Author Topic: LM5019 Buck controller ....constant on time mode  (Read 666 times)

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Offline ocsetTopic starter

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LM5019 Buck controller ....constant on time mode
« on: September 18, 2018, 03:58:14 pm »
The LM5019 is a Buck controller which is meant to operate  in constant on time mode.
The internal power FET is turned ON and stays on for the ON time as calculated by expression (3) of page 11 of the datasheet.

[however, the ON time can be prematurely curtailed if....
a).....the Vout  divider voltage goes above 1.62V
b)....the inductor current goes above 240mA]

The  internal FET OFF time is terminated either...........
a)...by the vout divider voltage falling   back through the reference voltage of 1.225V
b).....By the  OFF time as calculated by expression (4) of page 11

Presumably, the OFF time  given by expression (4) of page 11 never occurs unless the inductor current hits the 240mA  threshold?    :-//

If the inductor current  hits  the 240mA  threshold, then i would expect the OFF time to wait as long as it takes for the vout divider voltage to fall back though the 1.225V reference voltage....is this what happens?  :-//


LM5019 datasheet
http://www.ti.com/lit/ds/symlink/lm5019.pdf
 8)
« Last Edit: September 18, 2018, 04:02:18 pm by treez »
 

Offline Jebnor

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Re: LM5019 Buck controller ....constant on time mode
« Reply #1 on: September 18, 2018, 04:28:20 pm »
No idea, but I will add that concept to my bag of tricks.  An interesting spec sheet read
Before this, there was a typo.
 
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