Gain-adaptive Preamplifier Design for High Count Rate TPC Detector

To meet the readout requirements of high counting rate, large dynamic range, and low power consumption for Time Projection Chamber(TPC) detectors in high-intensity environments, a preamplifier chip with automatic gain adjustment was designed based on a 180 nm CMOS process. The chip consists of a Charge Sensitive Amplifier(CSA), a Class AB output buffer stage, a gain control module, and a trigger control module. Through on-chip logic signals controlling the switching of multiple switches, the chip’s conversion gain adapts to the input charge level. Additionally, switch bleeding enables the chip to operate at a counting rate of 1 MHz. Post-layout simulations show that the chip achieves an integral nonlinearity better than 0.4% across an input signal range of 2.2 to 16.5 pC. The chip has been submitted for foundry fabrication.