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 (VDDH) 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