Control of Switched Capacitor Step-Down Buck Converter

In this paper a simple two-loop voltage mode control scheme for the switched capacitor step down buck converter is proposed. This is a voltage-mode control scheme in which the external saw-tooth generator for the PWM generation is not required. The controller implementation requires only a single error amplifier and gives almost current mode control performance. The proposed switched capacitor converter gives lower ripple in the input current and reduces the input filtering requirements as compared to the conventional buck topology. For modelling the converter and for controller design state-space average method is used. Effectiveness of the proposed control scheme and performance improvement is demonstrated through simulations. Sample experimental results of load voltage regulation against load changes are provided to validate the proposed controlling scheme