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.