Abstract: A switched mode assisted linear regulator includes a linear amplifier (LA) and a buck converter configured as a current source. In example embodiments, the buck converter circuit includes a power switch M1 with an M1 body diode (tub), and includes buck turn-off circuitry configured to avoid negative inductor current by controlled switching of the tub to the higher of VIN and a second voltage. For DC-coupled configurations, boost functionality is provided by an LA boost supply, and the tub is switched to the boost supply. For AC-coupled configurations, boost functionality can be provided without boosting the LA supply rail by constraining signal peak-to-peak amplitude to be less than the LA supply voltage (maintaining a DC-average voltage on the AC-coupling capacitor), and the tub is switched to the higher of VIN and VOUT. The buck turn-off circuitry can include zero crossing detection to control M1 tub switches.

Abstract: A switched mode assisted linear regulator includes a linear amplifier (LA) and a buck converter configured as a current source. In example embodiments, the buck converter circuit includes a power switch M1 with an M1 body diode (tub), and includes buck turn-off circuitry configured to avoid negative inductor current by controlled switching of the tub to the higher of VIN and a second voltage. For DC-coupled configurations, boost functionality is provided by an LA boost supply, and the tub is switched to the boost supply. For AC-coupled configurations, boost functionality can be provided without boosting the LA supply rail by constraining signal peak-to-peak amplitude to be less than the LA supply voltage (maintaining a DC-average voltage on the AC-coupling capacitor), and the tub is switched to the higher of VIN and VOUT. The buck turn-off circuitry can include zero crossing detection to control M1 tub switches.

Abstract: Methods and apparatus for operating first and second switches arranged in a half-bridge configuration are described. First and second gate voltages on the first and second gates, respectively, of the first and second switches are controlled such that the first switch is on and the second switch is off. One of the first and second gate voltages is controlled such that the corresponding one of the first and second switches operates as a constant current source. After one of the first and second switches has been operating as a constant current source, the second gate voltage is controlled such that the second switch is on and the first gate voltage is controlled such that the first switch is off.

Abstract: The invention allows a phase lead compensation circuit to be integrated on the same chip as a switching regulator. The invention provides additional phase to the loop gain of the monolithic switching regulator. The additional phase is required near the unity gain frequency of the loop gain and is not continued indefinitely. The desired phase lead compensation function can be accomplished through the use of a transconductance amplifier driving a frequency-dependent load. The transconductance amplifier converts a differential input voltage signal into a single-ended output current. This output current flows through the frequency-dependent load.