Dialog Semiconductor (uk) Limited

Carsten Barth

Mark Johnathan Childs

Jens Masuch

Michele DeFazio

A multiphase power converter and a corresponding method is presented. The multiphase power converter contains a first and a second constituent switched-mode power converter. The first constituent switched-mode power converter provides, both in a first mode of operation and in a second mode of operation, a first phase current to an output of the converter. The second constituent switched-mode power converter provides, in the second mode, a second phase current to the output of the converter. The converter switches, depending on an operation condition of the converter, between the first mode and the second mode. A first transconductance of the first constituent switched-mode power converter is adapted when switching between the first mode and the second mode. By adapting the first transconductance, unsteadiness of the output voltage of the converter occurring during the switching between both modes of operation is minimized.

Multiphase power converter

The proposed disclosure combines peak-mode monitoring with valley-mode control, in a Buck switching converter, by means of a peak-current sampling circuit, not to turn the high side device off, but to control a slow loop, which in turn controls a variable offset incorporated into the loop control current. This helps the loop control current define the exact peak current, regardless of what other offsets, compensation ramp or peak-to-peak current ripple, are applied to the loop control current. The peak current is determined by an operational transconductance amplifier (OTA), whose maximum current is clamped to a programmed value. The loop control current is most likely implemented using a digital successive approximation register (SAR) system, but may also be implemented using a slow analog control loop.

Peak current servo

An object of the disclosure is to provide a multiphase Buck, Boost, or other switching converter to give high efficiency over the full range of output currents, and to maximize the total output current the switching converter is able to supply, by fully utilizing every phase of the switching converter. Further, another object of this disclosure is to balance the asymmetric transconductance, such that the load share between phases is optimized for different load levels of coil value, coil type, pass-device scaling, and frequency. Still further, another object of this disclosure requires that each of the switching converter operates at a similar point of saturation current at each point along the output load range, and each phase provides a different percentage of the total output current.

Growing community of inventors

Schwaebisch Gmuend, Germany

Carsten Barth