Switched mode assisted linear regulator with decoupled output impedance and signal path bandwidth

摘要

A switched mode assisted linear (SMAL) amplifier/regulator architecture can be configured to supply regulated power to a dynamic load, such as an RF power amplifier. Embodiments of a SMAL regulator can include a linear amplifier and a switched mode converter parallel coupled at a supply node, and configured such that the amplifier sets load voltage, while the amplifier and the switched converter are cooperatively controlled to supply load current. The amplifier can include separate feedback loops: an external relatively lower speed feedback loop for controlling signal path bandwidth, and an internal relatively higher speed feedback loop for controlling output impedance bandwidth of the linear amplifier. The linear amplifier can be AC coupled to the supply node, and the switched converter can be configured with a capacitive charge control loop that controls the switched converter to effectively control the amplifier to provide capacitive charge control.

主权项

1. A switch modes assisted (SMAL) regulator for supplying a regulated load voltage and associated load current to a dynamic load characterized by a signal bandwidth, comprising:
an amplifier circuit; and a switched mode converter (switcher) circuit coupled in parallel at a supply node coupled to the dynamic load; the SMAL regulator is configured to supply the regulated load voltage and the associated load current based on a signal path bandwidth, wherein:
the amplifier circuit, in response to a dynamic input signal, supplies the regulated load voltage;the switcher circuit, in response to a switching control signal with a switcher bandwidth that is less than the signal path bandwidth, supplies a switcher load current based on the switcher bandwidth; andthe amplifier circuit supplies an amplifier load current corresponding to the associated load current not supplied by the switcher load current; and the amplifier circuit is configured with first and second negative feedback loops such that the first feedback loop is a higher speed than the second negative feedback loop, and wherein:
the first negative feedback loop is configured to control an output impedance bandwidth of the amplifier circuit; andthe second negative feedback loop is configured to control the signal path bandwidth substantially independently of the output impedance bandwidth;thereby decoupling the configuration of the output impedance bandwidth from the signal path bandwidth.