Hi There
The Datasheet states a minimum on time of 200ns.
that corresponds to 4% PWM at 200kHz. What happens for a PWM < 4% at the input?
What are the deadtimes on the MP6519A?
I am Driving a TEC with the driver and would like to use 300kHz switching in order for my LC Filters to provide less ripple for the TEC. At the same time I need to be able to control the temperature even when it is close to ambient ( only low currents needed on the TEC)
Thank you and kind regards
Simon
Hello Simon,
Apologies for the delayed response. These are some good questions.
As for what happens for a PWM < 4% at the input given 200kHz in regard to your application:
- This corresponds to 200ns of on time (aligning with the minimum on time as stated by the datasheet and verified by yourself)
- With a PWM duty cycle of 4%, the driver may or may not fully turn on the MOSFET as the pulse width would be shorter than the minimum on time. This may manifest itself in the form of skipped pulses for example.
- If you need precise control of the TEC at low currents, you may want to consider operating at a lower PWM frequency to ensure the pulse width is greater than 200ns.
- Since TEC requires low currents near ambient temperatures, adding some sort of precision control circuit to reduce the switching frequency would yield better resolution for temperature control and ripple reduction in the TEC current. MPS has several options I would encourage you to explore.
As for the dead time of the MP6519A, here is the only explicit mention of it in the datasheet in normal operation (page 12):
Hopefully this provided some insight.
Best,
Krishan
