In this work, closed-loop self-oscillating driving circuits for gyroscopes based on DC PI controller are analyzed in theory. The condition for oscillation is achieved by solving electrical differential equation, and the effects of key factors on magnitude stability are discussed. Further, an ASIC based on PI controller is designed, which is verified by simulation. The test results of manufactured chip correspond with the theoretical analysis, showing that this ASIC is capable of driving low-Q gyroscopes at normal temperate and pressure. This theory for analysis and the designed chip contribute to guide the design of closed-loop driving for gyroscopes, also improving stability for oscillating circuits.