SSLV1.1 builds & fairy tales

[merlin el mago]

I changed BJT for Mosfet & R106 for 270R but same problem with CCS max. 890mA with 0.1R

 

[Salas]

What type CCS Mosfet you use?

 

[merlin el mago]

The GB irf530.

Oh my good this is for negative reg.

 

[merlin el mago]

Still same problem ccs 890mA Vout max 4.5v

 

[merlin el mago]

The ccs mosfet irf9610

 

[merlin el mago]

The shunt mosfet irf9530

 

[Salas]

Do you have any spare IRF9530 for CCS MOSFET to test? The 9610 is not reliable for long time at 1.2A and has large Vgs there because pushed. Not allowing enough difference from VFx3 Green.

 

[merlin el mago]

Changed the ccs mosfet irf9610 for other irf9610, now ccs 1.08A

 

[merlin el mago]

Do you want to change the ccs mosfet for irf9530?

 

[Salas]

Its samples differences in Vgs you just saw. Vgs is borderline with 3 Leds & 9610. When for heaters don't worry if 9530 slower. More reliable in high current. 9610 delicate. Watch current with only 0.1R. For 9530 will probably jump high in current.

 

[merlin el mago]

I have one more for the other reg.

In the other pcb I have 4 green LEDs, could I use irf9610?

I have other mosfets, there are others suitables for CCS?

 

[Salas]

What types you have?

 

[Salas]

In the other pcb I have 4 green LEDs, could I use irf9610?

With 4 Leds you can reach 1.2A for 9610 but it could fail in the long run.

 

[merlin el mago]

Sihp8n50d as substitute irf840

 

[merlin el mago]

I have more, but are in a small house that I have in the garden, I have to look for but now is raining here.

 

[merlin el mago]

I will try with the two IRF9530 that I have on hand.

 

[Salas]

Sihp8n50d as substitute irf840

Wrong polarity that's NMOS. For PMOS the gate arrow must point outwards in the datasheet MOSFET symbol when it doesn't say PMOS or NMOS in title.

 

[merlin el mago]

It's really strange Salas first atempt worked well with CCS & set Vout 6.3V nicely, 2nd atempt want to change the CCS resistor to adjust better the current to 1.2A changed 0.1R for 0.22R but CCS measured 0V & the voltage ref LEDs don't lit and of course Vout 0V, changed again the CCS resistor 0.22R for 0.1R guessing all going ok as 1st atempt but not: CCS 0V the voltage ref LEDs don't lit and of course Vout 0V.

 

[Salas]

Joints, pads, some disconnection or a part went off during rework (?)

 

[merlin el mago]

Can be, I will check all parts & surrondings involved.