topic Re: FS26 FCCU1 single PWM monitoring in Power Management

FS26 FCCU1 single PWM monitoring

aad1tya — Sun, 22 Dec 2024 15:54:04 GMT

Hi, can please someone tell me what should be the configuration for FS2633D FCCU1 PWM monitoring?
I have configured FCCU_CFG to 110 to use FCCU1 PWM monitoring and input level monitoring on FCCU2.

I can't get the reset to working even if I don't apply any PWM wave to FCCU1 pin. My watchdog reset is working fine so no hardware issue in the reset connection.

Also, it would be great if someone can give me an example of a valid PWM wave on FCCU1 or just explain in terms of duty cycle and frequency because the datasheet makes it a bit confusing. It would be a great help if this can be done.

Thanks a lot.

Re: FS26 FCCU1 single PWM monitoring

guoweisun — Mon, 23 Dec 2024 03:08:11 GMT

Hi aad1tya

We list all of the configuration information about FCCU PWM/lever monitoring in datasheet page188-190--->20.7.3 FCCU single PWM monitoring activated

For example FCCU configure PWM frequency /level threshold :

You can read them.

Hope this could help you!

Re: FS26 FCCU1 single PWM monitoring

aad1tya — Mon, 23 Dec 2024 09:30:54 GMT

My main confusion is regarding the PULSE_FCCU_HF and PULSE_FCCU_LF time. Are they related to the duty cycle of the wave?

And if good frequency range is between 10-45KHz then how is bad frequency is greater than 90KHz?

Will there be no fault if I just give a PWM of 30KHz (good frequency) of any duty cycle? Or is it something different?

Re: FS26 FCCU1 single PWM monitoring

guoweisun — Mon, 23 Dec 2024 13:05:17 GMT

1:You can get the detection time here for the high or low level on PWN monitoring :

2:bad frequency are below showed: <5KHZ or >90KHZ

Re: FS26 FCCU1 single PWM monitoring

aad1tya — Mon, 23 Dec 2024 17:31:20 GMT

So, when the wave is low it should b/w 51-80us and when its high it should be b/w 6-10?
Am I correct or is it something different?

And why the "good" PWM range of 10-45 KHz is different than the bad low and bad high frequency, shouldn't the bad frequency be less than 10KHz and greater than 45KHz according to that range?
What am I missing?

Re: FS26 FCCU1 single PWM monitoring

guoweisun — Tue, 24 Dec 2024 00:52:53 GMT

HI :

For example, tPULSE_FCCU_HF =8us, that means both high and low duration time is 8us, T=16us, corresponding PWM frequency is 62.5KHZ(50% duty cycle).

“tPULSE_FCCU_HF” means FCCU will report a failure if High or low pulse duration is smaller than 8us(typ), 6us(min), 10us(max).
“tPULSE_FCCU_LF” means FCCU will report a failure if High or low pulse duration is larger than 64us(typ), 51us(min), 80us(max).

As a result:

FCCU is 100% good when high or low duration time is within 10us~51us(frequency is within 9.8K~50K), there is some buffer considered, so FCCU12_GF = 10KHZ~45KHZ.
FCCU is 100% bad when high or low duration time is below 6us or above 80us(frequency is >83K or <6.25K), there is some buffer considered, so FFCCU12_BLF =5KHZ max and FFCCU12_BHF =90KHZ min.