d123
Advanced Member level 5
Hi,
I would never have thought that a) a discrete triangle wave without using a negative supply were so hard to get to be from anywhere near 0V to easier 1V. b) That a lot of triangles look like RC wave-shapes unless you sacrifice amplitude for neatness. c) That a temperature-stable 1V peak-to-peak triangle wave is very hard to make with comparators and op amps and pointless with transistors. XR2209 is min. 8V and 8038 is 10V, I have 3V.
Anyway, for a (SEPIC) voltage feedback control loop of error amplifier and comparator, using a triangle wave into the comparator, how much can triangle wave peak-to-peak voltage fluctuations with temperature affect the control loop? Could the DC-DC lose control of the regulation?
e.g. The 100kHz triangle wave:
-15C = 0.101V to 0.932V
+27C = 0.101V to 0.960V
+85C = 0.114V to 0.986V
Is that range of change likely to matter or is not important so long as the error amplifier is well-compensated?
- - - Updated - - -
Do peope who make 'discrete' triangle waves with e.g. a 555 and an LPF and similar generators accept rather curvy triangle waves as the straight-line neatness is not so necessary in reality?
I would never have thought that a) a discrete triangle wave without using a negative supply were so hard to get to be from anywhere near 0V to easier 1V. b) That a lot of triangles look like RC wave-shapes unless you sacrifice amplitude for neatness. c) That a temperature-stable 1V peak-to-peak triangle wave is very hard to make with comparators and op amps and pointless with transistors. XR2209 is min. 8V and 8038 is 10V, I have 3V.
Anyway, for a (SEPIC) voltage feedback control loop of error amplifier and comparator, using a triangle wave into the comparator, how much can triangle wave peak-to-peak voltage fluctuations with temperature affect the control loop? Could the DC-DC lose control of the regulation?
e.g. The 100kHz triangle wave:
-15C = 0.101V to 0.932V
+27C = 0.101V to 0.960V
+85C = 0.114V to 0.986V
Is that range of change likely to matter or is not important so long as the error amplifier is well-compensated?
- - - Updated - - -
Do peope who make 'discrete' triangle waves with e.g. a 555 and an LPF and similar generators accept rather curvy triangle waves as the straight-line neatness is not so necessary in reality?