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Nguyên văn bởi goldstar09
Minh thay tuy dung LM2576 cung co the giai quyet duoc van de chenh lech dien ap ra va dien ap vao, hieu suat cung kha cao. Tuy nhien neu thiet ke khong duoc tot thi gay nhieu, gay anh huong cho vi dieu khien.Ban van co the lam theo cach su dung nguon tuyen tinh, do la ket hop cac ic ho 78xx, cong voi viec su dung them transistor de ganh bot dong qua IC on ap, nham giam ton hao nhiet va su troi vi nhiet tren IC on ap. Cach lam nay tuy se giam hieu suat chung cua mach, nhung bu lai co the se co chat luong dien ap ra tot hon.
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Thanks.
7805 nong la do chenh lech ap qua cao, chu khong phai do dong tao nen. vi VDK va 1 so IC tieu thu dong rat it. (theo khuyen cao cua 7805 thi Vi = 7 to 20 V, toi da la 35V, nhung theo minh nghi thi tu khoang > 15V la no bat dau nong roi, mac du khong tai).
Minh thay thiet ke bo loc tot thi chac chan hon.
Ai co bo loc nao tot khong, da rap chay on dinh roi cho minh xin nhe.
Mai minh up cai mach minh lam theo datasheet cua LM2576. Tren dao dong ky co gai nhin kho chiu lam.