DESCRIPTION
Pre-Regulator A BiC/DMOS power integrated circuit process is used to integrate a high-voltage (120-V rated) lateral DMOS transistor with the CMOS PWM controller. By using an ion implant to shift the gate threshold to a negative value, as shown in Figure 1, the transistor is made to operate as a depletionmode device. FIGURE 1. Depletion-Mode MOSFET Characteristics FIGURE 2. Pre-regulator/Start-up Circuit FaxBack 408-970-5600, request 70577 1 AN703 Vishay Siliconix In some applications it is useful to turn off the pre-regulator Error Amplifier The bias resistor connected from pin 1 (BIAS) to pin 5 (-VIN) programs the current sources in the analog portion of the current-mode controller - including the error amplifier, the current-mode a
Vishay
