On-chip charge-pump with continuous frequency regulation for precision high-voltage generation

Closed-loop operation of charge-pumps is often taken advantage of in order to improve efficiency and to reduce the charge-pump output impedance and heavy sensitivity to supply and process variations. A fully integrated charge-pump, which utilizes continuous frequency control for the closed-loop operation, is presented in this paper. This means of control allows the charge-pump clock to settle to correct frequency according to current load while maintaining 50% duty ratio of the clock. The final high-voltage signal is generated by using a closed-loop amplifier, for which the pump creates the supply, and which then amplifies the desired low-voltage signal to correct level. The implemented pump with the regulator has an active chip area of 0.14 mm² and creates a nominal output of 10 V with 29 muA load current and 2.5 V minimum supply.