HP HSTNS-PL33 OUTPUT VOLTAGE MODIFICATION |
Output voltage adjustment tested on HP HSTNS-PL33; PN684530-201; PS-2152-1C-LF rev. 1 and X3.1.
HP HSTNS-PL33 has 12,2V/125A factory value of output. For a LDMOS power amplifier supply is necessary to install 4pcs PSU (series). Output voltage required is 12,5V (12,5Vx4=50V). Don't forget, 3 PSUs need to have floating output. GND screws located on secondary sides must to be isolated from earth connection.
The output voltage is changed by adjusting the reference voltage of TSV994 operational amplifier. Value of resistor 5K11 (marking 69B) will be decreased by parallel connection with a new 100K resistor. Don't touch the trimpots because the setpoint of over current protection will be affected. Maximum output voltage is 13,9V with load connected, installed paralel resistor 26,75Kohm. Over Voltage Protection is triggered above 13.9V.
13.01.2024
How to "disable" the dsPIC33FJ64GS606 MCU OVP (when required output voltage >13.9V):
- Connect a zener diode 2V7 between pin 14 and GND, the MCU will always read same "good" voltage even the output voltage is adjusted above 13.9V.
PSU was successfully tested between 12.2V...15.5V. Example, parallel resistor value 12K3 = 13.8V, 8K = 14.4V, installed according above instruction across 5K1 resistor.
OVP MCU input
Zener diode 2V7 installed to trick OVP
13.01.2024
Other way to adjust output voltage (feedback voltage divider):
- Output voltage can be also adjusted by installing a parallel resistor across 220Ω resistor. The advantage is one terminal connected to GND, smaller impedance, less susceptible to noise.
Recommended solution when external potentiometer is installed to adjust the output voltage. Example, parallel resistor 1K72 = 13.8V, 1K2 = 14.4V.
Location of 220Ω resistor, used to adjust output voltage
HP HSTNS pinout connection and Power ON jumper
SMPS Controller PCB
HP HSTNS-PL33 Main Board
