SI9100

Si9100 Vishay Siliconix 3-W High-Voltage Switchmode Regulator FEATURES D 10- to 70-V Input Range D Current-Mode Control D On-Chip 150-V, 5-W MOSFET Switch D Reference Selection Si9100 − "1% D High Efficiency Operation (> 80%) D Internal Start-Up Circuit D Internal Oscillator (1 MHz) D SHUTDOWN and RESET DESCRIPTION The Si9100 high-voltage switchmode regulators are monolithic BiC/DMOS integrated circuits which contain most of the components necessary to implement high-efficiency dc-to-dc converters up to 3 watts. They can either be operated from a low-voltage dc supply, or directly from a 10- to 70-V unregulated dc power source. The Si9100 may be used with an appropriate transformer to implement most single-ended isolated power converter topologies (i.e., flyback and forward), or by using a level shift circuit can generate a +5-V or a −5-V non-isolated output from a −48-V source. The Si9100 is available in both standard and lead (Pb)-free 14-pin plastic DIP and 20-pin PLCC packages which are specified to operate over the industrial temperature range of −40 _C to 85 _C. FUNCTIONAL BLOCK DIAGRAM FB 14 (20) Error Amplifier VREF 10 (14) − + 4 V (1%) Ref Gen 2V − + + − 1.2 V BIAS 1 (2) Current Sources To Internal Circuits C/L Comparator Current-Mode Comparator COMP 13 (18) DISCHARGE 9 (12) OSC IN 8 (11) OSC OUT 7 (10) OSC Clock (1/2 OSC) R Q S 3 (5) 5 (8) DRAIN −VIN (BODY) 4 (7) VCC 11 (16) 12 (17) VCC 6 (9) SOURCE +VIN 2 (3) 8.8 V − + 9.4 V − + Undervoltage Comparator...