A High-Temperature, High-Voltage Linear Regulator in 0.8-µm BCD-on-SOI

The sale of hybrid electric vehicles (HEVs) has increased 10 fold from the year 2001 to 2008 (1). Thus, high temperature electronics for HEV applications are desired in the engine compartment , power train, and brakes where the ambient temperature normally exceeds 150°C. Power converters (i.e. DC-DC converter, DC-AC inverter) inside the HEVs require Gate-Driver ICs to control the power switches. A Gate-Driver IC needs a step-down voltage regulator to convert the unregulated high input DC voltage (V DDH) to a regulated nominal CMOS voltage (i.e. 5 V), this step-down voltage regulator will supply voltage to the low-side buffer (pre-driver) and other digital and analog circuits inside Gate-Driver ICs. A linear voltage regulator is employed to accomplish this task; however, very few publications on high temperature voltage regulators are available. This research presents a high temperature linear voltage regulator designed and fabricated on a commercially available 0.8-µm BCD-on-SOI process. SOI processes offer 3 orders of magnitude smaller junction leakage current than bulk-CMOS processes at temperatures beyond 150°C. In addition, a pole swap compensation technique is utilized to achieve stability over a wide range (4 decades) of load current. The error amplifier inside the regulator is designed using an inversion coefficient methodology, and a temperature stable current reference is used to bias the error amplifier. The linear regulator provides an output voltage of 5.3 V at room temperature and can supply a maximum load current of 200 mA. Keywords-high temperature electronics, voltage regulator, inversion coefficient, temperature stable current reference, pole swap technique