I posted the same threat on dyiaudio.com
Hi guys, I have a little problem..
I made class D 200W RMS amplifier from Ejtagle from Faros de Electronica. I made 2 chanels for full bridge with phase inverter with TL072.
Output mosfets are IRF9540N and IRF540N. Amplifier is amasing and very powerfull, it has very strong bass too, and I like it very much but when I conected in full bridge, 100-200W before full power amp start to distord a little, then DC protection starts and raley disconect speaker.
I use +-40V and simple Led Vu meter for cliping indication calibrate on 26VAC on output on 1KHz sine.
In half bridge amp works fine even in full cliping but when I push in hard cliping DC protection starts.
Output Inductor: 2 x 106-2 for each amp
35uH + 1.5uF - has best results and biggest power
35uH + 1uF - little lower power before DC protection
35uH + 470nF - lower power then previous option
35uH + 220nF - the worst results, DC prot starts on 100-200W
22uH + all of these caps - Same results like before
47uH + all of these caps - Coil burning and go to smoke
On same core with inverted pahse results are the same.
I notice that WIHOUT speaker on 1KHz sine DC protection starts on 30VAC, 15KHz sine, DC prot start on 70V on 35uH+220n and that DC prot strats on lower volatge when I increase cap value (on example on 35uH+1uF 1KHz sine-DC prot starts on 27VAC, 15KHz sine-DC prot starts on 55VAC)
DC offset is 20mV on stand by mode without input signal
Problem is output inductor, maybe core go to situration on big current and produce DC voltage. When DC prot starts, DC voltage on output is 1V to 15V, I cant measure right value, digital multimeter is going creazy, and values are diferent all the time.
When relay disconect speakers, I hear somtng like Bzzzzzzz in inductor caps or output mosfets, cores are cold and dont hear enything form it.
On 4R load power is lower before DC prot then on 8R. Because of that I think that cores go to situration, i dont know..
What can I do, maybe go with bigger core like 130-2, I don know
I realy like this amp and I have to make it
Thanks if someone helps me
Hi guys, I have a little problem..
I made class D 200W RMS amplifier from Ejtagle from Faros de Electronica. I made 2 chanels for full bridge with phase inverter with TL072.
Output mosfets are IRF9540N and IRF540N. Amplifier is amasing and very powerfull, it has very strong bass too, and I like it very much but when I conected in full bridge, 100-200W before full power amp start to distord a little, then DC protection starts and raley disconect speaker.
I use +-40V and simple Led Vu meter for cliping indication calibrate on 26VAC on output on 1KHz sine.
In half bridge amp works fine even in full cliping but when I push in hard cliping DC protection starts.
Output Inductor: 2 x 106-2 for each amp
35uH + 1.5uF - has best results and biggest power
35uH + 1uF - little lower power before DC protection
35uH + 470nF - lower power then previous option
35uH + 220nF - the worst results, DC prot starts on 100-200W
22uH + all of these caps - Same results like before
47uH + all of these caps - Coil burning and go to smoke
On same core with inverted pahse results are the same.
I notice that WIHOUT speaker on 1KHz sine DC protection starts on 30VAC, 15KHz sine, DC prot start on 70V on 35uH+220n and that DC prot strats on lower volatge when I increase cap value (on example on 35uH+1uF 1KHz sine-DC prot starts on 27VAC, 15KHz sine-DC prot starts on 55VAC)
DC offset is 20mV on stand by mode without input signal
Problem is output inductor, maybe core go to situration on big current and produce DC voltage. When DC prot starts, DC voltage on output is 1V to 15V, I cant measure right value, digital multimeter is going creazy, and values are diferent all the time.
When relay disconect speakers, I hear somtng like Bzzzzzzz in inductor caps or output mosfets, cores are cold and dont hear enything form it.
On 4R load power is lower before DC prot then on 8R. Because of that I think that cores go to situration, i dont know..
What can I do, maybe go with bigger core like 130-2, I don know
I realy like this amp and I have to make it
Thanks if someone helps me