M3 Technology Inc.

Monolithic Power Systems, Inc.

Xi'an M3 Semiconductor Inc.

David Meng

Xiaoyu Xi

Bo Yang

Wei P Chen

Kaiwei Yao

Nuo Lou

An apparatus includes a buck converter portion of a buck-boost converter configured to operate under a constant on-time control scheme, wherein an on-time of a high-side switch of the buck converter portion is determined by a buck on-time timer, and a boost converter portion of the buck-boost converter configured to operate under a constant off-time control scheme, wherein an off-time of a low-side switch of the boost converter portion is determined by a boost off-time timer.

Buck-boost converter and hybrid control method

An apparatus includes a ramp generator configured to produce a set signal for determining a phase shift between a first phase and a second phase of a power converter, a first phase on-timer configured to produce a first reset signal for determining a turn-on time of a high-side switch of the first phase of the power converter, a second phase on-timer configured to produce a second reset signal for determining a turn-on time of a high-side switch of the second phase of the power converter, and a control logic block configured to generate gate drive signals for the first phase and the second phase of the power converter based on the set signal, the first reset signal and the second reset signal.

Dual-phase constant on-time power converter and control method

An apparatus includes a transistor coupled to a load through an output terminal of a load switch IC, a gate drive circuit connected to a gate of the transistor, wherein the gate drive circuit is configured such that in a short circuit event, a voltage on the gate of the transistor is gradually reduced, and wherein as a result of reducing the voltage on the gate of the transistor gradually, a negative voltage occurring at the output terminal of the load switch IC is minimized.

Load switch apparatus and control method

An apparatus includes a first timer configured to determine a turn-off time of a first high-side switch of a buck-boost converter, and a second timer configured to determine a turn-off time of a second low-side switch of the buck-boost converter based on a comparison between a first signal and a second signal, the first signal being proportional to an input voltage of the buck-boost converter, and the second signal being generated based on a signal proportional to an output voltage of the buck-boost converter.

Advanced constant off-time control for four-switch buck-boost converter

An apparatus includes a buck-boost converter comprising a buck portion and a boost portion connected in cascade, and a controller comprising a first timer and a second timer, wherein the first timer is configured to determine a turn-on time of a high-side switch of the buck portion, and wherein the first timer determines the turn-on time of the high-side switch of the buck portion based on a comparison between a first signal and a second signal, and wherein the first signal is proportional to an output voltage of the buck-boost converter and the second signal is generated based on a signal proportional to an input voltage of the buck-boost converter, and the second timer is configured to determine a turn-on time of a low-side switch of the boost portion.

Buck-boost converter and control method

A buck-boost converter comprises generating a first ramp using a first current source having a current level proportional to an input voltage of a buck-boost converter, and a second ramp using a second current source having a current level proportional to an output voltage of the buck-boost converter, generating a first threshold voltage proportional to a difference between the input voltage and the output voltage of the buck-boost converter, and a second threshold voltage proportional to the input voltage of the buck-boost converter, terminating a gate drive signal of a first low-side switch of the buck-boost converter based upon comparing the first threshold voltage and the first ramp, and terminating a gate drive signal of a second high-side switch of the buck-boost converter based upon comparing the second threshold voltage and the second ramp.

A controller includes a first timer for setting a turn-on time of a first high-side switch of a buck-boost converter, wherein the turn-on time of the first high-side switch is determined by an input voltage of the buck-boost converter, an output voltage of the buck-boost converter and a first predetermined bias voltage, a second timer for setting a turn-on time of a second low-side switch of the buck-boost converter, wherein the turn-on time of the second low-side switch is determined by the input voltage of the buck-boost converter, the output voltage of the buck-boost converter and a second predetermined bias voltage, and a valley current mode control device for setting a turn-on time of a first low-side switch and a turn-on time of a second high-side switch of the buck-boost converter.

A power converter comprises a first switch and a second switch connected in series between an input power source and ground, an inductor connected between a common node of the first switch and the second switch, and an output capacitor, a control apparatus comprising a feedback control apparatus and an ramp generator, wherein the ramp generator is configured to dynamically adjust an amplitude of a ramp based upon different operating conditions, an on-time control generator and a latch having a set input configured to receive an output signal of the control apparatus and a reset input configured to receive an output signal of the on-time control generator.

Power converter with adjustable ramp

A buck-boost converter comprises a first high-side switch and a first low-side switch connected in series between an input voltage terminal and ground, a second high-side switch and a second low-side switch connected in series between an output voltage terminal and ground, an inductor connected to a common node of the first high-side switch and the first low-side switch, and a common node of the second high-side switch and the second low-side switch and a control apparatus configured to generate gate drive signals, wherein the control apparatus comprises a first timer for setting a turn-off time of the first low-side switch, a second timer for setting a turn-off time of the second high-side switch and a peak current mode control device for setting a turn-off time of the first high-side switch and a turn-off time of the second low-side switch.

The present disclosure provides a system and method for managing a four-switch BUCKBOOST converter with a combination of a Constant Off-time (COT) control and a Peak Current Mode (PCM) control. With the COT control, the four-switch BUCKBOOST converter can automatically and smoothly transition between a BUCK mode, a BUCKBOOST mode, and a BOOST mode when input voltage varies. In some implementations, the four-switch BUCKBOOST converter only requires a simple, low-power-consumption and robust system control loop compensation with the PCM control for inductor current, and, thus, eliminates the need for oscillator and slope compensation circuit. The PCM control is used to determine turn-off-timing of switches of the four-switch BUCKBOOST converter. The system control loop compensation can provide cycle-by-cycle current limit function to protect the converter and load from over-current damages.

Advanced constant off-time control for four-switch buckboost converter

Control methods and apparatus are disclosed for operating a full-bridge inverter at resonant frequency mode, hybrid frequency mode, and fixed frequency mode. The operating frequency of the inverter equals to the user programmed frequency if the user programmed frequency is above the resonant tank frequency; and the operating frequency is synchronized with the resonant tank frequency if the user programmed frequency is below the resonant tank frequency.

Fixed lamp frequency synchronization with the resonant tank for discharge lamps

Control methods and apparatus are disclosed for operating an inverter at resonant mode, where the inverter adapts its frequency to the resonant tank characteristics before a lamp is struck, and operates at fixed frequency after the lamp is struck. Disclosed embodiments combine the advantages of operation in fixed mode as well as the variable mode.

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Los Altos, CA, United States of America

David Meng