High temperature integrated voltage regulator system design

A high temperature voltage regulator ASIC with auxiliary control and watch-dog functions has been designed for ambient temperatures from 273K to 473K. The circuit is implemented in a standard bulk 1.2 μm BiCMOS process and has been tested for temperatures up to 563K. The regulated output voltage range is externally adjustable from 5 to 12 V, and the regulator can deliver output currents up to 250 mA. The quiescent current consumption is 2.7 mA. The accuracy of the output voltage is almost exclusively determined by the on chip bandgap voltage accuracy because of the high loop-gain of the error amplifier. The bandgap voltage is nominally 1.25 V. The measured variation over the temperature range 273K to 473K is 15 mV (∼1.2%). The area of the chip is 5.2 mm², whereof the power transistor occupies more than 50%. The circuit is called HTPOWER-001B and will be manufactured by Maritime Well Services (MWS). The chip is part of a new family of oil well electronics based on SINTEF's high temperature ASICs called HTASlC, but is also suitable for other applications with a demand for high temperature operation.