Buck-boost based high linearity driver with separately controllable duty cycle for energizing and de-energizing phases

A tri-state buck-boost system having a freely changeable de-energizing duty cycle, comprising:

• a tri-state buck-boost converter configured to operate in an energizing phase in which energy of an inductor is increased, a de-energizing phase in which the energy of the inductor is decreased, and a freewheeling phase in which the energy of the inductor is allowed to recirculate, the tri-state buck-boost converter configured to produce a voltage output based on a power supply voltage, a variable energizing phase duty cycle De for operation in the energizing phase, and a variable de-energizing phase duty cycle Dd for operation in the de-energizing phase;
• and
• a buck-boost control loop, configured to:
• generate the variable de-energizing phase duty cycle Dd based on an input signal to optimize for a low duty cycle in the freewheeling phase,
• generate the variable energizing phase duty cycle De based on the control loop tracking the input signal, and
• control the tri-state buck-boost converter using the variable energizing phase duty cycle De and the variable de-energizing phase duty cycle Da.