A Low Ripple and Fast Transient Response Charge Pump in CMOS Image Sensors

This article proposed a fully integrated charge pump circuit for HDR CMOS image sensors (CISs). The proposed circuit uses a cross-coupled structure and utilizes pseudo continuous modulation technology so that it exhibits low ripple and fast transient response. The gate–source and the gate–drain voltage of each transistor are efficiently regulated and will not cause transistor damage and aging. This design is implemented in a $0.11 \, \mu \text{m}$ process, layout area is 0.036 mm2. The simulation results show the proposed charge pump achieves a recovery time (99.9%) of 66 ns with an undershoot of 127 mV while maintaining a steady-state ripple of less than 0.59 mVpp. The charge pump consumes a total power of 1.121 mW, ensuring energy-efficient operation.