Reg input 55VDC output 46VDC V1.0 RS
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R1=22r is not 500mA.
What is R1?
the CCS dissipation is [Vin - Vr1 - Vout] * Iccs
I'll guess at some inputs:
Vin =61V
Vr1 =2V
Vout = 46V
Iccs =0.5A
Pq1 = 6.5W
Ta=25degC
It would take quite a few seconds even with a tiny heatsink to burn out the CCS FET. With an small but adequate sink say 10C/W the sink rise would be 65Cdegrees above ambient.
Tc ~ 70Cdegrees above ambient. That puts Tc ~95degC
The temperature de-rating for the FET is 0.44. [150 - 95] / [150-25]
Your 150W FET is de-rated to 66W
Pq1 ~ 10% of maximum rating.
If the FET is cold it is not passing current.
It has almost certainly not been damaged by over-voltage.
It may have been damaged by soldering or handling or simply the circuit has a fault.
What is R1?
the CCS dissipation is [Vin - Vr1 - Vout] * Iccs
I'll guess at some inputs:
Vin =61V
Vr1 =2V
Vout = 46V
Iccs =0.5A
Pq1 = 6.5W
Ta=25degC
It would take quite a few seconds even with a tiny heatsink to burn out the CCS FET. With an small but adequate sink say 10C/W the sink rise would be 65Cdegrees above ambient.
Tc ~ 70Cdegrees above ambient. That puts Tc ~95degC
The temperature de-rating for the FET is 0.44. [150 - 95] / [150-25]
Your 150W FET is de-rated to 66W
Pq1 ~ 10% of maximum rating.
If the FET is cold it is not passing current.
It has almost certainly not been damaged by over-voltage.
It may have been damaged by soldering or handling or simply the circuit has a fault.
It's very very hot can left the finger few seconds.
Salas told me start with 10R 10W...
To low the voltage to 55VDC after the reg.
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