I am building a stereo amp using the Sure IRS2092 amp board along with a power supply I built myself. This is a simple linear power supply consisting of a 45+45 volt secondary toroidal transformer, a pair of rectifier bridges, and a pair of capacitor banks.
I measured the voltage using my DMM and it is putting out +/- 68 VDC. When I switch the power on to the supply/amp the amp briefly turns on for a split second (while the caps charge I assume) then turns off. When I remove the mains power the power supply caps start to discharge then the amp turns on until the caps drain down to a lower voltage.
Using crude measurement it seems that the amp operates between the voltages of 55 and 65 VDC, which is what its rated to operate at.
Now I am trying to determine if I need to get a 40+40 transformer to lower my voltages, or is there something else causing my amp to not turn on with the mains power connected to my transformer?
I am somewhat surprised that the over voltage protection would be set below 68 volts. Does anyone have any experience with this board? Any help will be greatly appreciated!
I measured the voltage using my DMM and it is putting out +/- 68 VDC. When I switch the power on to the supply/amp the amp briefly turns on for a split second (while the caps charge I assume) then turns off. When I remove the mains power the power supply caps start to discharge then the amp turns on until the caps drain down to a lower voltage.
Using crude measurement it seems that the amp operates between the voltages of 55 and 65 VDC, which is what its rated to operate at.
Now I am trying to determine if I need to get a 40+40 transformer to lower my voltages, or is there something else causing my amp to not turn on with the mains power connected to my transformer?
I am somewhat surprised that the over voltage protection would be set below 68 volts. Does anyone have any experience with this board? Any help will be greatly appreciated!
Its difficult to help without the circuit diagram.
The 2092 has low voltage resets but not high.
If VCC and VAA go low the 2092 resets.
I can only guess that there is some extra circuitry that resets the 2092 if an over voltage event occurs.
I have quite a bit of experience with the 2092 having designed a few high power amplifiers but haven't seen the problem you have.
The 2092 spec says it works up to 100 volts supply so your 68 is well within spec.
The 2092 has low voltage resets but not high.
If VCC and VAA go low the 2092 resets.
I can only guess that there is some extra circuitry that resets the 2092 if an over voltage event occurs.
I have quite a bit of experience with the 2092 having designed a few high power amplifiers but haven't seen the problem you have.
The 2092 spec says it works up to 100 volts supply so your 68 is well within spec.
The Sure Electronics amp is based on the Internal Rectifiers AMP7D-200 reference design. Here is a link to that: http://www.inductor.com/irf/iraudamp7d.pdf
If you look at page 22-24 it is explained there. I am guessing that Sure used a Zener Diode with a cascade voltage right at 65 volts for "Z100".
Is there an easy way to test this Zener?
If you look at page 22-24 it is explained there. I am guessing that Sure used a Zener Diode with a cascade voltage right at 65 volts for "Z100".
Is there an easy way to test this Zener?
There is overvoltage protection set at 68 volts.
If you get near or over 68 volts it will trip.
Change z100 for a slightly higher value.
The 3k3 resistors on VAA and VSS will allow 20mA at 68 volts so you are on the border of what the internal zeners will take.
A better solution would be to change z100 to 75 volts and change VAA/VSS 3k3 resistors to 4K7.
If you get near or over 68 volts it will trip.
Change z100 for a slightly higher value.
The 3k3 resistors on VAA and VSS will allow 20mA at 68 volts so you are on the border of what the internal zeners will take.
A better solution would be to change z100 to 75 volts and change VAA/VSS 3k3 resistors to 4K7.
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