow = PVDD voltage(=24V input)
CH2:green = SHA voltage
When power on, I thought that SHA output 12V=24V/2. However, SHA outputed 24V.
Is this the correct behavior?
Best regards,
Part Number: DRV8305
Dear all,
I confirmed power off test and had question.
I found that SHA was pulled 0V when PVDD went down about 5V.
CH1:yellow = PVDD voltage(=24V input)
CH2:green = SHA voltage
Does this behavior relate to Table 6 at datasheet? What is the mean of 'PL' at Table 6?
Best regards,
Hi, Rick-san,
Thanks for your support.
I will wait for your reply.
Thanks, Masami M.
Part Number: DRV8305-Q1
Dear, All
Customers are worried about dealing with the malfunction of DRV8305-Q1 state machine operation.
If they know that the DRV8305-Q1 state machine malfunctioned, is there any way to initialize the DRV8305-Q1 from the outside?
Please tell me how to do it.
Also, Is there a method to determine whether DRV8305-Q1 state machine malfunctions?
Thanks, Masami M.
Part Number: DRV8305