Hello I am new here, I need you regarding a montage that I have to make. I have an input PWM signal which varies from 0 to + 15V. I have to find an electronic assembly in order to obtain at output a PWM signal varying from 0 to -10V. I have a -10V power supply. However, I have the constraint of only use bipolar transistors. Did you know a montage allowing me to do this? thanks in advance