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1. (WO2001037413) MULTI-PHASE AND MULTI-MODULE POWER SUPPLIES WITH BALANCED CURRENT BETWEEN PHASES AND MODULES

Pub. No.:    WO/2001/037413    International Application No.:    PCT/US2000/042060
Publication Date: Sat May 26 01:59:59 CEST 2001 International Filing Date: Sat Nov 11 00:59:59 CET 2000
IPC: H02M 3/158
Applicants: SEMTECH CORPORATION
Inventors: YANG, Eric
GUO, Jason
Title: MULTI-PHASE AND MULTI-MODULE POWER SUPPLIES WITH BALANCED CURRENT BETWEEN PHASES AND MODULES
Abstract:
A multi-phase power supply utilizes a current sensor including a sensor inductor winding connected in parallel with a filter inductor winding at the output of each phase for sensing the phase currents and balancing the current by adjusting the duty cycle of each phase through feedback control. In addition, in a multi-module power supply configuration, current between power supply modules is balanced through use of the same current sensor and current sharing technique. Each phase of the power supply includes at least one input power source and a current sensor. The sensor inductor winding and the filter inductor winding have the same number of turns and are wound about a magnetic core also present at each phase. A differential amplifier at each phase senses and amplifies any voltage difference between the outputs of the sensor inductor winding and the corresponding filter inductor winding. A current-sharing bus is formed between each of the phases, carrying the summed and averaged outputs from all the differential amplifiers. A feedback correction circuit at each phase utilizes the voltage on the current-sharing bus as a reference to control a pulse width modulator in adjusting the duty cycle of the corresponding phase, thereby balancing the load current among the phases. In a multi-module, multi-phase power supply, the current-sharing bus and a voltage-sharing bus are extended between each module and the phases of each module to achieve the same current balancing between all phases and modules.