Abstract: The current regulation loop presented here controls squib drivers that are used to inflate multiple airbags in cars. Conventional approach uses an integrated poly resistor or sense transistor based current sensing, depending on the current range. In this paper, a current regulating High Side Driver (HSD) using an Aluminium metal sense resistor is proposed. This approach of using a metal resistor is new and is fabricated in a 40V, BiCMOS process. HSD is activated for 0.5ms and the current is regulated to 2A from a 33V supply. Regulation is within +/-10% variation despite 400ºC rise on the junction temperature of the power transistor. This design incorporates a new technique to provide an on-chip free-wheeling path due to inductive flyback when the HSD turns OFF, avoiding external Schottky diodes. This approach could be widely used for all current limitation circuits.
Keywords: Current sense, squib driver, LDMOS (Laterally Diffused MOS), metal resistor, self-heating, flyback.
Title: 2A Current Regulation Loop With a Metal Sense Resistor
Author: Sri Navaneeth Easwaran, Sunil Kashyap Venugopal, Deepak Sreedharan, Samir Camdzic, Robert Weigel
International Journal of Electrical and Electronics Research
ISSN 2348-6988 (online)
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