1.3 W Si-SiC Hybrid Linear Voltage Regulator With Gamma-Irradiation Resistance Over 3 MGy

A 1.3 W silicon-silicon carbide (Si-SiC) hybrid linear voltage regulator with gamma-irradiation resistance over 3 MGy(SiO2) has been developed. The 3Tr-VR consists of a SiC amplifier, resistor divider, a combining circuit of Si-BJTs with Radiation-Hardened By Design (RHBD) technique, and some passive parts. The SiC amplifier whose offset voltage hardly changed over 1 MGy was adopted as an error amplifier (EA) to suppress output voltage (VOUT) fluctuation. The combining circuit consist of an inverted Darlington transistor and a Darlington transistor was adopted as a pass transistor. The inverted Darlington transistor was adopted to operate the SiC amplifier below the upper limit output voltage even after gamma-irradiation, because the upper limit output voltage decrease due to gamma-irradiation. The Darlington transistor was adopted to maintain load current support capability. This is because the gain sufficient to maintain the target output power (1.3 W) can be ensured even if the gain decreases due to gamma-irradiation. However, when the gain of the pass transistor is increased, theVOUTof 3Tr-VR at 0 kGy becomes unstable in the high load resistor (RL) side. Thus, a parallel resistor (RP) was inserted in parallel with theRLto stabilize theVOUT. Since theRPflows a constant current regardless of theRL, the pass transistor can drive at over the minimum current. As a result, theVOUTof 3Tr-VR at 1.3 W hardly changed over 3 MGy.