Hello everyone.
I'm building a capacitance multiplier PSU based on this article.
(for who can't link to site : https://sound-au.com/project15.htm)
Looking at the Figure 3 - Complete Dual Capacitance Multiplier (Darlington Pair) schematic, there are 2 transistors and 1 diode per supply rail to make up "darlington pair" topology.
At first, I've tried to build a pcb following above schematic, but soon I realized there are no much space to place those transistors and the distance of transistor's heat sink and caps are too short.
So I gooogled it to find solution and I noticed about the "Darlington Transistors".
After while then, I found npn and pnp darlington transistors, manufactured by on semiconductor, looks okay to replace transistors above schematic.
The MJH6284G and MJH6287G. (here's the datasheet : https://www.mouser.kr/datasheet/2/308/1/MJH6284_D-2315692.pdf)
( also the datasheets of TIP35C and BD139G's
TIP35C : https://www.mouser.kr/datasheet/2/389/tip35c-1852460.pdf
BD139G : https://www.mouser.kr/datasheet/2/308/1/BD135_D-2310428.pdf )
According to the datasheet, The maximum dc current gain of 6284G is greater than the gains of tip35c*bd139.
Also the VCEO max and VCBO, VEBO value of TIP35C and MJH6284G are same, gain bandwidth of 6284G is larger than TIP35C's.
Most of the electrical characteristic of 6284G are same or better than the TIP35C, so can it be a replacement of "darlington pair" parts?
One thing I concern about is Continuous Collector Current. The TIP35C's is 25A, while the 6284G's is 20A.
Would the max current of transistor degrade performance of power supply?
The power requirements in my case is maximum 18V 2A per rail, so supplying that power seems not problem.
But I wonder lower collector current could be lead to higher ripple noise.
Giving me your opinion would be highly appreciated.
Thank you.
I'm building a capacitance multiplier PSU based on this article.
(for who can't link to site : https://sound-au.com/project15.htm)
Looking at the Figure 3 - Complete Dual Capacitance Multiplier (Darlington Pair) schematic, there are 2 transistors and 1 diode per supply rail to make up "darlington pair" topology.
At first, I've tried to build a pcb following above schematic, but soon I realized there are no much space to place those transistors and the distance of transistor's heat sink and caps are too short.
So I gooogled it to find solution and I noticed about the "Darlington Transistors".
After while then, I found npn and pnp darlington transistors, manufactured by on semiconductor, looks okay to replace transistors above schematic.
The MJH6284G and MJH6287G. (here's the datasheet : https://www.mouser.kr/datasheet/2/308/1/MJH6284_D-2315692.pdf)
( also the datasheets of TIP35C and BD139G's
TIP35C : https://www.mouser.kr/datasheet/2/389/tip35c-1852460.pdf
BD139G : https://www.mouser.kr/datasheet/2/308/1/BD135_D-2310428.pdf )
According to the datasheet, The maximum dc current gain of 6284G is greater than the gains of tip35c*bd139.
Also the VCEO max and VCBO, VEBO value of TIP35C and MJH6284G are same, gain bandwidth of 6284G is larger than TIP35C's.
Most of the electrical characteristic of 6284G are same or better than the TIP35C, so can it be a replacement of "darlington pair" parts?
One thing I concern about is Continuous Collector Current. The TIP35C's is 25A, while the 6284G's is 20A.
Would the max current of transistor degrade performance of power supply?
The power requirements in my case is maximum 18V 2A per rail, so supplying that power seems not problem.
But I wonder lower collector current could be lead to higher ripple noise.
Giving me your opinion would be highly appreciated.
Thank you.
Last edited:
Hi Conrad.
Thank you for advice and recommendation!
I found TIP120 and 140 families, sadly TIP140 seems discontinued by both ST and onsemi.
But TIP120 looks cost-efficient and suitable for my application!
And yes, I put 1 fuse before transformer, and I wonder also should I have to place fuse after rectifier...
Again, thank you for your kind reply!
Thank you for advice and recommendation!
I found TIP120 and 140 families, sadly TIP140 seems discontinued by both ST and onsemi.
But TIP120 looks cost-efficient and suitable for my application!
And yes, I put 1 fuse before transformer, and I wonder also should I have to place fuse after rectifier...
Again, thank you for your kind reply!