Control circuit design for high temperature linear regulators

A control circuit for high temperature positive linear voltage regulators has been designed. Target applications represent a broad range of requirements, while high temperature solutions are limited. Therefore, one of the primary objectives of the control circuit design is adaptability to a range of operating conditions. Design configurability is reflected in the specifications. Application options may be exercised by trimming at wafer level. The design has been implemented in an SOI CMOS technology with laser trimmable thin-film resistors. The process is capable of long term continuous operation at 225°C and short-term operation to 300°C. The control chip is designed to work in conjunction with an external N-channel power MOSFET. The design includes a voltage reference, the control loop for the main regulator, a separate on-chip 5 V regulator, current and/or power limiting circuitry, plus all necessary biasing circuitry, scaling resistors, and current-sense resistors. A shutdown control input allows for external means to shut off power to the load