This work presents a single-chip electronics interface for low power, high count rate gamma ray spectroscopy using a novel current nulling scheme that reduces power consumption to 8.8 mW at a count rate of 30 kcps. The current nulling circuit monitors and subtracts the time-varying PMT anode bias network current that would normally lead to a significant integration error at high count rates. This allows the use of low power, event-driven circuit topologies downstream at higher count rates than would otherwise be supported. With this method, the detection resolution degradation improves from 0.85%/kcps to 0.02%/kcps and the spectrum shift is reduced from -22 bins/kcps to 0.32 bins/kcps.