Making car amplifier SMPS with tl494 + DC Protection

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Re:Service manuals

Ok

I like to have the service manuals of kenwood car amplifiers "kac"
If you have service manuals of kenwood car amp. kac-626 please send me on my e-mail risto44091@hotmail.com
The SMPS of kenwood car amplifiers are very simple to build and my kac-626 is broken sow I like to repair but I dont have the service manual.
If you have the service manulas please send me and i will send you Lott os materials for making car amplifiers.

Yours faithfyllu
Risto Panovski from Macedonia
 
troubleshooting smps

Greetings,

I looked over the schematic and observed a few things. The SG3525 is a *voltage* mode controller (VMC). The topology is a push-pull center-tap (PPCT). One issue with the PPCT (as well as half-bridge, and full-bridge) is core saturation due to unequal pulse widths applied to each half of the primary. Once saturated, the transformer primary magnetizing current increases dramatically, and that may be why the FETs are getting hot. The two classical methods to avoid saturation with a PPCT are a coupling capacitor between the 12V input and the primary center tap, or the use of a *current* mode controller (CMC). Also, the 100 ohm gate resistors in each FET are very high in value. The FETs will not switch fast enough. I would use around 4.7 ohms instead. I hope this helps. Best regards.
 
Hi.

Remove transformer, and check mosfets, they should be cold when smps is runing.

I run my smps mosfets without heatsink, and they are cold under small load.

Current without load is from 100mA-500mA.


himanshuraval said:


hi grucho,

i have used 100ohms at all four mosfet and my toroid's core size is 35mm(outer dia)x15mm(hight) and winding is 4x4 pri. 12x12 sec.turns but buz11 is heatiing within 5 seconds
 
Grucho said:
Hi.

Remove transformer, and check mosfets, they should be cold when smps is runing.

I run my smps mosfets without heatsink, and they are cold under small load.

Current without load is from 100mA-500mA.


hi grucho
i have removed transformer and check mosfet that is properly working and no consupt currunt but i removed first secondry of transformer and check and thats no consupt current but when i connect the dc circuit the circuit take much current and then after i removed power caps of dc output smps is running with about 900ma to 1amp. without any load at dc output
 
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